/**
 * @file builtins.c
 * @brief Built-in Lisp functions for editor operations
 * @details Provides Lisp bindings for core editor functionality including
 * cursor movement, file operations, keybinding management, and text manipulation
 */

#include "../include/builtins.h"
#include "../include/data.h"
#include "../include/define.h"
#include "../include/editor_op.h"
#include "../include/file_io.h"
#include "../include/input.h"
#include "../include/row_op.h"
#include "../include/buffer.h"
#include "../include/split_screen.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/**
 * @brief Finds a prefix configuration by name
 * @details Searches the prefix array for a prefix matching the given name.
 * Returns the first prefix (default) if no match is found.
 * @param prefix_name Name of the prefix to search for (max 64 chars)
 * @return Matching prefix_t structure, or E.prefix[0] if not found
 * @note Updates global editor state E
 */
struct prefix_t find_prefix(const char prefix_name[64]) {
  int i = E.number_of_prefix + 1;
  while (i--) {
    if (!strcmp(prefix_name, E.prefix[i].prefix_name)) {
      return E.prefix[i];
    }
  }
  return E.prefix[0];
}

/**
 * @brief Lisp function to bind a command to a key sequence
 * @details Registers a keybinding with an associated Lisp command and optional
 * prefix modifier. Dynamically extends the keybind array.
 * @param args Lisp list of 3 arguments: (key-sequence command prefix-name)
 *        - key_sequence (string): The key or key combination to bind
 *        - command (Lisp): The Lisp command/function to execute
 *        - prefix_name (string): Prefix modifier name
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @note Updates global editor state E (key_binds array)
 */
Lisp mapKey(Lisp args, LispError *e, LispContext ctx) {
  /*
   * 3 arguments keybind command prefix
   */
  const char *key_sequence = lisp_string(lisp_car(args));
  args = lisp_cdr(args);
  // second argument
  Lisp func = lisp_car(args);

  E.key_binds = (struct keyBind_t *)realloc(
      E.key_binds, ++E.number_of_keybinds * sizeof(struct keyBind_t));
  E.key_binds[E.number_of_keybinds - 1].key_sequence =
      (char *)malloc(50 * sizeof(char));

  strncpy(E.key_binds[E.number_of_keybinds - 1].key_sequence, key_sequence, 50);

  E.key_binds[E.number_of_keybinds - 1].command = func;

  // Third argument
  args = lisp_cdr(args);
  const char *prefix_name = lisp_string(lisp_car(args));
  struct prefix_t prefix = find_prefix(prefix_name);

  E.key_binds[E.number_of_keybinds - 1].prefix_id = prefix.prefix_id;
  
  return lisp_null();
}

/**
 * @brief Lisp function to create a new terminal buffer
 * @details Creates a new terminal buffer and switches to it.
 * @param args Lisp arguments (ignored)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @note Updates global editor state E
 */
Lisp editorCreateTerminal(Lisp args, LispError *e, LispContext ctx) {
  int buffer_id = bufferCreateTerminal();
  if (buffer_id >= 0) {
    bufferSwitch(buffer_id);
  }
  return lisp_null();
}

/**
 * @brief Lisp function to move cursor in a specified direction
 * @details Moves the editor cursor up, down, left, or right based on direction string.
 * @param args Lisp list with one argument: direction string
 *        - "u": up, "d": down, "r": right, "l": left
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return Lisp boolean indicating whether movement was valid
 * @note Updates global editor state E
 * @see editorMoveCursor()
 */
Lisp moveCursor(Lisp args, LispError *e, LispContext ctx) {
  const char *direction = lisp_string(lisp_car(args));
  int is_in = 0;
  switch (direction[0]) {
  case 'u':
    is_in = editorMoveCursor(ARROW_UP);
    break;
  case 'd':
    is_in = editorMoveCursor(ARROW_DOWN);
    break;
  case 'r':
    is_in = editorMoveCursor(ARROW_RIGHT);
    break;
  case 'l':
    is_in = editorMoveCursor(ARROW_LEFT);
    break;
  }
  fprintf(stderr, "move lisp %d\n", is_in);
  return lisp_make_bool(is_in);
}

