overflow errors

# Conflicts:
#	include/builtins.h
#	include/data.h
#	include/editor_op.h
#	include/file_io.h
#	include/input.h
#	include/row_op.h
#	install.sh
#	main.c
#	meson.build
#	src/builtins.c
#	src/editor_op.c
#	src/file_io.c
#	src/init.c
#	src/input.c
#	src/output.c
#	src/row_op.c

.gitea/workflows/build.yml

@@ -6,7 +6,7 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-latest
+    runs-on: giorgio-runner
 
     steps:
       - name: Checkout code

README.md

@@ -1,7 +1,6 @@
 # Beluga
 
 Beluga is a project of CLI text editor that uses lisp as configuration language.
-It's abviously only working for **Linux**.
 
 ## Requirements
 
@@ -11,7 +10,7 @@ You will only need **meson** and a **C compiler** to compile the editor.
 ### From source
 Here is the installation line for development version:
 
-```git clone https://homelinuxserver.ddns.net/git/arthur/beluga.git ~/.beluga && cd ~/.beluga && meson setup build && meson compile -C build```
+```git clone https://git.giorgio-nas.fr/arthur/beluga.git && cd beluga && meson setup build && meson compile -C build```
 
 The executable file will be `build/beluga`. Feel free to add it to your path.
 
@@ -26,8 +25,8 @@ To open an existing file just type :
 
 Here is some few command that you will need :
 
-| keybind| command          |
-|--------|------------------|
-| Ctrl-Q | leave the editor |
-| Ctrl-S | Save a file      |
-| Ctrl-O | open file        |
+| keybind       | command          |
+|---------------|------------------|
+| Ctrl-x Ctrl-c | leave the editor |
+| Ctrl-x Ctrl-s | Save a file      |
+| Ctrl-x f      | open file        |

assets/beluga.txt

@@ -1,43 +1,43 @@
                       **#%#*****###%**
-                *##+--------------------=##*  
-             #*=----------------------------=*#*                                 
-          #*------------------------------------*#                               
-        %+----------------------------------------=#*                            
-       #+---------------------------------------------##                            
-     *#-------------------------------------------------=##                         
+                *##+--------------------=##*
+             #*=----------------------------=*#*
+          #*------------------------------------*#
+        %+----------------------------------------=#*
+       #+---------------------------------------------##
+     *#-------------------------------------------------=##
     *#----------------------------------------------------:-##
-    #----------------------------------------------------------##                   
-   #=--------------------------------------------------------------##                
-  +--------------------------+@#-%*-----------------------------------#*         
-  +--------------------------%@@@@#-------------------------------------**                              BELUGA - VERSION 1.1
+    #----------------------------------------------------------##
+   #=--------------------------------------------------------------##
+  +--------------------------+@#-%*-----------------------------------#*
+  +--------------------------%@@@@#-------------------------------------**                              BELUGA - VERSION 2.4
   *-=-------------------------#@@*---------------------------------------=%
   %*#==--------------------------------------------------------------------+#                           ----- KEY-BINDS -----
-  *%%=-=--------------------------------------------------------------------=#                          CTRL-q         leave
-  %=--------------------------------------------------------------------------#*                        CTRL-s          save
- %-----------------------------------------------------------------------------**                       CTRL-o     open-file
-*+--=---===----=---------------=*-----------------------------------------------** 
- #--=##      *#%#*+==----==+**+----------------------=  ***=---------------------% 
- *%**=-----------====    ==---------------------------------=+#+-----------------=#                                 
-   *%=----------------------------------------------------------=#*---------------#                                 
-     ##=----------------------------------=------------------------+%=------------+#                                
-       #%+---------------------------------=*------------------------+%------------#                                
-         *#%*=-------------=-----------------#-------------------------#+----------#                                
-             **#%#*******+=======-------------#=------------------------#----------#                                
-                #===#*=======------------------#*----=-----------=--=##*-----------#                                
-                 -====##=------------------------*%+------------=*#+=====----------#                                
-                 --=====+#*=----------------------=-=+*#####***+=======-----------=*                                
-                %------=====*%*=-------------------------========-----------------+*                                
-                 *-=--------====%%###+=--------------------------=-----------------#                                
-                  #-----------=%        +*##%%%%%%@@%%%%####*==---------------------**                              
-                    %=-------#*                                  #%*=-----------------+#                              
-                     *%+--=##                                       ##=-----------------=#*                           
-                        **                                       #+----=-------------------#*                       
-                                                               %+----------------------------#*                     
-                                                             *%-------------==----------------+#                    
-                                                            ##--------------==------------------#                     
-                                                           *#--------------===%-----------------=%                  
-                                                          ##---------------=-##*-----------------+#                 
-                                                        *#---------------==#+=#%-----------------%                 
-                                                       *%---------------+#      %*---------------#*                  
-                                                      *#------------=+#*          #%*=-----------#*                  
-                                                       #****##******                 *#%%##+=----%                 
+  *%%=-=--------------------------------------------------------------------=#                          CTRL-x CTRL-c  leave
+  %=--------------------------------------------------------------------------#*                        CTRL-x CTRL-s   save
+ %-----------------------------------------------------------------------------**                       CTRL-x f   open-file
+*+--=---===----=---------------=*-----------------------------------------------**
+ #--=##      *#%#*+==----==+**+----------------------=  ***=---------------------%
+ *%**=-----------====    ==---------------------------------=+#+-----------------=#
+   *%=----------------------------------------------------------=#*---------------#
+     ##=----------------------------------=------------------------+%=------------+#
+       #%+---------------------------------=*------------------------+%------------#
+         *#%*=-------------=-----------------#-------------------------#+----------#
+             **#%#*******+=======-------------#=------------------------#----------#
+                #===#*=======------------------#*----=-----------=--=##*-----------#
+                 -====##=------------------------*%+------------=*#+=====----------#
+                 --=====+#*=----------------------=-=+*#####***+=======-----------=*
+                %------=====*%*=-------------------------========-----------------+*
+                 *-=--------====%%###+=--------------------------=-----------------#
+                  #-----------=%        +*##%%%%%%@@%%%%####*==---------------------**
+                    %=-------#*                                  #%*=-----------------+#
+                     *%+--=##                                       ##=-----------------=#*
+                        **                                       #+----=-------------------#*
+                                                               %+----------------------------#*
+                                                             *%-------------==----------------+#
+                                                            ##--------------==------------------#
+                                                           *#--------------===%-----------------=%
+                                                          ##---------------=-##*-----------------+#
+                                                        *#---------------==#+=#%-----------------%
+                                                       *%---------------+#      %*---------------#*
+                                                      *#------------=+#*          #%*=-----------#*
+                                                       #****##******                 *#%%##+=----%

config/init.lisp

@@ -2,6 +2,13 @@
 
 (define TAB-LENGTH 4)
 (define QUIT-TIMES 1)
+(define THEME "dark")
+(define LSP #t)
+
+;; PACKAGES
+
+;; First git clone it
+;; (add-package "smart_delimiters")
 
 ;; FUNCTIONS
 
@@ -13,22 +20,76 @@
   )
 
 
-;; KEY MAPPING
+(define (char-between ch lo hi)
+  (if (char>=? ch lo)
+      (char<=? ch hi)
+      #f))
 
-(map-key "CTRL-q" editor-quit)
-(map-key "CTRL-d" editor-save)
-(map-key "ARROW-UP" '(move-cursor "up"))
-(map-key "ARROW-DOWN" '(move-cursor "down"))
-(map-key "ARROW-RIGHT" '(move-cursor "right"))
-(map-key "ARROW-LEFT" '(move-cursor "left"))
-(map-key "ENTER" editor-insert-new-line)
-(map-key "CTRL-a" move-cursor-beg-line)
-(map-key "CTRL-e" move-cursor-end-line)
-(map-key "BACKSPACE" editor-delete-previous-char)
-(map-key "DEL" editor-delete-next-char)
-(map-key "PAGE-UP" move-cursor-page-up)
-(map-key "PAGE-DOWN" move-cursor-page-down)
-(map-key "CTRL-o" editor-open-file)
-(map-key "CTRL-k" editor-del-row)
-(map-key "CTRL-s" editor-find)
+(define (alphanumericp ch)
+  (if ch
+      (if (char-between ch #\a #\z)
+          #t
+          (if (char-between ch #\A #\Z)
+              #t
+              (if (char-between ch #\0 #\9)
+                  #t
+                  #f)))
+      #f))
 
+
+(define (word-char-p ch)
+  (if (alphanumericp ch)
+      #t
+      #f))
+
+(define editor-move-to-end-of-word (lambda () (
+  (if (word-char-p (editor-read-char))
+	((move-cursor "right")
+	(editor-move-to-end-of-word))
+    ))
+                                     ))
+
+(define enter-and-tab
+  (lambda ()
+    (editor-insert-new-line)
+    (let ((is-in (move-cursor "up")))
+      (do ((ch (editor-read-char) (editor-read-char)))
+          ((and (not (char=? ch #\space)) is-in) #f)
+        (move-cursor "down")
+        (editor-insert-char " ")
+        (set! is-in (move-cursor "up")))
+      (move-cursor "down"))))
+
+(add-prefix "user")
+
+
+
+(map-key "CTRL-x" '(editor-set-prefix "user") "no-prefix")
+(map-key "CTRL-g" '(editor-set-prefix "no-prefix") "user")
+(map-key "CTRL-c" editor-quit "user")
+(map-key "CTRL-s" editor-save "user")
+(map-key "ARROW-UP" '(move-cursor "up") "no-prefix")
+(map-key "ARROW-DOWN" '(move-cursor "down") "no-prefix")
+(map-key "ARROW-RIGHT" '(move-cursor "right") "no-prefix")
+(map-key "ARROW-LEFT" '(move-cursor "left") "no-prefix")
+(map-key "ENTER" enter-and-tab "no-prefix")
+(map-key "CTRL-a" move-cursor-beg-line "no-prefix")
+(map-key "CTRL-e" move-cursor-end-line "no-prefix")
+(map-key "BACKSPACE" editor-delete-previous-char "no-prefix")
+(map-key "DEL" editor-delete-next-char "no-prefix")
+(map-key "PAGE-UP" move-cursor-page-up "no-prefix")
+(map-key "PAGE-DOWN" move-cursor-page-down "no-prefix")
+(map-key "f" editor-open-file "user")
+(map-key "TAB" editor-insert-tab "no-prefix")
+(map-key "CTRL-s" buffer-find "no-prefix")
+(map-key "CTRL-r" buffer-find-reverse "no-prefix")
+(map-key "ARROW-RIGHT" editor-switch-next-buffer "user")
+(map-key "\"" editor-split-screen-vertical "user")
+(map-key "o" editor-switch-next-pane "user")
+(map-key "*" editor-unify-panes "user")
+(map-key "CTRL-y" editor-paste "no-prefix")
+(map-key "CTRL-k" editor-cut-end-line "no-prefix")
+(map-key "a" editor-move-cursor-beg-buffer "user")
+(map-key "z" editor-move-cursor-end-buffer "user")
+(map-key "CTRL-h" editor-auto-complete "no-prefix")
+(map-key "C-x" lsp-complete "user")

include/buffer.h

@@ -0,0 +1,69 @@
+/**
+ * @file buffer.h
+ * @brief Buffer management for handling multiple open files
+ */
+
+#ifndef BUFFER_H_
+#define BUFFER_H_
+
+#include "data.h"
+
+/**
+ * @brief Creates a new buffer for a file
+ * @param filename Path to the file
+ * @return Buffer ID on success, -1 on failure
+ */
+int bufferCreate(const char *path, enum bufferStatus_e state);
+
+/**
+ * @brief Switches to a specific buffer by ID
+ * @param buffer_id The buffer ID to switch to
+ * @return 0 on success, -1 on failure
+ */
+int bufferSwitch(int buffer_id);
+
+struct buffer_t *bufferFindById(int buffer_id);
+
+/**
+ * @brief Closes a buffer by ID
+ * @param buffer_id The buffer ID to close
+ * @return 0 on success, -1 on failure
+ */
+int bufferClose(int buffer_id);
+
+/**
+ * @brief Gets the current active buffer
+ * @return Pointer to current buffer_t, NULL if none
+ */
+struct buffer_t *bufferGetCurrent(void);
+
+/**
+ * @brief Lists all open buffers
+ * @return Number of open buffers
+ */
+int bufferListAll(void);
+
+/**
+ * @brief Saves current buffer to disk
+ * @return 0 on success, -1 on failure
+ */
+int bufferSave(void);
+
+/**
+ * @brief Saves all buffers to disk
+ * @return 0 on success, -1 on failure
+ */
+int bufferSaveAll(void);
+
+void bufferFind(struct buffer_t *buf);
+void bufferFindReverse(struct buffer_t* buf);
+void bufferInsertNewLine();
+void bufferInsertBytes(const char *src, int n);
+void bufferDelBytes();
+void bufferRowInsertBytes(struct buffer_t *buffer, row_t *row, int at, const char *src, int n);
+void bufferRowDelByte(struct buffer_t *buffer, row_t *row, int at, int n);
+void bufferInsertRow(struct buffer_t *buffer, int at, char *s, size_t len);
+void bufferFreeRow(row_t *row);
+
+
+#endif

include/builtins.h

@@ -3,38 +3,60 @@
 
 #include "lisp.h"
 
+// Mouvement
+
 Lisp moveCursor(Lisp args, LispError *e, LispContext ctx);
-
-Lisp mapKey(Lisp args, LispError *e, LispContext ctx);
-
-void registerBuiltin(char * key_sequence, LispCFunc f);
-
-Lisp editorQuit(Lisp args, LispError *e, LispContext ctx);
-
-Lisp l_editorSave(Lisp args, LispError *e, LispContext ctx);
-
-Lisp l_editorInsertNewLine(Lisp args, LispError* e, LispContext ctx);
-
 Lisp moveCursorBeginLine(Lisp args, LispError *e, LispContext ctx);
-
 Lisp moveCursorEndLine(Lisp args, LispError *e, LispContext ctx);
-
-Lisp deletePreviousChar(Lisp args, LispError *e, LispContext ctx);
-
 Lisp editorMoveCursorPageUp(Lisp args, LispError* e, LispContext ctx);
-
 Lisp editorMoveCursorPageDown(Lisp args, LispError *e, LispContext ctx);
 
-Lisp editorOpenFile(Lisp args, LispError *e, LispContext ctx);
+// Text editing
 
+Lisp l_editorInsertNewLine(Lisp args, LispError* e, LispContext ctx);
+Lisp l_editorInserTab(Lisp args, LispError *e, LispContext ctx);
+Lisp deletePreviousChar(Lisp args, LispError *e, LispContext ctx);
 Lisp editorPrintC(Lisp args, LispError *e, LispContext ctx);
-
-Lisp addPackage(Lisp args, LispError *e, LispContext ctx);
-
-Lisp editorDelRow_L(Lisp args, LispError *e, LispContext ctx);
-
-Lisp editorFind_L(Lisp args, LispError *e, LispContext ctx);
-
 Lisp editorReadChar_L(Lisp args, LispError *e, LispContext ctx);
 
+// Editor
+
+Lisp editorQuit(Lisp args, LispError *e, LispContext ctx);
+Lisp l_editorSave(Lisp args, LispError *e, LispContext ctx);
+Lisp editorSetPrefix(Lisp args, LispError *e, LispContext ctx);
+Lisp editorPrefix(Lisp args, LispError *e, LispContext ctx);
+Lisp mapKey(Lisp args, LispError *e, LispContext ctx);
+void registerBuiltin(char * key_sequence, LispCFunc f);
+Lisp editorOpenFile(Lisp args, LispError *e, LispContext ctx);
+Lisp addPackage(Lisp args, LispError *e, LispContext ctx);
+
+
+// Buffer
+
+Lisp editorSwitchNextBuffer(Lisp args, LispError *e, LispContext ctx);
+Lisp bufferFind_L(Lisp args, LispError *e, LispContext ctx);
+Lisp bufferFindReverse_L(Lisp args, LispError *e, LispContext ctx);
+
+
+// Pane
+
+Lisp l_editorSplitScreenVertical(Lisp args, LispError *e, LispContext ctx);
+Lisp editorSwitchNextPane(Lisp args, LispError *e, LispContext ctx);
+Lisp editorUnifiedPanes(Lisp args, LispError *e, LispContext ctx);
+
+
+Lisp editorPaste(Lisp args, LispError *e, LispContext ctx);
+Lisp editorCutEndLine(Lisp args, LispError *e, LispContext ctx);
+
+Lisp editorMoveBegBuffer(Lisp args, LispError *e, LispContext ctx);
+Lisp editorMoveEndBuffer(Lisp args, LispError *e, LispContext ctx);
+
+// Other
+
+Lisp editorAutoComplete(Lisp args, LispError *e, LispContext ctx);
+// Lisp lspComplete(Lisp args, LispError *e, LispContext ctx);
+Lisp lspDefinition(Lisp args, LispError *e, LispContext ctx);
+
+void free_structs(void);
+
 #endif

include/cJSON.h

@@ -0,0 +1,306 @@
+/*
+  Copyright (c) 2009-2017 Dave Gamble and cJSON contributors
+
+  Permission is hereby granted, free of charge, to any person obtaining a copy
+  of this software and associated documentation files (the "Software"), to deal
+  in the Software without restriction, including without limitation the rights
+  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+  copies of the Software, and to permit persons to whom the Software is
+  furnished to do so, subject to the following conditions:
+
+  The above copyright notice and this permission notice shall be included in
+  all copies or substantial portions of the Software.
+
+  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+  THE SOFTWARE.
+*/
+
+#ifndef cJSON__h
+#define cJSON__h
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#if !defined(__WINDOWS__) && (defined(WIN32) || defined(WIN64) || defined(_MSC_VER) || defined(_WIN32))
+#define __WINDOWS__
+#endif
+
+#ifdef __WINDOWS__
+
+/* When compiling for windows, we specify a specific calling convention to avoid issues where we are being called from a project with a different default calling convention.  For windows you have 3 define options:
+
+CJSON_HIDE_SYMBOLS - Define this in the case where you don't want to ever dllexport symbols
+CJSON_EXPORT_SYMBOLS - Define this on library build when you want to dllexport symbols (default)
+CJSON_IMPORT_SYMBOLS - Define this if you want to dllimport symbol
+
+For *nix builds that support visibility attribute, you can define similar behavior by
+
+setting default visibility to hidden by adding
+-fvisibility=hidden (for gcc)
+or
+-xldscope=hidden (for sun cc)
+to CFLAGS
+
+then using the CJSON_API_VISIBILITY flag to "export" the same symbols the way CJSON_EXPORT_SYMBOLS does
+
+*/
+
+#define CJSON_CDECL __cdecl
+#define CJSON_STDCALL __stdcall
+
+/* export symbols by default, this is necessary for copy pasting the C and header file */
+#if !defined(CJSON_HIDE_SYMBOLS) && !defined(CJSON_IMPORT_SYMBOLS) && !defined(CJSON_EXPORT_SYMBOLS)
+#define CJSON_EXPORT_SYMBOLS
+#endif
+
+#if defined(CJSON_HIDE_SYMBOLS)
+#define CJSON_PUBLIC(type)   type CJSON_STDCALL
+#elif defined(CJSON_EXPORT_SYMBOLS)
+#define CJSON_PUBLIC(type)   __declspec(dllexport) type CJSON_STDCALL
+#elif defined(CJSON_IMPORT_SYMBOLS)
+#define CJSON_PUBLIC(type)   __declspec(dllimport) type CJSON_STDCALL
+#endif
+#else /* !__WINDOWS__ */
+#define CJSON_CDECL
+#define CJSON_STDCALL
+
+#if (defined(__GNUC__) || defined(__SUNPRO_CC) || defined (__SUNPRO_C)) && defined(CJSON_API_VISIBILITY)
+#define CJSON_PUBLIC(type)   __attribute__((visibility("default"))) type
+#else
+#define CJSON_PUBLIC(type) type
+#endif
+#endif
+
+/* project version */
+#define CJSON_VERSION_MAJOR 1
+#define CJSON_VERSION_MINOR 7
+#define CJSON_VERSION_PATCH 19
+
+#include <stddef.h>
+
+/* cJSON Types: */
+#define cJSON_Invalid (0)
+#define cJSON_False  (1 << 0)
+#define cJSON_True   (1 << 1)
+#define cJSON_NULL   (1 << 2)
+#define cJSON_Number (1 << 3)
+#define cJSON_String (1 << 4)
+#define cJSON_Array  (1 << 5)
+#define cJSON_Object (1 << 6)
+#define cJSON_Raw    (1 << 7) /* raw json */
+
+#define cJSON_IsReference 256
+#define cJSON_StringIsConst 512
+
+/* The cJSON structure: */
+typedef struct cJSON
+{
+    /* next/prev allow you to walk array/object chains. Alternatively, use GetArraySize/GetArrayItem/GetObjectItem */
+    struct cJSON *next;
+    struct cJSON *prev;
+    /* An array or object item will have a child pointer pointing to a chain of the items in the array/object. */
+    struct cJSON *child;
+
+    /* The type of the item, as above. */
+    int type;
+
+    /* The item's string, if type==cJSON_String  and type == cJSON_Raw */
+    char *valuestring;
+    /* writing to valueint is DEPRECATED, use cJSON_SetNumberValue instead */
+    int valueint;
+    /* The item's number, if type==cJSON_Number */
+    double valuedouble;
+
+    /* The item's name string, if this item is the child of, or is in the list of subitems of an object. */
+    char *string;
+} cJSON;
+
+typedef struct cJSON_Hooks
+{
+      /* malloc/free are CDECL on Windows regardless of the default calling convention of the compiler, so ensure the hooks allow passing those functions directly. */
+      void *(CJSON_CDECL *malloc_fn)(size_t sz);
+      void (CJSON_CDECL *free_fn)(void *ptr);
+} cJSON_Hooks;
+
+typedef int cJSON_bool;
+
+/* Limits how deeply nested arrays/objects can be before cJSON rejects to parse them.
+ * This is to prevent stack overflows. */
+#ifndef CJSON_NESTING_LIMIT
+#define CJSON_NESTING_LIMIT 1000
+#endif
+
+/* Limits the length of circular references can be before cJSON rejects to parse them.
+ * This is to prevent stack overflows. */
+#ifndef CJSON_CIRCULAR_LIMIT
+#define CJSON_CIRCULAR_LIMIT 10000
+#endif
+
+/* returns the version of cJSON as a string */
+CJSON_PUBLIC(const char*) cJSON_Version(void);
+
+/* Supply malloc, realloc and free functions to cJSON */
+CJSON_PUBLIC(void) cJSON_InitHooks(cJSON_Hooks* hooks);
+
+/* Memory Management: the caller is always responsible to free the results from all variants of cJSON_Parse (with cJSON_Delete) and cJSON_Print (with stdlib free, cJSON_Hooks.free_fn, or cJSON_free as appropriate). The exception is cJSON_PrintPreallocated, where the caller has full responsibility of the buffer. */
+/* Supply a block of JSON, and this returns a cJSON object you can interrogate. */
+CJSON_PUBLIC(cJSON *) cJSON_Parse(const char *value);
+CJSON_PUBLIC(cJSON *) cJSON_ParseWithLength(const char *value, size_t buffer_length);
+/* ParseWithOpts allows you to require (and check) that the JSON is null terminated, and to retrieve the pointer to the final byte parsed. */
+/* If you supply a ptr in return_parse_end and parsing fails, then return_parse_end will contain a pointer to the error so will match cJSON_GetErrorPtr(). */
+CJSON_PUBLIC(cJSON *) cJSON_ParseWithOpts(const char *value, const char **return_parse_end, cJSON_bool require_null_terminated);
+CJSON_PUBLIC(cJSON *) cJSON_ParseWithLengthOpts(const char *value, size_t buffer_length, const char **return_parse_end, cJSON_bool require_null_terminated);
+
+/* Render a cJSON entity to text for transfer/storage. */
+CJSON_PUBLIC(char *) cJSON_Print(const cJSON *item);
+/* Render a cJSON entity to text for transfer/storage without any formatting. */
+CJSON_PUBLIC(char *) cJSON_PrintUnformatted(const cJSON *item);
+/* Render a cJSON entity to text using a buffered strategy. prebuffer is a guess at the final size. guessing well reduces reallocation. fmt=0 gives unformatted, =1 gives formatted */
+CJSON_PUBLIC(char *) cJSON_PrintBuffered(const cJSON *item, int prebuffer, cJSON_bool fmt);
+/* Render a cJSON entity to text using a buffer already allocated in memory with given length. Returns 1 on success and 0 on failure. */
+/* NOTE: cJSON is not always 100% accurate in estimating how much memory it will use, so to be safe allocate 5 bytes more than you actually need */
+CJSON_PUBLIC(cJSON_bool) cJSON_PrintPreallocated(cJSON *item, char *buffer, const int length, const cJSON_bool format);
+/* Delete a cJSON entity and all subentities. */
+CJSON_PUBLIC(void) cJSON_Delete(cJSON *item);
+
+/* Returns the number of items in an array (or object). */
+CJSON_PUBLIC(int) cJSON_GetArraySize(const cJSON *array);
+/* Retrieve item number "index" from array "array". Returns NULL if unsuccessful. */
+CJSON_PUBLIC(cJSON *) cJSON_GetArrayItem(const cJSON *array, int index);
+/* Get item "string" from object. Case insensitive. */
+CJSON_PUBLIC(cJSON *) cJSON_GetObjectItem(const cJSON * const object, const char * const string);
+CJSON_PUBLIC(cJSON *) cJSON_GetObjectItemCaseSensitive(const cJSON * const object, const char * const string);
+CJSON_PUBLIC(cJSON_bool) cJSON_HasObjectItem(const cJSON *object, const char *string);
+/* For analysing failed parses. This returns a pointer to the parse error. You'll probably need to look a few chars back to make sense of it. Defined when cJSON_Parse() returns 0. 0 when cJSON_Parse() succeeds. */
+CJSON_PUBLIC(const char *) cJSON_GetErrorPtr(void);
+
+/* Check item type and return its value */
+CJSON_PUBLIC(char *) cJSON_GetStringValue(const cJSON * const item);
+CJSON_PUBLIC(double) cJSON_GetNumberValue(const cJSON * const item);
+
+/* These functions check the type of an item */
+CJSON_PUBLIC(cJSON_bool) cJSON_IsInvalid(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsFalse(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsTrue(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsBool(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsNull(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsNumber(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsString(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsArray(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsObject(const cJSON * const item);
+CJSON_PUBLIC(cJSON_bool) cJSON_IsRaw(const cJSON * const item);
+
+/* These calls create a cJSON item of the appropriate type. */
+CJSON_PUBLIC(cJSON *) cJSON_CreateNull(void);
+CJSON_PUBLIC(cJSON *) cJSON_CreateTrue(void);
+CJSON_PUBLIC(cJSON *) cJSON_CreateFalse(void);
+CJSON_PUBLIC(cJSON *) cJSON_CreateBool(cJSON_bool boolean);
+CJSON_PUBLIC(cJSON *) cJSON_CreateNumber(double num);
+CJSON_PUBLIC(cJSON *) cJSON_CreateString(const char *string);
+/* raw json */
+CJSON_PUBLIC(cJSON *) cJSON_CreateRaw(const char *raw);
+CJSON_PUBLIC(cJSON *) cJSON_CreateArray(void);
+CJSON_PUBLIC(cJSON *) cJSON_CreateObject(void);
+
+/* Create a string where valuestring references a string so
+ * it will not be freed by cJSON_Delete */
+CJSON_PUBLIC(cJSON *) cJSON_CreateStringReference(const char *string);
+/* Create an object/array that only references it's elements so
+ * they will not be freed by cJSON_Delete */
+CJSON_PUBLIC(cJSON *) cJSON_CreateObjectReference(const cJSON *child);
+CJSON_PUBLIC(cJSON *) cJSON_CreateArrayReference(const cJSON *child);
+
+/* These utilities create an Array of count items.
+ * The parameter count cannot be greater than the number of elements in the number array, otherwise array access will be out of bounds.*/
+CJSON_PUBLIC(cJSON *) cJSON_CreateIntArray(const int *numbers, int count);
+CJSON_PUBLIC(cJSON *) cJSON_CreateFloatArray(const float *numbers, int count);
+CJSON_PUBLIC(cJSON *) cJSON_CreateDoubleArray(const double *numbers, int count);
+CJSON_PUBLIC(cJSON *) cJSON_CreateStringArray(const char *const *strings, int count);
+
+/* Append item to the specified array/object. */
+CJSON_PUBLIC(cJSON_bool) cJSON_AddItemToArray(cJSON *array, cJSON *item);
+CJSON_PUBLIC(cJSON_bool) cJSON_AddItemToObject(cJSON *object, const char *string, cJSON *item);
+/* Use this when string is definitely const (i.e. a literal, or as good as), and will definitely survive the cJSON object.
+ * WARNING: When this function was used, make sure to always check that (item->type & cJSON_StringIsConst) is zero before
+ * writing to `item->string` */
+CJSON_PUBLIC(cJSON_bool) cJSON_AddItemToObjectCS(cJSON *object, const char *string, cJSON *item);
+/* Append reference to item to the specified array/object. Use this when you want to add an existing cJSON to a new cJSON, but don't want to corrupt your existing cJSON. */
+CJSON_PUBLIC(cJSON_bool) cJSON_AddItemReferenceToArray(cJSON *array, cJSON *item);
+CJSON_PUBLIC(cJSON_bool) cJSON_AddItemReferenceToObject(cJSON *object, const char *string, cJSON *item);
+
+/* Remove/Detach items from Arrays/Objects. */
+CJSON_PUBLIC(cJSON *) cJSON_DetachItemViaPointer(cJSON *parent, cJSON * const item);
+CJSON_PUBLIC(cJSON *) cJSON_DetachItemFromArray(cJSON *array, int which);
+CJSON_PUBLIC(void) cJSON_DeleteItemFromArray(cJSON *array, int which);
+CJSON_PUBLIC(cJSON *) cJSON_DetachItemFromObject(cJSON *object, const char *string);
+CJSON_PUBLIC(cJSON *) cJSON_DetachItemFromObjectCaseSensitive(cJSON *object, const char *string);
+CJSON_PUBLIC(void) cJSON_DeleteItemFromObject(cJSON *object, const char *string);
+CJSON_PUBLIC(void) cJSON_DeleteItemFromObjectCaseSensitive(cJSON *object, const char *string);
+
+/* Update array items. */
+CJSON_PUBLIC(cJSON_bool) cJSON_InsertItemInArray(cJSON *array, int which, cJSON *newitem); /* Shifts pre-existing items to the right. */
+CJSON_PUBLIC(cJSON_bool) cJSON_ReplaceItemViaPointer(cJSON * const parent, cJSON * const item, cJSON * replacement);
+CJSON_PUBLIC(cJSON_bool) cJSON_ReplaceItemInArray(cJSON *array, int which, cJSON *newitem);
+CJSON_PUBLIC(cJSON_bool) cJSON_ReplaceItemInObject(cJSON *object,const char *string,cJSON *newitem);
+CJSON_PUBLIC(cJSON_bool) cJSON_ReplaceItemInObjectCaseSensitive(cJSON *object,const char *string,cJSON *newitem);
+
+/* Duplicate a cJSON item */
+CJSON_PUBLIC(cJSON *) cJSON_Duplicate(const cJSON *item, cJSON_bool recurse);
+/* Duplicate will create a new, identical cJSON item to the one you pass, in new memory that will
+ * need to be released. With recurse!=0, it will duplicate any children connected to the item.
+ * The item->next and ->prev pointers are always zero on return from Duplicate. */
+/* Recursively compare two cJSON items for equality. If either a or b is NULL or invalid, they will be considered unequal.
+ * case_sensitive determines if object keys are treated case sensitive (1) or case insensitive (0) */
+CJSON_PUBLIC(cJSON_bool) cJSON_Compare(const cJSON * const a, const cJSON * const b, const cJSON_bool case_sensitive);
+
+/* Minify a strings, remove blank characters(such as ' ', '\t', '\r', '\n') from strings.
+ * The input pointer json cannot point to a read-only address area, such as a string constant, 
+ * but should point to a readable and writable address area. */
+CJSON_PUBLIC(void) cJSON_Minify(char *json);
+
+/* Helper functions for creating and adding items to an object at the same time.
+ * They return the added item or NULL on failure. */
+CJSON_PUBLIC(cJSON*) cJSON_AddNullToObject(cJSON * const object, const char * const name);
+CJSON_PUBLIC(cJSON*) cJSON_AddTrueToObject(cJSON * const object, const char * const name);
+CJSON_PUBLIC(cJSON*) cJSON_AddFalseToObject(cJSON * const object, const char * const name);
+CJSON_PUBLIC(cJSON*) cJSON_AddBoolToObject(cJSON * const object, const char * const name, const cJSON_bool boolean);
+CJSON_PUBLIC(cJSON*) cJSON_AddNumberToObject(cJSON * const object, const char * const name, const double number);
+CJSON_PUBLIC(cJSON*) cJSON_AddStringToObject(cJSON * const object, const char * const name, const char * const string);
+CJSON_PUBLIC(cJSON*) cJSON_AddRawToObject(cJSON * const object, const char * const name, const char * const raw);
+CJSON_PUBLIC(cJSON*) cJSON_AddObjectToObject(cJSON * const object, const char * const name);
+CJSON_PUBLIC(cJSON*) cJSON_AddArrayToObject(cJSON * const object, const char * const name);
+
+/* When assigning an integer value, it needs to be propagated to valuedouble too. */
+#define cJSON_SetIntValue(object, number) ((object) ? (object)->valueint = (object)->valuedouble = (number) : (number))
+/* helper for the cJSON_SetNumberValue macro */
+CJSON_PUBLIC(double) cJSON_SetNumberHelper(cJSON *object, double number);
+#define cJSON_SetNumberValue(object, number) ((object != NULL) ? cJSON_SetNumberHelper(object, (double)number) : (number))
+/* Change the valuestring of a cJSON_String object, only takes effect when type of object is cJSON_String */
+CJSON_PUBLIC(char*) cJSON_SetValuestring(cJSON *object, const char *valuestring);
+
+/* If the object is not a boolean type this does nothing and returns cJSON_Invalid else it returns the new type*/
+#define cJSON_SetBoolValue(object, boolValue) ( \
+    (object != NULL && ((object)->type & (cJSON_False|cJSON_True))) ? \
+    (object)->type=((object)->type &(~(cJSON_False|cJSON_True)))|((boolValue)?cJSON_True:cJSON_False) : \
+    cJSON_Invalid\
+)
+
+/* Macro for iterating over an array or object */
+#define cJSON_ArrayForEach(element, array) for(element = (array != NULL) ? (array)->child : NULL; element != NULL; element = element->next)
+
+/* malloc/free objects using the malloc/free functions that have been set with cJSON_InitHooks */
+CJSON_PUBLIC(void *) cJSON_malloc(size_t size);
+CJSON_PUBLIC(void) cJSON_free(void *object);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

