overflow errors

config/init.lisp

@@ -3,6 +3,7 @@
 (define TAB-LENGTH 4)
 (define QUIT-TIMES 1)
 (define THEME "dark")
+(define LSP #t)
 
 ;; PACKAGES
 
@@ -90,3 +91,5 @@
 (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

@@ -13,7 +13,7 @@
  * @param filename Path to the file
  * @return Buffer ID on success, -1 on failure
  */
-int bufferCreate(const char *filename, enum bufferStatus_e state);
+int bufferCreate(const char *path, enum bufferStatus_e state);
 
 /**
  * @brief Switches to a specific buffer by ID

include/builtins.h

@@ -53,7 +53,9 @@ 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);
 

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/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

@@ -5,15 +5,20 @@
 #include <termios.h>
 #include <time.h>
 
+#include "define.h"
+
 #include "lisp.h"
 
+typedef struct lsp_client_t LspClient;
+
 /**
  * \struct row_t
  * \brief Store one editor row
  * \param
  * */
 
-typedef struct row {
+typedef struct row
+{
     int size; /**< Size of the line */
     int cap; /**< Size of the render line */
     char* chars; /**< Characters of the line */
@@ -29,7 +34,8 @@ typedef struct context_buffer_t
 /**
  * @brief Split modes for screen layout
  */
-typedef enum {
+typedef enum
+{
     SPLIT_NONE = 0, // Single buffer fullscreen
     SPLIT_VERTICAL, // Left-right split
     SPLIT_HORIZONTAL // Top-bottom split
@@ -38,7 +44,8 @@ typedef enum {
 /**
  * @brief Represents an editor viewport/pane
  */
-typedef struct {
+typedef struct
+{
     int buffer_id; // Which buffer this pane displays
     int height; // Height of this pane
     int width; // Width of this pane
@@ -52,7 +59,8 @@ typedef struct {
 /**
  * @brief Screen layout manager
  */
-typedef struct {
+typedef struct
+{
     SplitMode mode;
     EditorPane* panes;
     int num_panes;
@@ -60,7 +68,8 @@ typedef struct {
 } ScreenLayout;
 
 
-typedef struct theme {
+typedef struct theme
+{
     char* BACKGROUND_COLOR;
     char* COLOR_KEYWORD;
     char* COLOR_TYPE;
@@ -68,41 +77,133 @@ typedef struct theme {
     char* COLOR_COMMENT;
     char* COLOR_NUMBER;
     char* COLOR_DEFAULT;
-
 } theme_t;
 
-enum bufferStatus_e {
+enum bufferStatus_e
+{
     IDLE,
     READ_ONLY,
     READ_AND_WRITE,
 };
 
-struct const_t {
+struct const_t
+{
     int TAB_LENGTH;
     int QUIT_TIMES;
     char* THEME;
+    int LSP;
 };
 
-struct prefix_t {
+struct prefix_t
+{
     char prefix_name[64];
     int prefix_id;
 };
 
-struct keyBind_t {
+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 {
+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 */
 };
@@ -111,16 +212,17 @@ struct buffer_t {
  * \struct editorConfig
  * \brief Containing our editor state.
  */
-struct editorConfig {
+struct editorConfig
+{
     int cursor_x, cursor_y; /**< Cursor position */
     int screenrows; /**< Terminal height*/
     int screencols; /**< Terminal width*/
 
     ScreenLayout layout;
 
-  row_t *rows;        /**< Store all the rows printed */
-
-  ContextBuffer* context_buffers;
+    LspClient* lsp_client;
+    CompletionPopup lsp_completion;
+    DiagnosticList lsp_diagnostics;
 
     int dirty;
 
@@ -156,7 +258,8 @@ struct editorConfig {
  * \brief Contains text to add before writing to screen.
  * */
 
-struct abuf {
+struct abuf
+{
     char* b; /**< Text that will be printed */
     int len; /**< Length of the text */
 };

include/define.h

@@ -12,8 +12,21 @@
 #define ERASE_END_LINE "\x1b[K"
 #define TAB "\t"
 #define SPACE "\x20"
+
+#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,
@@ -25,6 +38,7 @@ enum editorKey_e {
     END_LINE,
     PAGE_UP,
     PAGE_DOWN,
+    LSP_WAKE_KEY = 2000
   };
 
 #define ABUF_INIT {NULL, 0}

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/lisp_lib.h

@@ -1163,7 +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)
@@ -1737,7 +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)

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/split_screen.h

@@ -59,4 +59,8 @@ ScreenLayout *splitScreenGetLayout(void);
  */
 EditorPane *splitScreenGetActivePane(void);
 
+void freePane(EditorPane *pane);
+void freeScreenLayout(ScreenLayout *layout);
+
+
 #endif

include/utf8.h

@@ -11,6 +11,7 @@ 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

main.c

@@ -9,6 +9,8 @@
 #define _BSD_SOURCE
 #define _GNU_SOURCE
 
+#include <libgen.h>
+
 #include "include/buffer.h"
 #include "include/split_screen.h"
 #include <string.h>
@@ -19,31 +21,46 @@
 #include "include/input.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));
+    // 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;
+    }
 