/**
 * @brief Frees 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) {
  int i, j;
  free(E.prefix);
  for (i = 0; i < E.number_of_keybinds; ++i) {
    free(E.key_binds[i].key_sequence);
  }
  free(E.key_binds);
  // free layout
  free(E.layout.panes);

  // Free buffers
  for (i = 0; i < E.number_of_buffer; ++i) {
    free(E.buffers[i].filename);
    for (j = 0; j < E.buffers[i].numrows; ++j) {
      free(E.buffers[i].row[j].render);
      free(E.buffers[i].row[j].chars);
    }
    free(E.buffers[i].row);
  }
  
  free(E.init_file_path);
  fclose(E.fd_init_file);
  
}

/**
 * @brief Lisp function to quit the editor
 * @details Closes editor with unsaved changes protection. Prompts user to confirm
 * quit after multiple attempts if file is dirty. Cleans up resources and restores terminal.
 * @param args Lisp arguments (unused)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null() (never returns on successful exit)
 * @note Calls exit(0) to terminate program
 * @note Updates quit_times_buffer counter
 * @see free_structs()
 */
Lisp editorQuit(Lisp args, LispError *e, LispContext ctx) {
  if (E.dirty && E.quit_times_buffer > 0) {
    editorSetStatusMessage("WARNING! Changes hasn't been saved. Press Ctrl-Q "
                           "another time to quit.");
    --E.quit_times_buffer;
    return lisp_null();
  }
  free_structs();
  write(STDOUT_FILENO, "\x1b[2J", 4);
  write(STDOUT_FILENO, CURSOR_TOP_LEFT, 3);
  disableRawMode();
  lisp_shutdown(E.ctx);
  exit(0);

  return lisp_null();
}

/**
 * @brief Lisp function to save the current file
 * @details Wrapper around editorSave() for use in Lisp keybindings.
 * @param args Lisp arguments (unused)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @see editorSave()
 */

Lisp l_editorSplitScreenVertical(Lisp args, LispError *e, LispContext ctx) {
  if (E.number_of_buffer >= 2) {
        splitScreenVertical(E.buffers[0].buffer_id, E.buffers[1].buffer_id);
    } else {
        editorSetStatusMessage("Need at least 2 buffers open");
    }
  return lisp_null();
}

Lisp l_editorSave(Lisp args, LispError *e, LispContext ctx) {

  editorSave();

  return lisp_null();
}

/**
 * @brief Lisp function to insert a new line at cursor
 * @details Wrapper around editorInsertNewLine() for use in Lisp keybindings.
 * @param args Lisp arguments (unused)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @see editorInsertNewLine()
 */
Lisp l_editorInsertNewLine(Lisp args, LispError *e, LispContext ctx) {

  bufferInsertNewLine();

  return lisp_null();
}

/**
 * @brief Lisp function to insert a tab (spaces) at cursor
 * @details Inserts TAB_LENGTH spaces at the current cursor position.
 * @param args Lisp arguments (unused)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @note Uses E.constantes.TAB_LENGTH for indentation width
 */
Lisp l_editorInserTab(Lisp args, LispError *e, LispContext ctx) {

  for (int i = 0; i<E.constantes.TAB_LENGTH; ++i) {
    bufferInsertChar(' ');
  }

  return lisp_null();
}

/**
 * @brief Lisp function to move cursor to beginning of line
 * @details Moves cursor to column 0 of the current line.
 * @param args Lisp arguments (unused)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @note Updates global editor state E
 */
Lisp moveCursorBeginLine(Lisp args, LispError *e, LispContext ctx) {
  E.layout.panes[E.layout.active_pane].cursor_x = 0;
  return lisp_null();
}