include/color.h

@@ -0,0 +1,123 @@
+#ifndef COLOR_H_
+#define COLOR_H_
+
+
+// ============================================================================
+// TEXT STYLES / ATTRIBUTES
+// ============================================================================
+#define ANSI_RESET          "\x1b[0m"      // Reset all attributes
+#define ANSI_BOLD           "\x1b[1m"      // Bold text
+#define ANSI_DIM            "\x1b[2m"      // Dim/faint text
+#define ANSI_ITALIC         "\x1b[3m"      // Italic text
+#define ANSI_UNDERLINE      "\x1b[4m"      // Underline text
+#define ANSI_BLINK          "\x1b[5m"      // Blinking text
+#define ANSI_REVERSE        "\x1b[7m"      // Reverse video (invert colors)
+#define ANSI_HIDDEN         "\x1b[8m"      // Hidden/invisible text
+#define ANSI_STRIKETHROUGH  "\x1b[9m"      // Strikethrough text
+
+// ============================================================================
+// FOREGROUND COLORS (30-37 standard, 90-97 bright)
+// ============================================================================
+#define ANSI_BLACK          "\x1b[30m"
+#define ANSI_RED            "\x1b[31m"
+#define ANSI_GREEN          "\x1b[32m"
+#define ANSI_YELLOW         "\x1b[33m"
+#define ANSI_BLUE           "\x1b[34m"
+#define ANSI_MAGENTA        "\x1b[35m"
+#define ANSI_CYAN           "\x1b[36m"
+#define ANSI_WHITE          "\x1b[37m"
+
+// Bright/Light foreground colors (90-97)
+#define ANSI_BRIGHT_BLACK   "\x1b[90m"
+#define ANSI_BRIGHT_RED     "\x1b[91m"
+#define ANSI_BRIGHT_GREEN   "\x1b[92m"
+#define ANSI_BRIGHT_YELLOW  "\x1b[93m"
+#define ANSI_BRIGHT_BLUE    "\x1b[94m"
+#define ANSI_BRIGHT_MAGENTA "\x1b[95m"
+#define ANSI_BRIGHT_CYAN    "\x1b[96m"
+#define ANSI_BRIGHT_WHITE   "\x1b[97m"
+
+// ============================================================================
+// BACKGROUND COLORS (40-47 standard, 100-107 bright)
+// ============================================================================
+#define ANSI_BG_BLACK       "\x1b[40m"
+#define ANSI_BG_RED         "\x1b[41m"
+#define ANSI_BG_GREEN       "\x1b[42m"
+#define ANSI_BG_YELLOW      "\x1b[43m"
+#define ANSI_BG_BLUE        "\x1b[44m"
+#define ANSI_BG_MAGENTA     "\x1b[45m"
+#define ANSI_BG_CYAN        "\x1b[46m"
+#define ANSI_BG_WHITE       "\x1b[47m"
+
+// Bright/Light background colors (100-107)
+#define ANSI_BG_BRIGHT_BLACK   "\x1b[100m"
+#define ANSI_BG_BRIGHT_RED     "\x1b[101m"
+#define ANSI_BG_BRIGHT_GREEN   "\x1b[102m"
+#define ANSI_BG_BRIGHT_YELLOW  "\x1b[103m"
+#define ANSI_BG_BRIGHT_BLUE    "\x1b[104m"
+#define ANSI_BG_BRIGHT_MAGENTA "\x1b[105m"
+#define ANSI_BG_BRIGHT_CYAN    "\x1b[106m"
+#define ANSI_BG_BRIGHT_WHITE   "\x1b[107m"
+
+// ============================================================================
+// 256-COLOR MODE (for more colors)
+// ============================================================================
+// Foreground: \x1b[38;5;Nm  where N is 0-255
+// Background: \x1b[48;5;Nm  where N is 0-255
+// Example macros:
+#define ANSI_FG_256(N)      "\x1b[38;5;" #N "m"
+#define ANSI_BG_256(N)      "\x1b[48;5;" #N "m"
+
+// ============================================================================
+// TRUE COLOR / 24-BIT COLOR (RGB)
+// ============================================================================
+// Foreground: \x1b[38;2;R;G;Bm
+// Background: \x1b[48;2;R;G;Bm
+// Example macros:
+#define ANSI_FG_RGB(R,G,B)  "\x1b[38;2;" #R ";" #G ";" #B "m"
+#define ANSI_BG_RGB(R,G,B)  "\x1b[48;2;" #R ";" #G ";" #B "m"
+
+// ============================================================================
+// CURSOR MOVEMENT
+// ============================================================================
+#define ANSI_CURSOR_UP(N)       "\x1b[" #N "A"    // Move up N lines
+#define ANSI_CURSOR_DOWN(N)     "\x1b[" #N "B"    // Move down N lines
+#define ANSI_CURSOR_RIGHT(N)    "\x1b[" #N "C"    // Move right N columns
+#define ANSI_CURSOR_LEFT(N)     "\x1b[" #N "D"    // Move left N columns
+#define ANSI_CURSOR_HOME        "\x1b[H"          // Move to home (0,0)
+#define ANSI_CURSOR_HIDE        "\x1b[?25l"       // Hide cursor
+#define ANSI_CURSOR_SHOW        "\x1b[?25h"       // Show cursor
+
+// ============================================================================
+// SCREEN CONTROL
+// ============================================================================
+#define ANSI_CLEAR_SCREEN   "\x1b[2J"      // Clear entire screen
+#define ANSI_CLEAR_LINE     "\x1b[K"       // Clear from cursor to end of line
+#define ANSI_CLEAR_UP       "\x1b[1J"      // Clear from cursor to start
+#define ANSI_CLEAR_DOWN     "\x1b[0J"      // Clear from cursor to end
+
+// ============================================================================
+// EXAMPLE USAGE
+// ============================================================================
+/*
+#include <stdio.h>
+
+int main(void) {
+    // Simple color example
+    printf("%sHello in Red%s\n", ANSI_RED, ANSI_RESET);
+    
+    // Bold and colored
+    printf("%s%sBold Green%s\n", ANSI_BOLD, ANSI_GREEN, ANSI_RESET);
+    
+    // Background color
+    printf("%s%sYellow on Blue%s\n", ANSI_YELLOW, ANSI_BG_BLUE, ANSI_RESET);
+    
+    // Combine multiple styles
+    printf("%s%s%sUnderlined Bold Cyan%s\n", 
+           ANSI_UNDERLINE, ANSI_BOLD, ANSI_CYAN, ANSI_RESET);
+    
+    return 0;
+}
+*/
+
+#endif

include/completion.h

@@ -0,0 +1,26 @@
+//
+// Created by Giorgio on 25/05/2026.
+//
+
+#ifndef BELUGA_COMPLETION_H
+#define BELUGA_COMPLETION_H
+#include "data.h"
+
+
+int lspStart(LspClient* lsp, const char* project_root);
+void lspShutdown(LspClient* lsp);
+
+// Document sync — call these from your buffer open/save/edit hooks
+void lspDidOpen(LspClient* lsp, struct buffer_t* buf);
+void lspDidChange(LspClient* lsp, struct buffer_t* buf);
+void lspDidClose(LspClient* lsp, struct buffer_t* buf);
+
+// Requests
+void lspRequestCompletion(LspClient* lsp, struct buffer_t* buf,
+                          int line, int col,
+                          int screen_x, int screen_y);
+void lspRequestHover(LspClient* lsp, struct buffer_t* buf, int line, int col);
+void lspRequestDefinition(LspClient* lsp, struct buffer_t* buf, int line, int col);
+
+
+#endif //BELUGA_COMPLETION_H

include/data.h

@@ -5,70 +5,252 @@
 #include <termios.h>
 #include <time.h>
 
+#include "define.h"
+
 #include "lisp.h"
 
+typedef struct lsp_client_t LspClient;
+
 /**
- * \struct erow
+ * \struct row_t
  * \brief Store one editor row
  * \param
  * */
 
-typedef struct erow {
-  int size;     /**< Size of the line */
-  int rsize;    /**< Size of the render line */
-  char *chars;  /**< Characters of the line */
-  char *render; /**< The actual line we will print */
-} erow;
+typedef struct row
+{
+    int size; /**< Size of the line */
+    int cap; /**< Size of the render line */
+    char* chars; /**< Characters of the line */
+} row_t;
 
-enum editorStatus_e {
-  IDLE,
-  READ_ONLY,
-  READ_AND_WRITE, 
+typedef struct context_buffer_t
+{
+    int editor_x, editor_y;
+    int width, height;
+    row_t* rows;
+} ContextBuffer;
+
+/**
+ * @brief Split modes for screen layout
+ */
+typedef enum
+{
+    SPLIT_NONE = 0, // Single buffer fullscreen
+    SPLIT_VERTICAL, // Left-right split
+    SPLIT_HORIZONTAL // Top-bottom split
+} SplitMode;
+
+/**
+ * @brief Represents an editor viewport/pane
+ */
+typedef struct
+{
+    int buffer_id; // Which buffer this pane displays
+    int height; // Height of this pane
+    int width; // Width of this pane
+    int origin_x, origin_y;
+    int cursor_x; // Local cursor x in this pane
+    int cursor_y; // Local cursor y in this pane
+    int x_offset, y_offset;
+    int is_active; // Is this pane currently active
+} EditorPane;
+
+/**
+ * @brief Screen layout manager
+ */
+typedef struct
+{
+    SplitMode mode;
+    EditorPane* panes;
+    int num_panes;
+    int active_pane; // Index of active pane
+} ScreenLayout;
+
+
+typedef struct theme
+{
+    char* BACKGROUND_COLOR;
+    char* COLOR_KEYWORD;
+    char* COLOR_TYPE;
+    char* COLOR_STRING;
+    char* COLOR_COMMENT;
+    char* COLOR_NUMBER;
+    char* COLOR_DEFAULT;
+} theme_t;
+
+enum bufferStatus_e
+{
+    IDLE,
+    READ_ONLY,
+    READ_AND_WRITE,
 };
 
-struct const_t {
-  int TAB_LENGTH;
-  int QUIT_TIMES;
+struct const_t
+{
+    int TAB_LENGTH;
+    int QUIT_TIMES;
+    char* THEME;
+    int LSP;
 };
 
-struct keyBind_t {
-  char *key_sequence;
-  Lisp command;
-  
+struct prefix_t
+{
+    char prefix_name[64];
+    int prefix_id;
+};
+
+struct keyBind_t
+{
+    char* key_sequence;
+    int prefix_id;
+    Lisp command;
+};
+
+// In data.h — add these
+
+#include <pthread.h>
+
+#define LSP_MAX_PENDING 64
+
+typedef enum
+{
+    LSP_NOT_STARTED = 0,
+    LSP_INITIALIZING,
+    LSP_READY,
+    LSP_SHUTDOWN,
+} LspState;
+
+typedef struct
+{
+    int id;
+    void (*callback)(struct lsp_client_t* lsp, const char* json);
+} LspPending;
+
+typedef struct lsp_client_t
+{
+    // ── Process ───────────────────────────────────────────────────────────────
+    pid_t pid;
+    int write_fd;
+    int read_fd;
+    int completion_just_arrived;
+    int completion_requested;
+
+    int wake_pipe[2]; // [0] = read end (main loop), [1] = write end (reader thread)
+    // ── State ─────────────────────────────────────────────────────────────────
+    LspState state;
+    int next_id;
+
+    // ── Pending requests ──────────────────────────────────────────────────────
+    LspPending pending[LSP_MAX_PENDING];
+    int pending_count;
+
+    // ── Threading ─────────────────────────────────────────────────────────────
+    pthread_t reader_thread;
+    pthread_mutex_t lock;
+    pthread_cond_t ready_cond; // signaled when state → LSP_READY
+
+    // ── Completion context ────────────────────────────────────────────────────
+    int completion_cursor_x; // screen position when
+    int completion_cursor_y; // completion was requested
+} LspClient;
+
+typedef struct
+{
+    char label[128]; // display text  e.g. "printf"
+    char detail[64]; // type/sig hint e.g. "int (const char *, ...)"
+    int kind; // LSP CompletionItemKind (1=Text,2=Method,3=Function…)
+} CompletionItem;
+
+typedef struct
+{
+    CompletionItem items[COMPLETION_MAX_ITEMS];
+    int count;
+    int selected; // currently highlighted row
+    int visible; // is the popup shown?
+    int origin_x; // screen col where popup appears
+    int origin_y; // screen row where popup appears
+} CompletionPopup;
+
+typedef enum { DIAG_ERROR = 1, DIAG_WARNING, DIAG_HINT } DiagSeverity;
+
+typedef struct
+{
+    int buffer_id;
+    int line; // 0-based
+    int col_start; // 0-based
+    int col_end;
+    DiagSeverity severity;
+    char message[256];
+} Diagnostic;
+
+typedef struct
+{
+    Diagnostic entries[DIAG_MAX];
+    int count;
+} DiagnosticList;
+
+enum buffer_type { FILE_BUFF, TERMINAL_BUFF };
+
+struct buffer_t
+{
+    enum buffer_type type;
+    int buffer_id;
+    int b_lsp_open;
+    int x, y; /**< Position in the file */
+    row_t* row;
+    int numrows;
+    int b_has_changed;
+    char* filename;
+    char* path;
+    char * fullname;
+    enum bufferStatus_e state;
+    int dirty; /**< Has this buffer been modified since last save */
 };
 
 /**
  * \struct editorConfig
  * \brief Containing our editor state.
  */
-struct editorConfig {
-  int cursor_x, cursor_y; /**< Cursor position */
-  int rx;                 /**< Position in the render*/
-  int row_offset;         /**< Position scroll of lines */
-  int col_offset;         /**< Position scroll of colomns*/
-  int screenrows;         /**< Terminal height*/
-  int screencols;         /**< Terminal width*/
-  int numrows;            /**< Number of rows contained */
-  erow *row;              /**< Store all the rows printed */
-  int dirty;
-  char *filename;
-  enum editorStatus_e state;
-  char status_msg[80];
-  time_t status_msg_time;
-  struct termios orig_termios; /**< Terminal communication interface */
+struct editorConfig
+{
+    int cursor_x, cursor_y; /**< Cursor position */
+    int screenrows; /**< Terminal height*/
+    int screencols; /**< Terminal width*/
 
-  struct const_t constantes;
-  int quit_times_buffer;
+    ScreenLayout layout;
 
-  FILE *fd_init_file;
-  Lisp env;
-  LispContext ctx;     /** Lisp context */
-  Lisp ctx_data;       /** Lisp data context */
-  LispError ctx_error; /** Lisp ctx error */
+    LspClient* lsp_client;
+    CompletionPopup lsp_completion;
+    DiagnosticList lsp_diagnostics;
 
-  struct keyBind_t* key_binds;
-  int number_of_keybinds;
+    int dirty;
 
+    char* status_msg;
+    time_t status_msg_time;
+    struct termios orig_termios; /**< Terminal communication interface */
+
+    struct const_t constantes;
+    int quit_times_buffer;
+
+    char* init_file_path;
+    FILE* fd_init_file;
+    Lisp env;
+    LispContext ctx; /** Lisp context */
+    Lisp ctx_data; /** Lisp data context */
+    LispError ctx_error; /** Lisp ctx error */
+
+    struct keyBind_t* key_binds;
+    int number_of_keybinds;
+
+    struct prefix_t* prefix;
+    int number_of_prefix;
+    int prefix_state;
+
+    struct buffer_t buffers[64];
+    int number_of_buffer;
+
+    theme_t theme;
 };
 
 /**
@@ -76,9 +258,10 @@ struct editorConfig {
  * \brief Contains text to add before writing to screen.
  * */
 
-struct abuf {
-  char *b; /**< Text that will be printed */
-  int len; /**< Length of the text */
+struct abuf
+{
+    char* b; /**< Text that will be printed */
+    int len; /**< Length of the text */
 };
 
 extern struct editorConfig E;

include/define.h

@@ -2,28 +2,55 @@
 #define DEFINE_H_
 
 #define CTRL_KEY(k) ((k) & 0x1f)
+#define ALT(k) ((k) | 0x200)  // set bit 9 to mark as Option combo
+
 
 #define ESCAPE '\x1b'
 #define CURSOR_TOP_LEFT "\x1b[H"
 #define HIDE_CURSOR "\x1b[?25l"
 #define SHOW_CURSOR "\x1b[?25h"
 #define ERASE_END_LINE "\x1b[K"
+#define TAB "\t"
+#define SPACE "\x20"
 
-enum editorKey {
-  BACKSPACE = 127,
-  ARROW_LEFT = 1000,
-  ARROW_RIGHT,
-  ARROW_UP,
-  ARROW_DOWN,
-  DEL_KEY,
-  BEG_LINE,
-  END_LINE,
-  PAGE_UP,
-  PAGE_DOWN,
-};
+#ifndef PATH_MAX
+#define PATH_MAX 1024
+#endif
+
+/* Uncomment to see debug logs on stderr */
+#define APP_DEBUG
+
+#define COMPLETION_MAX_ITEMS  16
+#define COMPLETION_MAX_WIDTH  40
+#define COMPLETION_POPUP_H    8   // max visible rows
+#define DIAG_MAX 128
+
+#define GUTTER_WIDTH 2
+
+enum editorKey_e {
+    BACKSPACE = 127,
+    ARROW_LEFT = 1000,
+    ARROW_RIGHT,
+    ARROW_UP,
+    ARROW_DOWN,
+    DEL_KEY,
+    BEG_LINE,
+    END_LINE,
+    PAGE_UP,
+    PAGE_DOWN,
+    LSP_WAKE_KEY = 2000
+  };
 
 #define ABUF_INIT {NULL, 0}
 
-#define BELUGA_VERSION "1.1"
+#define BELUGA_VERSION "2.4"
+
+#ifdef __APPLE__
+#define CLIPBOARD_COPY_CMD  "pbcopy"
+#define CLIPBOARD_PASTE_CMD "pbpaste"
+#else
+#define CLIPBOARD_COPY_CMD  "xclip -selection clipboard"
+#define CLIPBOARD_PASTE_CMD "xclip -selection clipboard -o"
+#endif
 
 #endif // DEFINE_H_

include/editor_op.h

@@ -2,10 +2,12 @@
 #define EDITOR_OP_H_
 
 #include "data.h"
-void editorInsertChar(int c);
 
-void editorInsertNewLine();
+void editorSetStatusMessage(const char *fmt, ...);
+int editorRowCharCount(row_t *row, int x);
+int editorRowCxToByte(const row_t *row, int cursor_x);
+char *editorGetClipboard(void);
+void editorSetClipboard(const char *text, int len);
 
-void editorDelChar();
 
 #endif // EDITOR_OP_H_

include/file_io.h

@@ -2,21 +2,14 @@
 #define FILE_IO_H_
 
 #include "data.h"
-#include "row_op.h"
-#include "terminal.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/types.h>
 
-char *editorRowsToString(int *buffer_len);
-
-
 void editorCloseFile(void);
 
-void editorOpen(char *filename);
+void editorOpen(struct buffer_t *buffer);
 
 void editorSave();
 
-void editorFind();
-
 #endif // FILE_IO_H_

include/init.h

@@ -1,10 +1,6 @@
 #ifndef INIT_H_
 #define INIT_H_
 
-#include "builtins.h"
-#include "data.h"
-#include "terminal.h"
-#include <stdio.h>
 
 /**
  * \fn void initEditor()
@@ -15,4 +11,7 @@ void initBuiltins();
 
 void initEditor();
 
+void deInitEditor();
+
+
 #endif // INIT_H_

include/input.h

@@ -22,9 +22,9 @@
 
 char *editorPrompt(char *prompt, char * PlaceHolder, char bPathMode);
 
-char *key_to_string(int key);
+const char *fileCompletion(const char *path);
 
-void editorMoveCursor(int key);
+int editorMoveCursor(int key);
 
 int executeKeyBind(char *key_sequence);
 

include/lisp.h

@@ -1861,8 +1861,8 @@ static Lisp parse_symbol_(Lexer* lex, LispContext ctx)
     char scratch[LISP_IDENTIFIER_MAX];
     size_t length = lexer_copy_token(lex, 0, LISP_IDENTIFIER_MAX, scratch);
     // always convert symbols to uppercase
-    for (int i = 0; i < length; ++i)
-        scratch[i] = toupper(scratch[i]);
+    //   for (int i = 0; i < length; ++i)
+    //    scratch[i] = toupper(scratch[i]);
     return symbol_intern_(ctx.p->symbols, scratch, length, ctx);
 }
 
@@ -2075,8 +2075,10 @@ static Lisp parse(Lexer* lex, LispError* out_error, LispContext ctx)
         result = lisp_cons(get_sym(SYM_BEGIN, ctx), lisp_list_reverse(result), ctx);
     }
 
-    if (out_error) *out_error = error;
+    if (out_error)
+      *out_error = error;
     return result;
+
 }
 
 Lisp lisp_read(const char *program, LispError* out_error, LispContext ctx)
@@ -2122,6 +2124,7 @@ void* fread_all_(FILE* file, size_t* out_size) {
                 return NULL;
             }
             data = new_data;
+            memset(data + *out_size, 0, cap - *out_size);
         }
 
         size_t read = fread(data + *out_size, 1, BLOCK_SIZE, file);
@@ -3183,17 +3186,17 @@ LispContext lisp_init(void)
     ctx.p->macros = lisp_make_table(ctx);
 
     Lisp* c = ctx.p->symbol_cache;
-    c[SYM_IF] = lisp_make_symbol("IF", ctx);
-    c[SYM_BEGIN] = lisp_make_symbol("BEGIN", ctx);
-    c[SYM_QUOTE] = lisp_make_symbol("QUOTE", ctx);
-    c[SYM_QUASI_QUOTE] = lisp_make_symbol("QUASIQUOTE", ctx);
-    c[SYM_UNQUOTE] = lisp_make_symbol("UNQUOTE", ctx);
-    c[SYM_UNQUOTE_SPLICE] = lisp_make_symbol("UNQUOTESPLICE", ctx);
-    c[SYM_DEFINE] = lisp_make_symbol("_DEF", ctx);
-    c[SYM_DEFINE_MACRO] = lisp_make_symbol("DEFINE-MACRO", ctx);
-    c[SYM_SET] = lisp_make_symbol("_SET!", ctx);
+    c[SYM_IF] = lisp_make_symbol("if", ctx);
+    c[SYM_BEGIN] = lisp_make_symbol("begin", ctx);
+    c[SYM_QUOTE] = lisp_make_symbol("quote", ctx);
+    c[SYM_QUASI_QUOTE] = lisp_make_symbol("quasiquote", ctx);
+    c[SYM_UNQUOTE] = lisp_make_symbol("unquote", ctx);
+    c[SYM_UNQUOTE_SPLICE] = lisp_make_symbol("unquotesplice", ctx);
+    c[SYM_DEFINE] = lisp_make_symbol("_def", ctx);
+    c[SYM_DEFINE_MACRO] = lisp_make_symbol("define-macro", ctx);
+    c[SYM_SET] = lisp_make_symbol("_set!", ctx);
     c[SYM_LAMBDA] = lisp_make_symbol("/\\_", ctx);
-    c[SYM_CONS] = lisp_make_symbol("CONS", ctx);
+    c[SYM_CONS] = lisp_make_symbol("cons", ctx);
     return ctx;
 }
 

include/lisp_lib.h

@@ -36,7 +36,7 @@ static const char* lib_0_sequences_src_ =
            (if (pair? args) \n\
                (if (pair? (cdr args)) \n\
                    (if (pair? (cdr (cdr args))) \n\
-                       `(/\\_ ,(car args) ,(cons 'BEGIN (cdr args))) \n\
+                       `(/\\_ ,(car args) ,(cons 'begin (cdr args))) \n\
                        `(/\\_ ,(car args) ,(car (cdr args)))) \n\
                    (syntax-error \"lambda missing body expressions: (lambda (args) body)\")) \n\
                (syntax-error \"lambda missing argument: (lambda (args) body)\")))) \n\
@@ -44,18 +44,18 @@ static const char* lib_0_sequences_src_ =
 (define-macro set! (lambda (var x) \n\
                      (begin \n\
                        (if (not (symbol? var)) (syntax-error \"set! not a variable\")) \n\
-                       `(_SET! ,var ,x)))) \n\
+                       `(_set! ,var ,x)))) \n\
  \n\
 (define-macro define \n\
               (lambda (var . exprs) \n\
                 (if (symbol? var) \n\
                     (if (pair? (cdr exprs)) \n\
                         (syntax-error \"define: (define var x)\") \n\
-                        `(_DEF ,var ,(car exprs))) \n\
+                        `(_def ,var ,(car exprs))) \n\
                     (if (pair? var) \n\
-                        `(_DEF ,(car var) \n\
-                               (LAMBDA ,(cdr var) \n\
-                                       ,(if (null? (cdr exprs)) (car exprs) (cons 'BEGIN exprs)))) \n\
+                        `(_def ,(car var) \n\
+                               (lambda ,(cdr var) \n\
+                                       ,(if (null? (cdr exprs)) (car exprs) (cons 'begin exprs)))) \n\
                         (syntax-error \"define: not a symbol\") )))) \n\
   \n\
 (define (first x) (car x))  \n\
@@ -98,13 +98,13 @@ static const char* lib_0_sequences_src_ =
 (define (_expand-shorthand-body path)  \n\
   (if (null? path) (cons 'pair '())  \n\
       (list (if (char=? (car path) #\\A)  \n\
-            (cons 'CAR (_expand-shorthand-body (cdr path)))))))  \n\
+            (cons 'car (_expand-shorthand-body (cdr path)))))))  \n\
  \n\
 (define (_expand-shorthand text)  \n\
-  (cons 'DEFINE  (cons (list (string->symbol (string-append \"C\" text \"R\")) 'pair)  \n\
+  (cons 'define  (cons (list (string->symbol (string-append \"C\" text \"R\")) 'pair)  \n\
         (_expand-shorthand-body (string->list text)))))  \n\
  \n\
-(define-macro _shorthand-accessors (lambda args (cons 'BEGIN (map1 _expand-shorthand args))))  \n\
+(define-macro _shorthand-accessors (lambda args (cons 'begin (map1 _expand-shorthand args))))  \n\
  \n\
 (define (vector . args) (list->vector args)) \n\
  \n\
@@ -124,14 +124,14 @@ static const char* lib_0_sequences_src_ =
 
 static const char* lib_1_forms_src_ = 
 "(define (_make-lambda args body)  \n\
-  (list 'LAMBDA args (if (null? (cdr body)) (car body) (cons 'BEGIN body))))  \n\
+  (list 'lambda args (if (null? (cdr body)) (car body) (cons 'begin body))))  \n\
   \n\
  \n\
-; (LET <name> ((<var0> <expr0>) ... (<varN> <expr1>)) <body0> ... <bodyN>) \n\
-;  => ((LAMBDA (<var0> ... <varN>) (BEGIN <body0> ... <bodyN>)) <expr0> ... <expr1>)             \n\
+; (let <name> ((<var0> <expr0>) ... (<varN> <expr1>)) <body0> ... <bodyN>) \n\
+;  => ((lambda (<var0> ... <varN>) (begin <body0> ... <bodyN>)) <expr0> ... <expr1>)             \n\
 ;  => named  \n\
 ;    ((lambda () \n\
-;        (define <name> (LAMBDA (<var0> ... <varN>) (BEGIN <body0> ... <bodyN>))) \n\
+;        (define <name> (lambda (<var0> ... <varN>) (begin <body0> ... <bodyN>))) \n\
 ;        (<name> <expr0> ... <exprN>))) \n\
  \n\
 (define (_check-binding-list bindings)  \n\
@@ -145,7 +145,7 @@ static const char* lib_1_forms_src_ =
   (define initial-args (map1 (lambda (entry) (second entry)) bindings))  \n\
   (if (null? var)  \n\
       (cons body-func initial-args)  \n\
-      (list (_make-lambda '() (list (list 'DEFINE var body-func) (cons var initial-args))))))  \n\
+      (list (_make-lambda '() (list (list 'define var body-func) (cons var initial-args))))))  \n\
  \n\
 (define-macro let (lambda args   \n\
                     (if (pair? (first args))  \n\
@@ -153,8 +153,8 @@ static const char* lib_1_forms_src_ =
                         (_let->combination (first args) (second args) (cdr (cdr args))))))  \n\
  \n\
 (define (_let*-helper bindings body)  \n\
-  (if (null? bindings) (if (null? (cdr body)) (car body) (cons 'BEGIN body))  \n\
-      (list 'LET (list (car bindings)) (_let*-helper (cdr bindings) body))))  \n\
+  (if (null? bindings) (if (null? (cdr body)) (car body) (cons 'begin body))  \n\
+      (list 'let (list (car bindings)) (_let*-helper (cdr bindings) body))))  \n\
  \n\
 (define-macro let* (lambda (bindings . body)  \n\
                      (_check-binding-list bindings)  \n\
@@ -163,17 +163,17 @@ static const char* lib_1_forms_src_ =
 (define-macro letrec (lambda (bindings . body)  \n\
                        (_check-binding-list bindings)  \n\
                        (cons (_make-lambda (map1 (lambda (entry) (first entry)) bindings)  \n\
-                                           (append (map1 (lambda (entry) (list 'SET! (first entry) (second entry)))  \n\
+                                           (append (map1 (lambda (entry) (list 'set! (first entry) (second entry)))  \n\
                                                          bindings) body))  \n\
                              (map1 (lambda (entry) '()) bindings))))  \n\
  \n\
  \n\
-; (COND (<pred0> <expr0>) \n\
+; (cond (<pred0> <expr0>) \n\
 ;       (<pred1> <expr1>) \n\
 ;        ... \n\
 ;        (else <expr-1>))  \n\
 ; => \n\
-; (IF <pred0> <expr0> \n\
+; (if <pred0> <expr0> \n\
 ;      (if <pred1> <expr1> \n\
 ;          .... \n\
 ;      (if <predN> <exprN> <expr-1>)) ... ) \n\
@@ -187,11 +187,11 @@ static const char* lib_1_forms_src_ =
  \n\
 (define (_cond-helper clauses)  \n\
   (if (null? clauses) '()  \n\
-      (if (eq? (car (car clauses)) 'ELSE)  \n\
-          (cons 'BEGIN (cdr (car clauses)))  \n\
-          (list 'IF  \n\
+      (if (eq? (car (car clauses)) 'else)  \n\
+          (cons 'begin (cdr (car clauses)))  \n\
+          (list 'if  \n\
                 (car (car clauses))  \n\
-                (cons 'BEGIN (cdr (car clauses)))  \n\
+                (cons 'begin (cdr (car clauses)))  \n\
                 (_cond-helper (cdr clauses))))))  \n\
  \n\
 (define-macro cond (lambda clauses  \n\
@@ -206,26 +206,26 @@ static const char* lib_2_forms_src_ =
   (cond ((null? preds) #t)  \n\
         ((null? (cdr preds)) (car preds))  \n\
         (else  \n\
-          `(IF ,(car preds) ,(_and-helper (cdr preds)) #f))))  \n\
+          `(if ,(car preds) ,(_and-helper (cdr preds)) #f))))  \n\
 (define-macro and (lambda preds (_and-helper preds)))  \n\
  \n\
 (define (_or-helper preds var)  \n\
   (cond ((null? preds) #f)  \n\
         ((null? (cdr preds)) (car preds))  \n\
         (else  \n\
-          `(BEGIN (SET! ,var ,(car preds))  \n\
-                  (IF ,var ,var ,(_or-helper (cdr preds) var))))))  \n\
+          `(begin (set! ,var ,(car preds))  \n\
+                  (if ,var ,var ,(_or-helper (cdr preds) var))))))  \n\
  \n\
 (define-macro or (lambda preds  \n\
                    (let ((var (gensym)))  \n\
-                     `(LET ((,var '())) ,(_or-helper preds var)))))  \n\
+                     `(let ((,var '())) ,(_or-helper preds var)))))  \n\
  \n\
 (define-macro case (lambda (key . clauses)  \n\
                      (let ((expr (gensym)))  \n\
-                       `(LET ((,expr ,key))  \n\
-                          ,(cons 'COND (map1 (lambda (entry)  \n\
+                       `(let ((,expr ,key))  \n\
+                          ,(cons 'cond (map1 (lambda (entry)  \n\
                                                (cons (if (pair? (car entry))  \n\
-                                                         `(MEMV ,expr (quote ,(car entry)))  \n\
+                                                         `(memv ,expr (quote ,(car entry)))  \n\
                                                          (car entry))  \n\
                                                      (cdr entry))) clauses))))))  \n\
  \n\
@@ -234,23 +234,24 @@ static const char* lib_2_forms_src_ =
                 `(begin (set! ,l (cons ,v ,l)) ,l)))  \n\
  \n\
 ; (DO ((<var0> <init0> <step0>) ...)  (<test> <result>) <body>) \n\
-(define-macro do  \n\
-              (lambda (vars loop-check . loops)  \n\
-                (let ( (names '()) (inits '()) (steps '()) (f (gensym)) )  \n\
-                  (for-each1 (lambda (var)  \n\
-                               (push (car var) names)  \n\
-                               (set! var (cdr var))  \n\
-                               (push (car var) inits)  \n\
-                               (set! var (cdr var))  \n\
-                               (push (car var) steps)) vars)  \n\
-                  `((LAMBDA ()  \n\
-                      (DEFINE ,f (LAMBDA ,names  \n\
-                                   (IF ,(car loop-check)  \n\
-                                       ,(if (pair? (cdr loop-check)) (car (cdr loop-check)) '())  \n\
-                                       ,(cons 'BEGIN (append loops (list (cons f steps)))) )))  \n\
-                      ,(cons f inits)  \n\
-                      )) )))  \n\
  \n\
+(define-macro do   \n\
+  (lambda (vars loop-check . loops)   \n\
+    (let ( (names '()) (inits '()) (steps '()) (f (gensym)) )   \n\
+      (for-each1 (lambda (var-spec)   \n\
+                   (push (car var-spec) names) \n\
+                   (push (car (cdr var-spec)) inits) \n\
+                   (if (pair? (cdr (cdr var-spec))) \n\
+                       (push (car (cdr (cdr var-spec))) steps) \n\
+                       (push (car var-spec) steps))) vars)   \n\
+      `((lambda ()   \n\
+          (define ,f (lambda ,names   \n\
+                       (if ,(car loop-check)   \n\
+                           ,(if (pair? (cdr loop-check)) (car (cdr loop-check)) '())   \n\
+                           ,(cons 'begin (append loops (list (cons f steps)))) )))   \n\
+          ,(cons f inits)   \n\
+          )) ))) \n\
+\n\
 (define-macro dotimes  \n\
               (lambda (form body)  \n\
                 (apply (lambda (i n . result)  \n\
@@ -262,18 +263,18 @@ static const char* lib_2_forms_src_ =
 (define-macro swap! \n\
               (lambda (x y) \n\
                 (let ((temp (gensym))) \n\
-                  `(LET ((,temp ,x)) \n\
-                        (SET! ,temp ,x) \n\
-                        (SET! ,x ,y) \n\
-                        (SET! ,y ,temp))))) \n\
+                  `(let ((,temp ,x)) \n\
+                        (set! ,temp ,x) \n\
+                        (set! ,x ,y) \n\
+                        (set! ,y ,temp))))) \n\
  \n\
 (define-macro inc! ; CL incf \n\
               (lambda (x) \n\
-                `(SET! ,x (+ ,x 1)))) \n\
+                `(set! ,x (+ ,x 1)))) \n\
  \n\
 (define-macro dec! ; CL decf \n\
               (lambda (x) \n\
-                `(SET! ,x (- ,x 1))))";
+                `(set! ,x (- ,x 1))))";
 
 static const char* lib_3_math_src_ = 
 "(define (number? x) (real? x))  \n\
@@ -445,7 +446,7 @@ static const char* lib_4_sequences_src_ =
 
 static const char* lib_5_streams_src_ = 
 "(define-macro delay (lambda (expr) \n\
-                      `(make-promise ,(cons 'LAMBDA \n\
+                      `(make-promise ,(cons 'lambda \n\
                                             (cons '() \n\
                                                   (cons expr '())))))) \n\
  \n\
@@ -1162,7 +1163,7 @@ static Lisp sch_string_ref(Lisp args, LispError* e, LispContext ctx)
         return lisp_null();
     }
 