+    signal(SIGPIPE, SIG_IGN);
     enableRawMode();
     initEditor();
-  if (argc >= 2) {
+
     EditorPane *active = splitScreenGetActivePane();
-    active->buffer_id = bufferCreate(argv[1], READ_AND_WRITE);
-  } else {
-    strcat(splash_screen, getenv("HOME"));
-    strcat(splash_screen, "/.beluga/assets/beluga.txt");
+    struct buffer_t *buf;
 
     appDebug("splash : %s\n", splash_screen);
-    EditorPane *active = splitScreenGetActivePane();
     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);
+
+    free(splash_screen);  // Now guaranteed safe
 
     editorSetStatusMessage("HELP: Ctrl-x Ctrl-s = save | Ctrl-x Ctrl-c = quit");
-
-
     while (1) {
         editorRefreshScreen();
         editorProcessKeypress();

meson.build

@@ -7,6 +7,7 @@ project('beluga', 'c',
 
 cc = meson.get_compiler('c')
 m = cc.find_library('m', required: false)
+thread_dep = dependency('threads')
 
 # Source files
 src_files = files(
@@ -23,13 +24,14 @@ src_files = files(
   'src/builtins.c',
   'src/buffer.c',
   'src/split_screen.c',
-  'src/utf8.c'
+  'src/utf8.c',
+  'src/completion.c',
+  'src/lsp_ui.c',
+  'src/cJSON.c'
 )
 
 # Executable
 executable('beluga',
   src_files,
-  dependencies: [m]
-)
-  dependencies: [m]
+  dependencies: [m, thread_dep]
 )

src/append_buffer.c

@@ -11,4 +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

@@ -8,11 +8,14 @@
 #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"
 
 
@@ -55,18 +58,18 @@ struct buffer_t* bufferFindById(int buffer_id)
  * @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.
- * @param filename Path to the file
  * @return Buffer ID on success, -1 on failure
  */
-int bufferCreate(const char* filename, enum bufferStatus_e state)
+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(filename);
+    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)
     {
@@ -78,16 +81,35 @@ int bufferCreate(const char* filename, enum bufferStatus_e state)
     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;
@@ -323,7 +345,8 @@ void bufferFindReverse(struct buffer_t* buf)
     free(query);
 }
 
-void bufferInsertRow(struct buffer_t *buffer, int at, char *s, size_t len) {
+void bufferInsertRow(struct buffer_t* buffer, int at, char* s, size_t len)
+{
     if (at < 0 || at > buffer->numrows)
         return;
 
@@ -333,13 +356,14 @@ void bufferInsertRow(struct buffer_t *buffer, int at, char *s, size_t len) {
     buffer->row = tmp;
 
     /* Shift existing rows to make room at 'at' — no at++ */
-  if (at < buffer->numrows) {
+    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  = len;
-  buffer->row[at].cap   = len + 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;
@@ -357,17 +381,34 @@ void bufferFreeRow(row_t *row) { free(row->chars); }
  * \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) {
+                          const char* src, int n)
+{
     if (buffer->state == READ_ONLY)
         return;
-  if (row->size + n + 1 > row->cap) {
-    row->cap = (row->size + n + 1) * 2;
-    row->chars = realloc(row->chars, row->cap);
+    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 = realloc(row->chars, row->size + 2);
+
+    row->chars[row->size] = '\0';
     ++buffer->dirty;
 }
 
@@ -376,7 +417,8 @@ void bufferRowInsertBytes(struct buffer_t *buffer, row_t *row, 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) {
+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)
@@ -400,6 +442,7 @@ void bufferInsertBytes(const char* src, int n)
     }
     bufferRowInsertBytes(buf, &buf->row[buf->y], buf->x, src, n);
     buf->x += n;
+    buf->b_has_changed = 1;
 }
 
 void bufferDelBytes(void)
@@ -446,23 +489,27 @@ void bufferDelBytes(void)
     }
 }
 
-void bufferInsertNewLine(void) {
+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) {
+    if (buf->y >= buf->numrows)
+    {
         /* Cursor is past the last row: just append a blank line */
         bufferInsertRow(buf, buf->numrows, "", 0);
-    } else {
+    }
+    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: realloc inside bufferInsertRow may have moved the array */
+        /* Re-fetch: bRealloc inside bufferInsertRow may have moved the array */
         row = &buf->row[buf->y];
 
         /* Truncate the current row at the cursor */

src/builtins.c

@@ -15,12 +15,14 @@
 #include "../include/input.h"
 #include "../include/terminal.h"
 #include "../include/split_screen.h"
-#include "../include/completion.h"
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
+#include "include/completion.h"
+#include "include/init.h"
+
 /**
  * @brief Finds a prefix configuration by name
  * @details Searches the prefix array for a prefix matching the given name.
@@ -29,10 +31,13 @@
  * @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]) {
+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)) {
+    while (i--)
+    {
+        if (!strcmp(prefix_name, E.prefix[i].prefix_name))
+        {
             return E.prefix[i];
         }
     }
@@ -52,17 +57,22 @@ struct prefix_t find_prefix(const char prefix_name[64]) {
  * @return lisp_null()
  * @note Updates global editor state E (key_binds array)
  */
-Lisp mapKey(Lisp args, LispError *e, LispContext ctx) {
+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);
 
-  E.key_binds = (struct keyBind_t *)realloc(
+    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));
 
@@ -92,10 +102,12 @@ Lisp mapKey(Lisp args, LispError *e, LispContext ctx) {
  * @note Updates global editor state E
  * @see editorMoveCursor()
  */
-Lisp moveCursor(Lisp args, LispError *e, LispContext ctx) {
+Lisp moveCursor(Lisp args, LispError* e, LispContext ctx)
+{
     const char* direction = lisp_string(lisp_car(args));
     int is_in = 0;
-  switch (direction[0]) {
+    switch (direction[0])
+    {
     case 'u':
         is_in = editorMoveCursor(ARROW_UP);
         break;
@@ -108,35 +120,44 @@ Lisp moveCursor(Lisp args, LispError *e, LispContext ctx) {
     case 'l':
         is_in = editorMoveCursor(ARROW_LEFT);
         break;
+    default:
+        break;
     }
     appDebug("move lisp %d\n", is_in);
     return lisp_make_bool(is_in);
 }
 
