#include "ecex.h"

#include "ccdjit.h"
#include "common.h"
#include "config.h"
#include "util.h"

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

extern FILE *popen(const char *command, const char *type);
extern int pclose(FILE *stream);

#define ECEX_INITIAL_BUFFER_CAP 8
#define ECEX_INITIAL_COMMAND_CAP 32
#define ECEX_INITIAL_KEYBIND_CAP 32
#define ECEX_INITIAL_WINDOW_CAP 4
#define ECEX_INITIAL_MODE_CAP 8
#define ECEX_INITIAL_MODE_KEYBIND_CAP 16

ecex_window_t *ecex_current_window(ecex_t *ed);

static ecex_color_t ecex_color(float r, float g, float b) {
    ecex_color_t c = {r, g, b};
    return c;
}

static void ecex_theme_set_defaults(ecex_t *ed) {
    if (!ed) return;

    ed->theme.font_path = NULL;
    ed->theme.font_size = 22.0f;

    ed->theme.bg = ecex_color(0.08f, 0.09f, 0.11f);
    ed->theme.fg = ecex_color(0.88f, 0.88f, 0.86f);

    ed->theme.status_bg = ecex_color(0.15f, 0.15f, 0.18f);
    ed->theme.status_fg = ecex_color(0.86f, 0.86f, 0.84f);
    ed->theme.status_border = ecex_color(0.28f, 0.28f, 0.32f);

    ed->theme.cursor = ecex_color(1.0f, 1.0f, 1.0f);
    ed->theme.region_bg = ecex_color(0.22f, 0.34f, 0.48f);

    ed->theme.minibuffer_bg = ecex_color(0.10f, 0.11f, 0.14f);
    ed->theme.minibuffer_fg = ecex_color(0.95f, 0.95f, 0.90f);

    ed->theme.completion_fg = ecex_color(0.45f, 0.45f, 0.45f);
    ed->theme.completion_enabled = 1;

    ed->theme.interactive_highlight_bg = ecex_color(0.18f, 0.20f, 0.24f);
    ed->theme.interactive_highlight_fg = ecex_color(1.0f, 1.0f, 1.0f);
    ed->theme.current_line_bg = ecex_color(0.12f, 0.13f, 0.16f);
    ed->theme.search_bg = ecex_color(0.55f, 0.42f, 0.12f);
    ed->theme.line_numbers_enabled = 1;
    ed->theme.current_line_enabled = 1;
}

#define ECEX_COMMAND(name, fn) \
    do { \
        if (ecex_register_command(ed, (name), (fn)) != ECEX_OK) return ECEX_ERR; \
    } while (0)

#define ECEX_BIND(key, command) \
    do { \
        if (ecex_bind_key(ed, (key), (command)) != ECEX_OK) return ECEX_ERR; \
    } while (0)

#define CURRENT_BUFFER_OR_ERR(ed) \
    buffer_t *buf = ecex_current_buffer(ed); \
    if (!buf) return ECEX_ERR

static int cmd_quit(ecex_t *ed) {
    if (!ed) return ECEX_ERR;
    ed->should_quit = 1;
    return ECEX_OK;
}

static int cmd_next_buffer(ecex_t *ed) { return ecex_next_buffer(ed); }
static int cmd_previous_buffer(ecex_t *ed) { return ecex_previous_buffer(ed); }
static int cmd_split_window_right(ecex_t *ed) { return ecex_split_window_vertically(ed); }
static int cmd_split_window_below(ecex_t *ed) { return ecex_split_window_horizontally(ed); }
static int cmd_other_window(ecex_t *ed) { return ecex_other_window(ed); }
static int cmd_previous_window(ecex_t *ed) { return ecex_previous_window(ed); }
static int cmd_delete_window(ecex_t *ed) { return ecex_delete_window(ed); }
static int cmd_delete_other_windows(ecex_t *ed) { return ecex_delete_other_windows(ed); }
static int cmd_balance_windows(ecex_t *ed) { return ecex_balance_windows(ed); }

static int cmd_move_left(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); buffer_move_left(buf); return ECEX_OK; }
static int cmd_move_right(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); buffer_move_right(buf); return ECEX_OK; }
static int cmd_move_up(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); buffer_move_up(buf); return ECEX_OK; }
static int cmd_move_down(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); buffer_move_down(buf); return ECEX_OK; }
static int cmd_move_word_left(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); buffer_move_word_left(buf); return ECEX_OK; }
static int cmd_move_word_right(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); buffer_move_word_right(buf); return ECEX_OK; }
static int cmd_beginning_of_line(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); buffer_move_beginning_of_line(buf); return ECEX_OK; }
static int cmd_end_of_line(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); buffer_move_end_of_line(buf); return ECEX_OK; }
static int cmd_beginning_of_buffer(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); buffer_move_beginning_of_buffer(buf); return ECEX_OK; }
static int cmd_end_of_buffer(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); buffer_move_end_of_buffer(buf); return ECEX_OK; }