-    return lisp_make_char((int)lisp_string_ref(str, lisp_int(index)));
+    return lisp_make_char(lisp_string_ref(str, lisp_int(index)));
 }
 
 static Lisp sch_string_set(Lisp args, LispError* e, LispContext ctx)
@@ -1736,7 +1737,7 @@ static Lisp sch_pseudo_rand(Lisp args, LispError* e, LispContext ctx)
 
 static Lisp sch_univeral_time(Lisp args, LispError* e, LispContext ctx)
 {
-    return lisp_make_int((LispInt)time(NULL));
+    return lisp_make_int(time(NULL));
 }
 
 static Lisp sch_is_table(Lisp args, LispError* e, LispContext ctx)
@@ -1926,182 +1927,178 @@ static Lisp sch_is_cont(Lisp args, LispError* e, LispContext ctx)
 
 static const LispFuncDef lib_cfunc_defs[] = {
     
-    { "ERROR", sch_error },
-    { "SYNTAX-ERROR", sch_syntax_error },
+    { "error", sch_error },
+    { "syntax-error", sch_syntax_error },
 
-    // Output Procedures https://www.gnu.org/software/mit-scheme/documentation/mit-scheme-ref/Output-Procedures.html
-    { "_WRITE", sch_write },
-    { "_DISPLAY", sch_display },
-    { "_WRITE-CHAR", sch_write_char },
-    { "_FLUSH-OUTPUT-PORT", sch_flush },
-    { "_READ", sch_read },
-    { "INPUT-PORT?", sch_is_port_in },
-    { "OUTPUT-PORT?", sch_is_port_out },
-    { "OPEN-INPUT-FILE", sch_open_input },
-    { "OPEN-OUTPUT-FILE", sch_open_output },
-    { "CLOSE-INPUT-PORT", sch_port_close },
-    { "CLOSE-OUTPUT-PORT", sch_port_close },
-    { "EOF-OBJECT?", sch_is_eof },
+    // Output Procedures
+    { "_write", sch_write },
+    { "_display", sch_display },
+    { "_write-char", sch_write_char },
+    { "_flush-output-port", sch_flush },
+    { "_read", sch_read },
+    { "input-port?", sch_is_port_in },
+    { "output-port?", sch_is_port_out },
+    { "open-input-file", sch_open_input },
+    { "open-output-file", sch_open_output },
+    { "close-input-port", sch_port_close },
+    { "close-output-port", sch_port_close },
+    { "eof-object?", sch_is_eof },
     
-    // Universal Time https://www.gnu.org/software/mit-scheme/documentation/mit-scheme-ref/Universal-Time.html
-    { "GET-UNIVERSAL-TIME", sch_univeral_time },
-    { "PRINT-GC-STATISTICS", sch_print_gc_stats },
+    // Universal Time
+    { "get-universal-time", sch_univeral_time },
+    { "print-gc-statistics", sch_print_gc_stats },
     
-    { "MACROEXPAND", sch_macroexpand },
+    { "macroexpand", sch_macroexpand },
     
-    // Equivalence Predicates https://www.gnu.org/software/mit-scheme/documentation/mit-scheme-ref/Equivalence-Predicates.html
-    { "EQ?", sch_exact_eq },
-    { "EQV?", sch_equal },
-    { "EQUAL?", sch_equal_r },
+    // Equivalence Predicates
+    { "eq?", sch_exact_eq },
+    { "eqv?", sch_equal },
+    { "equal?", sch_equal_r },
     
-    // Booleans https://www.gnu.org/software/mit-scheme/documentation/mit-scheme-ref/Booleans.html
-    { "BOOLEAN?", sch_is_boolean },
-    { "NOT", sch_not },
+    // Booleans
+    { "boolean?", sch_is_boolean },
+    { "not", sch_not },
 
     // PAIRS
-    { "CONS", sch_cons },
-    { "CAR", sch_car },
-    { "CDR", sch_cdr },
-    { "SET-CAR!", sch_set_car },
-    { "SET-CDR!", sch_set_cdr },
-    { "NULL?", sch_is_null },
-    { "PAIR?", sch_is_pair },
+    { "cons", sch_cons },
+    { "car", sch_car },
+    { "cdr", sch_cdr },
+    { "set-car!", sch_set_car },
+    { "set-cdr!", sch_set_cdr },
+    { "null?", sch_is_null },
+    { "pair?", sch_is_pair },
 
-    // Lists https://groups.csail.mit.edu/mac/ftpdir/scheme-7.4/doc-html/scheme_8.html
-    { "LIST", sch_list },
-    { "LIST?", sch_is_list },
-    { "MAKE-LIST", sch_make_list },
-    { "LIST-COPY", sch_list_copy },
-    { "LENGTH", sch_length },
-    { "APPEND", sch_append },
-    { "APPEND-REVERSE!", sch_append_reverse },
-    { "LIST-REF", sch_list_ref },
-    { "NTHCDR", sch_list_advance },
+    // Lists
+    { "list", sch_list },
+    { "list?", sch_is_list },
+    { "make-list", sch_make_list },
+    { "list-copy", sch_list_copy },
+    { "length", sch_length },
+    { "append", sch_append },
+    { "append-reverse!", sch_append_reverse },
+    { "list-ref", sch_list_ref },
+    { "nthcdr", sch_list_advance },
 
-    // Vectors https://groups.csail.mit.edu/mac/ftpdir/scheme-7.4/doc-html/scheme_9.html#SEC82
-    { "VECTOR?", sch_is_vector },
-    { "MAKE-VECTOR", sch_make_vector },
-    { "VECTOR-GROW", sch_vector_grow },
-    { "VECTOR-LENGTH", sch_vector_length },
-    { "VECTOR-SET!", sch_vector_set },
-    { "VECTOR-SWAP!", sch_vector_swap },
-    { "VECTOR-REF", sch_vector_ref },
-    { "VECTOR-FILL!", sch_vector_fill },
-    { "VECTOR-ASSQ", sch_vector_assq },
-    { "SUBVECTOR", sch_subvector },
-    { "LIST->VECTOR", sch_list_to_vector },
-    { "VECTOR->LIST", sch_vector_to_list },
+    // Vectors
+    { "vector?", sch_is_vector },
+    { "make-vector", sch_make_vector },
+    { "vector-grow", sch_vector_grow },
+    { "vector-length", sch_vector_length },
+    { "vector-set!", sch_vector_set },
+    { "vector-swap!", sch_vector_swap },
+    { "vector-ref", sch_vector_ref },
+    { "vector-fill!", sch_vector_fill },
+    { "vector-assq", sch_vector_assq },
+    { "subvector", sch_subvector },
+    { "list->vector", sch_list_to_vector },
+    { "vector->list", sch_vector_to_list },
 
-    // Strings https://groups.csail.mit.edu/mac/ftpdir/scheme-7.4/doc-html/scheme_7.html#SEC61
-    { "STRING?", sch_is_string },
-    { "MAKE-STRING", sch_make_string },
-    { "STRING=?", sch_equal_r },
-    { "STRING<?", sch_string_less },
-    { "SUBSTRING", sch_substring },
-    { "STRING-NULL?", sch_string_is_null },
-    { "STRING-LENGTH", sch_string_length },
-    { "STRING-REF", sch_string_ref },
-    { "STRING-SET!", sch_string_set },
-    { "STRING-UPCASE", sch_string_upcase },
-    { "STRING-DOWNCASE", sch_string_downcase },
-    { "STRING-APPEND", sch_string_append },
-    { "STRING->LIST", sch_string_to_list },
-    { "LIST->STRING", sch_list_to_string },
-    { "STRING->NUMBER", sch_string_to_number },
-    { "NUMBER->STRING", sch_number_to_string },
+    // Strings
+    { "string?", sch_is_string },
+    { "make-string", sch_make_string },
+    { "string=?", sch_equal_r },
+    { "string<?", sch_string_less },
+    { "substring", sch_substring },
+    { "string-null?", sch_string_is_null },
+    { "string-length", sch_string_length },
+    { "string-ref", sch_string_ref },
+    { "string-set!", sch_string_set },
+    { "string-upcase", sch_string_upcase },
+    { "string-downcase", sch_string_downcase },
+    { "string-append", sch_string_append },
+    { "string->list", sch_string_to_list },
+    { "list->string", sch_list_to_string },
+    { "string->number", sch_string_to_number },
+    { "number->string", sch_number_to_string },
 
-    // Characters https://www.gnu.org/software/mit-scheme/documentation/mit-scheme-ref/Characters.html#Characters
-    { "CHAR?", sch_is_char },
-    { "CHAR=?", sch_equals },
-    { "CHAR<?", sch_char_less },
+    // Characters
+    { "char?", sch_is_char },
+    { "char=?", sch_equals },
+    { "char<?", sch_char_less },
 
-    { "CHAR-UPCASE", sch_char_upcase },
-    { "CHAR-DOWNCASE", sch_char_downcase },
-    { "CHAR-WHITESPACE?", sch_char_is_white },
-    { "CHAR-ALPHANUMERIC?", sch_char_is_alphanum },
-    { "CHAR-ALPHABETIC?", sch_char_is_alpha },
-    { "CHAR-NUMERIC?", sch_char_is_number },
-    { "CHAR->INTEGER", sch_char_to_int },
+    { "char-upcase", sch_char_upcase },
+    { "char-downcase", sch_char_downcase },
+    { "char-whitespace?", sch_char_is_white },
+    { "char-alphanumeric?", sch_char_is_alphanum },
+    { "char-alphabetic?", sch_char_is_alpha },
+    { "char-numeric?", sch_char_is_number },
+    { "char->integer", sch_char_to_int },
 
-    // Association Lists https://www.gnu.org/software/mit-scheme/documentation/mit-scheme-ref/Association-Lists.html
-    // Numerical operations https://www.gnu.org/software/mit-scheme/documentation/mit-scheme-ref/Numerical-operations.html
+    // Numerical operations
     { "=", sch_equals },
     { "+", sch_add },
     { "-", sch_sub },
     { "*", sch_mult },
     { "/", sch_divide },
     { "<", sch_less },
-    { "INTEGER?", sch_is_int },
-    { "EVEN?", sch_is_even },
-    { "REAL?", sch_is_real },
-    { "EXP", sch_exp },
-    { "EXPT", sch_power },
-    { "LOG", sch_log },
-    { "SIN", sch_sin },
-    { "COS", sch_cos },
-    { "TAN", sch_tan },
-    { "ATAN", sch_atan },
-    { "SQRT", sch_sqrt },
-    { "ROUND", sch_round },
-    { "FLOOR", sch_floor },
-    { "CEILING", sch_ceiling },
-    { "QUOTIENT", sch_quotient },
-    { "REMAINDER", sch_remainder },
-    { "MODULO", sch_modulo },
-    { "ABS", sch_abs },
-    { "MAGNITUDE", sch_abs },
-    { "EXACT?", sch_is_int },
-    { "EXACT->INEXACT", sch_to_inexact },
-    { "INEXACT->EXACT", sch_to_exact },
+    { "integer?", sch_is_int },
+    { "even?", sch_is_even },
+    { "real?", sch_is_real },
+    { "exp", sch_exp },
+    { "expt", sch_power },
+    { "log", sch_log },
+    { "sin", sch_sin },
+    { "cos", sch_cos },
+    { "tan", sch_tan },
+    { "atan", sch_atan },
+    { "sqrt", sch_sqrt },
+    { "round", sch_round },
+    { "floor", sch_floor },
+    { "ceiling", sch_ceiling },
+    { "quotient", sch_quotient },
+    { "remainder", sch_remainder },
+    { "modulo", sch_modulo },
+    { "abs", sch_abs },
+    { "magnitude", sch_abs },
+    { "exact?", sch_is_int },
+    { "exact->inexact", sch_to_inexact },
+    { "inexact->exact", sch_to_exact },
     
-    // Symbols https://www.gnu.org/software/mit-scheme/documentation/mit-scheme-ref/Symbols.html
-    { "SYMBOL?", sch_is_symbol },
-    { "SYMBOL<?", sch_symbol_less },
-    { "STRING->SYMBOL", sch_string_to_symbol },
-    { "SYMBOL->STRING", sch_symbol_to_string },
-    { "GENERATE-UNINTERNED-SYMBOL", sch_gensym },
-    { "GENSYM", sch_gensym },
+    // Symbols
+    { "symbol?", sch_is_symbol },
+    { "symbol<?", sch_symbol_less },
+    { "string->symbol", sch_string_to_symbol },
+    { "symbol->string", sch_symbol_to_string },
+    { "generate-uninterned-symbol", sch_gensym },
+    { "gensym", sch_gensym },
 
-    // Environments https://groups.csail.mit.edu/mac/ftpdir/scheme-7.4/doc-html/scheme_14.html
-    { "EVAL", sch_eval },
-    { "SCHEME-REPORT-ENVIRONMENT", sch_system_env },
-    { "INTERACTION-ENVIRONMENT", sch_user_env },
-    // { "THE-ENVIRONMENT", sch_current_env },
+    // Environments
+    { "eval", sch_eval },
+    { "scheme-report-environment", sch_system_env },
+    { "interaction-environment", sch_user_env },
     
-    // Hash Tables https://www.gnu.org/software/mit-scheme/documentation/mit-scheme-ref/Basic-Hash-Table-Operations.html#Basic-Hash-Table-Operations
-    { "HASH-TABLE?", sch_is_table },
-    { "MAKE-HASH-TABLE", sch_table_make },
-    { "HASH-TABLE-SET!", sch_table_set },
-    { "HASH-TABLE-REF", sch_table_get },
-    { "HASH-TABLE-SIZE", sch_table_size },
-    { "HASH-TABLE->ALIST", sch_table_to_alist },
+    // Hash Tables
+    { "hash-table?", sch_is_table },
+    { "make-hash-table", sch_table_make },
+    { "hash-table-set!", sch_table_set },
+    { "hash-table-ref", sch_table_get },
+    { "hash-table-size", sch_table_size },
+    { "hash-table->alist", sch_table_to_alist },
 
-    { "PROMISE?", sch_is_promise },
-    { "MAKE-PROMISE", sch_make_promise },
-    { "_PROMISE-PROCEDURE", sch_promise_proc },
-    { "_PROMISE-STORE!", sch_promise_store },
-    { "PROMISE-VALUE", sch_promise_val },
-    { "PROMISE-FORCED?", sch_promise_forced },
+    { "promise?", sch_is_promise },
+    { "make-promise", sch_make_promise },
+    { "_promise-procedure", sch_promise_proc },
+    { "_promise-store!", sch_promise_store },
+    { "promise-value", sch_promise_val },
+    { "promise-forced?", sch_promise_forced },
     
-    // Procedures https://www.gnu.org/software/mit-scheme/documentation/mit-scheme-ref/Procedure-Operations.html#Procedure-Operations
-    { "APPLY", sch_apply },
-    { "COMPILED-PROCEDURE?", sch_is_func },
-    { "COMPOUND-PROCEDURE?", sch_is_lambda },
-    { "PROCEDURE-ENVIRONMENT", sch_lambda_env },
-    // TOOD: Almost standard
-    { "PROCEDURE-BODY", sch_lambda_body },
-    { "CALL/CC", sch_call_cc },
-    { "CONTINUATION?", sch_is_cont },
+    // Procedures
+    { "apply", sch_apply },
+    { "compiled-procedure?", sch_is_func },
+    { "compound-procedure?", sch_is_lambda },
+    { "procedure-environment", sch_lambda_env },
+    { "procedure-body", sch_lambda_body },
+    { "call/cc", sch_call_cc },
+    { "continuation?", sch_is_cont },
 
-    // Random Numbers https://www.gnu.org/software/mit-scheme/documentation/mit-scheme-ref/Random-Numbers.html
-    { "RANDOM", sch_pseudo_rand },
-    { "RANDOM-SEED!", sch_pseudo_seed },
+    // Random Numbers
+    { "random", sch_pseudo_rand },
+    { "random-seed!", sch_pseudo_seed },
    
-    // Garbage Collection https://www.gnu.org/software/mit-scheme/documentation/mit-scheme-user/Garbage-Collection.html
-    { "GC-FLIP", sch_gc_flip },
+    // Garbage Collection
+    { "gc-flip", sch_gc_flip },
     
     { NULL, NULL }
-    
 };
 
 void lisp_lib_load(LispContext ctx)
@@ -2111,14 +2108,14 @@ void lisp_lib_load(LispContext ctx)
 
     lisp_table_set(
             table,
-            lisp_make_symbol("_CURRENT-OUTPUT-PORT", ctx),
+            lisp_make_symbol("_current-output-port", ctx),
             lisp_make_port(stdout, 0),
             ctx
             );
 
     lisp_table_set(
             table,
-            lisp_make_symbol("_CURRENT-INPUT-PORT", ctx),
+            lisp_make_symbol("_current-input-port", ctx),
             lisp_make_port(stdin, 1),
             ctx
             );

include/lsp_ui.h

@@ -0,0 +1,35 @@
+//
+// Created by Giorgio on 27/05/2026.
+//
+
+#ifndef BELUGA_LSP_UI_H
+#define BELUGA_LSP_UI_H
+
+
+#include "data.h"
+#include "buffer.h"   // for abuf
+
+
+// ── Public API ────────────────────────────────────────────────────────────────
+
+// Call from editorRefreshScreen() — appends popup/underlines to abuf
+void lspUiDrawCompletion(struct abuf *ab, CompletionPopup *popup);
+void lspUiDrawDiagnostics(struct abuf *ab, DiagnosticList *diags,
+                          EditorPane *pane, struct buffer_t *buf);
+
+// Input handling — returns 1 if the key was consumed by the popup
+int  lspUiHandleKey(CompletionPopup *popup, int key);
+
+// Parse clangd JSON into our structs
+void lspParseCompletion(const char *json, CompletionPopup *popup,
+                        int screen_x, int screen_y);
+void lspParseDiagnostics(const char *json, DiagnosticList *diags, int buffer_id);
+
+void lspUiDrawGutter(struct abuf *ab, DiagnosticList *diags,
+                     int buf_id, int line);
+const char *lspUiDiagnosticAtCursor(DiagnosticList *diags,
+                                    int buffer_id, int cursor_line);
+
+
+#endif
+

include/output.h

@@ -1,11 +1,7 @@
 #ifndef OUTPUT_H_
 #define OUTPUT_H_
 
-#include "append_buffer.h"
 #include "data.h"
-#include "define.h"
-#include "row_op.h"
-#include <stdio.h>
 #include <unistd.h>
 
 /**
@@ -13,8 +9,6 @@
  * \brief Draws left rows of the editor.
  */
 
-void editorDrawRows(struct abuf *ab);
-
 void editorRefreshScreen();
 
 void editorScroll();
@@ -23,6 +17,4 @@ void editorDrawStatusBar(struct abuf *ab);
 
 void editorDrawMessageBar(struct abuf *ab);
 
-void editorSetStatusMessage(const char *fmt, ...);
-
 #endif // OUTPUT_H_

include/row_op.h

@@ -8,22 +8,8 @@
 #include <time.h>
 #include <unistd.h>
 
-int editorRowCxToRx(erow *row, int cursor_x);
 
-int editorRowRxToCx(erow *row, int rx);
 
-void editorUpdateRow(erow *row);
 
-void editorInsertRow(int at, char *s, size_t len);
-
-void editorFreeRow(erow *row);
-
-void editorDelRow(int at);
-
-void editorRowInsertChar(erow *row, int at, int c);
-
-void editorRowAppendString(erow *row, char *s, size_t len);
-
-void editorRowDelchar(erow *row, int at);
 
 #endif // ROW_OP_H_

include/split_screen.h

@@ -0,0 +1,66 @@
+/**
+ * @file split_screen.h
+ * @brief Split screen management for displaying multiple buffers
+ */
+
+#ifndef SPLIT_SCREEN_H_
+#define SPLIT_SCREEN_H_
+
+#include "data.h"
+
+/**
+ * @brief Initializes split screen system
+ */
+void splitScreenInit(void);
+
+/**
+ * @brief Splits screen vertically (left-right)
+ * @param buffer_id_left Buffer ID for left pane
+ * @param buffer_id_right Buffer ID for right pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenVertical(int buffer_id_left, int buffer_id_right);
+
+/**
+ * @brief Splits screen horizontally (top-bottom)
+ * @param buffer_id_top Buffer ID for top pane
+ * @param buffer_id_bottom Buffer ID for bottom pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenHorizontal(int buffer_id_top, int buffer_id_bottom);
+
+/**
+ * @brief Returns to single buffer fullscreen
+ */
+void splitScreenUnify(void);
+
+/**
+ * @brief Switches active pane (focus moves between splits)
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenSwitchPane(void);
+
+/**
+ * @brief Updates the active pane's buffer
+ * @param buffer_id New buffer ID for active pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenSetPaneBuffer(int buffer_id);
+
+/**
+ * @brief Gets current screen layout
+ * @return Pointer to current ScreenLayout
+ */
+ScreenLayout *splitScreenGetLayout(void);
+
+/**
+ * @brief Gets active pane
+ * @return Pointer to active EditorPane
+ */
+EditorPane *splitScreenGetActivePane(void);
+
+void freePane(EditorPane *pane);
+void freeScreenLayout(ScreenLayout *layout);
+
+
+#endif

include/syntax_highlighter.h

@@ -0,0 +1,21 @@
+#ifndef SYNTAX_HIGHLIGHTER_H_
+#define SYNTAX_HIGHLIGHTER_H_
+
+
+// Color codes that only affect foreground, preserving your background color
+#define COLOR_RESET         "\x1b[39m"            // Reset all (4 bytes)
+
+// Token types
+typedef enum {
+  TOKEN_KEYWORD,
+  TOKEN_TYPE,
+  TOKEN_STRING,
+  TOKEN_COMMENT,
+  TOKEN_NUMBER,
+  TOKEN_OPERATOR,
+  TOKEN_DEFAULT
+} TokenType;
+
+char *highlight_line(const char * line, int *length);
+
+#endif

include/terminal.h

@@ -4,8 +4,6 @@
 
 /* includes */
 
-#include "data.h"
-#include "define.h"
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -31,4 +29,8 @@ int getCursorPosition(int *rows, int *cols);
 
 int getWindowSize(int *rows, int *cols);
 
+char *keyToString(int key);
+
+void appDebug(const char *fmt, ...);
+
 #endif

include/utf8.h

@@ -0,0 +1,17 @@
+//
+// Created by Giorgio on 01/05/2026.
+//
+
+#ifndef BELUGA_UTF8_H
+#define BELUGA_UTF8_H
+#include <stdint.h>
+
+uint32_t readUtf8Char(void);
+int utf8Encode(uint32_t cp, char *buf);
+int utf8Seqlen(unsigned char c);
+int codepointWidth(uint32_t codepoint);
+uint32_t utf8Decode(const char** s);
+int is_word_char(const char *s);
+
+
+#endif //BELUGA_UTF8_H

install.sh

@@ -16,8 +16,10 @@ fi
 
 echo "Create config files ..."
 mkdir -pv ~/.beluga/
-cp -rv ./assets/ ~/.beluga/
+mkdir -pv ~/.beluga/assets/
+cp -rv ./assets/beluga.txt ~/.beluga/assets/
 mkdir -pv ~/.beluga/packages/
+mkdir -pv ~/.beluga/config/
 
 read -p "Do you want to replace your config file or keep it (init.lisp.bak) / (init.lisp.new) ? (Y/n)" confirm
 if [[ "$confirm" =~ ^[Yy]$ ]]; then

main.c

@@ -5,47 +5,65 @@
  * interactions. \version 0.1 \date 21 septembre 2024
  */
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-
 #define _DEFAULT_SOURCE
 #define _BSD_SOURCE
 #define _GNU_SOURCE
 
+#include <libgen.h>
+
+#include "include/buffer.h"
+#include "include/split_screen.h"
+#include <string.h>
+#include <unistd.h>
+
 #include "include/data.h"
-#include "include/file_io.h"
 #include "include/init.h"
 #include "include/input.h"
-#include "include/output.h"
+#include "include/editor_op.h"
 #include "include/terminal.h"
+#include "include/completion.h"
+#include <signal.h>
+
 
 struct editorConfig E;
 
 int main(int argc, char *argv[]) {
+    // Get HOME with NULL check
+    const char *home = getenv("HOME");
+    if (!home) {
+        fprintf(stderr, "Error: HOME environment variable not set\n");
+        return 1;
+    }
 
-  char * splash_screen = (char *) calloc(256, sizeof(char));
-  
-  enableRawMode();
-  initEditor();
-  if (argc >= 2) {
-    E.state = READ_AND_WRITE;
-    editorOpen(argv[1]);
-  } else {
-    strcat(splash_screen, getenv("HOME"));
-    strcat(splash_screen, "/.beluga/assets/beluga.txt");
-    fprintf(stderr, "%s\n", splash_screen);
-    editorOpen(splash_screen);
-  }
-  free(splash_screen);
+    // Allocate and build splash screen path safely
+    char *splash_screen;
+    if (asprintf(&splash_screen, "%s/.beluga/assets/beluga.txt", home) == -1) {
+        fprintf(stderr, "Error: Failed to allocate splash screen path\n");
+        return 1;
+    }
 
-  editorSetStatusMessage("HELP: Ctrl-S = save | Ctrl-Q = quit");
+    signal(SIGPIPE, SIG_IGN);
+    enableRawMode();
+    initEditor();
 
+    EditorPane *active = splitScreenGetActivePane();
+    struct buffer_t *buf;
 
-  while (1) {
-    editorRefreshScreen();
-    editorProcessKeypress();
-  }
-  return 0;
+    appDebug("splash : %s\n", splash_screen);
+    active->buffer_id = bufferCreate(splash_screen, READ_ONLY);
+
+    if (argc >= 2) {
+        active->buffer_id = bufferCreate(argv[1], READ_AND_WRITE);
+        buf = &E.buffers[active->buffer_id];
+        appDebug("project root : %s\n", dirname(buf->fullname));
+    }
+
+    free(splash_screen);  // Now guaranteed safe
+
+    editorSetStatusMessage("HELP: Ctrl-x Ctrl-s = save | Ctrl-x Ctrl-c = quit");
+    while (1) {
+        editorRefreshScreen();
+        editorProcessKeypress();
+    }
+    return 0;
 }

meson.build

@@ -1,18 +1,20 @@
 project('beluga', 'c',
-  version : '1.1',
+  version : '2.3',
   default_options : [
     'c_std=none',
   ]
 )
 
 cc = meson.get_compiler('c')
-m = cc.find_library('m', required: false)            
+m = cc.find_library('m', required: false)
+thread_dep = dependency('threads')
 
 # Source files
 src_files = files(
   'main.c',
   'src/append_buffer.c',
   'src/editor_op.c',
+  'src/syntax_highlighter.c',
   'src/file_io.c',
   'src/init.c',
   'src/input.c',
@@ -20,10 +22,16 @@ src_files = files(
   'src/row_op.c',
   'src/terminal.c',
   'src/builtins.c',
+  'src/buffer.c',
+  'src/split_screen.c',
+  'src/utf8.c',
+  'src/completion.c',
+  'src/lsp_ui.c',
+  'src/cJSON.c'
 )
 
 # Executable
 executable('beluga',
   src_files,
-  dependencies: [m]
+  dependencies: [m, thread_dep]
 )

src/append_buffer.c

@@ -1,7 +1,5 @@
 #include "../include/append_buffer.h"
 
-extern struct editorConfig E;
-
 void abAppend(struct abuf *ab, const char *s, int len) {
   char *new = realloc(ab->b, ab->len + len);
 
@@ -13,4 +11,8 @@ void abAppend(struct abuf *ab, const char *s, int len) {
   ab->len += len;
 }
 