 /**
- * @brief Frees all dynamically allocated editor structures
+ * @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 free_structs(void) {
+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);
-  // free layout
-  free(E.layout.panes);
+    E.key_binds = NULL;
+    E.number_of_keybinds = 0;
 
-  // Free buffers
+    // 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);
@@ -153,23 +174,25 @@ void free_structs(void) {
  * @return lisp_null() (never returns on successful exit)
  * @note Calls exit(0) to terminate program
  * @note Updates quit_times_buffer counter
- * @see free_structs()
+ * @see bFree_structs()
  */
-Lisp editorQuit(Lisp args, LispError *e, LispContext ctx) {
-  if (E.dirty && E.quit_times_buffer > 0) {
+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();
     }
-  free_structs();
+    bFree_structs();
     write(STDOUT_FILENO, "\x1b[2J", 4);
     write(STDOUT_FILENO, CURSOR_TOP_LEFT, 3);
-  disableRawMode();
+    lspShutdown(E.lsp_client);
     lisp_shutdown(E.ctx);
+    // deInitEditor();
+    disableRawMode();
     exit(0);
-
-  return lisp_null();
 }
 
 /**
@@ -182,19 +205,22 @@ Lisp editorQuit(Lisp args, LispError *e, LispContext ctx) {
  * @see editorSave()
  */
 
-Lisp l_editorSplitScreenVertical(Lisp args, LispError *e, LispContext ctx) {
-  if (E.number_of_buffer >= 2) {
+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 {
+    }
+    else
+    {
         editorSetStatusMessage("Need at least 2 buffers open");
     }
     return lisp_null();
 }
 
-Lisp l_editorSave(Lisp args, LispError *e, LispContext ctx) {
-
+Lisp l_editorSave(Lisp args, LispError* e, LispContext ctx)
+{
     editorSave();
-
     return lisp_null();
 }
 
@@ -207,8 +233,8 @@ Lisp l_editorSave(Lisp args, LispError *e, LispContext ctx) {
  * @return lisp_null()
  * @see editorInsertNewLine()
  */
-Lisp l_editorInsertNewLine(Lisp args, LispError *e, LispContext ctx) {
-
+Lisp l_editorInsertNewLine(Lisp args, LispError* e, LispContext ctx)
+{
     bufferInsertNewLine();
 
     return lisp_null();
@@ -223,8 +249,10 @@ Lisp l_editorInsertNewLine(Lisp args, LispError *e, LispContext ctx) {
  * @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) {
+Lisp l_editorInserTab(Lisp args, LispError* e, LispContext ctx)
+{
+    for (int i = 0; i < E.constantes.TAB_LENGTH; ++i)
+    {
         bufferInsertBytes(" ", 1);
     }
 
@@ -240,7 +268,8 @@ Lisp l_editorInserTab(Lisp args, LispError *e, LispContext ctx) {
  * @return lisp_null()
  * @note Updates global editor state E
  */
-Lisp moveCursorBeginLine(Lisp args, LispError *e, LispContext ctx) {
+Lisp moveCursorBeginLine(Lisp args, LispError* e, LispContext ctx)
+{
     EditorPane* active = splitScreenGetActivePane();
     struct buffer_t* buf = bufferFindById(active->buffer_id);
     buf->x = 0;
@@ -256,7 +285,8 @@ Lisp moveCursorBeginLine(Lisp args, LispError *e, LispContext ctx) {
  * @return lisp_null()
  * @note Updates global editor state E
  */
-Lisp moveCursorEndLine(Lisp args, LispError *e, LispContext ctx) {
+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;
@@ -272,7 +302,8 @@ Lisp moveCursorEndLine(Lisp args, LispError *e, LispContext ctx) {
  * @return lisp_null()
  * @see editorDelChar()
  */
-Lisp deletePreviousChar(Lisp args, LispError *e, LispContext ctx) {
+Lisp deletePreviousChar(Lisp args, LispError* e, LispContext ctx)
+{
     bufferDelBytes();
     return lisp_null();
 }
@@ -288,11 +319,13 @@ Lisp deletePreviousChar(Lisp args, LispError *e, LispContext ctx) {
  * @note Updates global editor state E
  * @see editorMoveCursor()
  */
-Lisp editorMoveCursorPageUp(Lisp args, LispError *e, LispContext ctx) {
+Lisp editorMoveCursorPageUp(Lisp args, LispError* e, LispContext ctx)
+{
     EditorPane* active = splitScreenGetActivePane();
     active->cursor_y = active->y_offset;
     int times = E.screenrows;
-  while (--times) {
+    while (--times)
+    {
         editorMoveCursor(ARROW_UP);
     }
     return lisp_null();
@@ -309,15 +342,18 @@ Lisp editorMoveCursorPageUp(Lisp args, LispError *e, LispContext ctx) {
  * @note Updates global editor state E
  * @see editorMoveCursor()
  */
-Lisp editorMoveCursorPageDown(Lisp args, LispError *e, LispContext ctx) {
+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) {
+    if (active->cursor_y > buffer->numrows)
+    {
         active->cursor_y = buffer->numrows;
     }
     int times = E.screenrows;
-  while (--times) {
+    while (--times)
+    {
         editorMoveCursor(ARROW_DOWN);
     }
 