/**
 * @brief Lisp function to move cursor to end of line
 * @details Moves cursor to the end of the current line content.
 * @param args Lisp arguments (unused)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @note Updates global editor state E
 */
Lisp moveCursorEndLine(Lisp args, LispError *e, LispContext ctx) {
  EditorPane *active = splitScreenGetActivePane();
  struct buffer_t *buf = bufferFindById(active->buffer_id);
  if (active->cursor_y < buf->numrows) {
    active->cursor_x = buf->row[active->cursor_y].size;
  }
  return lisp_null();
}

/**
 * @brief Lisp function to delete character before cursor
 * @details Wrapper around editorDelChar() for use in Lisp keybindings.
 * @param args Lisp arguments (unused)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @see editorDelChar()
 */
Lisp deletePreviousChar(Lisp args, LispError *e, LispContext ctx) {
  bufferDelChar();
  return lisp_null();
}

/**
 * @brief Lisp function to move cursor up by one screen
 * @details Scrolls up one full screen height, moving cursor to top of visible area.
 * @param args Lisp arguments (unused)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @note Updates global editor state E
 * @see editorMoveCursor()
 */
Lisp editorMoveCursorPageUp(Lisp args, LispError *e, LispContext ctx) {
  EditorPane *active = splitScreenGetActivePane();
  active->cursor_y = active->row_offset;
  int times = E.screenrows;
  while (--times) {
    editorMoveCursor(ARROW_UP);
  }
  return lisp_null();
}

/**
 * @brief Lisp function to move cursor down by one screen
 * @details Scrolls down one full screen height, moving cursor to bottom of visible area.
 * @param args Lisp arguments (unused)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @note Updates global editor state E
 * @see editorMoveCursor()
 */
Lisp editorMoveCursorPageDown(Lisp args, LispError *e, LispContext ctx) {
  EditorPane *active = splitScreenGetActivePane();
  struct buffer_t *buffer = bufferFindById(active->buffer_id);
  active->cursor_y = active->row_offset + E.screenrows - 1;
  if (active->cursor_y > buffer->numrows) {
    active->cursor_y = buffer->numrows;
  }
  int times = E.screenrows;
  while (--times) {
    editorMoveCursor(ARROW_DOWN);
  }

  return lisp_null();
}

/**
 * @brief Lisp function to open a file
 * @details Prompts user for filename and opens the file for editing.
 * @param args Lisp arguments (unused)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @note Updates global editor state E
 * @see editorOpen()
 * @see editorPrompt()
 */
Lisp editorOpenFile(Lisp args, LispError *e, LispContext ctx) {
  char *filename = editorPrompt("Open : %s", getenv("PWD"), 1);
  if (filename){
    //    editorOpen(filename);
    EditorPane *active = splitScreenGetActivePane();
    active->buffer_id = bufferCreate(filename);
  }
  free(filename);
  

  return lisp_null();
}

/**
 * @brief Lisp function to insert a character
 * @details Extracts a character from Lisp string argument and inserts it at cursor.
 * @param args Lisp list with one string argument
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @note Uses first character of the string argument
 */
Lisp editorPrintC(Lisp args, LispError *e, LispContext ctx) {
  char c = lisp_string(lisp_car(args))[0];
  bufferInsertChar(c);
  return lisp_null();
}

/**
 * @brief Lisp function to load and execute a package
 * @details Loads a Lisp package from the user's packages directory
 * (~/.beluga/packages/<package_name>/init.lisp) and evaluates it.
 * @param args Lisp list with one argument: package name (string)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @note Package files must be valid Lisp code
 * @note Package directory defaults to ~/.beluga/packages/
 */
Lisp addPackage(Lisp args, LispError *e, LispContext ctx) {
  const char *package_name = lisp_string(lisp_car(args));
  fprintf(stderr, "%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");
  fprintf(stderr, "%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);
  fclose(fd_package);
  free(package_dir);

  return lisp_null();
}

/**
 * @brief Lisp function to delete the current row
 * @details Removes the line at the current cursor position.
 * @param args Lisp arguments (unused)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @note Updates global editor state E
 * @see editorDelRow()
 */
Lisp editorDelRow_L(Lisp args, LispError *e, LispContext ctx) {
  EditorPane *active = splitScreenGetActivePane();
  struct buffer_t *buffer = bufferFindById(active->buffer_id);
  bufferDelRow(buffer, active->cursor_y);
  return lisp_null();
}