-void abFree(struct abuf *ab) { free(ab->b); }
+void abFree(struct abuf *ab) {
+  free(ab->b);
+  ab->b = NULL;
+  ab->len = 0;
+}

src/buffer.c

@@ -0,0 +1,524 @@
+/**
+ * @file buffer.c
+ * @brief Buffer management implementation for multiple open files
+ */
+
+#include "../include/buffer.h"
+#include "../include/file_io.h"
+#include "../include/editor_op.h"
+#include "../include/data.h"
+#include "include/split_screen.h"
+#include <_string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <libgen.h>
+#include <string.h>
+#include <sys/stat.h>
+
+#include "include/completion.h"
+#include "include/input.h"
+
+
+/**
+ * @brief Finds a buffer by filename
+ * @param filename The filename to search for
+ * @return Buffer ID if found, -1 if not found
+ */
+static int bufferFindByFilename(const char* filename)
+{
+    for (int i = 0; i < E.number_of_buffer; i++)
+    {
+        if (E.buffers[i].filename != NULL &&
+            strcmp(E.buffers[i].filename, filename) == 0)
+        {
+            return E.buffers[i].buffer_id;
+        }
+    }
+    return -1;
+}
+
+/**
+ * @brief Finds a buffer by ID
+ * @param buffer_id The buffer ID to find
+ * @return Pointer to buffer, NULL if not found
+ */
+struct buffer_t* bufferFindById(int buffer_id)
+{
+    for (int i = 0; i < E.number_of_buffer; i++)
+    {
+        if (E.buffers[i].buffer_id == buffer_id)
+        {
+            return &E.buffers[i];
+        }
+    }
+    return NULL;
+}
+
+/**
+ * @brief Creates a new buffer for a file
+ * @details Allocates buffer slot, loads file content, saves buffer metadata.
+ * If file is already open, switches to existing buffer instead.
+ * @return Buffer ID on success, -1 on failure
+ */
+int bufferCreate(const char* path, enum bufferStatus_e state)
+{
+    appDebug("Creating new buffer");
+    char* filename = basename((char*)path);
+    // Check if file is already open
+    const int existing_id = bufferFindByFilename(path);
+    if (existing_id != -1)
+    {
+        return bufferSwitch(existing_id);
+    }
+    // Check if we have space for more buffers
+    if (E.number_of_buffer >= 64)
+    {
+        editorSetStatusMessage("Error: maximum buffers reached (64)");
+        return -1;
+    }
+
+    // Initialize new buffer
+    struct buffer_t* new_buf = &E.buffers[E.number_of_buffer];
+    new_buf->buffer_id = E.number_of_buffer;
+    new_buf->filename = strdup(filename);
+    if (!new_buf->filename)
+    {
+        return -1;
+    }
+    new_buf->fullname = malloc(1024 * sizeof(char));
+    if (!new_buf->fullname)
+    {
+        free(new_buf->filename);
+        return -1;
+    }
+    realpath(path, new_buf->fullname);
+    new_buf->path = dirname(new_buf->fullname);
+    new_buf->type = FILE_BUFF;
+    new_buf->state = state;
+    new_buf->x = 0;
+    new_buf->y = 0;
+    new_buf->dirty = 0; // New file starts clean
+    new_buf->b_lsp_open = 0;
+
+    // Load file content using existing editorOpen
+    editorOpen(new_buf);
+    E.number_of_buffer++;
+    if (new_buf->filename[strlen(new_buf->filename) - 1] == 'c')
+    {
+        if (E.lsp_client->state == LSP_SHUTDOWN)
+            lspStart(E.lsp_client, dirname(new_buf->path));
+        while (E.lsp_client->state != LSP_READY);
+        lspDidOpen(E.lsp_client, new_buf);
+    }
+
+    editorSetStatusMessage("Opened: %s (buffer %d)", filename, new_buf->buffer_id);
+    return new_buf->buffer_id;
+}
+
+/**
+ * @brief Switches to a specific buffer by ID
+ * @details Saves current buffer state, loads target buffer content and state.
+ * @param buffer_id The buffer ID to switch to
+ * @return 0 on success, -1 on failure
+ */
+int bufferSwitch(int buffer_id)
+{
+    struct buffer_t* target = bufferFindById(buffer_id);
+    if (target == NULL)
+    {
+        E.layout.panes[E.layout.active_pane].buffer_id = buffer_id;
+        editorSetStatusMessage("Error: buffer not found");
+        return -1;
+    }
+
+
+    editorSetStatusMessage("Switched to: %s (buffer %d)",
+                           target->filename, buffer_id);
+    return 0;
+}
+
+/**
+ * @brief Closes a buffer by ID
+ * @details Frees buffer resources and removes from buffer list.
+ * Prompts to save unsaved changes. If closing current buffer,
+ * switches to next available buffer.
+ * @param buffer_id The buffer ID to close
+ * @return 0 on success, -1 on failure
+ */
+int bufferClose(int buffer_id)
+{
+    struct buffer_t* buf = bufferFindById(buffer_id);
+    if (buf == NULL)
+    {
+        editorSetStatusMessage("Error: buffer not found");
+        return -1;
+    }
+
+    EditorPane* active = splitScreenGetActivePane();
+
+    // If this is the current buffer, find next buffer to switch to
+    if (active->buffer_id == buffer_id)
+    {
+        int next_id = -1;
+
+        // Try to switch to next buffer
+        for (int i = 0; i < E.number_of_buffer; i++)
+        {
+            if (E.buffers[i].buffer_id != buffer_id)
+            {
+                next_id = E.buffers[i].buffer_id;
+                break;
+            }
+        }
+
+        if (next_id != -1)
+        {
+            bufferSwitch(next_id);
+        }
+        else
+        {
+            // No other buffers, clear editor
+            editorCloseFile();
+        }
+    }
+
+    // Free buffer resources
+    free(buf->filename);
+    buf->filename = NULL;
+    buf->buffer_id = -1;
+
+    // Remove from buffer list by shifting
+    for (int i = 0; i < E.number_of_buffer; i++)
+    {
+        if (E.buffers[i].buffer_id == buffer_id)
+        {
+            for (int j = i; j < E.number_of_buffer - 1; j++)
+            {
+                E.buffers[j] = E.buffers[j + 1];
+            }
+            E.number_of_buffer--;
+            break;
+        }
+    }
+
+    editorSetStatusMessage("Closed buffer %d", buffer_id);
+    return 0;
+}
+
+/**
+ * @brief Gets the current active buffer
+ * @return Pointer to current buffer_t, NULL if none
+ */
+struct buffer_t* bufferGetCurrent(void)
+{
+    EditorPane* active = splitScreenGetActivePane();
+    return bufferFindById(active->buffer_id);
+}
+
+/**
+ * @brief Lists all open buffers
+ * @details Prints buffer information to status message
+ * @return Number of open buffers
+ */
+int bufferListAll(void)
+{
+    if (E.number_of_buffer == 0)
+    {
+        editorSetStatusMessage("No buffers open");
+        return 0;
+    }
+
+    char buf[256] = "";
+    int offset = 0;
+    EditorPane* active = splitScreenGetActivePane();
+
+    for (int i = 0; i < E.number_of_buffer; i++)
+    {
+        struct buffer_t* b = &E.buffers[i];
+        char marker = (b->buffer_id == active->buffer_id) ? '*' : ' ';
+        offset += snprintf(&buf[offset], sizeof(buf) - offset,
+                           "%c%d:%s ", marker, b->buffer_id,
+                           b->filename ? b->filename : "[No Name]");
+    }
+
+    editorSetStatusMessage("Buffers: %s", buf);
+    return E.number_of_buffer;
+}
+
+/**
+ * @brief Saves current buffer to disk
+ * @return 0 on success, -1 on failure
+ */
+int bufferSave(void)
+{
+    EditorPane* active = splitScreenGetActivePane();
+    if (active->buffer_id == -1)
+    {
+        editorSetStatusMessage("Error: no buffer active");
+        return -1;
+    }
+
+    editorSave();
+    return 0;
+}
+
+/**
+ * @brief Saves all buffers to disk
+ * @details Iterates through all buffers, saves each one
+ * @return 0 on success, -1 on failure
+ */
+int bufferSaveAll(void)
+{
+    int saved = 0;
+    int failed = 0;
+
+    for (int i = 0; i < E.number_of_buffer; i++)
+    {
+        if (bufferSwitch(E.buffers[i].buffer_id) == 0)
+        {
+            if (E.dirty && bufferSave() == 0)
+            {
+                saved++;
+            }
+        }
+        else
+        {
+            failed++;
+        }
+    }
+
+    editorSetStatusMessage("Saved %d buffers (%d failed)", saved, failed);
+    return (failed == 0) ? 0 : -1;
+}
+
+/**
+ * @brief Searches for a string in the document
+ * @details Prompts user for a search query, then searches forward from current
+ * cursor position. Updates cursor position to the first match found.
+ * @note Updates global editor state E (cursor position, row_offset)
+ * @note Search is case-sensitive and operates on rendered line content
+ * @note Searches begin from the line after current cursor position
+ * @see editorPrompt()
+ * @see editorRowRxToCx()
+ */
+void bufferFind(struct buffer_t* buf)
+{
+    appDebug("searching\n");
+    char* query = editorPrompt("Search: %s (ESC to cancel)", "", 0);
+
+    if (query == NULL)
+        return;
+    int i;
+    for (i = buf->y + 1; i < buf->numrows; i++)
+    {
+        row_t* row = &buf->row[i];
+        char* match = strstr(row->chars, query);
+        if (match)
+        {
+            buf->y = i;
+            break;
+        }
+    }
+    free(query);
+}
+
+void bufferFindReverse(struct buffer_t* buf)
+{
+    appDebug("searching\n");
+    char* query = editorPrompt("Reverse search: %s (ESC to cancel)", "", 0);
+
+    if (query == NULL)
+        return;
+    int i;
+    if (!buf->y)
+        return;
+    for (i = buf->y - 1; i >= 0; i--)
+    {
+        row_t* row = &buf->row[i];
+        char* match = strstr(row->chars, query);
+        if (match)
+        {
+            buf->y = i;
+            break;
+        }
+    }
+    free(query);
+}
+
+void bufferInsertRow(struct buffer_t* buffer, int at, char* s, size_t len)
+{
+    if (at < 0 || at > buffer->numrows)
+        return;
+
+    row_t* tmp = realloc(buffer->row, sizeof(row_t) * (buffer->numrows + 1));
+    if (!tmp)
+        return;
+    buffer->row = tmp;
+
+    /* Shift existing rows to make room at 'at' — no at++ */
+    if (at < buffer->numrows)
+    {
+        memmove(&buffer->row[at + 1], &buffer->row[at],
+                sizeof(row_t) * (buffer->numrows - at)); /* not -at+1 */
+    }
+
+    buffer->row[at].size = (int)len;
+    buffer->row[at].cap = (int)len + 1;
+    buffer->row[at].chars = malloc(len + 1);
+    if (!buffer->row[at].chars)
+        return;
+    memcpy(buffer->row[at].chars, s, len);
+    buffer->row[at].chars[len] = '\0'; /* always NUL-terminate */
+
+    buffer->numrows++;
+    buffer->dirty++;
+}
+
+void bufferFreeRow(row_t* row) { free(row->chars); }
+
+/**
+ * \fn editorRowInsertChar(erow *row, int at, int c)
+ * \param at Index of where we want to insert the char */
+
+void bufferRowInsertBytes(struct buffer_t* buffer, row_t* row, int at,
+                          const char* src, int n)
+{
+    if (buffer->state == READ_ONLY)
+        return;
+    if (at < 0 || at > row->size)
+    {
+        return;
+    }
+    if (row->size + n + 1 > row->cap)
+    {
+        size_t new_cap = row->cap == 0 ? 128 : row->cap * 2;
+        while (new_cap < row->size + n + 1) {
+            new_cap *= 2;
+        }
+        char *new_chars = realloc(row->chars, new_cap);
+        if (!new_chars) {
+            return;  // Allocation failed
+        }
+        row->chars = new_chars;
+        row->cap = (int) new_cap;
+    }
+    memmove(row->chars + at + n, row->chars + at, row->size - at);
+
+    // Copy new bytes
+    memcpy(row->chars + at, src, n);
+    row->size += n;
+
+    row->chars[row->size] = '\0';
+    ++buffer->dirty;
+}
+
+/**
+ * \fn bufferRowDelChar(struct bufferConfig *E, frow *frow, int at)
+ * \brief Delete the a char at the chosen position on the given row
+ * \param at Index of the char to delete
+ * \param row Row on operation is made */
+void bufferRowDelByte(struct buffer_t* buffer, row_t* row, int at, int n)
+{
+    if (buffer->state == READ_ONLY)
+        return;
+    if (at < 0 || at >= row->size)
+        return;
+    memmove(row->chars + at, row->chars + at + n, row->size - at - n);
+    row->size -= n;
+    row->chars[row->size] = '\0';
+    buffer->x -= n;
+    ++buffer->dirty;
+}
+
+
+void bufferInsertBytes(const char* src, int n)
+{
+    appDebug("bufferInsertBytes \r\n");
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buf = bufferFindById(active->buffer_id);
+    if (buf->y == buf->numrows)
+    {
+        bufferInsertRow(buf, buf->numrows, "", 0);
+    }
+    bufferRowInsertBytes(buf, &buf->row[buf->y], buf->x, src, n);
+    buf->x += n;
+    buf->b_has_changed = 1;
+}
+
+void bufferDelBytes(void)
+{
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buf = bufferFindById(active->buffer_id);
+
+    /* Nothing to delete */
+    if (buf->numrows == 0) return;
+    if (buf->x == 0 && buf->y == 0) return;
+
+    /* Use row_offset, not col_offset, for row indexing */
+    row_t* r = &buf->row[buf->y];
+
+    if (buf->x > 0)
+    {
+        int byte_end = editorRowCxToByte(r, buf->x);
+        int byte_start = editorRowCxToByte(r, buf->x - 1);
+        int char_width = byte_end - byte_start; /* byte width of the character */
+
+        bufferRowDelByte(buf, r, byte_start, char_width);
+        E.dirty = 1;
+    }
+    else
+    {
+        /* Merge current row into the previous one */
+        row_t* prev = &buf->row[buf->y - 1]; // FIX: was buf->y (same as r)
+        int prev_char_count = editorRowCharCount(prev, prev->size);
+
+        bufferRowInsertBytes(buf, prev, prev->size, r->chars, r->size);
+        free(r->chars);
+        r->chars = NULL;
+
+        memmove(&buf->row[buf->y],
+                &buf->row[buf->y + 1],
+                sizeof(row_t) * (buf->numrows - buf->y - 1));
+        buf->numrows--;
+
+        active->cursor_x = prev_char_count;
+        buf->x = prev_char_count;
+        active->cursor_y--;
+        buf->y--;
+        E.dirty = 1;
+    }
+}
+
+void bufferInsertNewLine(void)
+{
+    appDebug("Inserting new line\n");
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buf = bufferFindById(active->buffer_id);
+
+    appDebug("buf x %d\n", buf->x);
+
+    if (buf->y >= buf->numrows)
+    {
+        /* Cursor is past the last row: just append a blank line */
+        bufferInsertRow(buf, buf->numrows, "", 0);
+    }
+    else
+    {
+        row_t* row = &buf->row[buf->y];
+
+        /* Insert the tail (from cursor to end) as a new row below */
+        bufferInsertRow(buf, buf->y + 1, &row->chars[buf->x], row->size - buf->x);
+
+        /* Re-fetch: bRealloc inside bufferInsertRow may have moved the array */
+        row = &buf->row[buf->y];
+
+        /* Truncate the current row at the cursor */
+        row->size = buf->x;
+        row->chars[row->size] = '\0';
+        /* Do NOT touch row->cap — the allocation is still valid */
+    }
+
+    buf->y++;
+    buf->x = 0;
+    appDebug("Insert new line done\n");
+}

src/builtins.c

@@ -1,174 +1,661 @@
+/**
+ * @file builtins.c
+ * @brief Built-in Lisp functions for editor operations
+ * @details Provides Lisp bindings for core editor functionality including
+ * cursor movement, file operations, keybinding management, and text
+ * manipulation
+ */
+
 #include "../include/builtins.h"
-#include "../include/define.h"
-#include "../include/input.h"
-#include "../include/file_io.h"
-#include "../include/editor_op.h"
-#include "../include/row_op.h"
+#include "../include/buffer.h"
 #include "../include/data.h"
+#include "../include/define.h"
+#include "../include/editor_op.h"
+#include "../include/file_io.h"
+#include "../include/input.h"
+#include "../include/terminal.h"
+#include "../include/split_screen.h"
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-Lisp mapKey(Lisp args, LispError *e, LispContext ctx) {
-  const char *key_sequence = lisp_string(lisp_car(args));
-  args = lisp_cdr(args);
-  // second argument
-  Lisp func = lisp_car(args);
+#include "include/completion.h"
+#include "include/init.h"
 
-  E.key_binds =
-      (struct keyBind_t *)realloc(E.key_binds, ++E.number_of_keybinds * sizeof(struct keyBind_t));
-  E.key_binds[E.number_of_keybinds - 1].key_sequence = (char *) malloc(50 * sizeof(char));
-
-  strncpy(E.key_binds[E.number_of_keybinds - 1].key_sequence, key_sequence, 50);
-
-  E.key_binds[E.number_of_keybinds - 1].command = func;
-
-  return lisp_null();
+/**
+ * @brief Finds a prefix configuration by name
+ * @details Searches the prefix array for a prefix matching the given name.
+ * Returns the first prefix (default) if no match is found.
+ * @param prefix_name Name of the prefix to search for (max 64 chars)
+ * @return Matching prefix_t structure, or E.prefix[0] if not found
+ * @note Updates global editor state E
+ */
+struct prefix_t find_prefix(const char prefix_name[64])
+{
+    int i = E.number_of_prefix + 1;
+    while (i--)
+    {
+        if (!strcmp(prefix_name, E.prefix[i].prefix_name))
+        {
+            return E.prefix[i];
+        }
+    }
+    return E.prefix[0];
 }
 
-Lisp moveCursor(Lisp args, LispError *e, LispContext ctx) {
-  const char *direction = lisp_string(lisp_car(args));
-  switch (direction[0]) {
-  case 'u':
-    editorMoveCursor(ARROW_UP);
-    break;
-  case 'd':
-    editorMoveCursor(ARROW_DOWN);
-    break;
-  case 'r':
-    editorMoveCursor(ARROW_RIGHT);
-    break;
-  case 'l':
-    editorMoveCursor(ARROW_LEFT);
-    break;
-  }
+/**
+ * @brief Lisp function to bind a command to a key sequence
+ * @details Registers a keybinding with an associated Lisp command and optional
+ * prefix modifier. Dynamically extends the keybind array.
+ * @param args Lisp list of 3 arguments: (key-sequence command prefix-name)
+ *        - key_sequence (string): The key or key combination to bind
+ *        - command (Lisp): The Lisp command/function to execute
+ *        - prefix_name (string): Prefix modifier name
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E (key_binds array)
+ */
+Lisp mapKey(Lisp args, LispError* e, LispContext ctx)
+{
+    /*
+     * 3 arguments keybind command prefix
+     */
+    const char* key_sequence = lisp_string(lisp_car(args));
+    void* memory_temp;
+    args = lisp_cdr(args);
+    // second argument
+    const Lisp func = lisp_car(args);
 
+    memory_temp = realloc(
+        E.key_binds, ++E.number_of_keybinds * sizeof(struct keyBind_t));
+    E.key_binds = (struct keyBind_t*)memory_temp;
+    if (!E.key_binds)
+        editorQuit(args, e, ctx);
+    E.key_binds[E.number_of_keybinds - 1].key_sequence =
+        (char*)malloc(50 * sizeof(char));
 
-  return lisp_null();
-}
+    strncpy(E.key_binds[E.number_of_keybinds - 1].key_sequence, key_sequence, 50);
+
+    E.key_binds[E.number_of_keybinds - 1].command = func;
+
+    // Third argument
+    args = lisp_cdr(args);
+    const char* prefix_name = lisp_string(lisp_car(args));
+    struct prefix_t prefix = find_prefix(prefix_name);
+
+    E.key_binds[E.number_of_keybinds - 1].prefix_id = prefix.prefix_id;
 
-Lisp editorQuit(Lisp args, LispError* e, LispContext ctx) {
-  if (E.dirty && E.quit_times_buffer > 0) {
-    editorSetStatusMessage("WARNING! Changes hasn't been saved. Press Ctrl-Q "
-                           "another time to quit.");
-    --E.quit_times_buffer;
     return lisp_null();
-  }
-  write(STDOUT_FILENO, "\x1b[2J", 4);
-  write(STDOUT_FILENO, CURSOR_TOP_LEFT, 3);
-  disableRawMode();
-  exit(0);
-
-  return lisp_null();
-
-  
 }
 
-
-Lisp l_editorSave(Lisp args, LispError* e, LispContext ctx) {
-
-  editorSave();
-  
-  return lisp_null();
-
-  
+/**
+ * @brief Lisp function to move cursor in a specified direction
+ * @details Moves the editor cursor up, down, left, or right based on direction
+ * string.
+ * @param args Lisp list with one argument: direction string
+ *        - "u": up, "d": down, "r": right, "l": left
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return Lisp boolean indicating whether movement was valid
+ * @note Updates global editor state E
+ * @see editorMoveCursor()
+ */
+Lisp moveCursor(Lisp args, LispError* e, LispContext ctx)
+{
+    const char* direction = lisp_string(lisp_car(args));
+    int is_in = 0;
+    switch (direction[0])
+    {
+    case 'u':
+        is_in = editorMoveCursor(ARROW_UP);
+        break;
+    case 'd':
+        is_in = editorMoveCursor(ARROW_DOWN);
+        break;
+    case 'r':
+        is_in = editorMoveCursor(ARROW_RIGHT);
+        break;
+    case 'l':
+        is_in = editorMoveCursor(ARROW_LEFT);
+        break;
+    default:
+        break;
+    }
+    appDebug("move lisp %d\n", is_in);
+    return lisp_make_bool(is_in);
 }
 
-Lisp l_editorInsertNewLine(Lisp args, LispError* e, LispContext ctx) {
+/**
+ * @brief bFrees all dynamically allocated editor structures
+ * @details Releases memory for prefix table, keybinds, filename, and all rows.
+ * Called during shutdown to prevent memory leaks.
+ * @note Updates global editor state E
+ */
+void bFree_structs(void)
+{
+    int i, j;
+    free(E.prefix);
+    for (i = 0; i < E.number_of_keybinds; ++i) {
+        free(E.key_binds[i].key_sequence);
+        E.key_binds[i].key_sequence = NULL;
+    }
+    free(E.key_binds);
+    E.key_binds = NULL;
+    E.number_of_keybinds = 0;
 
-  editorInsertNewLine();
-  
-  return lisp_null();
+    // Similar fix for buffers
+    for (i = 0; i < E.number_of_buffer; ++i) {
+        free(E.buffers[i].filename);
+        E.buffers[i].filename = NULL;
+        for (j = 0; j < E.buffers[i].numrows; ++j) {
+            free(E.buffers[i].row[j].chars);
+            E.buffers[i].row[j].chars = NULL;
+        }
+        free(E.buffers[i].row);
+        E.buffers[i].row = NULL;
+    }
+    // bFree layout
+    free(E.layout.panes);
 
-  
+    free(E.init_file_path);
+    fclose(E.fd_init_file);
 }
 
-Lisp moveCursorBeginLine(Lisp args, LispError *e, LispContext ctx) {
-  E.cursor_x = 0;
-  return lisp_null();
+/**
+ * @brief Lisp function to quit the editor
+ * @details Closes editor with unsaved changes protection. Prompts user to
+ * confirm quit after multiple attempts if file is dirty. Cleans up resources
+ * and restores terminal.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null() (never returns on successful exit)
+ * @note Calls exit(0) to terminate program
+ * @note Updates quit_times_buffer counter
+ * @see bFree_structs()
+ */
+Lisp editorQuit(Lisp args, LispError* e, LispContext ctx)
+{
+    if (E.dirty && E.quit_times_buffer > 0)
+    {
+        editorSetStatusMessage("WARNING! Changes hasn't been saved. Press Ctrl-Q "
+            "another time to quit.");
+        --E.quit_times_buffer;
+        return lisp_null();
+    }
+    bFree_structs();
+    write(STDOUT_FILENO, "\x1b[2J", 4);
+    write(STDOUT_FILENO, CURSOR_TOP_LEFT, 3);
+    lspShutdown(E.lsp_client);
+    lisp_shutdown(E.ctx);
+    // deInitEditor();
+    disableRawMode();
+    exit(0);
 }
 
-Lisp moveCursorEndLine(Lisp args, LispError* e, LispContext ctx) {
-  if (E.cursor_y < E.numrows) {
-    E.cursor_x = E.row[E.cursor_y].size;
-  }
-  return lisp_null();
+/**
+ * @brief Lisp function to save the current file
+ * @details Wrapper around editorSave() for use in Lisp keybindings.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @see editorSave()
+ */
+
+Lisp l_editorSplitScreenVertical(Lisp args, LispError* e, LispContext ctx)
+{
+    if (E.number_of_buffer >= 2)
+    {
+        splitScreenVertical(E.buffers[0].buffer_id, E.buffers[1].buffer_id);
+    }
+    else
+    {
+        editorSetStatusMessage("Need at least 2 buffers open");
+    }
+    return lisp_null();
 }
 
-
-Lisp deletePreviousChar(Lisp args, LispError* e, LispContext ctx) {
-  editorDelChar();
-  return lisp_null();
+Lisp l_editorSave(Lisp args, LispError* e, LispContext ctx)
+{
+    editorSave();
+    return lisp_null();
 }
 
-Lisp editorMoveCursorPageUp(Lisp args, LispError* e, LispContext ctx) {
-  E.cursor_y = E.row_offset;
-  int times = E.screenrows;
-  while (--times) {
-    editorMoveCursor(ARROW_UP);
-  }
-  return lisp_null();
+/**
+ * @brief Lisp function to insert a new line at cursor
+ * @details Wrapper around editorInsertNewLine() for use in Lisp keybindings.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @see editorInsertNewLine()
+ */
+Lisp l_editorInsertNewLine(Lisp args, LispError* e, LispContext ctx)
+{
+    bufferInsertNewLine();
+
+    return lisp_null();
 }
 
-Lisp editorMoveCursorPageDown(Lisp args, LispError* e, LispContext ctx) {
-  E.cursor_y = E.row_offset + E.screenrows - 1;
-  if (E.cursor_y > E.numrows) {
-    E.cursor_y = E.numrows;
-  }
-  int times = E.screenrows;
-  while (--times) {
-    editorMoveCursor(ARROW_DOWN);
-  }
+/**
+ * @brief Lisp function to insert a tab (spaces) at cursor
+ * @details Inserts TAB_LENGTH spaces at the current cursor position.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Uses E.constantes.TAB_LENGTH for indentation width
+ */
+Lisp l_editorInserTab(Lisp args, LispError* e, LispContext ctx)
+{
+    for (int i = 0; i < E.constantes.TAB_LENGTH; ++i)
+    {
+        bufferInsertBytes(" ", 1);
+    }
 
-  return lisp_null();
+    return lisp_null();
 }
 
-Lisp editorOpenFile(Lisp args, LispError *e, LispContext ctx) {
-  char *filename = editorPrompt("Open : %s", getenv("PWD"), 1);
-  if (filename)
-    editorOpen(filename);
-
-  return lisp_null();
+/**
+ * @brief Lisp function to move cursor to beginning of line
+ * @details Moves cursor to column 0 of the current line.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E
+ */
+Lisp moveCursorBeginLine(Lisp args, LispError* e, LispContext ctx)
+{
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buf = bufferFindById(active->buffer_id);
+    buf->x = 0;
+    return lisp_null();
 }
 
-
-Lisp editorPrintC(Lisp args, LispError *e, LispContext ctx) {
-  char c = lisp_string(lisp_car(args))[0];
-  editorInsertChar(c);
-  return lisp_null();
+/**
+ * @brief Lisp function to move cursor to end of line
+ * @details Moves cursor to the end of the current line content.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E
+ */
+Lisp moveCursorEndLine(Lisp args, LispError* e, LispContext ctx)
+{
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buf = bufferFindById(active->buffer_id);
+    buf->x = buf->row[buf->y].size;
+    return lisp_null();
 }
 
-Lisp addPackage(Lisp args, LispError *e, LispContext ctx) {
-  const char *package_name = lisp_string(lisp_car(args));
-  char *package_dir = (char *) calloc(256, sizeof(char));
-  FILE *fd_package = NULL;
-  strcat(package_dir, getenv("HOME"));
-  strcat(package_dir, "/.beluga/packages/");
-  strcat(package_dir, package_name);
-  strcat(package_dir, "/init.lisp");
-  fd_package = fopen(package_dir, "r");
-  lisp_eval(lisp_read_file(fd_package, &E.ctx_error, E.ctx), &E.ctx_error,
-            E.ctx);
-  fclose(fd_package);
-  free(package_dir);
-  
-  return lisp_null();
-  
+/**
+ * @brief Lisp function to delete character before cursor
+ * @details Wrapper around editorDelChar() for use in Lisp keybindings.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @see editorDelChar()
+ */
+Lisp deletePreviousChar(Lisp args, LispError* e, LispContext ctx)
+{
+    bufferDelBytes();
+    return lisp_null();
 }
 
-Lisp editorDelRow_L(Lisp args, LispError *e, LispContext ctx) {
-  editorDelRow(E.cursor_y);
-  return lisp_null();
+/**
+ * @brief Lisp function to move cursor up by one screen
+ * @details Scrolls up one full screen height, moving cursor to top of visible
+ * area.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E
+ * @see editorMoveCursor()
+ */
+Lisp editorMoveCursorPageUp(Lisp args, LispError* e, LispContext ctx)
+{
+    EditorPane* active = splitScreenGetActivePane();
+    active->cursor_y = active->y_offset;
+    int times = E.screenrows;
+    while (--times)
+    {
+        editorMoveCursor(ARROW_UP);
+    }
+    return lisp_null();
 }
 
-Lisp editorFind_L(Lisp args, LispError *e, LispContext ctx) {
-	editorFind();
-	return lisp_null();
+/**
+ * @brief Lisp function to move cursor down by one screen
+ * @details Scrolls down one full screen height, moving cursor to bottom of
+ * visible area.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E
+ * @see editorMoveCursor()
+ */
+Lisp editorMoveCursorPageDown(Lisp args, LispError* e, LispContext ctx)
+{
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buffer = bufferFindById(active->buffer_id);
+    active->cursor_y = active->y_offset + E.screenrows - 1;
+    if (active->cursor_y > buffer->numrows)
+    {
+        active->cursor_y = buffer->numrows;
+    }
+    int times = E.screenrows;
+    while (--times)
+    {
+        editorMoveCursor(ARROW_DOWN);
+    }
+
+    return lisp_null();
 }
 
-Lisp editorReadChar_L(Lisp args, LispError *e, LispContext ctx) {
-	fprintf(stderr, "char read : %c\n", E.row[E.cursor_y].render[E.cursor_x]);
-	return lisp_make_char(E.row[E.cursor_y].render[E.cursor_x]);
+/**
+ * @brief Lisp function to open a file
+ * @details Prompts user for filename and opens the file for editing.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E
+ * @see editorOpen()
+ * @see editorPrompt()
+ */
+Lisp editorOpenFile(Lisp args, LispError* e, LispContext ctx)
+{
+    char* filename = editorPrompt("Open : %s", getenv("PWD"), 1);
+    if (filename)
+    {
+        //    editorOpen(filename);
+        EditorPane* active = splitScreenGetActivePane();
+        active->buffer_id = bufferCreate(filename, READ_AND_WRITE);
+    }
+    free(filename);
+
+    return lisp_null();
 }
 