@@ -335,9 +371,11 @@ Lisp editorMoveCursorPageDown(Lisp args, LispError *e, LispContext ctx) {
  * @see editorOpen()
  * @see editorPrompt()
  */
-Lisp editorOpenFile(Lisp args, LispError *e, LispContext ctx) {
+Lisp editorOpenFile(Lisp args, LispError* e, LispContext ctx)
+{
     char* filename = editorPrompt("Open : %s", getenv("PWD"), 1);
-  if (filename) {
+    if (filename)
+    {
         //    editorOpen(filename);
         EditorPane* active = splitScreenGetActivePane();
         active->buffer_id = bufferCreate(filename, READ_AND_WRITE);
@@ -357,9 +395,10 @@ Lisp editorOpenFile(Lisp args, LispError *e, LispContext ctx) {
  * @return lisp_null()
  * @note Uses first character of the string argument
  */
-Lisp editorPrintC(Lisp args, LispError *e, LispContext ctx) {
+Lisp editorPrintC(Lisp args, LispError* e, LispContext ctx)
+{
     const char* src = lisp_string(lisp_car(args));
-  bufferInsertBytes(src, strlen(src));
+    bufferInsertBytes(src, (int) strlen(src));
     return lisp_null();
 }
 
@@ -374,28 +413,38 @@ Lisp editorPrintC(Lisp args, LispError *e, LispContext ctx) {
  * @note Package files must be valid Lisp code
  * @note Package directory defaults to ~/.beluga/packages/
  */
-Lisp addPackage(Lisp args, LispError *e, LispContext ctx) {
+Lisp addPackage(Lisp args, LispError* e, LispContext ctx)
+{
     const char* package_name = lisp_string(lisp_car(args));
     appDebug("%s\n", package_name);
-  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");
-  appDebug("%s\n", package_dir);
-  fd_package = fopen(package_dir, "r");
-  lisp_eval(lisp_read_file(fd_package, &E.ctx_error, E.ctx), &E.ctx_error,
-            E.ctx);
+    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) {
+Lisp editorSwitchNextBuffer(Lisp args, LispError* e, LispContext ctx)
+{
     appDebug("switch buffer\n");
-  if (E.number_of_buffer > 0) {
+    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;
@@ -404,13 +453,16 @@ Lisp editorSwitchNextBuffer(Lisp args, LispError *e, LispContext ctx) {
     return lisp_null();
 }
 
-Lisp editorSwitchNextPane(Lisp args, LispError *e, LispContext ctx) {
+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) {
+Lisp editorUnifiedPanes(Lisp args, LispError* e, LispContext ctx)
+{
+    if (E.layout.num_panes - 1)
+    {
         splitScreenUnify();
     }
     return lisp_null();
@@ -425,7 +477,8 @@ Lisp editorUnifiedPanes(Lisp args, LispError *e, LispContext ctx) {
  * @return lisp_null()
  * @see editorFind()
  */
-Lisp bufferFind_L(Lisp args, LispError *e, LispContext ctx) {
+Lisp bufferFind_L(Lisp args, LispError* e, LispContext ctx)
+{
     appDebug("LispFind\n");
     EditorPane* active = splitScreenGetActivePane();
     struct buffer_t* buffer = bufferFindById(active->buffer_id);
@@ -442,7 +495,8 @@ Lisp bufferFind_L(Lisp args, LispError *e, LispContext ctx) {
  * @return lisp_null()
  * @see editorFind()
  */
-Lisp bufferFindReverse_L(Lisp args, LispError *e, LispContext ctx) {
+Lisp bufferFindReverse_L(Lisp args, LispError* e, LispContext ctx)
+{
     appDebug("LispFind\n");
     EditorPane* active = splitScreenGetActivePane();
     struct buffer_t* buffer = bufferFindById(active->buffer_id);
@@ -459,13 +513,17 @@ Lisp bufferFindReverse_L(Lisp args, LispError *e, LispContext ctx) {
  * @param ctx Lisp context
  * @return Lisp character object representing the character at cursor
  */
-Lisp editorReadChar_L(Lisp args, LispError *e, LispContext ctx) {
+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) {
+    if (buffer->row[buffer->y].chars[buffer->x] == 0)
+    {
         returned_char = lisp_make_char('a');
-  } else {
+    }
+    else
+    {
         returned_char = lisp_make_char(buffer->row[buffer->y].chars[buffer->x]);
     }
     return returned_char;
@@ -482,7 +540,8 @@ Lisp editorReadChar_L(Lisp args, LispError *e, LispContext ctx) {
  * @note Updates global editor state E (prefix_state)
  * @see find_prefix()
  */
-Lisp editorSetPrefix(Lisp args, LispError *e, LispContext ctx) {
+Lisp editorSetPrefix(Lisp args, LispError* e, LispContext ctx)
+{
     /*
      * Set the prefix state of editor to the prefix in argument
      */
@@ -505,7 +564,8 @@ Lisp editorSetPrefix(Lisp args, LispError *e, LispContext ctx) {
  * @return lisp_null()
  * @note Updates global editor state E (prefix array)
  */
-Lisp editorPrefix(Lisp args, LispError *e, LispContext ctx) {
+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;
@@ -526,7 +586,9 @@ Lisp editorCutEndLine(Lisp args, LispError *e, LispContext ctx)
 {
     EditorPane* active = splitScreenGetActivePane();
     struct buffer_t* buffer = bufferFindById(active->buffer_id);
-  int bytes_to_delete = buffer->row[buffer->y].size - buffer->x;
+    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--)
@@ -556,6 +618,44 @@ Lisp editorMoveEndBuffer(Lisp args, LispError *e, LispContext ctx)
 
