/**
 * @file file_io.c
 * @brief File I/O operations module for the Beluga text editor
 * @details Handles file loading, saving, searching, and buffer management.
 * Provides functionality for opening/closing files, persisting changes to disk,
 * and searching for text patterns within the document.
 */

#include "../include/file_io.h"
#include "../include/editor_op.h"
#include "../include/input.h"
#include "../include/buffer.h"
#include "../include/data.h"
#include "../include/split_screen.h"
#include <fcntl.h>
#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
 * @details Clears all rows, resets cursor position, scroll offsets, and file
 * metadata. Does not prompt to save unsaved changes.
 * @note Updates global editor state E
 */
void editorCloseFile(void) {
  EditorPane *active = splitScreenGetActivePane();
  struct buffer_t *buf = bufferFindById(active->buffer_id);
  active->cursor_x = 0;
  active->cursor_y = 0;
  active->rx = 0;
  active->row_offset = 0;
  active->col_offset = 0;
  for (int i = 0; i < buf->numrows; ++i) {
    free(buf->row[i].chars);
    free(buf->row[i].render);
  }
  buf->numrows = 0;
  free(buf->row);
  buf->row = NULL;
  buf->dirty = 0;
  free(buf->filename);
  buf->filename = NULL;
  E.status_msg[0] = '\0';
  E.status_msg_time = 0;
}

/**
 * @brief Opens a file for editing
 * @details Loads file content into editor rows, one line per row. If another
 * file is already open, it is closed first (without saving). File is opened in
 * a+ (read/append) mode to allow both reading and modification.
 * @param filename Path to the file to open (relative or absolute)
 * @note Updates global editor state E
 * @note Calls die() on file open failure
 * @note Newline characters are stripped from loaded lines
 * @see editorInsertRow()
 */
void editorOpen(struct buffer_t* buffer) {
  FILE *fp;

  fp = fopen(buffer->filename, "a+");
  if (!fp)
    die("fopen");

  char *line = NULL;
  size_t line_cap = 0;
  ssize_t line_len;

  while ((line_len = getline(&line, &line_cap, fp)) != -1) {
    while (line_len > 0 &&
           (line[line_len - 1] == '\n' || line[line_len - 1] == '\r')) {
      --line_len;
    }
    bufferInsertRow(buffer, buffer->numrows, line, line_len);
    free(line);
    line = NULL;
  }
  free(line);
  fclose(fp);
  E.dirty = 0;
}

/**
 * @brief Saves the current file to disk
 * @details Prompts for filename if not set, converts all rows to a buffer,
 * writes to disk using open/ftruncate/write, and updates dirty flag.
 * Displays status messages on success or failure.
 * @note Updates global editor state E (dirty flag)
 * @note If no filename is set, prompts user via editorPrompt()
 * @note Uses O_RDWR | O_CREAT with mode 0644
 * @see editorRowsToString()
 */
void editorSave() {
  EditorPane *active = splitScreenGetActivePane();
  struct buffer_t *buffer = bufferFindById(active->buffer_id);
  int len;
  char *buf;
  int fd;
  if (buffer->filename == NULL) {
    buffer->filename = editorPrompt("Save as: %s (ESC to cancel)", "", 1);
    if (buffer->filename == NULL) {
      editorSetStatusMessage("Save aborted");
      return;
    }
  }
  buf = bufferRowsToString(buffer, &len);
  fd = open(buffer->filename, O_RDWR | O_CREAT, 0644);
  if (fd != -1) {
    if (ftruncate(fd, len) != -1) {
      if (write(fd, buf, len) == len) {
        close(fd);
        free(buf);
        E.dirty = 0;
        editorSetStatusMessage("%d bytes written to disk", len);
        return;
      }
    }
    close(fd);
  }
  free(buf);
  editorSetStatusMessage("Can't save! I/O error: %s", strerror(errno));
}

/**
 * @brief Searches for a string in the document
 * @details Prompts user for a search query, then searches forward from current
 * cursor position. Updates cursor position to the first match found.
 * @note Updates global editor state E (cursor position, row_offset)
 * @note Search is case-sensitive and operates on rendered line content
 * @note Searches begin from the line after current cursor position
 * @see editorPrompt()
 * @see editorRowRxToCx()
 */
void bufferFind(struct buffer_t *buf) {
  fprintf(stderr, "searching\n");
  char *query = editorPrompt("Search: %s (ESC to cancel)", "", 0);
  EditorPane *active = splitScreenGetActivePane();

  if (query == NULL)
    return;
  int i;
  for (i = active->cursor_y + 1; i < buf->numrows; i++) {
    frow *row = &buf->row[i];
    char *match = strstr(row->render, query);
    if (match) {
      active->cursor_y = i;
      active->cursor_x = bufferRowRxToCx(row, match - row->render);
      buf->row_offset = buf->numrows;
      break;
    }
  }
  free(query);
}