+/**
+ * @brief Lisp function to insert a character
+ * @details Extracts a character from Lisp string argument and inserts it at
+ * cursor.
+ * @param args Lisp list with one string argument
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Uses first character of the string argument
+ */
+Lisp editorPrintC(Lisp args, LispError* e, LispContext ctx)
+{
+    const char* src = lisp_string(lisp_car(args));
+    bufferInsertBytes(src, (int) strlen(src));
+    return lisp_null();
+}
+
+/**
+ * @brief Lisp function to load and execute a package
+ * @details Loads a Lisp package from the user's packages directory
+ * (~/.beluga/packages/<package_name>/init.lisp) and evaluates it.
+ * @param args Lisp list with one argument: package name (string)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Package files must be valid Lisp code
+ * @note Package directory defaults to ~/.beluga/packages/
+ */
+Lisp addPackage(Lisp args, LispError* e, LispContext ctx)
+{
+    const char* package_name = lisp_string(lisp_car(args));
+    appDebug("%s\n", package_name);
+    const char *home = getenv("HOME");
+    if (!home) {
+        return lisp_null();
+    }
+
+    char *package_dir;
+    if (asprintf(&package_dir, "%s/.beluga/packages/%s/init.lisp", home, package_name) == -1) {
+        return lisp_null();
+    }
+
+    FILE* fd_package = fopen(package_dir, "r");
+    if (!fd_package) {
+        free(package_dir);
+        return lisp_null();
+    }
+
+    lisp_eval(lisp_read_file(fd_package, &E.ctx_error, E.ctx), &E.ctx_error, E.ctx);
+    fclose(fd_package);
+    free(package_dir);
+
+    return lisp_null();
+}
+
+Lisp editorSwitchNextBuffer(Lisp args, LispError* e, LispContext ctx)
+{
+    appDebug("switch buffer\n");
+    if (E.number_of_buffer > 0)
+    {
+        EditorPane* active = splitScreenGetActivePane();
+        int next_idx = (active->buffer_id + 1) % E.number_of_buffer;
+        active->buffer_id = next_idx;
+    }
+
+    return lisp_null();
+}
+
+Lisp editorSwitchNextPane(Lisp args, LispError* e, LispContext ctx)
+{
+    splitScreenSwitchPane();
+    return lisp_null();
+}
+
+Lisp editorUnifiedPanes(Lisp args, LispError* e, LispContext ctx)
+{
+    if (E.layout.num_panes - 1)
+    {
+        splitScreenUnify();
+    }
+    return lisp_null();
+}
+
+/**
+ * @brief Lisp function to search for text
+ * @details Wrapper around editorFind() for use in Lisp keybindings.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @see editorFind()
+ */
+Lisp bufferFind_L(Lisp args, LispError* e, LispContext ctx)
+{
+    appDebug("LispFind\n");
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buffer = bufferFindById(active->buffer_id);
+    bufferFind(buffer);
+    return lisp_null();
+}
+
+/**
+ * @brief Lisp function to search for text
+ * @details Wrapper around editorFind() for use in Lisp keybindings.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @see editorFind()
+ */
+Lisp bufferFindReverse_L(Lisp args, LispError* e, LispContext ctx)
+{
+    appDebug("LispFind\n");
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buffer = bufferFindById(active->buffer_id);
+    bufferFindReverse(buffer);
+    return lisp_null();
+}
+
+/**
+ * @brief Lisp function to read character at cursor
+ * @details Returns the character at the current cursor position as a Lisp
+ * character. Returns 'a' if at end of line.
+ * @param args Lisp arguments (unused)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return Lisp character object representing the character at cursor
+ */
+Lisp editorReadChar_L(Lisp args, LispError* e, LispContext ctx)
+{
+    Lisp returned_char;
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buffer = bufferFindById(active->buffer_id);
+    if (buffer->row[buffer->y].chars[buffer->x] == 0)
+    {
+        returned_char = lisp_make_char('a');
+    }
+    else
+    {
+        returned_char = lisp_make_char(buffer->row[buffer->y].chars[buffer->x]);
+    }
+    return returned_char;
+}
+
+/**
+ * @brief Lisp function to set the current prefix mode
+ * @details Changes the editor's prefix state to a named prefix, affecting which
+ * keybindings are active. Updates status message to show active prefix.
+ * @param args Lisp list with one argument: prefix name (string)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E (prefix_state)
+ * @see find_prefix()
+ */
+Lisp editorSetPrefix(Lisp args, LispError* e, LispContext ctx)
+{
+    /*
+     * Set the prefix state of editor to the prefix in argument
+     */
+    const char* prefix_name = lisp_string(lisp_car(args));
+    struct prefix_t prefix = find_prefix(prefix_name);
+    E.prefix_state = prefix.prefix_id;
+    editorSetStatusMessage("prefix %s", prefix.prefix_name);
+    appDebug("%s set\n", prefix_name);
+
+    return lisp_null();
+}
+
+/**
+ * @brief Lisp function to define a new prefix modifier
+ * @details Registers a named prefix modifier that can be used with keybindings
+ * to create context-aware command sequences (e.g., Ctrl-X as a prefix).
+ * @param args Lisp list with one argument: prefix name (string, max 64 chars)
+ * @param e Error pointer for Lisp error handling
+ * @param ctx Lisp context
+ * @return lisp_null()
+ * @note Updates global editor state E (prefix array)
+ */
+Lisp editorPrefix(Lisp args, LispError* e, LispContext ctx)
+{
+    E.prefix = (struct prefix_t*)realloc(E.prefix, (++(E.number_of_prefix) + 1) *
+                                         sizeof(struct prefix_t));
+    E.prefix[E.number_of_prefix].prefix_id = E.number_of_prefix;
+    strncpy(E.prefix[E.number_of_prefix].prefix_name, lisp_string(lisp_car(args)),
+            64);
+    return lisp_null();
+}
+
+Lisp editorPaste(Lisp args, LispError* e, LispContext ctx)
+{
+    const char* char_to_paste = editorGetClipboard();
+    appDebug("editor-paste, %s\n", char_to_paste);
+    bufferInsertBytes(char_to_paste, (int)strlen(char_to_paste));
+    return lisp_null();
+}
+
+Lisp editorCutEndLine(Lisp args, LispError* e, LispContext ctx)
+{
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buffer = bufferFindById(active->buffer_id);
+    int bytes_to_delete = editorRowCharCount(&buffer->row[buffer->y],
+                                             buffer->row[buffer->y].chars[buffer->row[buffer->y].size]) -
+        editorRowCharCount(&buffer->row[buffer->y], buffer->x);
+    editorSetClipboard(&buffer->row[buffer->y].chars[buffer->x], bytes_to_delete);
+    buffer->x = buffer->row[buffer->y].size;
+    while (bytes_to_delete--)
+    {
+        bufferDelBytes();
+    }
+    return lisp_null();
+}
+
+Lisp editorMoveBegBuffer(Lisp args, LispError* e, LispContext ctx)
+{
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buffer = bufferFindById(active->buffer_id);
+    buffer->x = 0;
+    buffer->y = 0;
+    return lisp_null();
+}
+
+Lisp editorMoveEndBuffer(Lisp args, LispError* e, LispContext ctx)
+{
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buffer = bufferFindById(active->buffer_id);
+    buffer->x = buffer->row[buffer->numrows - 1].size;
+    buffer->y = buffer->numrows - 1;
+    return lisp_null();
+}
+
+Lisp editorAutoComplete(Lisp args, LispError* e, LispContext ctx)
+{
+    if (!E.constantes.LSP) {
+        return lisp_null();
+    }
+    // createContextBuffer(E.cursor_x - 2, E.cursor_y + 1, "hello");
+    appDebug("editor-auto-complete\n");
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buffer = bufferFindById(active->buffer_id);
+    E.lsp_completion.visible = 1;
+    lspRequestCompletion(
+        E.lsp_client,
+        buffer,
+        buffer->y, // file line
+        buffer->x, // file col
+        active->cursor_x + active->origin_x + GUTTER_WIDTH, // screen x
+        active->cursor_y + active->origin_y // screen y
+    );
+    return lisp_null();
+}
+
+Lisp lspDefinition(Lisp args, LispError* e, LispContext ctx)
+{
+    if (!E.constantes.LSP) {
+        return lisp_null();
+    }
+    (void)args;
+    (void)e;
+    (void)ctx;
+    if (!E.lsp_client || E.lsp_client->state != LSP_READY)
+        return lisp_null();
+
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buf = bufferFindById(active->buffer_id);
+    if (!buf) return lisp_null();
+
+    lspRequestDefinition(
+        E.lsp_client, buf,
+        active->cursor_y + active->y_offset,
+        active->cursor_x + active->x_offset
+    );
+    return lisp_null();
+}

src/completion.c

@@ -0,0 +1,594 @@
+//
+// Created by Giorgio on 25/05/2026.
+//
+
+#include "../include/completion.h"
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/syslimits.h>
+
+#include "include/append_buffer.h"
+#include "include/cJSON.h"
+#include "include/data.h"
+#include "include/lsp_ui.h"
+#include "include/split_screen.h"
+#include "include/terminal.h"
+
+static void lsp_send(int fd, const char* json)
+{
+    int body_len = strlen(json);
+    char header[1024];
+    int header_len = snprintf(header, sizeof(header),
+                              "Content-Length: %d\r\n\r\n", body_len);
+
+    // Write header + body atomically in two writes, no dprintf mixing
+    write(fd, header, header_len);
+    write(fd, json, body_len);
+
+    // Log to stderr for debugging
+    appDebug("[LSP →] Content-Length: %d | %s\n", body_len, json);
+    fflush(stderr);
+}
+
+static char* lsp_recv(int fd)
+{
+    char header[1024];
+    int content_length = 0;
+
+    while (1)
+    {
+        int i = 0;
+        char c;
+        int n;
+        // Read until \n
+        while ((n = read(fd, &c, 1)) == 1 && c != '\n')
+            header[i++] = c;
+        if (n <= 0) return NULL;
+        header[i] = '\0';
+        // Strip \r explicitly
+        while (i > 0 && (header[i - 1] == '\r' || header[i - 1] == ' '))
+            header[--i] = '\0';
+        if (i == 0) break; // blank line = end of headers
+        if (strncmp(header, "Content-Length: ", 16) == 0)
+            content_length = atoi(header + 16);
+    }
+
+    if (content_length == 0) return NULL;
+
+    char* body = malloc(content_length + 1);
+    int total = 0;
+    while (total < content_length)
+    {
+        int n = read(fd, body + total, content_length - total);
+        if (n <= 0)
+        {
+            free(body);
+            return NULL;
+        }
+        total += n;
+    }
+    body[content_length] = '\0';
+    return body;
+}
+
+static void lsp_dispatch(LspClient* lsp, const char* json)
+{
+    if (!json) return;
+
+    cJSON* root = cJSON_Parse(json);
+    if (!root)
+    {
+        appDebug("[LSP ←] Failed to parse JSON: %.120s\n", json);
+        return;
+    }
+
+    cJSON* method = cJSON_GetObjectItem(root, "method");
+    cJSON* id = cJSON_GetObjectItem(root, "id");
+    cJSON* result = cJSON_GetObjectItem(root, "result");
+    cJSON* error = cJSON_GetObjectItem(root, "error");
+
+    // ── Error response ────────────────────────────────────────────────────────
+    if (error)
+    {
+        cJSON* msg = cJSON_GetObjectItem(error, "message");
+        appDebug("[LSP ←] ERROR: %s\n",
+                msg ? msg->valuestring : "(no message)");
+        cJSON_Delete(root);
+        return;
+    }
+
+    // ── Notification (no id, has method) ─────────────────────────────────────
+    if (method && !id)
+    {
+        const char* m = method->valuestring;
+        appDebug("[LSP ←] NOTIF: %s\n", m);
+
+        if (strcmp(m, "textDocument/publishDiagnostics") == 0)
+        {
+            // Find which buffer this diagnostic belongs to
+            cJSON* params = cJSON_GetObjectItem(root, "params");
+            cJSON* uri = cJSON_GetObjectItem(params, "uri");
+            int buf_id = splitScreenGetActivePane()->buffer_id;
+
+            appDebug("[LSP ←] Diagnostics for buffer %d\n", buf_id);
+
+            pthread_mutex_lock(&lsp->lock);
+            lspParseDiagnostics(json, &E.lsp_diagnostics, buf_id);
+            pthread_mutex_unlock(&lsp->lock);
+            write(lsp->wake_pipe[1], "d", 1);
+        }
+
+        else if (strcmp(m, "window/logMessage") == 0)
+        {
+            cJSON* params = cJSON_GetObjectItem(root, "params");
+            cJSON* message = cJSON_GetObjectItem(params, "message");
+            appDebug("[LSP ←] LOG: %s\n",
+                    message ? message->valuestring : "");
+        }
+        E.lsp_client->completion_just_arrived = 1;
+
+
+        cJSON_Delete(root);
+        return;
+    }
+
+    // ── Response (has id + result) ────────────────────────────────────────────
+    if (id && result)
+    {
+        int response_id = id->valueint;
+        appDebug("[LSP ←] RESPONSE id=%d\n", response_id);
+
+        // initialize response → send initialized + mark ready
+        if (lsp->state == LSP_INITIALIZING)
+        {
+            appDebug("[LSP ←] Initialize OK, sending initialized\n");
+            lsp_send(lsp->write_fd,
+                     "{\"jsonrpc\":\"2.0\",\"method\":\"initialized\",\"params\":{}}");
+
+            pthread_mutex_lock(&lsp->lock);
+            lsp->state = LSP_READY;
+            pthread_cond_signal(&lsp->ready_cond);
+            pthread_mutex_unlock(&lsp->lock);
+            E.lsp_client->completion_just_arrived = 1;
+
+            cJSON_Delete(root);
+            return;
+        }
+
+        // completion response → parse items and show popup
+        cJSON* items = cJSON_GetObjectItem(result, "items");
+        if (items && cJSON_IsArray(items))
+        {
+            int count = cJSON_GetArraySize(items);
+            appDebug("[LSP ←] Completion: %d items\n", count);
+
+            // Print each item to stderr for debugging
+            cJSON* item;
+            int i = 0;
+            cJSON_ArrayForEach(item, items)
+            {
+                cJSON* label = cJSON_GetObjectItem(item, "label");
+                cJSON* detail = cJSON_GetObjectItem(item, "detail");
+                cJSON* kind = cJSON_GetObjectItem(item, "kind");
+                appDebug("  [%d] kind=%-2d  %-40s  %s\n",
+                        i++,
+                        kind ? kind->valueint : 0,
+                        label ? label->valuestring : "(no label)",
+                        detail ? detail->valuestring : "");
+                if (i >= 10)
+                {
+                    appDebug("  ... (%d more)\n", count - 10);
+                    break;
+                }
+            }
+
+            pthread_mutex_lock(&lsp->lock);
+            lspParseCompletion(json, &E.lsp_completion,
+                               lsp->completion_cursor_x,
+                               lsp->completion_cursor_y);
+            pthread_mutex_unlock(&lsp->lock);
+            E.lsp_client->completion_just_arrived = 1;
+
+            appDebug("[POPUP] visible=%d count=%d origin=(%d,%d)\n",
+                    E.lsp_completion.visible,
+                    E.lsp_completion.count,
+                    E.lsp_completion.origin_x,
+                    E.lsp_completion.origin_y);
+            write(lsp->wake_pipe[1], "c", 1);
+
+            cJSON_Delete(root);
+            return;
+        }
+
+        // definition response → jump to location
+        cJSON* uri_item = cJSON_GetObjectItem(result, "uri");
+        if (uri_item)
+        {
+            cJSON* range = cJSON_GetObjectItem(result, "range");
+            cJSON* start = cJSON_GetObjectItem(range, "start");
+            int line = cJSON_GetObjectItem(start, "line")->valueint;
+            int col = cJSON_GetObjectItem(start, "character")->valueint;
+            appDebug("[LSP ←] Definition: %s:%d:%d\n",
+                    uri_item->valuestring, line, col);
+            E.lsp_client->completion_just_arrived = 1;
+
+            // TODO: jump to that location
+            cJSON_Delete(root);
+            return;
+        }
+
+        appDebug("[LSP ←] Unhandled response id=%d: %.80s\n",
+                response_id, json);
+    }
+
+    cJSON_Delete(root);
+}
+
+static void* lsp_reader(void* arg)
+{
+    LspClient* lsp = (LspClient*)arg;
+    while (lsp->state != LSP_SHUTDOWN)
+    {
+        char* msg = lsp_recv(lsp->read_fd);
+        if (!msg) break; // ← pipe closed or error, exit cleanly
+        lsp_dispatch(lsp, msg);
+        free(msg);
+    }
+    return NULL;
+}
+
+// ─── lifecycle ───────────────────────────────────────────────────────────────
+
+int lspStart(LspClient *lsp, const char *project_root)
+{
+    // ── Pipes ─────────────────────────────────────────────────────────────────
+    int to_clangd[2], from_clangd[2];
+
+    if (pipe(to_clangd) < 0 || pipe(from_clangd) < 0) {
+        fprintf(stderr, "[LSP] pipe() failed\n");
+        free(lsp);
+        return 0;
+    }
+    if (pipe(lsp->wake_pipe) < 0) {
+        fprintf(stderr, "[LSP] wake pipe() failed\n");
+        free(lsp);
+        return 0;
+    }
+
+    // ── Fork clangd ───────────────────────────────────────────────────────────
+    lsp->pid = fork();
+    if (lsp->pid < 0) {
+        fprintf(stderr, "[LSP] fork() failed\n");
+        free(lsp);
+        return 0;
+    }
+
+    if (lsp->pid == 0) {
+        // Child — become clangd
+        dup2(to_clangd[0],   STDIN_FILENO);
+        dup2(from_clangd[1], STDOUT_FILENO);
+        close(to_clangd[1]);
+        close(from_clangd[0]);
+        close(lsp->wake_pipe[0]);
+        close(lsp->wake_pipe[1]);
+        execlp("clangd", "clangd",
+               "--log=error",
+               "--completion-style=detailed",
+               NULL);
+        fprintf(stderr, "[LSP] execlp failed — is clangd installed?\n");
+        _exit(1);
+    }
+
+    // Parent — keep write end of to_clangd, read end of from_clangd
+    close(to_clangd[0]);
+    close(from_clangd[1]);
+    lsp->write_fd = to_clangd[1];
+    lsp->read_fd  = from_clangd[0];
+    lsp->next_id  = 1;
+    lsp->state    = LSP_INITIALIZING;
+
+    // ── Threading ─────────────────────────────────────────────────────────────
+    pthread_mutex_init(&lsp->lock,       NULL);
+    pthread_cond_init (&lsp->ready_cond, NULL);
+
+    // Start reader thread BEFORE sending initialize
+    // so it can handle the response
+    pthread_create(&lsp->reader_thread, NULL, lsp_reader, lsp);
+
+    // ── Send initialize ───────────────────────────────────────────────────────
+    char abs_root[PATH_MAX];
+    if (realpath(project_root, abs_root) == NULL)
+        strncpy(abs_root, project_root, PATH_MAX - 1);
+
+    cJSON *req        = cJSON_CreateObject();
+    cJSON *params     = cJSON_CreateObject();
+    cJSON *caps       = cJSON_CreateObject();
+    cJSON *td_caps    = cJSON_CreateObject();
+    cJSON *comp_caps  = cJSON_CreateObject();
+    cJSON *comp_item  = cJSON_CreateObject();
+
+    cJSON_AddStringToObject(req,       "jsonrpc",   "2.0");
+    cJSON_AddNumberToObject(req,       "id",        lsp->next_id++);
+    cJSON_AddStringToObject(req,       "method",    "initialize");
+
+    // rootUri
+    char root_uri[PATH_MAX + 8];
+    snprintf(root_uri, sizeof(root_uri), "file://%s", abs_root);
+    cJSON_AddNumberToObject(params, "processId", getpid());
+    cJSON_AddStringToObject(params, "rootUri",   root_uri);
+
+    // Capabilities — tell clangd what we support
+    cJSON_AddBoolToObject  (comp_item, "snippetSupport",        0);
+    cJSON_AddBoolToObject  (comp_item, "commitCharactersSupport", 0);
+    cJSON_AddItemToObject  (comp_caps, "completionItem", comp_item);
+    cJSON_AddItemToObject  (td_caps,   "completion",     comp_caps);
+    cJSON_AddItemToObject  (td_caps,   "hover",          cJSON_CreateObject());
+    cJSON_AddItemToObject  (td_caps,   "definition",     cJSON_CreateObject());
+    cJSON_AddItemToObject  (td_caps,   "publishDiagnostics", cJSON_CreateObject());
+    cJSON_AddItemToObject  (caps,      "textDocument",   td_caps);
+    cJSON_AddItemToObject  (params,    "capabilities",   caps);
+    cJSON_AddItemToObject  (req,       "params",         params);
+
+    char *msg = cJSON_PrintUnformatted(req);
+    lsp_send(lsp->write_fd, msg);
+    free(msg);
+    cJSON_Delete(req);
+
+    // ── Wait for LSP_READY ────────────────────────────────────────────────────
+    // Reader thread will handle the initialize response,
+    // send "initialized", and signal ready_cond
+    pthread_mutex_lock(&lsp->lock);
+    while (lsp->state != LSP_READY) {
+        struct timespec ts;
+        clock_gettime(CLOCK_REALTIME, &ts);
+        ts.tv_sec += 5;   // 5 second timeout — clangd should respond fast
+        int rc = pthread_cond_timedwait(&lsp->ready_cond, &lsp->lock, &ts);
+        if (rc == ETIMEDOUT) {
+            fprintf(stderr, "[LSP] timeout waiting for initialize response\n");
+            pthread_mutex_unlock(&lsp->lock);
+            // Don't kill clangd — it might still come up, just return what we have
+            return 1;
+        }
+    }
+    pthread_mutex_unlock(&lsp->lock);
+
+    fprintf(stderr, "[LSP] ready — clangd initialized at %s\n", abs_root);
+    return 1;
+}
+// ─── document sync ───────────────────────────────────────────────────────────
+
+// Build the full buffer text into a bAlloc'd string
+static char* buffer_to_text(struct buffer_t* buf)
+{
+    int total = 0;
+    for (int i = 0; i < buf->numrows; i++)
+        total += buf->row[i].size + 1; // +1 for \n
+    char* text = malloc(total + 1);
+    char* p = text;
+    for (int i = 0; i < buf->numrows; i++)
+    {
+        memcpy(p, buf->row[i].chars, buf->row[i].size);
+        p += buf->row[i].size;
+        *p++ = '\n';
+    }
+    *p = '\0';
+    return text;
+}
+
+void lspDidOpen(LspClient* lsp, struct buffer_t* buf)
+{
+    appDebug("[LSP] opening file");
+    if (lsp->state != LSP_READY || buf->b_lsp_open) return;
+
+
+    char uri[PATH_MAX + 8];
+    snprintf(uri, sizeof(uri), "file://%s", buf->fullname);
+
+    const char* lang = "c";
+    if (strstr(buf->filename, ".cpp") || strstr(buf->filename, ".cc"))
+        lang = "cpp";
+
+    char* raw = buffer_to_text(buf);
+
+    // Let cJSON handle ALL escaping — don't touch the text yourself
+    cJSON* root = cJSON_CreateObject();
+    cJSON* params = cJSON_CreateObject();
+    cJSON* td = cJSON_CreateObject();
+
+    cJSON_AddStringToObject(root, "jsonrpc", "2.0");
+    cJSON_AddStringToObject(root, "method", "textDocument/didOpen");
+
+    cJSON_AddStringToObject(td, "uri", uri);
+    cJSON_AddStringToObject(td, "languageId", lang);
+    cJSON_AddNumberToObject(td, "version", 1);
+    cJSON_AddStringToObject(td, "text", raw); // cJSON escapes this
+
+    cJSON_AddItemToObject(params, "textDocument", td);
+    cJSON_AddItemToObject(root, "params", params);
+
+    char* msg = cJSON_PrintUnformatted(root);
+    lsp_send(lsp->write_fd, msg);
+
+    free(msg);
+    free(raw);
+    cJSON_Delete(root);
+    buf->b_lsp_open = 1;
+}
+
+void lspDidChange(LspClient* lsp, struct buffer_t* buf)
+{
+    if (lsp->state != LSP_READY || !buf->b_lsp_open) return;
+
+
+    char uri[PATH_MAX + 8];
+    snprintf(uri, sizeof(uri), "file://%s", buf->fullname);
+
+    char* raw = buffer_to_text(buf);
+
+    cJSON* root = cJSON_CreateObject();
+    cJSON* params = cJSON_CreateObject();
+    cJSON* td = cJSON_CreateObject();
+    cJSON* changes = cJSON_CreateArray();
+    cJSON* change = cJSON_CreateObject();
+
+    cJSON_AddStringToObject(root, "jsonrpc", "2.0");
+    cJSON_AddStringToObject(root, "method", "textDocument/didChange");
+
+    cJSON_AddStringToObject(td, "uri", uri);
+    cJSON_AddNumberToObject(td, "version", buf->dirty);
+
+    cJSON_AddStringToObject(change, "text", raw); // full content sync
+    cJSON_AddItemToArray(changes, change);
+
+    cJSON_AddItemToObject(params, "textDocument", td);
+    cJSON_AddItemToObject(params, "contentChanges", changes);
+    cJSON_AddItemToObject(root, "params", params);
+
+    char* msg = cJSON_PrintUnformatted(root);
+    lsp_send(lsp->write_fd, msg);
+
+    free(msg);
+    free(raw);
+    cJSON_Delete(root);
+}
+
+void lspDidClose(LspClient* lsp, struct buffer_t* buf)
+{
+
+    char uri[PATH_MAX + 8];
+    snprintf(uri, sizeof(uri), "file://%s", buf->fullname);
+
+    cJSON* root = cJSON_CreateObject();
+    cJSON* params = cJSON_CreateObject();
+    cJSON* td = cJSON_CreateObject();
+    cJSON_AddStringToObject(root, "jsonrpc", "2.0");
+    cJSON_AddStringToObject(root, "method", "textDocument/didClose");
+    cJSON_AddStringToObject(td, "uri", uri); // ← fixed
+    cJSON_AddItemToObject(params, "textDocument", td);
+    cJSON_AddItemToObject(root, "params", params);
+    char* msg = cJSON_PrintUnformatted(root);
+    lsp_send(lsp->write_fd, msg);
+    free(msg);
+    cJSON_Delete(root);
+    buf->b_lsp_open = 0;
+}
+
+// ─── requests ────────────────────────────────────────────────────────────────
+
+void lspRequestCompletion(LspClient* lsp, struct buffer_t* buf,
+                          int line, int col,
+                          int screen_x, int screen_y)
+{
+    if (lsp->state != LSP_READY) return;
+    lsp->completion_cursor_x = screen_x;
+    lsp->completion_cursor_y = screen_y;
+
+    appDebug("LSP REQUEST COMP");
+
+    char* msg;
+    char uri[PATH_MAX + 8];
+    snprintf(uri, sizeof(uri), "file://%s", buf->fullname);
+    appDebug("FULLNAME : %s\n", buf->fullname);
+
+    cJSON* req = cJSON_CreateObject();
+    cJSON* params = cJSON_CreateObject();
+    cJSON* td = cJSON_CreateObject();
+    cJSON* position = cJSON_CreateObject();
+
+    cJSON_AddStringToObject(req, "jsonrpc", "2.0");
+    cJSON_AddNumberToObject(req, "id", lsp->next_id++);
+    cJSON_AddStringToObject(req, "method", "textDocument/completion");
+
+    cJSON_AddStringToObject(td, "uri", uri);
+
+    cJSON_AddNumberToObject(position, "line", line);
+    cJSON_AddNumberToObject(position, "character", col);
+    cJSON_AddItemToObject(params, "position", position);
+
+    cJSON_AddItemToObject(params, "textDocument", td);
+    cJSON_AddItemToObject(req, "params", params);
+
+    msg = cJSON_PrintUnformatted(req);
+    lsp_send(lsp->write_fd, msg);
+    E.lsp_client->completion_requested = 1;
+    cJSON_Delete(req);
+    free(msg);
+}
+
+void lspRequestDefinition(LspClient* lsp, struct buffer_t* buf, int line, int col)
+{
+    if (lsp->state != LSP_READY) return;
+    char* msg;
+    asprintf(&msg,
+             "{\"jsonrpc\":\"2.0\",\"id\":%d,\"method\":\"textDocument/definition\","
+             "\"params\":{\"textDocument\":{\"uri\":\"file://%s\"},"
+             "\"position\":{\"line\":%d,\"character\":%d}}}",
+             lsp->next_id++, buf->filename, line, col);
+    lsp_send(lsp->write_fd, msg);
+    free(msg);
+}
+
+void lspShutdown(LspClient *lsp)
+{
+    if (!lsp || lsp->state == LSP_SHUTDOWN) return;
+
+    lsp->state = LSP_SHUTDOWN;
+
+    // 1. Send didClose for all open buffers
+    for (int i = 0; i < E.number_of_buffer; i++) {
+        if (E.buffers[i].b_lsp_open)
+            lspDidClose(lsp, &E.buffers[i]);
+    }
+
+    // 2. Send shutdown request (clangd expects this before exit)
+    cJSON *req = cJSON_CreateObject();
+    cJSON_AddStringToObject(req, "jsonrpc", "2.0");
+    cJSON_AddNumberToObject(req, "id",      lsp->next_id++);
+    cJSON_AddStringToObject(req, "method",  "shutdown");
+    cJSON_AddNullToObject  (req, "params");
+    char *msg = cJSON_PrintUnformatted(req);
+    lsp_send(lsp->write_fd, msg);
+    free(msg);
+    cJSON_Delete(req);
+
+    // 3. Wait briefly for the shutdown response (2s timeout)
+    struct timeval tv = { .tv_sec = 2, .tv_usec = 0 };
+    fd_set fds;
+    FD_ZERO(&fds);
+    FD_SET(lsp->read_fd, &fds);
+    if (select(lsp->read_fd + 1, &fds, NULL, NULL, &tv) > 0) {
+        char *resp = lsp_recv(lsp->read_fd);
+        free(resp);
+    }
+
+    // 4. Send exit notification
+    lsp_send(lsp->write_fd,
+        "{\"jsonrpc\":\"2.0\",\"method\":\"exit\",\"params\":null}");
+
+    // 5. Close write pipe first — reader thread will get EOF and exit
+    close(lsp->write_fd);
+    lsp->write_fd = -1;
+
+    // 6. Wake the main loop so it doesn't stay blocked in select()
+    write(lsp->wake_pipe[1], "q", 1);
+
+    // 7. Wait for reader thread to finish
+    pthread_join(lsp->reader_thread, NULL);
+
+    // 8. Close remaining fds
+    close(lsp->read_fd);
+    lsp->read_fd = -1;
+    close(lsp->wake_pipe[0]);
+    close(lsp->wake_pipe[1]);
+
+    // 9. Destroy synchronization primitives
+    pthread_mutex_destroy(&lsp->lock);
+    pthread_cond_destroy (&lsp->ready_cond);
+
+    // 10. Reap the clangd process
+    waitpid(lsp->pid, NULL, 0);
+
+    free(lsp);
+}

src/editor_op.c

@@ -1,47 +1,142 @@
 #include "../include/editor_op.h"
+
+#include <stdarg.h>
+
 #include "../include/row_op.h"
+#include "../include/buffer.h"
+#include "../include/data.h"
+#include "../include/split_screen.h"
+#include "../include/terminal.h"
+#include "../include/utf8.h"
 
 
 extern struct editorConfig E;
 
-void editorInsertChar(int c) {
-    if (E.cursor_y == E.numrows) {
-      editorInsertRow(E.numrows, "", 0);
+
+/**
+ * @brief Sets a temporary status message for display
+ * @details Formats and stores a message that will be displayed in the message
+ * bar for 5 seconds. Uses printf-style variable argument formatting.
+ * @param fmt Printf-style format string
+ * @param ... Variable arguments for format string
+ * @note Updates global editor state E (status_msg, status_msg_time)
+ * @see editorDrawMessageBar()
+ */
+void editorSetStatusMessage(const char* fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+    vsnprintf(E.status_msg, E.screencols, fmt, ap);
+    va_end(ap);
+    E.status_msg_time = time(NULL);
+}
+
+/**
+ * @brief Moves the cursor based on arrow key input
+ * @details Updates cursor position (E.cursor_x, E.cursor_y) based on the given
+ * key direction. Handles line wrapping and boundary conditions. Prevents cursor
+ * from exceeding line lengths.
+ * @param key The arrow key code (ARROW_UP, ARROW_DOWN, ARROW_LEFT, ARROW_RIGHT)
+ * @return 1 if cursor movement was valid, 0 if cursor was constrained to line boundary
+ * @note Updates global editor state E
+ */
+int editorMoveCursor(int key) {
+    EditorPane *active = splitScreenGetActivePane();
+    struct buffer_t *buf = bufferFindById(active->buffer_id);
+    row_t *row = &buf->row[buf->y];
+    switch (key) {
+    case ARROW_RIGHT:
+        if (row && buf->x < row->size) {
+            int len = utf8Seqlen(row->chars[buf->x]);
+            buf->x += len;
+        } else if (row && buf->y < buf->numrows - 1) {
+            buf->y++;
+            buf->x = 0;
+        }
+        break;
+    case ARROW_DOWN:
+        if (buf->y < buf->numrows - 1) {
+
+            buf->y++;
+        }
+        break;
+    case ARROW_UP:
+        if (buf->y != 0) {
+            --buf->y;
+        }
+        break;
+    case ARROW_LEFT:
+        if (buf->x != 0) {
+            --buf->x;
+        } else if (buf->y > 0) {
+            --buf->y;
+            buf->x = buf->row[buf->y].size;
+        }
+        break;
+    default:
+        break;
     }
-    editorRowInsertChar(&E.row[E.cursor_y], E.cursor_x, c);
-    E.cursor_x++;
+    return 1;
 }
 
-void editorInsertNewLine() {
-  erow *row;
-  if (!E.cursor_x) {
-    editorInsertRow(E.cursor_y, "", 0);
-  } else {
-    row = &E.row[E.cursor_y];
-    editorInsertRow(E.cursor_y + 1, &row->chars[E.cursor_x],
-                    row->size - E.cursor_x);
-    row = &E.row[E.cursor_y];
-    row->size = E.cursor_x;
-    row->chars[row->size] = '\0';
-    editorUpdateRow(row);
-  }
-  ++E.cursor_y;
-  E.cursor_x = 0;
+char *editorGetClipboard(void) {
+    FILE *pipe = popen(CLIPBOARD_PASTE_CMD, "r");
+    if (!pipe) return NULL;
+
+    size_t cap = 4096;
+    size_t len = 0;
+    char *buf = malloc(cap);
+    if (!buf) {
+        pclose(pipe);
+        return NULL;
+    }
+
+    int c;
+    while ((c = fgetc(pipe)) != EOF) {
+        if (len + 1 >= cap) {
+            cap *= 2;
+            char *new_buf = realloc(buf, cap);
+            if (!new_buf) {
+                free(buf);
+                pclose(pipe);
+                return NULL;
+            }
+            buf = new_buf;
+        }
+        buf[len++] = (char)c;
+    }
+    buf[len] = '\0';
+    pclose(pipe);
+    return buf;
 }
 
-void editorDelChar() {
-  erow *row;
-  if (E.cursor_y == E.numrows || !(E.cursor_x || E.cursor_y)) {
-    return;
-  }
-  row = &E.row[E.cursor_y];
-  if (E.cursor_x > 0) {
-    editorRowDelchar(row, E.cursor_x - 1);
-    --E.cursor_x;
-  } else {
-    E.cursor_x = E.row[E.cursor_y - 1].size;
-    editorRowAppendString(&E.row[E.cursor_y - 1], row->chars, row->size);
-    editorDelRow(E.cursor_y);
-    --E.cursor_y;
-  }
+void editorSetClipboard(const char *text, int len) {
+    FILE *pipe = popen(CLIPBOARD_COPY_CMD, "w");
+    if (!pipe) return;
+    fwrite(text, 1, len, pipe);
+    pclose(pipe);
 }
+
+int editorRowCxToByte(const row_t *row, int cursor_x) {
+    int i = 0, col = 0;
+    while (col < cursor_x && i < row->size) {
+        int sl = utf8Seqlen((unsigned char)row->chars[i]);
+        if (sl < 1)
+            sl = 1;
+        col++;
+        i += sl;
+    }
+    return i;
+}
+
+int editorRowCharCount(row_t *row, int x) {
+    int n = 0, i = 0;
+    while (i < x && i < row->size) {
+        int sl = utf8Seqlen((unsigned char)row->chars[i]);
+        if (sl < 1)
+            sl = 1;
+        n++;
+        i += sl;
+    }
+    return n;
+}

src/file_io.c

@@ -1,130 +1,126 @@
+/**
+ * @file file_io.c
+ * @brief File I/O operations module for the Beluga text editor
+ * @details Handles file loading, saving, searching, and buffer management.
+ * Provides functionality for opening/closing files, persisting changes to disk,
+ * and searching for text patterns within the document.
+ */
+
 #include "../include/file_io.h"
+#include "../include/editor_op.h"
 #include "../include/input.h"
-#include "../include/output.h"
+#include "../include/buffer.h"
+#include "../include/data.h"
+#include "../include/split_screen.h"
+#include "../include/row_op.h"
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <time.h>
 #include <unistd.h>
+#include <errno.h>
 
-extern char *strdup(const char *);
-extern ssize_t getline(char **restrict lineptr, size_t *restrict n,
-                       FILE *restrict stream);
-extern int ftruncate(int fd, off_t length);
-extern struct editorConfig E;
-
-char *editorRowsToString(int *buffer_len) {
-    int tot_len = 0;
-    int j;
-    char *buf;
-    char *p;
-
-    for (j = 0; j < E.numrows; ++j) {
-        tot_len += E.row[j].size + 1;
-    }
-    *buffer_len = tot_len;
-    buf = malloc(tot_len);
-    p = buf;
-    for (j = 0; j < E.numrows; ++j) {
-        memcpy(p, E.row[j].chars, E.row[j].size);
-        p += E.row[j].size;
-        *p = '\n';
-        p++;
-    }
-
-    return buf;
-}
 
+/**
+ * @brief Closes the current file and resets editor state
+ * @details Clears all rows, resets cursor position, scroll offsets, and file
+ * metadata. Does not prompt to save unsaved changes.
+ * @note Updates global editor state E
+ */
 void editorCloseFile(void) {
-    E.cursor_x = 0;
-    E.cursor_y = 0;
-    E.rx = 0;
-    E.row_offset = 0;
-    E.col_offset = 0;
-    E.numrows = 0;
-    E.row = NULL;
-    E.dirty = 0;
-    E.filename = NULL;
-    E.status_msg[0] = '\0';
-    E.status_msg_time = 0;
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buf = bufferFindById(active->buffer_id);
+  active->cursor_x = 0;
+  active->cursor_y = 0;
+  active->x_offset = 0;
+  active->y_offset = 0;
+  for (int i = 0; i < buf->numrows; ++i) {
+    free(buf->row[i].chars);
+  }
+  buf->numrows = 0;
+  free(buf->row);
+  buf->row = NULL;
+  buf->dirty = 0;
+  free(buf->filename);
+  buf->filename = NULL;
+  E.status_msg[0] = '\0';
+  E.status_msg_time = 0;
 }
 