 Lisp editorAutoComplete(Lisp args, LispError* e, LispContext ctx)
 {
-  createContextBuffer(E.cursor_x - 2, E.cursor_y + 1, "hello");
+    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

@@ -49,13 +49,13 @@ int editorMoveCursor(int key) {
         if (row && buf->x < row->size) {
             int len = utf8Seqlen(row->chars[buf->x]);
             buf->x += len;
-        } else if (row && buf->y < buf->numrows) {
+        } else if (row && buf->y < buf->numrows - 1) {
             buf->y++;
             buf->x = 0;
         }
         break;
     case ARROW_DOWN:
-        if (buf->y < buf->numrows) {
+        if (buf->y < buf->numrows - 1) {
 
             buf->y++;
         }
@@ -73,6 +73,8 @@ int editorMoveCursor(int key) {
             buf->x = buf->row[buf->y].size;
         }
         break;
+    default:
+        break;
     }
     return 1;
 }
@@ -84,18 +86,28 @@ char *editorGetClipboard(void) {
     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;
-            buf = realloc(buf, cap);
+            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; // caller must free
+    return buf;
 }
 
 void editorSetClipboard(const char *text, int len) {

src/file_io.c

@@ -17,11 +17,9 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <time.h>
 #include <unistd.h>
 #include <errno.h>
 
-extern struct editorConfig E;
 
 /**
  * @brief Closes the current file and resets editor state
@@ -54,7 +52,7 @@ void editorCloseFile(void) {
  * @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 filename Path to the file to open (relative or absolute)
+ * @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
@@ -62,13 +60,12 @@ void editorCloseFile(void) {
  */
 void editorOpen(struct buffer_t* buffer) {
   FILE *fp;
-
-  fp = fopen(buffer->filename, "a+");
+  fp = fopen(buffer->fullname, "a+");
   if (!fp)
     die("fopen");
 
   char *line = NULL;
-  size_t line_cap;
+  size_t line_cap = 0;
   ssize_t line_len;
 
   rewind(fp);
@@ -78,12 +75,11 @@ void editorOpen(struct buffer_t* buffer) {
            (line[line_len - 1] == '\n' || line[line_len - 1] == '\r')) {
       --line_len;
            }
-    appDebug("line %s\n", line);
     bufferInsertRow(buffer, buffer->numrows, line, line_len);
     free(line);
     line = NULL;
+    line_cap = 0;  // Reset for next iteration
   }
-  free(line);
   fclose(fp);
   E.dirty = 0;
 }
@@ -110,11 +106,11 @@ void editorSave() {
       return;
     }
   }
-  fd = open(buffer->filename, O_RDWR | O_CREAT, 0644);
+  fd = open(buffer->fullname, O_WRONLY | O_CREAT | O_TRUNC, 0644);
   if (fd != -1) {
     for (int i = 0; i < buffer->numrows; ++i)
     {
-      len = strlen(buffer->row[i].chars);
+      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));

src/init.c

@@ -49,12 +49,15 @@ void initBuiltins() {
   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 initConfig() {
 
   E.ctx = lisp_init();
-  E.ctx.p->err_port = fopen("log.err", "w");
+  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
@@ -71,6 +74,8 @@ void initConfig() {
 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);
@@ -95,7 +100,7 @@ void initEditor() {
   if (getWindowSize(&E.screenrows, &E.screencols) == -1) {
     die("getWindowSize");
   }
-  appDebug("%d %d\n", E.screenrows, E.screencols);
+  appDebug("%d %d", E.screenrows, E.screencols);
   E.screenrows -= 2;
 
 
@@ -112,14 +117,26 @@ void initEditor() {
   active->width = E.screencols;
   active->height = E.screenrows;
 
-  E.init_file_path = (char *)calloc(256, sizeof(char));
-  strcat(E.init_file_path, getenv("HOME"));
-  strcat(E.init_file_path, "/.beluga/config/init.lisp");
-  appDebug("%s\n", E.init_file_path);
-  E.fd_init_file = fopen(E.init_file_path, "r");
+  const char *home = getenv("HOME");
+  if (!home) {
+    die("HOME environment variable not set");
+  }
 
-  // Status bar
-  E.status_msg = (char *)calloc(E.screencols, sizeof(char));
+  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;
 
@@ -132,8 +149,10 @@ void initEditor() {
   strncpy(E.prefix[0].prefix_name, "no-prefix", 64);
   E.prefix_state = 0;
 
-  initConfig();
+  E.lsp_client = (LspClient*)malloc(sizeof(LspClient));
+  E.lsp_client->state = LSP_SHUTDOWN;
 
+  initConfig();
   initTheme();
 
   // To modify
@@ -149,3 +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

@@ -2,29 +2,26 @@
 #include "../include/define.h"
 #include "../include/editor_op.h"
 #include "../include/output.h"
-#include "include/data.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 <sys/stat.h>
-#include <unistd.h>
 
 #include "include/terminal.h"
 #include "include/utf8.h"
 
-extern struct editorConfig E;
-
 /**
  * @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
+ * @details Manages user input processing, key bindings, cursor movement, and
+ * file path completion
  */
 