Lisp editorSwitchNextBuffer(Lisp args, LispError *e, LispContext ctx) {
  fprintf(stderr, "switch buffer\n");
  if (E.number_of_buffer > 0) {
    EditorPane *active = splitScreenGetActivePane();
    int next_idx = (active->buffer_id + 1) % E.number_of_buffer;
    active->buffer_id = next_idx;
    }

  return lisp_null();
}

Lisp editorSwitchNextPane(Lisp args, LispError *e, LispContext ctx) {
  splitScreenSwitchPane();
  return lisp_null();
}

Lisp editorUnifiedPanes(Lisp args, LispError *e, LispContext ctx) {
  if (E.layout.num_panes - 1) {
    splitScreenUnify();
  }
  return lisp_null();
}

/**
 * @brief Lisp function to search for text
 * @details Wrapper around editorFind() for use in Lisp keybindings.
 * @param args Lisp arguments (unused)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @see editorFind()
 */
Lisp bufferFind_L(Lisp args, LispError *e, LispContext ctx) {
  fprintf(stderr, "LispFind\n");
  EditorPane *active = splitScreenGetActivePane();
  struct buffer_t *buffer = bufferFindById(active->buffer_id);
  bufferFind(buffer);
  return lisp_null();
}

/**
 * @brief Lisp function to read character at cursor
 * @details Returns the character at the current cursor position as a Lisp character.
 * Returns 'a' if at end of line.
 * @param args Lisp arguments (unused)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return Lisp character object representing the character at cursor
 */
Lisp editorReadChar_L(Lisp args, LispError *e, LispContext ctx) {
  Lisp returned_char;
  EditorPane *active = splitScreenGetActivePane();
  struct buffer_t *buffer = bufferFindById(active->buffer_id);
  if (buffer->row[active->cursor_y].render[active->cursor_x] == 0) {
    returned_char = lisp_make_char('a');
  } else {
    
     returned_char = lisp_make_char(buffer->row[active->cursor_y].render[active->cursor_x]); 
  }
  return returned_char;
}

/**
 * @brief Lisp function to set the current prefix mode
 * @details Changes the editor's prefix state to a named prefix, affecting which
 * keybindings are active. Updates status message to show active prefix.
 * @param args Lisp list with one argument: prefix name (string)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @note Updates global editor state E (prefix_state)
 * @see find_prefix()
 */
Lisp editorSetPrefix(Lisp args, LispError *e, LispContext ctx) {
  /*
   * Set the prefix state of editor to the prefix in argument
   */
  const char *prefix_name = lisp_string(lisp_car(args));
  struct prefix_t prefix = find_prefix(prefix_name);
  E.prefix_state = prefix.prefix_id;
  editorSetStatusMessage("prefix %s", prefix.prefix_name);
  fprintf(stderr, "%s set\n", prefix_name);

  return lisp_null();
}

/**
 * @brief Lisp function to define a new prefix modifier
 * @details Registers a named prefix modifier that can be used with keybindings
 * to create context-aware command sequences (e.g., Ctrl-X as a prefix).
 * @param args Lisp list with one argument: prefix name (string, max 64 chars)
 * @param e Error pointer for Lisp error handling
 * @param ctx Lisp context
 * @return lisp_null()
 * @note Updates global editor state E (prefix array)
 */
Lisp editorPrefix(Lisp args, LispError *e, LispContext ctx) {
  E.prefix = (struct prefix_t *)realloc(E.prefix, (++(E.number_of_prefix) + 1) *
                                                      sizeof(struct prefix_t));
  E.prefix[E.number_of_prefix].prefix_id = E.number_of_prefix;
  strncpy(E.prefix[E.number_of_prefix].prefix_name, lisp_string(lisp_car(args)),
          64);
  return lisp_null();
}