-void editorOpen(char *filename) {
-    FILE *fp;
+/**
+ * @brief Opens a file for editing
+ * @details Loads file content into editor rows, one line per row. If another
+ * file is already open, it is closed first (without saving). File is opened in
+ * a+ (read/append) mode to allow both reading and modification.
+ * @param buffer Path to the file to open (relative or absolute)
+ * @note Updates global editor state E
+ * @note Calls die() on file open failure
+ * @note Newline characters are stripped from loaded lines
+ * @see editorInsertRow()
+ */
+void editorOpen(struct buffer_t* buffer) {
+  FILE *fp;
+  fp = fopen(buffer->fullname, "a+");
+  if (!fp)
+    die("fopen");
 
-    // Test if a file is already open
-    if (E.filename != NULL) {
-        editorCloseFile();
-        E.state = READ_AND_WRITE;
-    }
+  char *line = NULL;
+  size_t line_cap = 0;
+  ssize_t line_len;
 
-    free(E.filename);
-    E.filename = strdup(filename);
+  rewind(fp);
 
-    fp = fopen(filename, "a+");
-    if (!fp)
-        die("fopen");
-
-    char *line = NULL;
-    size_t line_cap = 0;
-    ssize_t line_len;
-
-    while ((line_len = getline(&line, &line_cap, fp)) != -1) {
-        while (line_len > 0 &&
-               (line[line_len - 1] == '\n' || line[line_len - 1] == '\r')) {
-            --line_len;
-        }
-        editorInsertRow(E.numrows, line, line_len);
-    }
+  while ((line_len = getline(&line, &line_cap, fp)) != -1) {
+    while (line_len > 0 &&
+           (line[line_len - 1] == '\n' || line[line_len - 1] == '\r')) {
+      --line_len;
+           }
+    bufferInsertRow(buffer, buffer->numrows, line, line_len);
     free(line);
-    fclose(fp);
-    E.dirty = 0;
+    line = NULL;
+    line_cap = 0;  // Reset for next iteration
+  }
+  fclose(fp);
+  E.dirty = 0;
 }
 
+/**
+ * @brief Saves the current file to disk
+ * @details Prompts for filename if not set, converts all rows to a buffer,
+ * writes to disk using open/ftruncate/write, and updates dirty flag.
+ * Displays status messages on success or failure.
+ * @note Updates global editor state E (dirty flag)
+ * @note If no filename is set, prompts user via editorPrompt()
+ * @note Uses O_RDWR | O_CREAT with mode 0644
+ * @see editorRowsToString()
+ */
 void editorSave() {
-    int len;
-    char *buf;
-    int fd;
-    if (E.filename == NULL) {
-        E.filename = editorPrompt("Save as: %s (ESC to cancel)", "", 1);
-        if (E.filename == NULL) {
-            editorSetStatusMessage("Save aborted");
-            return;
-        }
-    }
-    buf = editorRowsToString(&len);
-    fd = open(E.filename, O_RDWR | O_CREAT, 0644);
-    if (fd != -1) {
-        if (ftruncate(fd, len) != -1) {
-            if (write(fd, buf, len) == len) {
-                close(fd);
-                free(buf);
-                E.dirty = 0;
-                editorSetStatusMessage("%d bytes written to disk", len);
-                return;
-            }
-        }
-        close(fd);
-    }
-    free(buf);
-    editorSetStatusMessage("Can't save! I/O error: %s", strerror(errno));
-}
-
-void editorFind() {
-  char *query = editorPrompt("Search: %s (ESC to cancel)", "", 0);
-  if (query == NULL) return;
-  int i;
-  for (i = E.cursor_y + 1; i < E.numrows; i++) {
-    erow *row = &E.row[i];
-    char *match = strstr(row->render, query);
-    if (match) {
-      E.cursor_y = i;
-      E.cursor_x = editorRowRxToCx(row, match - row->render);
-      E.row_offset = E.numrows;
-      break;
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buffer = bufferFindById(active->buffer_id);
+  int len;
+  int fd;
+  if (buffer->filename == NULL) {
+    buffer->filename = editorPrompt("Save as: %s (ESC to cancel)", "", 1);
+    if (buffer->filename == NULL) {
+      editorSetStatusMessage("Save aborted");
+      return;
     }
   }
-  free(query);
-}
+  fd = open(buffer->fullname, O_WRONLY | O_CREAT | O_TRUNC, 0644);
+  if (fd != -1) {
+    for (int i = 0; i < buffer->numrows; ++i)
+    {
+      len = (int) strlen(buffer->row[i].chars);
+      if (write(fd, buffer->row[i].chars, len) != len) {
+        close(fd);
+        editorSetStatusMessage("Can't save! I/O error: %s", strerror(errno));
 
+        return;
+      }
+      write(fd, "\n", 1);
+    }
+    buffer->dirty = 0;
+    close(fd);
+  }
+  editorSetStatusMessage("File saved");
+}

src/init.c

@@ -1,68 +1,63 @@
 #include "../include/init.h"
+#include "../include/builtins.h"
+#include "../include/color.h"
 #include "../include/data.h"
 #include "../include/terminal.h"
-#include "../include/builtins.h"
+#include "../include/split_screen.h"
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 
 #define LISP_IMPLEMENTATION
 #include "../include/lisp.h"
 #include "../include/lisp_lib.h"
 
-extern struct editorConfig;
-
+struct editorConfig;
 
 void registerBuiltin(char *key_sequence, LispCFunc f) {
   lisp_env_define(E.ctx.p->env, lisp_make_symbol(key_sequence, E.ctx),
                   lisp_make_func(f), E.ctx);
-  
+
 }
 
 void initBuiltins() {
-  // move cursor
-  registerBuiltin("MOVE-CURSOR", moveCursor);
-  registerBuiltin("MAP-KEY", mapKey);
-  registerBuiltin("EDITOR-QUIT", editorQuit);
-  registerBuiltin("EDITOR-SAVE", l_editorSave);
-  registerBuiltin("EDITOR-INSERT-NEW-LINE", l_editorInsertNewLine);
-  registerBuiltin("MOVE-CURSOR-BEG-LINE", moveCursorBeginLine);
-  registerBuiltin("MOVE-CURSOR-END-LINE", moveCursorEndLine);
-  registerBuiltin("EDITOR-DELETE-PREVIOUS-CHAR", deletePreviousChar);
-  registerBuiltin("MOVE-CURSOR-PAGE-UP", editorMoveCursorPageUp);
-  registerBuiltin("MOVE-CURSOR-PAGE-DOWN", editorMoveCursorPageDown);
-  registerBuiltin("EDITOR-OPEN-FILE", editorOpenFile);
-  registerBuiltin("EDITOR-INSERT-CHAR", editorPrintC);
-  registerBuiltin("ADD-PACKAGE", addPackage);
-  registerBuiltin("EDITOR-DEL-ROW", editorDelRow_L);
-	registerBuiltin("EDITOR-FIND", editorFind_L);
-	registerBuiltin("EDITOR-READ-CHAR", editorReadChar_L);
+  // Registering C functions as lisp macro
+  registerBuiltin("move-cursor", moveCursor);
+  registerBuiltin("map-key", mapKey);
+  registerBuiltin("editor-quit", editorQuit);
+  registerBuiltin("editor-save", l_editorSave);
+  registerBuiltin("editor-insert-new-line", l_editorInsertNewLine);
+  registerBuiltin("move-cursor-beg-line", moveCursorBeginLine);
+  registerBuiltin("move-cursor-end-line", moveCursorEndLine);
+  registerBuiltin("editor-delete-previous-char", deletePreviousChar);
+  registerBuiltin("move-cursor-page-up", editorMoveCursorPageUp);
+  registerBuiltin("move-cursor-page-down", editorMoveCursorPageDown);
+  registerBuiltin("editor-open-file", editorOpenFile);
+  registerBuiltin("editor-insert-char", editorPrintC);
+  registerBuiltin("add-package", addPackage);
+  registerBuiltin("buffer-find", bufferFind_L);
+  registerBuiltin("buffer-find-reverse", bufferFindReverse_L);
+  registerBuiltin("editor-read-char", editorReadChar_L);
+  registerBuiltin("add-prefix", editorPrefix);
+  registerBuiltin("editor-set-prefix", editorSetPrefix);
+  registerBuiltin("editor-insert-tab", l_editorInserTab);
+  registerBuiltin("editor-switch-next-buffer", editorSwitchNextBuffer);
+  registerBuiltin("editor-split-screen-vertical", l_editorSplitScreenVertical);
+  registerBuiltin("editor-switch-next-pane", editorSwitchNextPane);
+  registerBuiltin("editor-unify-panes", editorUnifiedPanes);
+  registerBuiltin("editor-paste", editorPaste);
+  registerBuiltin("editor-cut-end-line", editorCutEndLine);
+  registerBuiltin("editor-move-cursor-beg-buffer", editorMoveBegBuffer);
+  registerBuiltin("editor-move-cursor-end-buffer", editorMoveEndBuffer);
+  registerBuiltin("editor-auto-complete", editorAutoComplete);
+  // registerBuiltin("lsp-complete",    lspComplete);
+  registerBuiltin("lsp-definition",  lspDefinition);
 }
 
-void initEditor() {
-  char * init_file_path = (char *) calloc(256, sizeof(char));
-  E.cursor_x = 0;
-  E.cursor_y = 0;
-  E.rx = 0;
-  E.row_offset = 0;
-  E.col_offset = 0;
-  E.numrows = 0;
-  E.row = NULL;
-  E.dirty = 0;
-  E.filename = NULL;
-  E.state = READ_ONLY;
-  E.status_msg[0] = '\0';
-  E.status_msg_time = 0;
-  if (getWindowSize(&E.screenrows, &E.screencols) == -1) {
-    die("getWindowSize");
-  }
-  E.screenrows -= 2;
+void initConfig() {
 
-  E.number_of_keybinds = 0;
-
-  strcat(init_file_path, getenv("HOME"));
-  strcat(init_file_path, "/.beluga/config/init.lisp");
-  printf("%s\n", init_file_path);
-  E.fd_init_file = fopen(init_file_path, "r");
   E.ctx = lisp_init();
+  E.ctx.p->err_port = fopen("lisp_log.err", "w");
   E.env = lisp_env(E.ctx);
   lisp_lib_load(E.ctx);
   // Init builtins lisp functions
@@ -70,12 +65,96 @@ void initEditor() {
 
   // Read config file
   E.ctx_data = lisp_read_file(E.fd_init_file, &E.ctx_error, E.ctx);
-  free(init_file_path);
   if (E.ctx_error != LISP_ERROR_NONE) {
     die("init failed");
   }
   lisp_eval(E.ctx_data, &E.ctx_error, E.ctx);
-  
+}
+
+void initTheme() {
+  E.constantes.THEME = (char *)lisp_string(
+      lisp_eval(lisp_read("THEME", &E.ctx_error, E.ctx), &E.ctx_error, E.ctx));
+  E.constantes.LSP = lisp_bool(lisp_eval(lisp_read("LSP", &E.ctx_error, E.ctx), &E.ctx_error, E.ctx));
+  appDebug("LSP ON : %d", E.constantes.LSP);
+  if (strcmp(E.constantes.THEME, "dark") == 0) {
+    E.theme.BACKGROUND_COLOR = ANSI_BG_RGB(40, 44, 52);
+    E.theme.COLOR_KEYWORD = ANSI_FG_RGB(198, 120, 221);
+    E.theme.COLOR_TYPE = ANSI_FG_RGB(97, 175, 239);
+    E.theme.COLOR_STRING = ANSI_FG_RGB(152, 195, 121);
+    E.theme.COLOR_COMMENT = ANSI_FG_RGB(92, 99, 112);
+    E.theme.COLOR_NUMBER = ANSI_FG_RGB(209, 154, 102);
+    E.theme.COLOR_DEFAULT = ANSI_FG_RGB(171, 178, 191);
+  } else {
+    E.theme.BACKGROUND_COLOR = ANSI_BG_RGB(250, 251, 252);
+    E.theme.COLOR_KEYWORD = ANSI_FG_RGB(166, 38, 164);
+    E.theme.COLOR_TYPE = ANSI_FG_RGB(4, 90, 180);
+    E.theme.COLOR_STRING = ANSI_FG_RGB(80, 161, 79);
+    E.theme.COLOR_COMMENT = ANSI_FG_RGB(152, 152, 152);
+    E.theme.COLOR_NUMBER = ANSI_FG_RGB(206, 102, 54);
+    E.theme.COLOR_DEFAULT = ANSI_FG_RGB(86, 89, 90);
+  }
+}
+
+void initEditor() {
+
+  if (getWindowSize(&E.screenrows, &E.screencols) == -1) {
+    die("getWindowSize");
+  }
+  appDebug("%d %d", E.screenrows, E.screencols);
+  E.screenrows -= 2;
+
+
+  // Init graphics variables
+  splitScreenInit();
+  EditorPane *active = splitScreenGetActivePane();
+  E.cursor_x = 0;
+  E.cursor_y = 0;
+
+  active->cursor_x = 0;
+  active->cursor_y = 0;
+  active->origin_x = 0;
+  active->origin_y = 0;
+  active->width = E.screencols;
+  active->height = E.screenrows;
+
+  const char *home = getenv("HOME");
+  if (!home) {
+    die("HOME environment variable not set");
+  }
+
+  if (asprintf(&E.init_file_path, "%s/.beluga/config/init.lisp", home) == -1) {
+    die("asprintf failed");
+  }
+
+  E.fd_init_file = fopen(E.init_file_path, "r");
+  if (!E.fd_init_file) {
+    // File might not exist, that's okay for some cases
+    // Handle accordingly
+  }
+
+  E.status_msg = calloc(E.screencols, sizeof(char));
+  if (!E.status_msg) {
+    die("malloc failed");
+  }
+  E.status_msg[0] = '\0';
+  E.status_msg[0] = '\0';
+  E.status_msg_time = 0;
+
+  // Key binds
+  E.number_of_keybinds = 0;
+  E.number_of_prefix = 0;
+  // General prefix is 0 (no prefix)
+  E.prefix = (struct prefix_t *)malloc(sizeof(struct prefix_t));
+  E.prefix[0].prefix_id = 0;
+  strncpy(E.prefix[0].prefix_name, "no-prefix", 64);
+  E.prefix_state = 0;
+
+  E.lsp_client = (LspClient*)malloc(sizeof(LspClient));
+  E.lsp_client->state = LSP_SHUTDOWN;
+
+  initConfig();
+  initTheme();
+
   // To modify
 
   E.constantes.TAB_LENGTH =
@@ -89,3 +168,25 @@ void initEditor() {
 
   E.quit_times_buffer = E.constantes.QUIT_TIMES;
 }
+
+void deInitEditor()
+{
+  freeScreenLayout(&E.layout);
+  free(E.lsp_client);
+  free(E.status_msg);
+  free(E.init_file_path);
+  free(E.key_binds);
+  for (int i = 0; i < E.number_of_keybinds; i++)
+  {
+    free(E.key_binds[i].key_sequence);
+  }
+  for (int i = 0; i < E.number_of_buffer; ++i)
+  {
+    free(E.buffers[i].filename);
+    free(E.buffers[i].path);
+    free(E.buffers[i].fullname);
+    free(E.buffers[i].row->chars);
+    free(E.buffers[i].row);
+  }
+
+}

src/input.c

@@ -1,84 +1,126 @@
 #include "../include/input.h"
+#include "../include/define.h"
 #include "../include/editor_op.h"
 #include "../include/output.h"
-#include "../include/define.h"
+#include "include/buffer.h"
+#include "include/builtins.h"
+#include "../include/completion.h"
+#include "include/data.h"
+#include "include/split_screen.h"
 #include <ctype.h>
-#include <sys/stat.h>
 #include <dirent.h>
-#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
+#include <sys/stat.h>
 
-extern struct editorConfig E;
+#include "include/terminal.h"
+#include "include/utf8.h"
 
-char * file_completion(const char *path) {
-	DIR * dir;
-	struct dirent *entry;
-	char directory[128];
-	char predict[128];
-	int predict_len = 0;
+/**
+ * @file input.c
+ * @brief Input handling module for the Beluga text editor
+ * @details Manages user input processing, key bindings, cursor movement, and
+ * file path completion
+ */
 
+/**
+ * @brief Returns the first file completion match for the given path
+ * @details Searches the directory containing the given path prefix and returns
+ * the first file or directory entry that matches the filename prefix.
+ * Appends a trailing slash for directory entries.
+ * @param path The file path to complete (can be relative or absolute)
+ * @return Pointer to the completed file path (dynamically allocated), or NULL
+ * if:
+ *         - path ends with '/' (already a directory)
+ *         - no matching entries found
+ *         - directory cannot be opened
+ * @note Caller is responsible for bFreeing the returned string
+ * @note Uses static buffer internally; may return stale pointers across calls
+ */
+const char *fileCompletion(const char *path) {
+  DIR *dir;
+  struct dirent *entry;
+  char directory[256];
+  char predict[128];
+  const char *last_slash;
+  int predict_len = 0;
+  size_t dir_len;
+
+  // path is a directory
   if (path[strlen(path) - 1] == '/') {
-    return path;
+    appDebug("[FILE COMP] is dir\n");
+    strncpy(directory, path, 256);
   }
 
-	// Find dir name
-	char * last_slash = strrchr(path, '/');
-	if (last_slash) {
-		size_t dir_len = last_slash - path + 1; // length of dir_path
-		strncpy(directory, path, dir_len);
-		predict_len = strlen(path) - dir_len - 1;
-		strncpy(predict, last_slash + 1, predict_len);
-		directory[dir_len] = '\0';
-		predict[predict_len] = '\0';
-		fprintf(stderr, "%s %s\n", directory, predict);
-	} else {
-		return NULL;
-	}
-
+  // Find dir name
+  last_slash = strrchr(path, '/');
+  if (last_slash) {
+    dir_len = last_slash - path + 1; // length of dir_path
+    strncpy(directory, path, dir_len);
+    predict_len = (int)(strlen(path) - dir_len);
+    strncpy(predict, last_slash + 1, predict_len);
+    directory[dir_len] = '\0';
+    predict[predict_len] = '\0';
+    appDebug("%s %s\n", directory, predict);
+  } else {
+    appDebug("[FILE COMP] dir not found\n");
+    return strdup(path);
+  }
 
   dir = opendir(directory);
   if (!dir)
-  	return NULL;
-	
-	while ((entry = readdir(dir)) != NULL) {
-        if (strncmp(entry->d_name, predict, predict_len) == 0) {
-            static char full_path[128];
-            snprintf(full_path, sizeof(full_path), "%s%s", directory, entry->d_name);
+    return strdup(path);
 
-            struct stat st;
-            if (stat(full_path, &st) == 0 && S_ISDIR(st.st_mode)) {
-                strcat(full_path, "/"); // add slash for directories
-            }
+  while ((entry = readdir(dir)) != NULL) {
+    if (strncmp(entry->d_name, predict, predict_len) == 0) {
+      static char full_path[1024];
+      snprintf(full_path, sizeof(full_path), "%s%s", directory, entry->d_name);
 
-            return strdup(full_path);
-        }
+      struct stat st;
+      if (stat(full_path, &st) == 0 && S_ISDIR(st.st_mode)) {
+        strcat(full_path, "/"); // add slash for directories
+      }
+      closedir(dir);
+
+      return strdup(full_path);
     }
+  }
 
-    // Cleanup when no more entries
-    closedir(dir);
-    dir = NULL;
-    return NULL;
-
+  // Cleanup when no more entries
+  closedir(dir);
+  dir = NULL;
+  free(entry);
+  appDebug("[FILE COMP] no entries\n");
+  return strdup(path);
 }
 
 /**
- * \fn char * editorPrompt(struct editorConfig *E, char *prompt, char bPathMode)
- * \brief Return user input in a prompt when enter is hit. */
-
-char *editorPrompt(char *prompt, char * placeHolder, char bPathMode) {
-  size_t buf_size = 128;
+ * @brief Displays an interactive prompt and returns user input
+ * @details Allows the user to enter text in a prompt with optional path
+ * completion via Tab key. Supports backspace, delete, and escape key handling.
+ * Dynamically allocates memory for the input buffer.
+ * @param prompt The prompt message format string (printf-style)
+ * @param placeHolder Initial text to display in the input buffer
+ * @param bPathMode If non-zero, enables Tab key file path completion
+ * @return Pointer to the user-entered text (dynamically allocated), or NULL if:
+ *         - User pressed ESC to cancel
+ *         - Input buffer is empty when Enter is pressed
+ * @note Caller is responsible for bFreeing the returned string
+ * @note Uses editorReadKey() for input and editorRefreshScreen() for display
+ */
+char *editorPrompt(char *prompt, char *placeHolder, char bPathMode) {
+  size_t buf_size = 256;
+  appDebug("[FILE COMP] %s %d\n", placeHolder, strlen(placeHolder));
   char *buf = malloc(buf_size);
   size_t buf_len = 0;
   int c = 0;
   buf[0] = '\0';
-	strcpy(buf, placeHolder);
-	buf_len = strlen(placeHolder);
+  strcpy(buf, placeHolder);
+  buf_len = strlen(placeHolder);
 
   while (1) {
-		editorSetStatusMessage(prompt, buf);
+    editorSetStatusMessage(prompt, buf);
     editorRefreshScreen();
     c = editorReadKey();
     if (c == DEL_KEY || c == CTRL_KEY('h') || c == BACKSPACE) {
@@ -95,162 +137,148 @@ char *editorPrompt(char *prompt, char * placeHolder, char bPathMode) {
         return buf;
       }
     } else if (bPathMode && c == '\t') {
-			char path[128];
-		  char * pwd;
-			if (buf[0] != '/') {
-				pwd = getenv("PWD");
-			  fprintf(stderr, "%s\n", pwd);
-			  memcpy(path, pwd, strlen(pwd));
-				path[strlen(pwd)] = '/';
-				strncat(path, buf, buf_len);
-			} else {
-				strcpy(path, buf);
-			}
-			memset(buf, 0, 128);
-			buf_len = 0;
-		  strcpy(buf, file_completion(path));
-			buf_len = strlen(buf);
-			buf[buf_len] = '\0';
-		  
-    } else if (!iscntrl(c) && c < 128) {
+      char path[256];
+      char *pwd;
+      if (buf[0] != '/') {
+        pwd = getenv("PWD");
+        appDebug("%s\n", pwd);
+        memcpy(path, pwd, strlen(pwd));
+        path[strlen(pwd)] = '/';
+        strncat(path, buf, buf_len);
+      } else {
+        strcpy(path, buf);
+      }
+      memset(buf, 0, 256);
+      char *buf_complete = (char *)fileCompletion(path);
+      strcpy(buf, buf_complete);
+      free(buf_complete);
+      buf_len = strlen(buf);
+      buf[buf_len] = '\0';
+
+    } else if (!iscntrl(c) && c < 256) {
       if (buf_len == buf_size - 1) {
         buf_size *= 2;
-        buf = realloc(buf, buf_size);
-      }
-      buf[buf_len++] = c;
-      buf[buf_len] = '\0';
-    }
-  }
-}
-
-char *key_to_string(int key) {
-  static char key_str[32];
-
-  char tmp[10];
-  sprintf(tmp, "%d", key);
-
-
-  // First test enter key
-
-  if (key == '\r') {
-    strcpy(key_str, "ENTER");
-  } else if (key >= 1 && key <= 26) { // CTRL keys
-    snprintf(key_str, sizeof(key_str), "CTRL-%c", 'a' + key - 1);
-  } else {
-    switch (key) {
-    case ARROW_UP:
-      strcpy(key_str, "ARROW-UP");
-      break;
-    case ARROW_DOWN:
-      strcpy(key_str, "ARROW-DOWN");
-      break;
-    case ARROW_LEFT:
-      strcpy(key_str, "ARROW-LEFT");
-      break;
-    case ARROW_RIGHT:
-      strcpy(key_str, "ARROW-RIGHT");
-      break;
-    case PAGE_UP:
-      strcpy(key_str, "PAGE-UP");
-      fprintf(stderr, "pagr up\n");
-      break;
-    case PAGE_DOWN:
-      strcpy(key_str, "PAGE-DOWN");
-      break;
-    case DEL_KEY:
-      fprintf(stderr, "delete key\n");
-      strcpy(key_str, "DEL");
-      
-      break;
-    case BACKSPACE:
-      strcpy(key_str, "BACKSPACE");
-      break;
-    case '\r':
-      strcpy(key_str, "ENTER");
-      break;
-    case '\x1b':
-      strcpy(key_str, "ESCAPE");
-      break;
-    case BEG_LINE:
-      strcpy(key_str, "HOME");
-      break;
-    case END_LINE:
-      strcpy(key_str, "END");
-      break;
-    default:
-      // For regular characters
-      if (isprint(key)) {
-        snprintf(key_str, sizeof(key_str), "%c", key);
-      } else {
-        snprintf(key_str, sizeof(key_str), "KEY-%d", key);
+        char *new_buf = realloc(buf, buf_size);
+        if (!new_buf) {
+          free(buf);
+          return NULL;
+        }
+        buf = new_buf;
       }
     }
   }
-  return key_str;
-}
-
-
-void editorMoveCursor(int key) {
-  erow *row = (E.cursor_y >= E.numrows) ? NULL : &E.row[E.cursor_y];
-  int row_len;
-  switch (key) {
-  case ARROW_RIGHT:
-    if (row && E.cursor_x < row->size) {
-      ++E.cursor_x;
-    } else if (row && E.cursor_x == row->size) {
-      E.cursor_y++;
-      E.cursor_x = 0;
-    }
-    break;
-  case ARROW_DOWN:
-    if (E.cursor_y < E.numrows) {
-      ++E.cursor_y;
-    }
-    break;
-  case ARROW_UP:
-    if (E.cursor_y != 0) {
-      --E.cursor_y;
-    }
-    break;
-  case ARROW_LEFT:
-    if (E.cursor_x != 0) {
-      --E.cursor_x;
-    } else if (E.cursor_y > 0) {
-      --E.cursor_y;
-      E.cursor_x = E.row[E.cursor_y].size;
-    }
-    break;
-  }
-
-  row = (E.cursor_y >= E.numrows) ? NULL : &E.row[E.cursor_y];
-  row_len = row ? row->size : 0;
-  if (E.cursor_x > row_len) {
-    E.cursor_x = row_len;
-  }
 }
 
+/**
+ * @brief Executes the command bound to a key sequence
+ * @details Searches the keybinding table for a matching key sequence and
+ * prefix state, then evaluates the associated Lisp command.
+ * @param key_sequence The string representation of the key sequence
+ * @return 1 if a matching keybinding was found and executed, 0 otherwise
+ * @note Updates global editor state E (prefix_state)
+ * @note Uses Lisp interpreter to evaluate bound commands
+ */
 int executeKeyBind(char *key_sequence) {
   int i;
+  int previous_state = 0;
+  appDebug("pressed %s\n", key_sequence);
   for (i = 0; i < E.number_of_keybinds; ++i) {
     if (!strcmp(key_sequence, E.key_binds[i].key_sequence)) {
-  
-        fprintf(stderr, "lisp function %s\n", key_sequence);
-        // It's a symbol, create a function call
-        lisp_eval(lisp_cons(E.key_binds[i].command, lisp_null(), E.ctx),
-                  &E.ctx_error, E.ctx);
-        return 1;
+      if (E.prefix_state != E.key_binds[i].prefix_id) {
+        continue;
+      }
+      previous_state = E.prefix_state;
+      // It's a symbol, create a function call
+      lisp_eval(lisp_cons(E.key_binds[i].command, lisp_null(), E.ctx),
+                &E.ctx_error, E.ctx);
+      if (E.prefix_state == previous_state)
+        E.prefix_state = 0;
+      return 1;
     }
   }
   return 0;
 }
 
+/**
+ * @brief Processes a single keypress from the user
+ * @details Reads a key, checks if it matches any registered keybinding,
+ * and either executes the bound command or inserts the character. Resets
+ * the quit buffer counter on successful key processing.
+ * @note Updates global editor state E
+ * @note Calls editorReadKey() to get input and editorInsertChar() for unbound
+ * keys
+ */
 void editorProcessKeypress() {
   int c = editorReadKey();
+  char key_sequence[8];
+  EditorPane *active = splitScreenGetActivePane();
+  struct buffer_t *buf = bufferFindById(active->buffer_id);
 
-  if (executeKeyBind(key_to_string(c))) {
+  if (E.constantes.LSP && buf->b_lsp_open) {
+    if (c == LSP_WAKE_KEY)
+      return;
+    if (E.lsp_client && E.lsp_completion.visible) {
+      if (c == ARROW_UP || c == CTRL_KEY('p')) {
+        if (E.lsp_completion.selected > 0)
+          E.lsp_completion.selected--;
+        return; // consumed, redraw on next loop
+      }
+      if (c == ARROW_DOWN || c == CTRL_KEY('n')) {
+        if (E.lsp_completion.selected < E.lsp_completion.count - 1)
+          E.lsp_completion.selected++;
+        return;
+      }
+      if (c == '\r') {
+        CompletionItem *item =
+            &E.lsp_completion.items[E.lsp_completion.selected];
+
+
+        // Find how many chars the user already typed by looking at the
+        // current word (chars before cursor on the same line)
+        int file_col = active->cursor_x + active->x_offset;
+        row_t *row = &buf->row[active->cursor_y + active->y_offset];
+
+        // Walk backwards from cursor to find start of current word
+        int word_start = file_col;
+        while (word_start > 0 &&
+               (isalnum((unsigned char)row->chars[word_start - 1]) ||
+                row->chars[word_start - 1] == '_'))
+          word_start--;
+
+        int already_typed = file_col - word_start; // chars user already typed
+
+        // Insert only the suffix — what comes after what's already typed
+        const char *suffix = item->label + already_typed;
+        for (int i = 0; suffix[i]; i++)
+          bufferInsertBytes(&suffix[i], 1);
+
+        E.lsp_completion.visible = 0;
+        return;
+      }
+      if (c == ESCAPE) {
+        E.lsp_completion.visible = 0;
+        return;
+      }
+      // Any other key: dismiss popup and fall through to normal handling
+      E.lsp_completion.visible = 0;
+    }
+  }
+
+  if (executeKeyBind(keyToString(c))) {
     return;
   }
-  editorInsertChar(c);
-  E.quit_times_buffer = E.constantes.QUIT_TIMES;
+  int seq_len = utf8Encode(c, key_sequence);
+  appDebug("key seq : %s\n", key_sequence);
+  bufferInsertBytes(key_sequence, seq_len);
+  if (buf->b_lsp_open && is_word_char(key_sequence)) {
 