 /**
@@ -33,11 +30,12 @@ extern struct editorConfig E;
  * 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:
+ * @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 freeing the returned string
+ * @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) {
@@ -60,7 +58,7 @@ const char *fileCompletion(const char *path) {
   if (last_slash) {
     dir_len = last_slash - path + 1; // length of dir_path
     strncpy(directory, path, dir_len);
-    predict_len = strlen(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';
@@ -99,16 +97,16 @@ const char *fileCompletion(const char *path) {
 
 /**
  * @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.
+ * @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 freeing the returned string
+ * @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) {
@@ -151,7 +149,6 @@ char *editorPrompt(char *prompt, char *placeHolder, char bPathMode) {
         strcpy(path, buf);
       }
       memset(buf, 0, 256);
-      buf_len = 0;
       char *buf_complete = (char *)fileCompletion(path);
       strcpy(buf, buf_complete);
       free(buf_complete);
@@ -161,15 +158,16 @@ char *editorPrompt(char *prompt, char *placeHolder, char bPathMode) {
     } else if (!iscntrl(c) && c < 256) {
       if (buf_len == buf_size - 1) {
         buf_size *= 2;
-        buf = realloc(buf, buf_size);
+        char *new_buf = realloc(buf, buf_size);
+        if (!new_buf) {
+          free(buf);
+          return NULL;
+        }
+        buf = new_buf;
       }
-      buf[buf_len++] = c;
-      buf[buf_len] = '\0';
     }
   }
 }
-
-
 
 /**
  * @brief Executes the command bound to a key sequence
@@ -207,11 +205,64 @@ int executeKeyBind(char *key_sequence) {
  * 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
+ * @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 (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;
@@ -219,5 +270,15 @@ void editorProcessKeypress() {
   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

@@ -15,13 +15,12 @@
 #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
  */
@@ -70,6 +69,9 @@ static void editorDrawPane(struct abuf* ab, EditorPane* pane)
         }
         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')
@@ -180,11 +182,13 @@ void editorScroll()
             if (active->cursor_x == 0 && active->x_offset)
             {
                 active->x_offset--;
-            } else
+            }
+            else
             {
                 active->cursor_x--;
             }
-        } else
+        }
+        else
         {
             // RIGHT
             if (rel_x > active->cursor_x + active->x_offset)
@@ -192,7 +196,8 @@ void editorScroll()
                 if (active->cursor_x == active->width - 1)
                 {
                     active->x_offset++;
-                } else
+                }
+                else
                 {
                     active->cursor_x++;
                 }
@@ -204,7 +209,8 @@ void editorScroll()
             if (active->cursor_y == 0 && active->y_offset)
             {
                 active->y_offset--;
-            } else
+            }
+            else
             {
                 active->cursor_y--;
             }
@@ -215,12 +221,12 @@ void editorScroll()
             if (active->cursor_y == active->height - 1)
             {
                 active->y_offset++;
-            } else
+            }
+            else
             {
                 active->cursor_y++;
             }
         }
-
     }
 }
 
@@ -296,12 +302,9 @@ void editorDrawStatusBar(struct abuf* ab)
             abAppend(ab, render_status, render_len);
             break;
         }
-        else
-        {
         abAppend(ab, " ", 1);
         ++len;
     }
-    }
 
     abAppend(ab, "\x1b[m", 3); // normal text mode
     abAppend(ab, "\r\n", 2);
@@ -328,7 +331,6 @@ void editorDrawMessageBar(struct abuf* ab)
     }
 }
 
-
 /**
  * @brief Performs complete screen refresh and buffer synchronization
  * @details Clears screen, redraws all visible content (rows, status bar,
@@ -348,26 +350,66 @@ void editorRefreshScreen()
     abAppend(&ab, HIDE_CURSOR, 6);
     abAppend(&ab, CURSOR_TOP_LEFT, 3);
     abAppend(&ab, E.theme.BACKGROUND_COLOR,
-             (int) strlen(E.theme.BACKGROUND_COLOR)); // RGB background is 12 bytes
+             (int)strlen(E.theme.BACKGROUND_COLOR));
 
-    // Draw all panes
     editorScroll();
-    editorDrawAllPanes(&ab);
 
-    // Draw status bar and message bar
+
+    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);
-    // editorDrawContextBuffer(&ab);
-
-    // Position cursor in active pane
-    EditorPane* active = splitScreenGetActivePane();
-    if (active != NULL)
+    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);
+             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);

src/split_screen.c

@@ -9,6 +9,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+
 extern struct editorConfig E;
 
 /**
@@ -19,7 +20,12 @@ void splitScreenInit(void) {
     E.layout.num_panes = 1;
     E.layout.active_pane = 0;
 
-    E.layout.panes = malloc(sizeof(EditorPane) * 2);
+    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
@@ -48,7 +54,7 @@ int splitScreenVertical(int buffer_id_left, int buffer_id_right) {
         return -1;
     }
 
-    // Reallocate panes array
+    // bReallocate panes array
     E.layout.panes = realloc(E.layout.panes, sizeof(EditorPane) * 2);
     E.layout.mode = SPLIT_VERTICAL;
     E.layout.num_panes = 2;
@@ -99,7 +105,7 @@ int splitScreenHorizontal(int buffer_id_top, int buffer_id_bottom) {
         return -1;
     }
 
-    // Reallocate panes array
+    // bReallocate panes array
     E.layout.panes = realloc(E.layout.panes, sizeof(EditorPane) * 2);
     E.layout.mode = SPLIT_HORIZONTAL;
     E.layout.num_panes = 2;
@@ -216,3 +222,15 @@ 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

@@ -5,6 +5,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+
 extern struct editorConfig E;
 
 const char *c_keywords[] = {
@@ -32,15 +33,6 @@ static int utf8_char_len(const char *s)
     return 1; // continuation byte or invalid — advance 1 to avoid infinite loop
 }
 
-// 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
 int is_word_char(const char *s)
 {
   uint32_t cp = utf8Decode(&s);
@@ -61,12 +53,20 @@ int is_word_char(const char *s)
   if ((cp >= 0x3040 && cp <= 0x309F) ||
       (cp >= 0x30A0 && cp <= 0x30FF)) return 1;
   if (cp >= 0xAC00 && cp <= 0xD7A3) return 1;
-    if ((cp >= 0x0660 && cp <= 0x0669) ||
-        (cp >= 0x06F0 && cp <= 0x06F9)) 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++) {
@@ -110,9 +110,13 @@ int comment_section = 0;
 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 = strlen(line);
+  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;
 
@@ -125,31 +129,31 @@ char *highlight_line(const char *line, int *length) {
     }
 
     if (comment_section) {
-      result_pos += sprintf(&result[result_pos], "%s", E.theme.COLOR_COMMENT);
+      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 += sprintf(&result[result_pos], "%s", COLOR_RESET);
+      result_pos += snprintf(&result[result_pos], 10, "%s", COLOR_RESET);
       continue;
     }
 
     // Handle line comments
     if (line[i] == '/' && line[i + 1] == '/') {
-      result_pos += sprintf(&result[result_pos], "%s", E.theme.COLOR_COMMENT);
+      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 += sprintf(&result[result_pos], "%s", COLOR_RESET);
+      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 += sprintf(&result[result_pos], "%s", E.theme.COLOR_COMMENT);
+      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') {
@@ -161,13 +165,13 @@ char *highlight_line(const char *line, int *length) {
         }
         copy_utf8_char(result, &result_pos, line, &i);
       }
-      result_pos += sprintf(&result[result_pos], "%s", COLOR_RESET);
+      result_pos += snprintf(&result[result_pos], 10, "%s", COLOR_RESET);
       continue;
     }
 
     // Handle strings
     if (line[i] == '"') {
-      result_pos += sprintf(&result[result_pos], "%s\"", E.theme.COLOR_STRING);
+      result_pos += snprintf(&result[result_pos], 10, "%s\"", E.theme.COLOR_STRING);
       i++;
       while (line[i] != '\0' && line[i] != '"') {
         if (line[i] == '\\') {
@@ -179,13 +183,13 @@ char *highlight_line(const char *line, int *length) {
       }
       if (line[i] == '"')
         result[result_pos++] = line[i++];
-      result_pos += sprintf(&result[result_pos], "%s", COLOR_RESET);
+      result_pos += snprintf(&result[result_pos], 10, "%s", COLOR_RESET);
       continue;
     }
 
     // Handle character literals
     if (line[i] == '\'') {
-      result_pos += sprintf(&result[result_pos], "%s'", E.theme.COLOR_STRING);
+      result_pos += snprintf(&result[result_pos], 10, "%s'", E.theme.COLOR_STRING);
       i++;
       while (line[i] != '\0' && line[i] != '\'') {
         if (line[i] == '\\') {
@@ -197,17 +201,17 @@ char *highlight_line(const char *line, int *length) {
       }
       if (line[i] == '\'')
         result[result_pos++] = line[i++];
-      result_pos += sprintf(&result[result_pos], "%s", COLOR_RESET);
+      result_pos += snprintf(&result[result_pos], 10, "%s", COLOR_RESET);
       continue;
     }
 
     // Handle numbers
     if (line[i] >= '0' && line[i] <= '9') {
-      result_pos += sprintf(&result[result_pos], "%s", E.theme.COLOR_NUMBER);
+      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 += sprintf(&result[result_pos], "%s", COLOR_RESET);
+      result_pos += snprintf(&result[result_pos], 10, "%s", COLOR_RESET);
       continue;
     }
 
@@ -231,15 +235,15 @@ char *highlight_line(const char *line, int *length) {
       else if (is_type(word))
         type = TOKEN_TYPE;
 
-      result_pos += sprintf(&result[result_pos], "%s%s%s", get_color(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 += sprintf(&result[result_pos], "%s", E.theme.COLOR_DEFAULT);
+    result_pos += snprintf(&result[result_pos], 10, "%s", E.theme.COLOR_DEFAULT);
     copy_utf8_char(result, &result_pos, line, &i);
-    result_pos += sprintf(&result[result_pos], "%s", COLOR_RESET);
+    result_pos += snprintf(&result[result_pos], 10, "%s", COLOR_RESET);
   }
 
   result[result_pos] = '\0';

src/terminal.c

@@ -10,9 +10,12 @@
 #include <string.h>
 #include <unistd.h>
 
-#include "include/utf8.h"
+#include "../include/buffer.h"
+#include "../include/split_screen.h"
+#include "../include/utf8.h"
 
-void die(const char *s) {
+void die(const char* s)
+{
     write(STDOUT_FILENO, "\x1b[2J", 4);
     write(STDOUT_FILENO, CURSOR_TOP_LEFT, 3);
     lisp_shutdown(E.ctx);
@@ -20,14 +23,18 @@ void die(const char *s) {
     exit(1);
 }
 