+    if (E.lsp_client && E.lsp_client->state == LSP_READY) {
+      lspDidChange(E.lsp_client, buf);
+
+      E.lsp_client->completion_just_arrived = 0; // consume the flag
+    }
+    buf->b_has_changed = 0;
+    editorAutoComplete(lisp_null(), &E.ctx_error, E.ctx);
+  }
+  E.quit_times_buffer = E.constantes.QUIT_TIMES;
 }

src/lsp_ui.c

@@ -0,0 +1,330 @@
+//
+// Created by Giorgio on 27/05/2026.
+//
+
+#include "include/lsp_ui.h"
+#include "include/data.h"
+#include <stdio.h>
+#include <string.h>
+
+// We use cJSON — drop cJSON.c + cJSON.h into src/ and include/
+#include "include/cJSON.h"
+#include "include/append_buffer.h"
+#include "include/terminal.h"
+
+// ─── ANSI helpers ─────────────────────────────────────────────────────────────
+
+// Move terminal cursor to absolute (col, row) — 1-based
+static void ab_move(struct abuf *ab, int row, int col) {
+    char esc[32];
+    int  n = snprintf(esc, sizeof(esc), "\x1b[%d;%dH", row, col);
+    abAppend(ab, esc, n);   // your existing abAppend
+}
+
+static void ab_sgr(struct abuf *ab, const char *codes) {
+    char esc[32];
+    int  n = snprintf(esc, sizeof(esc), "\x1b[%sm", codes);
+    abAppend(ab, esc, n);
+}
+
+#define AB_RESET(ab)      ab_sgr(ab, "0")
+#define AB_BOLD(ab)       ab_sgr(ab, "1")
+#define AB_DIM(ab)        ab_sgr(ab, "2")
+#define AB_FG(ab, c)      ab_sgr(ab, c)   // e.g. "32" = green
+#define AB_BG(ab, c)      ab_sgr(ab, c)   // e.g. "44" = blue bg
+
+// ─── Completion item kind → short tag ────────────────────────────────────────
+
+static const char *kind_tag(int k) {
+    switch (k) {
+        case  2: return "mth";  // Method
+        case  3: return "fn ";  // Function
+        case  4: return "ctr";  // Constructor
+        case  5: return "fld";  // Field
+        case  6: return "var";  // Variable
+        case  7: return "cls";  // Class
+        case  9: return "ifc";  // Interface
+        case 14: return "kwd";  // Keyword
+        default: return "   ";
+    }
+}
+
+static const char *kind_color(int k) {
+    switch (k) {
+        case  3: return "33";   // yellow  — functions
+        case  2: return "36";   // cyan    — methods
+        case  7: return "35";   // magenta — classes
+        case 14: return "34";   // blue    — keywords
+        case  5:
+        case  6: return "32";   // green   — fields/vars
+        default: return "37";   // white
+    }
+}
+
+// ─── Draw completion popup ───────────────────────────────────────────────────
+//
+//  ┌─────────────────────────────────────┐
+//  │ fn  printf          int (const …)  │  ← selected (bold, inverted)
+//  │ fn  fprintf                        │
+//  │ fn  sprintf                        │
+//  └─────────────────────────────────────┘
+//
+// Drawn using absolute cursor positioning — safe to call inside
+// editorRefreshScreen() before the final write().
+
+void lspUiDrawCompletion(struct abuf *ab, CompletionPopup *popup) {
+    appDebug("[DRAW] visible=%d count=%d origin=(%d,%d)\n",
+            popup->visible, popup->count,
+            popup->origin_x, popup->origin_y);
+    if (!popup->visible || popup->count == 0) return;
+
+    int visible_count = popup->count < COMPLETION_POPUP_H
+                      ? popup->count : COMPLETION_POPUP_H;
+    int box_w = COMPLETION_MAX_WIDTH;
+
+    // Scroll window so selected item is always visible
+    int scroll = 0;
+    if (popup->selected >= COMPLETION_POPUP_H)
+        scroll = popup->selected - COMPLETION_POPUP_H + 1;
+    // ── top border ────────────────────────────────────────────────────────────
+    ab_move(ab, popup->origin_y, popup->origin_x);
+    ab_sgr(ab, "0;37;40");          // white on black
+    abAppend(ab, "┌", 3);           // UTF-8 box chars (3 bytes each)
+    for (int i = 0; i < box_w - 2; i++) abAppend(ab, "─", 3);
+    abAppend(ab, "┐", 3);
+
+    // ── rows ──────────────────────────────────────────────────────────────────
+    for (int i = 0; i < visible_count; i++) {
+        int idx = i + scroll;
+        CompletionItem *it = &popup->items[idx];
+        int is_sel = (idx == popup->selected);
+
+        ab_move(ab, popup->origin_y + 1 + i, popup->origin_x);
+
+        if (is_sel) ab_sgr(ab, "7");        // reverse video (highlight)
+        else        ab_sgr(ab, "0;37;40");
+
+        abAppend(ab, "| ", 2);
+
+        // kind tag in color
+        if (!is_sel) ab_sgr(ab, kind_color(it->kind));
+        abAppend(ab, kind_tag(it->kind), 3);
+        abAppend(ab, " ", 1);
+        if (!is_sel) AB_RESET(ab);
+        if (!is_sel) ab_sgr(ab, "37;40");
+
+        // label — left column, fixed width 20
+        char label_col[21];
+        snprintf(label_col, sizeof(label_col), "%-20s", it->label);
+        if (is_sel) AB_BOLD(ab);
+        abAppend(ab, label_col, 20);
+        if (is_sel) ab_sgr(ab, "22"); // bold off
+
+        abAppend(ab, " ", 1);
+
+        // detail — right column, dimmed
+        if (!is_sel) AB_DIM(ab);
+        char detail_col[14];
+        snprintf(detail_col, sizeof(detail_col), "%-13s", it->detail);
+        abAppend(ab, detail_col, 13);
+
+        AB_RESET(ab);
+        if (is_sel) ab_sgr(ab, "7");
+        else        ab_sgr(ab, "37;40");
+        abAppend(ab, " |", 2);
+        AB_RESET(ab);
+    }
+
+    // ── scroll indicator on right border if needed ────────────────────────────
+    if (popup->count > COMPLETION_POPUP_H) {
+        int bar_row = popup->origin_y + 1 +
+                      (popup->selected * (COMPLETION_POPUP_H - 1))
+                      / (popup->count - 1);
+        ab_move(ab, bar_row, popup->origin_x + box_w - 1);
+        ab_sgr(ab, "0;37;40");
+        abAppend(ab, "█", 3);
+        AB_RESET(ab);
+    }
+
+    // ── bottom border ─────────────────────────────────────────────────────────
+    ab_move(ab, popup->origin_y + 1 + visible_count, popup->origin_x);
+    ab_sgr(ab, "0;37;40");
+    abAppend(ab, "└", 3);
+    for (int i = 0; i < box_w - 2; i++) abAppend(ab, "─", 3);
+    abAppend(ab, "┘", 3);
+    AB_RESET(ab);
+}
+
+// ─── Handle popup keys ────────────────────────────────────────────────────────
+// Returns 1 if key was consumed, 0 if editor should handle it normally.
+
+int lspUiHandleKey(CompletionPopup *popup, int key) {
+    if (!popup->visible) return 0;
+
+    switch (key) {
+        case '\x1b':
+        case '\r':  // ESC — dismiss
+            popup->visible = 0;
+            return 1;
+
+        // Arrow up / Ctrl-p
+        case 'A' + 0x80:
+        case 0x10:
+            if (popup->selected > 0) popup->selected--;
+            return 1;
+
+        // Arrow down / Ctrl-n
+        case 'B' + 0x80:
+        case 0x0e:
+            if (popup->selected < popup->count - 1) popup->selected++;
+            return 1;
+
+        default:
+            // Any printable key: dismiss popup, let editor handle it
+            popup->visible = 0;
+            return 0;
+    }
+}
+
+static DiagSeverity diag_worst_on_line(DiagnosticList *diags,
+                                       int buffer_id, int line) {
+    DiagSeverity worst = 0;
+    for (int i = 0; i < diags->count; i++) {
+        Diagnostic *d = &diags->entries[i];
+        if (d->buffer_id == buffer_id && d->line == line) {
+            if (d->severity > worst) worst = d->severity;  // ERROR > WARN > HINT
+        }
+    }
+    return worst;
+}
+
+// Call this once per screen row, right before you draw the row text.
+// ab     : your append buffer
+// diags  : &E.lsp_diagnostics
+// buf_id : active buffer id
+// line   : file line number (0-based) for this screen row
+void lspUiDrawGutter(struct abuf *ab, DiagnosticList *diags,
+                     int buf_id, int line) {
+    DiagSeverity s = diag_worst_on_line(diags, buf_id, line);
+    switch (s) {
+        case DIAG_ERROR:
+            ab_sgr(ab, "1;31");         // bold red
+            abAppend(ab, "●", 3);
+            break;
+        case DIAG_WARNING:
+            ab_sgr(ab, "1;33");         // bold yellow
+            abAppend(ab, "◆", 3);
+            break;
+        case DIAG_HINT:
+            ab_sgr(ab, "2;37");         // dim white
+            abAppend(ab, "·", 1);
+            break;
+        default:
+            abAppend(ab, " ", 1);       // no diagnostic
+            break;
+    }
+    AB_RESET(ab);
+    abAppend(ab, " ", 1);  // gutter padding
+}
+
+// Returns the diagnostic message for the line the cursor is on, or NULL.
+const char *lspUiDiagnosticAtCursor(DiagnosticList *diags,
+                                    int buffer_id, int cursor_line) {
+    for (int i = 0; i < diags->count; i++) {
+        Diagnostic *d = &diags->entries[i];
+        if (d->buffer_id == buffer_id && d->line == cursor_line)
+            return d->message;
+    }
+    return NULL;
+}
+
+// ─── Parse clangd JSON → our structs ─────────────────────────────────────────
+
+void lspParseCompletion(const char *json, CompletionPopup *popup,
+                        int screen_x, int screen_y) {
+    popup->count    = 0;
+    popup->selected = 0;
+    popup->origin_x = screen_x + 1;
+    popup->origin_y = screen_y + 2;  // one row below cursor
+
+    cJSON *root  = cJSON_Parse(json);
+    if (!root) return;
+    cJSON *result = cJSON_GetObjectItem(root, "result");
+    if (!result) { cJSON_Delete(root); return; }
+    // result can be a list or {isIncomplete, items:[…]}
+    cJSON *items = cJSON_IsArray(result)
+                 ? result
+                 : cJSON_GetObjectItem(result, "items");
+    if (!items) { cJSON_Delete(root); return; }
+
+    cJSON *item;
+    cJSON_ArrayForEach(item, items) {
+        if (popup->count >= COMPLETION_MAX_ITEMS) break;
+        CompletionItem *ci = &popup->items[popup->count++];
+
+        cJSON *label  = cJSON_GetObjectItem(item, "label");
+        cJSON *detail = cJSON_GetObjectItem(item, "detail");
+        cJSON *kind   = cJSON_GetObjectItem(item, "kind");
+
+        const char *raw_label = label ? label->valuestring : "";
+        if (raw_label[0] == ' ') raw_label++;
+
+        strncpy(ci->label,  raw_label,                          127);
+        strncpy(ci->detail, detail ? detail->valuestring : "",   63);
+
+        if (!kind)
+            ci->kind = 0;
+        else
+            ci->kind = kind->valueint;
+    }
+
+    popup->visible = (popup->count > 0);
+    cJSON_Delete(root);
+}
+
+void lspParseDiagnostics(const char *json, DiagnosticList *diags,
+                         int buffer_id) {
+    cJSON *root = cJSON_Parse(json);
+    if (!root) return;
+
+    cJSON *params = cJSON_GetObjectItem(root, "params");
+    if (!params) { cJSON_Delete(root); return; }
+    cJSON *diag_arr = cJSON_GetObjectItem(params, "diagnostics");
+    if (!diag_arr) { cJSON_Delete(root); return; }
+
+    // Remove old entries for this buffer
+    int w = 0;
+    for (int i = 0; i < diags->count; i++)
+        if (diags->entries[i].buffer_id != buffer_id)
+            diags->entries[w++] = diags->entries[i];
+    diags->count = w;
+
+    cJSON *d;
+    cJSON_ArrayForEach(d, diag_arr) {
+        if (diags->count >= DIAG_MAX) break;
+        Diagnostic *diag = &diags->entries[diags->count++];
+        diag->buffer_id = buffer_id;
+
+        cJSON *range    = cJSON_GetObjectItem(d, "range");
+        cJSON *start    = cJSON_GetObjectItem(range, "start");
+        cJSON *end_pos  = cJSON_GetObjectItem(range, "end");
+        cJSON *sev      = cJSON_GetObjectItem(d, "severity");
+        cJSON *msg      = cJSON_GetObjectItem(d, "message");
+
+        diag->line      = cJSON_GetObjectItem(start, "line")->valueint;
+        diag->col_start = cJSON_GetObjectItem(start, "character")->valueint;
+        diag->col_end   = cJSON_GetObjectItem(end_pos, "character")->valueint;
+        diag->severity  = sev ? (DiagSeverity)sev->valueint : DIAG_ERROR;
+
+        const char *raw = msg ? msg->valuestring : "";
+        int i = 0;
+        while (raw[i] && raw[i] != '\n' && i < 255)
+        {
+            diag->message[i] = raw[i];
+            i++;
+        }
+        diag->message[i] = '\0';
+    }
+
+    cJSON_Delete(root);
+}

src/output.c

@@ -1,137 +1,417 @@
+/**
+ * @file output.c
+ * @brief Screen rendering and output module for the Beluga text editor
+ * @details Handles all screen updates, cursor positioning, status bar
+ * rendering, and display synchronization using ANSI escape sequences
+ */
+
 #include "../include/output.h"
-#include <stdarg.h>
+#include "../include/append_buffer.h"
+#include "../include/buffer.h"
+#include "../include/editor_op.h"
+#include "../include/data.h"
+#include "../include/define.h"
+#include "../include/row_op.h"
+#include "../include/split_screen.h"
+#include "../include/syntax_highlighter.h"
+#include "../include/terminal.h"
+#include "../include/lsp_ui.h"
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <time.h>
 
-extern struct editorConfig E;
+/**
+ * @brief Renders a single pane with its buffer content
+ */
+static void editorDrawPane(struct abuf* ab, EditorPane* pane)
+{
+    int file_row;
+    char pos_buf[32];
+    int pos_len;
+    int byte_len_to_print;
+    int bytes_to_print;
+    char* highlighted;
 
-void editorDrawRows(struct abuf *ab) {
-  int y;
-  char welcome[80];
-  int welcome_len;
-  int padding;
-  int len;
-  int file_row;
-  for (y = 0; y < E.screenrows; ++y) {
-    file_row = y + E.row_offset;
-    if (file_row >= E.numrows) {
-      if (E.numrows == 0 && y == E.screenrows / 3) {
-        welcome_len =
-            snprintf(welcome, sizeof(welcome),
-                     "Beluga text editor -- version %s", BELUGA_VERSION);
-        if (welcome_len > E.screencols) {
-          welcome_len = E.screencols;
+    if (pane == NULL || pane->buffer_id < 0)
+        return;
+
+    const struct buffer_t* buf = bufferFindById(pane->buffer_id);
+    if (buf == NULL)
+        return;
+
+    // Draw all pane
+    for (int y = 0; y < pane->height; y++)
+    {
+        file_row = y + pane->y_offset;
+
+        // Set cursor at start of pane row
+        pos_len = snprintf(pos_buf, sizeof(pos_buf), "\x1b[%d;%dH",
+                           pane->origin_y + y + 1, pane->origin_x + 1);
+        abAppend(ab, pos_buf, pos_len);
+
+        // Apply background color (6 bytes for RGB format)
+        abAppend(ab, E.theme.BACKGROUND_COLOR, (int)strlen(E.theme.BACKGROUND_COLOR));
+
+
+        // pane line is out of buffer
+        if (file_row >= buf->numrows)
+        {
+            // Empty line - show tilde
+
+            abAppend(ab, "~", 1);
+            for (int i = 0;
+                 i < pane->width - 1;
+                 ++i)
+            {
+                abAppend(ab, " ", 1);
+            }
         }
-        padding = (E.screencols - welcome_len) / 2;
-        if (padding) {
-          abAppend(ab, "~", 1);
-          --padding;
+        else
+        {
+            if (E.constantes.LSP) {
+                    lspUiDrawGutter(ab, &E.lsp_diagnostics, pane->buffer_id, file_row);
+            }
+
+
+            if (buf->filename[strlen(buf->filename) - 1] == 'c' || buf->filename[strlen(buf->filename) - 1] == 'h')
+            {
+                // Render line with syntax highlighting, constrain to pane width
+                highlighted = highlight_line(
+                    &buf->row[file_row].chars[pane->x_offset], &byte_len_to_print);
+
+                // Print only up to pane width
+                abAppend(ab, highlighted, byte_len_to_print);
+                free(highlighted);
+            }
+            else
+            {
+                // Render basic line
+                bytes_to_print =
+                    buf->row[file_row].size - pane->x_offset < pane->width
+                        ? buf->row[file_row].size - pane->x_offset
+                        : pane->width;
+                abAppend(ab, &buf->row[file_row].chars[pane->x_offset], bytes_to_print);
+            }
+            // Fill remaining space with background color to pane width
+            for (int i = 0;
+                 i < pane->width - editorRowCharCount(&buf->row[file_row], pane->width) + pane->x_offset;
+                 ++i)
+            {
+                abAppend(ab, " ", 1);
+            }
         }
-        while (padding--) {
-          abAppend(ab, " ", 1);
+    }
+}
+
+/**
+ * @brief Renders all panes based on current split configuration
+ */
+static void editorDrawAllPanes(struct abuf* ab)
+{
+    const ScreenLayout* layout = splitScreenGetLayout();
+
+    if (layout->num_panes == 1)
+    {
+        // Single pane fullscreen
+        editorDrawPane(ab, &layout->panes[0]);
+    }
+    else if (layout->num_panes == 2)
+    {
+        // Draw both panes
+        for (int i = 0; i < 2; i++)
+        {
+            editorDrawPane(ab, &layout->panes[i]);
+
+            // Draw pane border/divider if not the last pane
+            if (layout->mode == SPLIT_VERTICAL && i == 0)
+            {
+                // Draw vertical divider
+                int divider_col = layout->panes[0].width;
+                for (int y = 0; y < layout->panes[0].height; y++)
+                {
+                    char pos_buf[32];
+                    snprintf(pos_buf, sizeof(pos_buf), "\x1b[%d;%dH", y + 1, divider_col);
+                    abAppend(ab, pos_buf, (int)strlen(pos_buf));
+                    abAppend(ab, "\x1b[1m|\x1b[0m", 9); // Bold pipe divider
+                }
+            }
+            else if (layout->mode == SPLIT_HORIZONTAL && i == 0)
+            {
+                // Draw horizontal divider
+                int divider_row = layout->panes[0].height;
+                char pos_buf[32];
+                snprintf(pos_buf, sizeof(pos_buf), "\x1b[%d;%dH", divider_row + 1, 1);
+                abAppend(ab, pos_buf, (int)strlen(pos_buf));
+                for (int x = 0; x < E.screencols; x++)
+                {
+                    abAppend(ab, "\x1b[1m-\x1b[0m", 9); // Bold dash divider
+                }
+            }
         }
-        abAppend(ab, welcome, welcome_len);
-      } else {
-        abAppend(ab, "~", 1);
-      }
-    } else {
-      len = E.row[file_row].rsize - E.col_offset;
-      if (len < 0)
-        len = 0;
-      if (len > E.screencols)
+    }
+}
+
+/**
+ * @brief Updates scroll offsets to keep cursor visible on screen
+ * @details Adjusts E.row_offset and E.col_offset to ensure the cursor remains
+ * within the visible viewport. Also updates E.rx (rendered x-coordinate).
+ * @note Updates global editor state E
+ * @see editorRowCxToRx()
+ */
+void editorScroll()
+{
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buf = bufferFindById(active->buffer_id);
+    int rel_x, rel_y;
+
+    // compute relative coordinates
+    rel_x = editorRowCharCount(&buf->row[buf->y], buf->x);
+    appDebug("counting %d\n", rel_x);
+    rel_y = buf->y;
+
+    appDebug("%d %d / %d %d\n", active->cursor_x, active->x_offset,
+             active->cursor_y, active->y_offset);
+
+    while (rel_x != active->cursor_x + active->x_offset ||
+        rel_y != active->cursor_y + active->y_offset)
+    {
+        if (rel_x < active->cursor_x + active->x_offset)
+        {
+            // LEFT
+            if (active->cursor_x == 0 && active->x_offset)
+            {
+                active->x_offset--;
+            }
+            else
+            {
+                active->cursor_x--;
+            }
+        }
+        else
+        {
+            // RIGHT
+            if (rel_x > active->cursor_x + active->x_offset)
+            {
+                if (active->cursor_x == active->width - 1)
+                {
+                    active->x_offset++;
+                }
+                else
+                {
+                    active->cursor_x++;
+                }
+            }
+        }
+
+        if (rel_y < active->cursor_y + active->y_offset)
+        {
+            if (active->cursor_y == 0 && active->y_offset)
+            {
+                active->y_offset--;
+            }
+            else
+            {
+                active->cursor_y--;
+            }
+        }
+
+        if (rel_y > active->cursor_y + active->y_offset)
+        {
+            if (active->cursor_y == active->height - 1)
+            {
+                active->y_offset++;
+            }
+            else
+            {
+                active->cursor_y++;
+            }
+        }
+    }
+}
+
+char* basename(char* path)
+{
+    int len = (int)strlen(path);
+
+
+    for (int i = len - 1; i > 0; i--)
+    {
+        if (path[i] == '/')
+        {
+            path = path + i + 1;
+            break;
+        }
+    }
+    return path;
+}
+
+/**
+ * @brief Renders the status bar at the bottom of the screen
+ * @details Displays filename, line count, dirty flag, and current cursor
+ * position in an inverted color bar. Right-aligns the cursor position
+ * indicator.
+ * @param ab Pointer to append buffer structure for accumulating output
+ * @note Uses ANSI escape codes for color inversion
+ */
+void editorDrawStatusBar(struct abuf* ab)
+{
+    // TO MODIFY
+    int len, render_len;
+    char status[E.screencols], render_status[E.screencols * 4];
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buf = bufferFindById(active->buffer_id);
+
+    abAppend(ab, "\x1b[7m", 4); // inverting colors
+
+    const char* mode_str = "";
+    ScreenLayout* layout = splitScreenGetLayout();
+    if (layout->mode == SPLIT_VERTICAL)
+        mode_str = " [V-SPLIT]";
+    else if (layout->mode == SPLIT_HORIZONTAL)
+        mode_str = " [H-SPLIT]";
+
+    // Build buffer status showing all buffers with dirty indicators
+    char buf_status[1024] = "";
+    int offset = 0;
+    for (int i = 0; i < E.number_of_buffer; i++)
+    {
+        struct buffer_t* b = &E.buffers[i];
+        char marker = (b->buffer_id == active->buffer_id) ? '>' : ' ';
+        char dirty_marker = b->dirty ? '*' : ' ';
+        offset += snprintf(&buf_status[offset], sizeof(buf_status) - offset,
+                           "%c%d:%s%c ", marker, b->buffer_id,
+                           b->filename ? basename(b->filename) : "[No Name]", dirty_marker);
+    }
+
+    len = snprintf(status, sizeof(status), "%s%s", buf_status, mode_str);
+
+    render_len = snprintf(render_status, sizeof(render_status), "%d/%d",
+                          active->cursor_y + 1, buf->numrows);
+
+    if (len > E.screencols)
+    {
         len = E.screencols;
-      abAppend(ab, &E.row[file_row].render[E.col_offset], len);
     }
-    abAppend(ab, ERASE_END_LINE, 3);
+
+    abAppend(ab, status, len);
+    while (len < E.screencols)
+    {
+        if (E.screencols - len == render_len + 1)
+        {
+            abAppend(ab, render_status, render_len);
+            break;
+        }
+        abAppend(ab, " ", 1);
+        ++len;
+    }
+
+    abAppend(ab, "\x1b[m", 3); // normal text mode
     abAppend(ab, "\r\n", 2);
-  }
 }
 
-void editorScroll() {
-  E.rx = E.cursor_x;
-  if (E.cursor_y < E.numrows) {
-    E.rx = editorRowCxToRx(&E.row[E.cursor_y], E.cursor_x);
-  }
-
-  if (E.cursor_y < E.row_offset) {
-    E.row_offset = E.cursor_y;
-  }
-  if (E.cursor_y >= E.row_offset + E.screenrows) {
-    E.row_offset = E.cursor_y - E.screenrows + 1;
-  }
-  if (E.rx < E.col_offset) {
-    E.col_offset = E.rx;
-  }
-  if (E.rx >= E.col_offset + E.screencols) {
-    E.col_offset = E.rx - E.screencols + 1;
-  }
-}
-
-void editorDrawStatusBar(struct abuf *ab) {
-  int len, render_len;
-  char status[80], render_status[80];
-
-  abAppend(ab, "\x1b[7m", 4); // inverting colors
-  len = snprintf(status, sizeof(status), "%.20s - %d lines%s",
-                 E.filename ? E.filename : "[No Name]", E.numrows,
-                 E.dirty ? "*" : "");
-  render_len = snprintf(render_status, sizeof(render_status), "%d/%d",
-                        E.cursor_y + 1, E.numrows);
-  if (len > E.screencols) {
-    len = E.screencols;
-  }
-  abAppend(ab, status, len);
-  while (len < E.screencols) {
-    if (E.screencols - len == render_len) {
-      abAppend(ab, render_status, render_len);
-      break;
-    } else {
-      abAppend(ab, " ", 1);
-      ++len;
+/**
+ * @brief Renders the message bar below the status bar
+ * @details Displays temporary status messages for a limited time (5 seconds).
+ * Only displays message if within time window and within screen width.
+ * @param ab Pointer to append buffer structure for accumulating output
+ * @note Messages are set by editorSetStatusMessage()
+ */
+void editorDrawMessageBar(struct abuf* ab)
+{
+    int msg_len = (int)strlen(E.status_msg);
+    abAppend(ab, ERASE_END_LINE, 3);
+    if (msg_len > E.screencols)
+    {
+        msg_len = E.screencols;
+    }
+    if (msg_len && time(NULL) - E.status_msg_time < 5)
+    {
+        abAppend(ab, E.status_msg, msg_len);
     }
-  }
-  abAppend(ab, "\x1b[m", 3); // normal text mode
-  abAppend(ab, "\r\n", 2);
 }
 
-void editorDrawMessageBar(struct abuf *ab) {
-  int msg_len = strlen(E.status_msg);
-  abAppend(ab, ERASE_END_LINE, 3);
-  if (msg_len > E.screencols) {
-    msg_len = E.screencols;
-  }
-  if (msg_len && time(NULL) - E.status_msg_time < 5) {
-    abAppend(ab, E.status_msg, msg_len);
-  }
-}
-
-void editorRefreshScreen() {
-  editorScroll();
-  struct abuf ab = ABUF_INIT;
-  char buf[32];
-
-  abAppend(&ab, HIDE_CURSOR, 6);
-  abAppend(&ab, CURSOR_TOP_LEFT, 3);
-
-  editorDrawRows(&ab);
-  editorDrawStatusBar(&ab);
-  editorDrawMessageBar(&ab);
-
-  snprintf(buf, sizeof(buf), "\x1b[%d;%dH", (E.cursor_y - E.row_offset) + 1,
-           (E.rx - E.col_offset) + 1);
-  abAppend(&ab, buf, strlen(buf));
-
-  abAppend(&ab, SHOW_CURSOR, 6);
-
-  write(STDOUT_FILENO, ab.b, ab.len);
-  abFree(&ab);
-}
-
-void editorSetStatusMessage(const char *fmt, ...) {
-  va_list ap;
-  va_start(ap, fmt);
-  vsnprintf(E.status_msg, sizeof(E.status_msg), fmt, ap);
-  va_end(ap);
-  E.status_msg_time = time(NULL);
+/**
+ * @brief Performs complete screen refresh and buffer synchronization
+ * @details Clears screen, redraws all visible content (rows, status bar,
+ * message bar), positions cursor, and writes accumulated buffer to stdout. This
+ * is the main rendering function called each frame.
+ * @note Updates global editor state E (via editorScroll())
+ * @see editorDrawRows()
+ * @see editorDrawStatusBar()
+ * @see editorDrawMessageBar()
+ */
+
+void editorRefreshScreen()
+{
+    struct abuf ab = ABUF_INIT;
+    char buf[32];
+
+    abAppend(&ab, HIDE_CURSOR, 6);
+    abAppend(&ab, CURSOR_TOP_LEFT, 3);
+    abAppend(&ab, E.theme.BACKGROUND_COLOR,
+             (int)strlen(E.theme.BACKGROUND_COLOR));
+
+    editorScroll();
+
+
+    EditorPane* active = splitScreenGetActivePane();
+    struct buffer_t* buffer = bufferFindById(active->buffer_id);
+
+    editorDrawAllPanes(&ab);
+    if (E.constantes.LSP) {
+
+        // ── LSP: draw completion popup every frame while visible ──────────────────
+        appDebug("[REFRESH] lsp_completion.visible=%d\n",
+                E.lsp_completion.visible);
+        while (E.lsp_client->completion_requested && !E.lsp_client->completion_just_arrived);
+        // reset flags
+        E.lsp_client->completion_just_arrived = 0;
+        E.lsp_client->completion_requested = 0;
+
+        // ── LSP: diagnostic for current line in status bar ────────────────────────
+        const char* diag = lspUiDiagnosticAtCursor(
+            &E.lsp_diagnostics,
+            active->buffer_id,
+            buffer->y);
+        if (diag) {
+            char single_line[512];
+            int i = 0;
+
+            // Copy until newline, \0, or screen width
+            while (diag[i] && diag[i] != '\n' && i < E.screencols - 4)
+            {
+                single_line[i] = diag[i];
+                i++;
+            }
+
+            // If message was truncated, add ellipsis
+            if (diag[i] != '\0' && diag[i] != '\n')
+            {
+                single_line[i++] = '.';
+                single_line[i++] = '.';
+                single_line[i++] = '.';
+            }
+            single_line[i] = '\0';
+            editorSetStatusMessage("● %s", single_line);
+        }
+
+    }
+    editorDrawStatusBar(&ab);
+    editorDrawMessageBar(&ab);
+    if (E.constantes.LSP && (E.lsp_client && E.lsp_client->state == LSP_READY))
+    {
+        lspUiDrawCompletion(&ab, &E.lsp_completion);
+    }
+
+
+    // ── Position cursor (account for gutter width) ────────────────────────────
+    snprintf(buf, sizeof(buf), "\x1b[%d;%dH",
+             active->cursor_y + active->origin_y + 1,
+             active->cursor_x + active->origin_x + 1 + (E.constantes.LSP ? GUTTER_WIDTH : 0));
+    abAppend(&ab, buf, (int)strlen(buf));
+
+    abAppend(&ab, SHOW_CURSOR, 6);
+    write(STDOUT_FILENO, ab.b, ab.len);
+    abFree(&ab);
 }

src/row_op.c

@@ -1,4 +1,6 @@
 #include "../include/row_op.h"
+#include "../include/data.h"
+#include "../include/utf8.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -6,146 +8,5 @@
 
 extern struct editorConfig E;
 
-int editorRowCxToRx(erow *row, int cursor_x) {
-  int render_x = 0;
-  int i;
-  for (i = 0; i < cursor_x; ++i) {
-    if (row->chars[i] == '\t') {
-      render_x += (E.constantes.TAB_LENGTH - 1) - (render_x % E.constantes.TAB_LENGTH);
-    }
-    render_x++;
-  }
-  return render_x;
-}
 
-int editorRowRxToCx(erow *row, int rx) {
-  int cur_rx = 0;
-  int cx;
-  for (cx = 0; cx < row->size; cx++) {
-    if (row->chars[cx] == '\t')
-      cur_rx += (E.constantes.TAB_LENGTH - 1) - (cur_rx % E.constantes.TAB_LENGTH);
-    cur_rx++;
-    if (cur_rx > rx) return cx;
-  }
-  return cx;
-}
 