-void disableRawMode() {
-  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1) {
+void disableRawMode()
+{
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1)
+    {
         die("tcsetattr");
     }
 }
 
-void enableRawMode() {
-  if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1) {
+void enableRawMode()
+{
+    if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1)
+    {
         die("tcgetattr");
     }
 
@@ -39,24 +46,34 @@ void enableRawMode() {
     raw.c_cc[VMIN] = 0;
     raw.c_cc[VTIME] = 1;
 
-  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) {
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1)
+    {
         die("tcgetattr");
     }
 }
 
 #include <ctype.h> /* isprint */
 
-char *keyToString(int key) {
+char* keyToString(int key)
+{
     static char key_str[32];
 
-  if (key == '\r') {
+    if (key == '\r')
+    {
         strcpy(key_str, "ENTER");
-  } else if (key == 0x09) {
+    }
+    else if (key == 0x09)
+    {
         strcpy(key_str, "TAB");
-  } else if (key >= 1 && key <= 26) {
+    }
+    else if (key >= 1 && key <= 26)
+    {
         snprintf(key_str, sizeof(key_str), "CTRL-%c", 'a' + key - 1);
-  } else {
-    switch (key) {
+    }
+    else
+    {
+        switch (key)
+        {
         case ARROW_UP:
             strcpy(key_str, "ARROW-UP");
             break;
@@ -91,14 +108,19 @@ char *keyToString(int key) {
             strcpy(key_str, "ESCAPE");
             break;
         default:
-      if (key > 127) {
+            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)) {
+            }
+            else if (isprint(key))
+            {
                 snprintf(key_str, sizeof(key_str), "%c", key);
-      } else {
+            }
+            else
+            {
                 snprintf(key_str, sizeof(key_str), "KEY-%d", key);
             }
         }
@@ -106,14 +128,57 @@ char *keyToString(int key) {
     return key_str;
 }
 
-int editorReadKey() {
+int editorReadKey()
+{
     char c;
-  /* read first byte — may be start of UTF-8 or escape */
-  while (read(STDIN_FILENO, &c, 1) != 1)
-    ;
+    int nread;
+
+    while (1)
+    {
+        fd_set fds;
+        FD_ZERO(&fds);
+        FD_SET(STDIN_FILENO, &fds);
+
+        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;
+        }
+    }
+
+
     appDebug("f : %hhu %ld\r\n", c, 0x200);
 
-  if (c == '\x1b') {
+    if (c == '\x1b')
+    {
         char seq[6];
         /* try to read escape sequence */
         if (read(STDIN_FILENO, &seq[0], 1) != 1)
@@ -122,12 +187,16 @@ int editorReadKey() {
             return '\x1b';
         appDebug("f2 : %s\r\n", seq);
 
-    if (seq[0] == '[') {
-      if (seq[1] >= '0' && seq[1] <= '9') {
+        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]) {
+                if (seq[2] == '~')
+                {
+                    switch (seq[1])
+                    {
                     case '1':
                         return BEG_LINE;
                     case '3':
@@ -144,8 +213,11 @@ int editorReadKey() {
                         return END_LINE;
                     }
                 }
-      } else {
-        switch (seq[1]) {
+            }
+            else
+            {
+                switch (seq[1])
+                {
                 case 'A':
                     return ARROW_UP;
                 case 'B':
@@ -166,7 +238,8 @@ int editorReadKey() {
 
     /* multi-byte UTF-8: read remaining bytes */
     int seqlen = utf8Seqlen((unsigned char)c);
-  if (seqlen > 1) {
+    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};
@@ -182,56 +255,66 @@ int editorReadKey() {
     return (unsigned char)c;
 }
 
-int getCursorPosition(int *rows, int *cols) {
+int getCursorPosition(int* rows, int* cols)
+{
     char buf[32];
     unsigned int i = 0;
 
-  if (write(STDOUT_FILENO, "\x1b[6n", 4) != 4) {
+    if (write(STDOUT_FILENO, "\x1b[6n", 4) != 4)
+    {
         return -1;
     }
 
-  while (i < sizeof(buf) - 1) {
-    if (read(STDIN_FILENO, &buf[i], 1) != 1) {
+    while (i < sizeof(buf) - 1)
+    {
+        if (read(STDIN_FILENO, &buf[i], 1) != 1)
+        {
             break;
         }
-    if (buf[i] == 'R') {
+        if (buf[i] == 'R')
+        {
             break;
         }
         ++i;
     }
     buf[i] = '\0';
 
-  if (buf[0] != '\x1b' || buf[1] != '[') {
+    if (buf[0] != '\x1b' || buf[1] != '[')
+    {
         return -1;
     }
-  if (sscanf(&buf[2], "%d;%d", rows, cols) != 2) {
+    if (sscanf(&buf[2], "%d;%d", rows, cols) != 2)
+    {
         return -1;
     }
 
     return 0;
 }
 
-int getWindowSize(int *rows, int *cols) {
+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) {
+    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);
-  } else {
+    }
     *cols = ws.ws_col;
     *rows = ws.ws_row;
     return 0;
 }
-}
 
-void appDebug(const char *fmt, ...) {
+void appDebug(const char* fmt, ...)
+{
 #ifdef APP_DEBUG
     va_list ap;
-  char message[256];
+    char message[1024];
     va_start(ap, fmt);
-  vsnprintf(message, 256, fmt, ap);
+    vsnprintf(message, 1024, fmt, ap);
     va_end(ap);
     fprintf(stderr, "%s\n", message);
 #endif

test/main.c

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