-/**
- * \fn editorUpdateRow(erow *row)
- * \brief Copy content of \p row in \p row->render.
- *  */
-
-void editorUpdateRow(erow *row) {
-  int i, i_render;
-  int tabs = 0;
-
-  // counting number of tabs
-
-  for (i = 0; i < row->size; ++i) {
-    tabs +=
-        (row->chars[i] == '\t'); /**< increment tabs of 1 if chars[i] is one. */
-  }
-
-  free(row->render);
-  row->render = malloc(row->size + tabs * (E.constantes.TAB_LENGTH - 1) +
-                       1); /**< Tabs needs E.constantes.TAB_LENGTH chars so E.constantes.TAB_LENGTH - 1
-                              more than the first already counted. */
-
-  // end of counting
-  i_render = 0;
-  for (i = 0; i < row->size; ++i) {
-    if (row->chars[i] == '\t') {
-      row->render[i_render++] = ' ';
-      while (i_render % E.constantes.TAB_LENGTH) {
-        row->render[i_render++] =
-            ' '; /**< Addind the right amount of spaces for tabs */
-      }
-    } else {
-      row->render[i_render++] = row->chars[i];
-    }
-  }
-  row->render[i_render] = '\0'; // Don't forget the end of string character.
-  row->rsize = i_render;
-}
-
-void editorInsertRow(int at, char *s, size_t len) {
-  if (at < 0 || at > E.numrows) {
-    
-    return;
-  }
-  erow *tmp = (erow *)realloc(E.row, sizeof(erow) * (E.numrows + 1));
-  if (!tmp) {
-    return;
-  }
-  E.row = tmp;
-  memmove(&E.row[at + 1], &E.row[at], sizeof(erow) * (E.numrows - at));
-
-  E.row[at].size = len;
-  E.row[at].chars = malloc(len + 1);
-  memcpy(E.row[at].chars, s, len);
-  E.row[at].chars[len] = '\0';
-
-  E.row[at].rsize = 0;
-  E.row[at].render = NULL;
-  editorUpdateRow(&E.row[at]);
-
-  ++E.numrows;
-  ++E.dirty;
-}
-
-void editorFreeRow(erow *row) {
-  free(row->render);
-  free(row->chars);
-}
-
-void editorDelRow(int at) {
-  if (at < 0 || at >= E.numrows) {
-    return;
-  }
-  editorFreeRow(&E.row[at]);
-  memmove(&E.row[at], &E.row[at + 1], sizeof(erow) * (E.numrows - at - 1));
-  --E.numrows;
-  ++E.dirty;
-}
-
-/**
- * \fn editorRowInsertChar(erow *row, int at, int c)
- * \param at Index of where we want to insert the char */
-
-void editorRowInsertChar(erow *row, int at, int c) {
-  if (E.state == READ_ONLY)
-    return;
-  if (at < 0 || at > row->size) {
-    at = row->size;
-  }
-  row->chars = realloc(row->chars, row->size + 2);
-  memmove(&row->chars[at + 1], &row->chars[at], row->size - at + 1);
-  ++row->size;
-  row->chars[at] = c;
-  editorUpdateRow(row);
-  ++E.dirty;
-}
-
-void editorRowAppendString(erow *row, char *s, size_t len) {
-  row->chars = realloc(row->chars, row->size + len + 1);
-  memcpy(&row->chars[row->size], s, len);
-  row->size += len;
-  row->chars[row->size] = '\0';
-  editorUpdateRow(row);
-  ++E.dirty;
-}
-
-/**
- * \fn editorRowDelChar(struct editorConfig *E, erow *erow, int at)
- * \brief Delete the a char at the chosen position on the given row
- * \param at Index of the char to delete
- * \param row Row on operation is made */
-void editorRowDelchar(erow *row, int at) {
-  if (at < 0 || at >= row->size) {
-    return;
-  }
-  memmove(&row->chars[at], &row->chars[at + 1], row->size - at);
-  --row->size;
-  editorUpdateRow(row);
-  ++E.dirty;
-}

src/split_screen.c

@@ -0,0 +1,236 @@
+/**
+ * @file split_screen.c
+ * @brief Split screen implementation
+ */
+
+#include "../include/split_screen.h"
+#include "../include/buffer.h"
+#include "../include/editor_op.h"
+#include <stdlib.h>
+#include <string.h>
+
+
+extern struct editorConfig E;
+
+/**
+ * @brief Initializes split screen system with single fullscreen pane
+ */
+void splitScreenInit(void) {
+    E.layout.mode = SPLIT_NONE;
+    E.layout.num_panes = 1;
+    E.layout.active_pane = 0;
+
+    EditorPane *new_panes = realloc(E.layout.panes, sizeof(EditorPane) * 2);
+    if (!new_panes) {
+        editorSetStatusMessage("Error: realloc failed");
+        return;
+    }
+    E.layout.panes = new_panes;
+
+    // Initialize single fullscreen pane
+    E.layout.panes[0].buffer_id = -1; // No buffer for now
+    E.layout.panes[0].origin_y = 0;
+    E.layout.panes[0].origin_x = 0;
+    E.layout.panes[0].height = E.screenrows - 2;  // Leave room for status bar
+    E.layout.panes[0].width = E.screencols;
+    E.layout.panes[0].cursor_x = 0;
+    E.layout.panes[0].cursor_y = 0;
+    E.layout.panes[0].y_offset = 0;
+    E.layout.panes[0].x_offset = 0;
+    E.layout.panes[0].is_active = 1;
+}
+
+/**
+ * @brief Splits screen vertically (left-right)
+ * @param buffer_id_left Buffer ID for left pane
+ * @param buffer_id_right Buffer ID for right pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenVertical(int buffer_id_left, int buffer_id_right) {
+    // Verify both buffers exist
+    if (bufferFindById(buffer_id_left) == NULL ||
+        bufferFindById(buffer_id_right) == NULL) {
+        editorSetStatusMessage("Error: invalid buffer IDs");
+        return -1;
+    }
+
+    // bReallocate panes array
+    E.layout.panes = realloc(E.layout.panes, sizeof(EditorPane) * 2);
+    E.layout.mode = SPLIT_VERTICAL;
+    E.layout.num_panes = 2;
+    E.layout.active_pane = 0;
+
+    int half_width = E.screencols / 2;
+    int pane_height = E.screenrows;  // Leave room for status bar
+
+    // Left pane
+    E.layout.panes[0].buffer_id = buffer_id_left;
+    E.layout.panes[0].origin_y = 0;
+    E.layout.panes[0].origin_x = 0;
+    E.layout.panes[0].height = pane_height;
+    E.layout.panes[0].width = half_width;
+    E.layout.panes[0].cursor_x = 0;
+    E.layout.panes[0].cursor_y = 0;
+    E.layout.panes[0].y_offset = 0;
+    E.layout.panes[0].x_offset = 0;
+    E.layout.panes[0].is_active = 1;
+
+    // Right pane
+    E.layout.panes[1].buffer_id = buffer_id_right;
+    E.layout.panes[1].origin_y = 0;
+    E.layout.panes[1].origin_x = half_width;
+    E.layout.panes[1].height = pane_height;
+    E.layout.panes[1].width = E.screencols - half_width;
+    E.layout.panes[1].cursor_x = 0;
+    E.layout.panes[1].cursor_y = 0;
+    E.layout.panes[1].y_offset = 0;
+    E.layout.panes[1].x_offset = 0;
+    E.layout.panes[1].is_active = 0;
+
+    editorSetStatusMessage("Vertical split: %d | %d", buffer_id_left, buffer_id_right);
+    return 0;
+}
+
+/**
+ * @brief Splits screen horizontally (top-bottom)
+ * @param buffer_id_top Buffer ID for top pane
+ * @param buffer_id_bottom Buffer ID for bottom pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenHorizontal(int buffer_id_top, int buffer_id_bottom) {
+    // Verify both buffers exist
+    if (bufferFindById(buffer_id_top) == NULL ||
+        bufferFindById(buffer_id_bottom) == NULL) {
+        editorSetStatusMessage("Error: invalid buffer IDs");
+        return -1;
+    }
+
+    // bReallocate panes array
+    E.layout.panes = realloc(E.layout.panes, sizeof(EditorPane) * 2);
+    E.layout.mode = SPLIT_HORIZONTAL;
+    E.layout.num_panes = 2;
+    E.layout.active_pane = 0;
+
+    int half_height = (E.screenrows - 2) / 2;  // Account for status bar
+
+    // Top pane
+    E.layout.panes[0].buffer_id = buffer_id_top;
+    E.layout.panes[0].origin_y = 0;
+    E.layout.panes[0].origin_x = 0;
+    E.layout.panes[0].height = half_height;
+    E.layout.panes[0].width = E.screencols;
+    E.layout.panes[0].cursor_x = 0;
+    E.layout.panes[0].cursor_y = 0;
+    E.layout.panes[0].y_offset = 0;
+    E.layout.panes[0].x_offset = 0;
+    E.layout.panes[0].is_active = 1;
+
+    // Bottom pane
+    E.layout.panes[1].buffer_id = buffer_id_bottom;
+    E.layout.panes[1].origin_y = half_height;
+    E.layout.panes[1].origin_x = 0;
+    E.layout.panes[1].height = E.screenrows - 2 - half_height;
+    E.layout.panes[1].width = E.screencols;
+    E.layout.panes[1].cursor_x = 0;
+    E.layout.panes[1].cursor_y = 0;
+    E.layout.panes[1].x_offset = 0;
+    E.layout.panes[1].y_offset = 0;
+    E.layout.panes[1].is_active = 0;
+
+    editorSetStatusMessage("Horizontal split: %d / %d", buffer_id_top, buffer_id_bottom);
+    return 0;
+}
+
+/**
+ * @brief Returns to single buffer fullscreen
+ */
+void splitScreenUnify(void) {
+    E.layout.mode = SPLIT_NONE;
+    E.layout.num_panes = 1;
+    E.layout.active_pane = 0;
+
+    E.layout.panes[0].origin_x = 0;
+    E.layout.panes[0].origin_y = 0;
+    E.layout.panes[0].height = E.screenrows;
+    E.layout.panes[0].width = E.screencols;
+    E.layout.panes[0].is_active = 1;
+
+    editorSetStatusMessage("Unified view");
+}
+
+/**
+ * @brief Switches active pane (focus moves between splits)
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenSwitchPane(void) {
+    if (E.layout.num_panes < 2) {
+        editorSetStatusMessage("No split to switch");
+        return -1;
+    }
+
+    // Deactivate current pane
+    E.layout.panes[E.layout.active_pane].is_active = 0;
+
+    // Move to next pane
+    E.layout.active_pane = (E.layout.active_pane + 1) % E.layout.num_panes;
+
+    // Activate new pane
+    E.layout.panes[E.layout.active_pane].is_active = 1;
+
+    editorSetStatusMessage("Switched to pane %d (buffer %d)",
+                          E.layout.active_pane,
+                          E.layout.panes[E.layout.active_pane].buffer_id);
+    return 0;
+}
+
+/**
+ * @brief Updates the active pane's buffer
+ * @param buffer_id New buffer ID for active pane
+ * @return 0 on success, -1 on failure
+ */
+int splitScreenSetPaneBuffer(int buffer_id) {
+    if (bufferFindById(buffer_id) == NULL) {
+        editorSetStatusMessage("Error: invalid buffer ID");
+        return -1;
+    }
+
+    EditorPane *active = &E.layout.panes[E.layout.active_pane];
+    active->buffer_id = buffer_id;
+    active->cursor_x = 0;
+    active->cursor_y = 0;
+    active->origin_x = 0;
+    active->origin_y = 0;
+
+    editorSetStatusMessage("Pane %d now showing buffer %d",
+                          E.layout.active_pane, buffer_id);
+    return 0;
+}
+
+/**
+ * @brief Gets current screen layout
+ * @return Pointer to current ScreenLayout
+ */
+ScreenLayout *splitScreenGetLayout(void) {
+    return &E.layout;
+}
+
+/**
+ * @brief Gets active pane
+ * @return Pointer to active EditorPane
+ */
+EditorPane *splitScreenGetActivePane(void) {
+    if (E.layout.num_panes == 0) return NULL;
+    return &E.layout.panes[E.layout.active_pane];
+}
+
+void freeScreenLayout(ScreenLayout *layout) {
+    if (layout) {
+        free(layout->panes);
+        layout->panes = NULL;
+    }
+}
+
+void freePane(EditorPane *pane)
+{
+    free(pane);
+}

src/syntax_highlighter.c

@@ -0,0 +1,252 @@
+#include "../include/syntax_highlighter.h"
+#include "../include/data.h"
+#include "../include/utf8.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+extern struct editorConfig E;
+
+const char *c_keywords[] = {
+    "if",     "else",     "while",    "for",     "do",       "switch",
+    "case",   "break",    "#include", "#define", "#if", "#endif", "#ifndef", "continue", "return",
+    "goto",   "struct",   "union",    "enum",    "typedef",  "static",
+    "extern", "const",    "volatile", "sizeof",  "auto",     "register",
+    "inline", "restrict", NULL};
+
+// C types
+const char *c_types[] = {"int",    "char", "float", "double",
+                         "void",   "long", "short", "unsigned",
+                         "signed", "bool", NULL};
+
+// Returns the byte length of the UTF-8 character starting at s.
+// Never returns 0 for a non-NUL byte, so callers won't infinite-loop.
+static int utf8_char_len(const char *s)
+{
+    unsigned char c = (unsigned char)*s;
+    if (c == 0)              return 0;
+    if (c < 0x80)            return 1;
+    if ((c & 0xE0) == 0xC0)  return 2;
+    if ((c & 0xF0) == 0xE0)  return 3;
+    if ((c & 0xF8) == 0xF0)  return 4;
+    return 1; // continuation byte or invalid — advance 1 to avoid infinite loop
+}
+
+int is_word_char(const char *s)
+{
+  uint32_t cp = utf8Decode(&s);
+
+  if ((cp >= 'a' && cp <= 'z') || (cp >= 'A' && cp <= 'Z') ||
+      (cp >= '0' && cp <= '9') || cp == '_' || cp == '#')
+    return 1;
+
+  if (cp == 0xFFFD) return 0;
+
+  if (cp >= 0x00C0 && cp <= 0x017F) return 1;
+  if (cp >= 0x0370 && cp <= 0x03FF) return 1;
+  if (cp >= 0x0400 && cp <= 0x04FF) return 1;
+  if (cp >= 0x0600 && cp <= 0x06FF) return 1;
+  if (cp >= 0x05D0 && cp <= 0x05EA) return 1;
+  if (cp >= 0x0900 && cp <= 0x097F) return 1;
+  if (cp >= 0x4E00 && cp <= 0x9FFF) return 1;
+  if ((cp >= 0x3040 && cp <= 0x309F) ||
+      (cp >= 0x30A0 && cp <= 0x30FF)) return 1;
+  if (cp >= 0xAC00 && cp <= 0xD7A3) return 1;
+
+  return 0;
+}
+
+// Copy one full UTF-8 character from src+i into dst+pos, advance both indices.
+static void copy_utf8_char(char *dst, int *dst_pos, const char *src, int *src_pos)
+{
+    int len = utf8_char_len(&src[*src_pos]);
+    for (int b = 0; b < len; b++)
+        dst[(*dst_pos)++] = src[(*src_pos)++];
+}
+
+// Check if character is alphanumeric or underscore
+
+// Check if string is a keyword
+int is_keyword(const char *word) {
+  for (int i = 0; c_keywords[i] != NULL; i++) {
+    if (strcmp(word, c_keywords[i]) == 0)
+      return 1;
+  }
+  return 0;
+}
+
+// Check if string is a type
+int is_type(const char *word) {
+  for (int i = 0; c_types[i] != NULL; i++) {
+    if (strcmp(word, c_types[i]) == 0)
+      return 1;
+  }
+  return 0;
+}
+
+// Get color code for token type
+const char *get_color(TokenType type) {
+  switch (type) {
+  case TOKEN_KEYWORD:
+    return E.theme.COLOR_KEYWORD;
+  case TOKEN_TYPE:
+    return E.theme.COLOR_TYPE;
+  case TOKEN_STRING:
+    return E.theme.COLOR_STRING;
+  case TOKEN_COMMENT:
+    return E.theme.COLOR_COMMENT;
+  case TOKEN_NUMBER:
+    return E.theme.COLOR_NUMBER;
+  default:
+    return E.theme.COLOR_DEFAULT;
+  }
+}
+
+int comment_section = 0;
+
+// Highlight a line of C code and return the highlighted string
+// Returns a newly allocated string that must be freed by the caller
+char *highlight_line(const char *line, int *length) {
+  // Each byte can expand to at most (color_prefix + 4 bytes + color_reset).
+  // Allocate generously based on line length to avoid overflow.
+  int line_len = (int) strlen(line);
+  int buf_size = line_len * 32 + 256;
+  char *result = malloc(buf_size);
+  if (!result) {
+    *length = 0;
+    return NULL;
+  }
+  int result_pos = 0;
+  int i = 0;
+
+  while (line[i] != '\0' && line[i] != '\n') {
+    // Skip whitespace — copy full UTF-8 char (whitespace is always ASCII,
+    // but using copy_utf8_char keeps the pattern consistent)
+    if (line[i] == ' ' || line[i] == '\t') {
+      copy_utf8_char(result, &result_pos, line, &i);
+      continue;
+    }
+
+    if (comment_section) {
+      result_pos += snprintf(&result[result_pos], 10, "%s", E.theme.COLOR_COMMENT);
+      while (line[i] != '\0' && line[i] != '\n') {
+        if (line[i] == '*' && line[i + 1] == '/') {
+          comment_section = 0;
+        }
+        copy_utf8_char(result, &result_pos, line, &i);
+      }
+      result_pos += snprintf(&result[result_pos], 10, "%s", COLOR_RESET);
+      continue;
+    }
+
+    // Handle line comments
+    if (line[i] == '/' && line[i + 1] == '/') {
+      result_pos += snprintf(&result[result_pos], 10, "%s", E.theme.COLOR_COMMENT);
+      while (line[i] != '\0' && line[i] != '\n') {
+        copy_utf8_char(result, &result_pos, line, &i);
+      }
+      result_pos += snprintf(&result[result_pos], 10, "%s", COLOR_RESET);
+      continue;
+    }
+
+    // Handle block comments
+    if (line[i] == '/' && line[i + 1] == '*') {
+      comment_section = 1;
+      result_pos += snprintf(&result[result_pos], 10, "%s", E.theme.COLOR_COMMENT);
+      result[result_pos++] = line[i++];
+      result[result_pos++] = line[i++];
+      while (line[i] != '\0') {
+        if (line[i] == '*' && line[i + 1] == '/') {
+          result[result_pos++] = line[i++];
+          result[result_pos++] = line[i++];
+          comment_section = 0;
+          break;
+        }
+        copy_utf8_char(result, &result_pos, line, &i);
+      }
+      result_pos += snprintf(&result[result_pos], 10, "%s", COLOR_RESET);
+      continue;
+    }
+
+    // Handle strings
+    if (line[i] == '"') {
+      result_pos += snprintf(&result[result_pos], 10, "%s\"", E.theme.COLOR_STRING);
+      i++;
+      while (line[i] != '\0' && line[i] != '"') {
+        if (line[i] == '\\') {
+          result[result_pos++] = line[i++];
+          copy_utf8_char(result, &result_pos, line, &i);
+        } else {
+          copy_utf8_char(result, &result_pos, line, &i);
+        }
+      }
+      if (line[i] == '"')
+        result[result_pos++] = line[i++];
+      result_pos += snprintf(&result[result_pos], 10, "%s", COLOR_RESET);
+      continue;
+    }
+
+    // Handle character literals
+    if (line[i] == '\'') {
+      result_pos += snprintf(&result[result_pos], 10, "%s'", E.theme.COLOR_STRING);
+      i++;
+      while (line[i] != '\0' && line[i] != '\'') {
+        if (line[i] == '\\') {
+          result[result_pos++] = line[i++];
+          copy_utf8_char(result, &result_pos, line, &i);
+        } else {
+          copy_utf8_char(result, &result_pos, line, &i);
+        }
+      }
+      if (line[i] == '\'')
+        result[result_pos++] = line[i++];
+      result_pos += snprintf(&result[result_pos], 10, "%s", COLOR_RESET);
+      continue;
+    }
+
+    // Handle numbers
+    if (line[i] >= '0' && line[i] <= '9') {
+      result_pos += snprintf(&result[result_pos], 10, "%s", E.theme.COLOR_NUMBER);
+      while (is_word_char(&line[i]) || line[i] == '.') {
+        copy_utf8_char(result, &result_pos, line, &i);
+      }
+      result_pos += snprintf(&result[result_pos], 10, "%s", COLOR_RESET);
+      continue;
+    }
+
+    // Handle identifiers and keywords
+    if (is_word_char(&line[i])) {
+      int start = i;
+      // Advance by full UTF-8 character widths, not single bytes
+      while (line[i] != '\0' && is_word_char(&line[i]))
+        i += utf8_char_len(&line[i]);
+
+      char word[256];
+      int word_len = i - start;
+      if (word_len >= (int)sizeof(word))
+        word_len = (int)sizeof(word) - 1;
+      strncpy(word, &line[start], word_len);
+      word[word_len] = '\0';
+
+      TokenType type = TOKEN_DEFAULT;
+      if (is_keyword(word))
+        type = TOKEN_KEYWORD;
+      else if (is_type(word))
+        type = TOKEN_TYPE;
+
+      result_pos += snprintf(&result[result_pos], 100, "%s%s%s", get_color(type),
+                            word, COLOR_RESET);
+      continue;
+    }
+
+    // Handle operators and other characters (including non-ASCII multi-byte)
+    result_pos += snprintf(&result[result_pos], 10, "%s", E.theme.COLOR_DEFAULT);
+    copy_utf8_char(result, &result_pos, line, &i);
+    result_pos += snprintf(&result[result_pos], 10, "%s", COLOR_RESET);
+  }
+
+  result[result_pos] = '\0';
+  *length = result_pos + 1;
+  return result;
+}

src/terminal.c

@@ -1,149 +1,321 @@
 #include "../include/terminal.h"
+
+#include <ctype.h>
+
 #include "../include/data.h"
+#include "../include/define.h"
 
+#include <stdarg.h>
 #include <stdio.h>
+#include <string.h>
+#include <unistd.h>
 
-void die(const char *s) {
-  write(STDOUT_FILENO, "\x1b[2J", 4);
-  write(STDOUT_FILENO, CURSOR_TOP_LEFT, 3);
-  lisp_shutdown(E.ctx);
-  perror(s);
-  exit(1);
+#include "../include/buffer.h"
+#include "../include/split_screen.h"
+#include "../include/utf8.h"
+
+void die(const char* s)
+{
+    write(STDOUT_FILENO, "\x1b[2J", 4);
+    write(STDOUT_FILENO, CURSOR_TOP_LEFT, 3);
+    lisp_shutdown(E.ctx);
+    perror(s);
+    exit(1);
 }
 
-void disableRawMode() {
-  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1) {
-    die("tcsetattr");
-  }
-}
-
-void enableRawMode() {
-  if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1) {
-    die("tcgetattr");
-  }
-
-  struct termios raw = E.orig_termios;
-  raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
-  raw.c_oflag &= ~(OPOST);
-  raw.c_cflag |= (CS8);
-  raw.c_lflag &= ~(ECHO | ICANON | ISIG | IEXTEN);
-  raw.c_cc[VMIN] = 0;
-  raw.c_cc[VTIME] = 1;
-
-  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) {
-    die("tcgetattr");
-  }
-}
-
-int editorReadKey() {
-  int nread;
-  char c;
-  char seq[3];
-  while ((nread = read(STDIN_FILENO, &c, 1)) != 1) {
-    if (nread == -1 && errno != EAGAIN) {
-      die("read");
+void disableRawMode()
+{
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1)
+    {
+        die("tcsetattr");
     }
-  }
+}
 
-  if (c == '\x1b') {
-    if (read(STDIN_FILENO, &seq[0], 1) != 1 ||
-        read(STDIN_FILENO, &seq[1], 1) != 1) {
-      return '\x1b';
+void enableRawMode()
+{
+    if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1)
+    {
+        die("tcgetattr");
     }
-    if (seq[0] == '[') {
-      if (seq[1] >= '0' && seq[1] <= '9') {
-        if (read(STDIN_FILENO, &seq[2], 1) != 1) {
-          return '\x1b';
+
+    struct termios raw = E.orig_termios;
+    raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
+    raw.c_oflag &= ~(OPOST);
+    raw.c_cflag |= (CS8);
+    raw.c_lflag &= ~(ECHO | ICANON | ISIG | IEXTEN);
+    raw.c_cc[VMIN] = 0;
+    raw.c_cc[VTIME] = 1;
+
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1)
+    {
+        die("tcgetattr");
+    }
+}
+
+#include <ctype.h> /* isprint */
+
+char* keyToString(int key)
+{
+    static char key_str[32];
+
+    if (key == '\r')
+    {
+        strcpy(key_str, "ENTER");
+    }
+    else if (key == 0x09)
+    {
+        strcpy(key_str, "TAB");
+    }
+    else if (key >= 1 && key <= 26)
+    {
+        snprintf(key_str, sizeof(key_str), "CTRL-%c", 'a' + key - 1);
+    }
+    else
+    {
+        switch (key)
+        {
+        case ARROW_UP:
+            strcpy(key_str, "ARROW-UP");
+            break;
+        case ARROW_DOWN:
+            strcpy(key_str, "ARROW-DOWN");
+            break;
+        case ARROW_LEFT:
+            strcpy(key_str, "ARROW-LEFT");
+            break;
+        case ARROW_RIGHT:
+            strcpy(key_str, "ARROW-RIGHT");
+            break;
+        case PAGE_UP:
+            strcpy(key_str, "PAGE-UP");
+            break;
+        case PAGE_DOWN:
+            strcpy(key_str, "PAGE-DOWN");
+            break;
+        case DEL_KEY:
+            strcpy(key_str, "DEL");
+            break;
+        case BACKSPACE:
+            strcpy(key_str, "BACKSPACE");
+            break;
+        case BEG_LINE:
+            strcpy(key_str, "HOME");
+            break;
+        case END_LINE:
+            strcpy(key_str, "END");
+            break;
+        case '\x1b':
+            strcpy(key_str, "ESCAPE");
+            break;
+        default:
+            if (key > 127)
+            {
+                /* UTF-8 code point — re-encode into the buffer */
+                char buf[5] = {0};
+                int n = utf8Encode((uint32_t)key, buf);
+                snprintf(key_str, sizeof(key_str), "%.*s", n, buf);
+            }
+            else if (isprint(key))
+            {
+                snprintf(key_str, sizeof(key_str), "%c", key);
+            }
+            else
+            {
+                snprintf(key_str, sizeof(key_str), "KEY-%d", key);
+            }
         }
-        if (seq[2] == '~') {
-          switch (seq[1]) {
-          case '1':
-            return BEG_LINE;
-          case '3':
-            return DEL_KEY;
-          case '4':
-            return END_LINE;
-          case '5':
-            return PAGE_UP;
-          case '6':
-            return PAGE_DOWN;
-          case '7':
-            return BEG_LINE;
-          case '8':
-            return END_LINE;
-          }
-        }
-      } else {
-
-        switch (seq[1]) {
-        case 'A':
-          return ARROW_UP;
-        case 'B':
-          return ARROW_DOWN;
-        case 'C':
-          return ARROW_RIGHT;
-        case 'D':
-          return ARROW_LEFT;
-        case 'H':
-          return BEG_LINE;
-        case 'F':
-          return END_LINE;
-        }
-      }
-    } else if (seq[0] == 'O') {
-      switch (seq[1]) {
-      case 'H':
-        return BEG_LINE;
-      case 'F':
-        return END_LINE;
-      }
     }
-    return '\x1b';
-  } else {
-    return c;
-  }
+    return key_str;
 }
 
-int getCursorPosition(int *rows, int *cols) {
-  char buf[32];
-  unsigned int i = 0;
+int editorReadKey()
+{
+    char c;
+    int nread;
 
-  if (write(STDOUT_FILENO, "\x1b[6n", 4) != 4) {
-    return -1;
-  }
+    while (1)
+    {
+        fd_set fds;
+        FD_ZERO(&fds);
+        FD_SET(STDIN_FILENO, &fds);
 
-  while (i < sizeof(buf) - 1) {
-    if (read(STDIN_FILENO, &buf[i], 1) != 1) {
-      break;
+        int max_fd = STDIN_FILENO;
+
+        // Only watch wake pipe if LSP is ready AND active buffer is open
+        EditorPane* active = splitScreenGetActivePane();
+        struct buffer_t* buf = active ? bufferFindById(active->buffer_id) : NULL;
+        int lsp_active = E.lsp_client
+            && E.lsp_client->wake_pipe[0] > 0
+            && E.lsp_client->state == LSP_READY
+            && buf
+            && buf->b_lsp_open; // ← only if this buffer is tracked
+
+        if (lsp_active)
+        {
+            FD_SET(E.lsp_client->wake_pipe[0], &fds);
+            if (E.lsp_client->wake_pipe[0] > max_fd)
+                max_fd = E.lsp_client->wake_pipe[0];
+        }
+
+        int ready = select(max_fd + 1, &fds, NULL, NULL, NULL);
+        if (ready <= 0) continue;
+
+        if (lsp_active && FD_ISSET(E.lsp_client->wake_pipe[0], &fds))
+        {
+            char tmp[16];
+            read(E.lsp_client->wake_pipe[0], tmp, sizeof(tmp));
+            return LSP_WAKE_KEY;
+        }
+
+        if (FD_ISSET(STDIN_FILENO, &fds))
+        {
+            nread = read(STDIN_FILENO, &c, 1);
+            if (nread == 1) break;
+        }
     }
-    if (buf[i] == 'R') {
-      break;
+
+
+    appDebug("f : %hhu %ld\r\n", c, 0x200);
+
+    if (c == '\x1b')
+    {
+        char seq[6];
+        /* try to read escape sequence */
+        if (read(STDIN_FILENO, &seq[0], 1) != 1)
+            return '\x1b';
+        if (read(STDIN_FILENO, &seq[1], 1) != 1)
+            return '\x1b';
+        appDebug("f2 : %s\r\n", seq);
+
+        if (seq[0] == '[')
+        {
+            if (seq[1] >= '0' && seq[1] <= '9')
+            {
+                if (read(STDIN_FILENO, &seq[2], 1) != 1)
+                    return '\x1b';
+                if (seq[2] == '~')
+                {
+                    switch (seq[1])
+                    {
+                    case '1':
+                        return BEG_LINE;
+                    case '3':
+                        return DEL_KEY;
+                    case '4':
+                        return END_LINE;
+                    case '5':
+                        return PAGE_UP;
+                    case '6':
+                        return PAGE_DOWN;
+                    case '7':
+                        return BEG_LINE;
+                    case '8':
+                        return END_LINE;
+                    }
+                }
+            }
+            else
+            {
+                switch (seq[1])
+                {
+                case 'A':
+                    return ARROW_UP;
+                case 'B':
+                    return ARROW_DOWN;
+                case 'C':
+                    return ARROW_RIGHT;
+                case 'D':
+                    return ARROW_LEFT;
+                case 'H':
+                    return BEG_LINE;
+                case 'F':
+                    return END_LINE;
+                }
+            }
+        }
+        return '\x1b';
     }
-    ++i;
-  }
-  buf[i] = '\0';
 
-  if (buf[0] != '\x1b' || buf[1] != '[') {
-    return -1;
-  }
-  if (sscanf(&buf[2], "%d;%d", rows, cols) != 2) {
-    return -1;
-  }
+    /* multi-byte UTF-8: read remaining bytes */
+    int seqlen = utf8Seqlen((unsigned char)c);
+    if (seqlen > 1)
+    {
+        /* pack into a pseudo-codepoint just to pass bytes through;
+           we handle encoding/decoding at the row level */
+        char buf[4] = {c, 0, 0, 0};
+        for (int i = 1; i < seqlen; i++)
+            if (read(STDIN_FILENO, &buf[i], 1) != 1)
+                break;
+        /* decode and return as uint32, but we need int — use high range */
+        const char* p = buf;
+        uint32_t cp = utf8Decode(&p);
+        return (int)cp; /* caller re-encodes when inserting */
+    }
 
-  return 0;
+    return (unsigned char)c;
 }
 
-int getWindowSize(int *rows, int *cols) {
-  struct winsize ws;
+int getCursorPosition(int* rows, int* cols)
+{
+    char buf[32];
+    unsigned int i = 0;
 
-  if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 || ws.ws_col == 0) {
-    if (write(STDOUT_FILENO, "\x1b[999C\x1b[999B", 12) != 12) {
-      return -1;
+    if (write(STDOUT_FILENO, "\x1b[6n", 4) != 4)
+    {
+        return -1;
+    }
+
+    while (i < sizeof(buf) - 1)
+    {
+        if (read(STDIN_FILENO, &buf[i], 1) != 1)
+        {
+            break;
+        }
+        if (buf[i] == 'R')
+        {
+            break;
+        }
+        ++i;
+    }
+    buf[i] = '\0';
+
+    if (buf[0] != '\x1b' || buf[1] != '[')
+    {
+        return -1;
+    }
+    if (sscanf(&buf[2], "%d;%d", rows, cols) != 2)
+    {
+        return -1;
+    }
+
+    return 0;
+}
+
+int getWindowSize(int* rows, int* cols)
+{
+    struct winsize ws;
+
+    if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 || ws.ws_col == 0)
+    {
+        if (write(STDOUT_FILENO, "\x1b[999C\x1b[999B", 12) != 12)
+        {
+            return -1;
+        }
+        return getCursorPosition(rows, cols);
     }
-    return getCursorPosition(rows, cols);
-  } else {
     *cols = ws.ws_col;
     *rows = ws.ws_row;
     return 0;
-  }
+}
+
+void appDebug(const char* fmt, ...)
+{
+#ifdef APP_DEBUG
+    va_list ap;
+    char message[1024];
+    va_start(ap, fmt);
+    vsnprintf(message, 1024, fmt, ap);
+    va_end(ap);
+    fprintf(stderr, "%s\n", message);
+#endif
 }

src/utf8.c

@@ -0,0 +1,147 @@
+/**
+ * @file utf8.c
+ */
+
+#include "../include/utf8.h"
+
+#include <stdint.h>
+#include <unistd.h>
+
+
+uint32_t readUtf8Char(void)
+{
+    unsigned char buf[4];
+
+    read(STDIN_FILENO, &buf[0], 1);
+
+    int extra;
+    uint32_t cp;
+
+    if (buf[0] < 0x80)
+    {
+        cp = buf[0];
+        extra = 0;
+    }
+    else if (buf[0] < 0xC0) { return 0xFFFD; } // stray continuation
+    else if (buf[0] < 0xE0)
+    {
+        cp = buf[0] & 0x1F;
+        extra = 1;
+    }
+    else if (buf[0] < 0xF0)
+    {
+        cp = buf[0] & 0x0F;
+        extra = 2;
+    }
+    else
+    {
+        cp = buf[0] & 0x07;
+        extra = 3;
+    }
+
+    if (extra > 0)
+    {
+        read(STDIN_FILENO, &buf[1], extra); // read remaining bytes at once
+        for (int i = 0; i < extra; i++)
+            cp = (cp << 6) | (buf[1 + i] & 0x3F);
+    }
+
+    return cp;
+}
+
+uint32_t utf8Decode(const char** s)
+{
+    unsigned char c = (unsigned char)**s;
+    uint32_t cp;
+    int extra;
+    if (c < 0x80)
+    {
+        cp = c;
+        extra = 0;
+    }
+    else if (c < 0xC0)
+    {
+        (*s)++;
+        return 0xFFFD;
+    }
+    else if (c < 0xE0)
+    {
+        cp = c & 0x1F;
+        extra = 1;
+    }
+    else if (c < 0xF0)
+    {
+        cp = c & 0x0F;
+        extra = 2;
+    }
+    else
+    {
+        cp = c & 0x07;
+        extra = 3;
+    }
+    (*s)++;
+    while (extra--)
+    {
+        c = (unsigned char)**s;
+        if ((c & 0xC0) != 0x80) return 0xFFFD;
+        cp = (cp << 6) | (c & 0x3F);
+        (*s)++;
+    }
+    return cp;
+}
+
+// buf must have at least 4 bytes; returns bytes written
+int utf8Encode(uint32_t cp, char* buf)
+{
+    if (cp < 0x80)
+    {
+        buf[0] = cp;
+        return 1;
+    }
+    if (cp < 0x800)
+    {
+        buf[0] = 0xC0 | (cp >> 6);
+        buf[1] = 0x80 | (cp & 0x3F);
+        return 2;
+    }
+    if (cp < 0x10000)
+    {
+        buf[0] = 0xE0 | (cp >> 12);
+        buf[1] = 0x80 | ((cp >> 6) & 0x3F);
+        buf[2] = 0x80 | (cp & 0x3F);
+        return 3;
+    }
+    buf[0] = 0xF0 | (cp >> 18);
+    buf[1] = 0x80 | ((cp >> 12) & 0x3F);
+    buf[2] = 0x80 | ((cp >> 6) & 0x3F);
+    buf[3] = 0x80 | (cp & 0x3F);
+    return 4;
+}
+
+int utf8Seqlen(unsigned char c)
+{
+    if (c < 0x80) return 1;
+    if (c < 0xC0) return 0; /* continuation — shouldn't be leading */
+    if (c < 0xE0) return 2;
+    if (c < 0xF0) return 3;
+    return 4;
+}
+
+/**
+ * @param codepoint utf8 codepoint of a char
+ * @return length of the codepoint
+ */
+int codepointWidth(uint32_t codepoint)
+{
+    if (codepoint < 0x20 || codepoint == 0x7F) return 0;
+    /* rough double-width ranges */
+    if ((codepoint >= 0x1100 && codepoint <= 0x115F) ||
+        (codepoint >= 0x2E80 && codepoint <= 0x303E) ||
+        (codepoint >= 0x3041 && codepoint <= 0x33BF) ||
+        (codepoint >= 0xAC00 && codepoint <= 0xD7AF) ||
+        (codepoint >= 0xF900 && codepoint <= 0xFAFF) ||
+        (codepoint >= 0xFF01 && codepoint <= 0xFF60) ||
+        (codepoint >= 0x1F300 && codepoint <= 0x1FAFF))
+        return 2;
+    return 1;
+}

test/main.c

@@ -0,0 +1,3 @@
+int main() {
+	printf("hello");
+}