static int cmd_undo(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); return buffer_undo(buf); }
static int cmd_redo(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); return buffer_redo(buf); }
static int cmd_backspace(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); return buffer_backspace(buf); }
static int cmd_delete_forward(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); return buffer_delete_forward(buf); }
static int cmd_newline(ecex_t *ed) {
    CURRENT_BUFFER_OR_ERR(ed);
    if (buffer_is_interactive(buf)) {
        return ecex_interactive_activate_current_line(ed);
    }
    return buffer_insert_char(buf, '\n');
}
static int cmd_kill_line(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); return buffer_kill_line(buf); }
static int cmd_clear_buffer(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); return buffer_clear(buf); }
static int cmd_set_mark(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); buffer_set_mark(buf, buf->point); return ECEX_OK; }
static int cmd_clear_mark(ecex_t *ed) { CURRENT_BUFFER_OR_ERR(ed); buffer_clear_mark(buf); return ECEX_OK; }


static int cmd_yank(ecex_t *ed) {
    CURRENT_BUFFER_OR_ERR(ed);
    const char *text = ecex_clipboard_get(ed);
    if (!text || !text[0]) return ECEX_OK;
    return buffer_replace_selection(buf, text);
}

static int cmd_copy_region(ecex_t *ed) {
    CURRENT_BUFFER_OR_ERR(ed);
    if (!buffer_has_selection(buf)) return ECEX_OK;

    size_t start = 0;
    size_t end = 0;
    buffer_selection_range(buf, &start, &end);

    char *text = buffer_substring(buf, start, end);
    if (!text) return ECEX_ERR;

    int result = ecex_clipboard_set(ed, text);
    free(text);
    return result;
}

static int cmd_kill_region(ecex_t *ed) {
    CURRENT_BUFFER_OR_ERR(ed);
    if (!buffer_has_selection(buf)) return ECEX_OK;

    size_t start = 0;
    size_t end = 0;
    buffer_selection_range(buf, &start, &end);

    char *text = buffer_substring(buf, start, end);
    if (!text) return ECEX_ERR;

    int result = ecex_clipboard_set(ed, text);
    free(text);
    if (result != ECEX_OK) return result;

    return buffer_delete_selection(buf);
}

static int cmd_list_commands(ecex_t *ed) { return ecex_list_commands(ed); }
static int cmd_list_buffers(ecex_t *ed) { return ecex_list_buffers(ed); }
static int cmd_switch_buffer(ecex_t *ed) { ecex_request_prompt(ed, ECEX_PROMPT_SWITCH_BUFFER, "Switch buffer: "); return ECEX_OK; }
static int cmd_kill_buffer_command(ecex_t *ed) { ecex_request_prompt(ed, ECEX_PROMPT_KILL_BUFFER, "Kill buffer: "); return ECEX_OK; }
static int cmd_compile(ecex_t *ed) { ecex_request_prompt(ed, ECEX_PROMPT_COMPILE, "Compile: "); return ECEX_OK; }
static int cmd_grep(ecex_t *ed) { ecex_request_prompt(ed, ECEX_PROMPT_GREP, "Grep: "); return ECEX_OK; }
static int cmd_recompile(ecex_t *ed) { return ecex_rerun_compile(ed); }
static int cmd_regrep(ecex_t *ed) { return ecex_rerun_grep(ed); }
static int cmd_next_error(ecex_t *ed) { return ecex_next_interactive_action(ed); }
static int cmd_previous_error(ecex_t *ed) { return ecex_previous_interactive_action(ed); }
static int cmd_comment_region(ecex_t *ed) { return ecex_comment_region(ed); }
static int cmd_uncomment_region(ecex_t *ed) { return ecex_uncomment_region(ed); }
static int cmd_toggle_line_numbers(ecex_t *ed) { if (!ed) return ECEX_ERR; ed->theme.line_numbers_enabled = !ed->theme.line_numbers_enabled; return ECEX_OK; }
static int cmd_toggle_current_line(ecex_t *ed) { if (!ed) return ECEX_ERR; ed->theme.current_line_enabled = !ed->theme.current_line_enabled; return ECEX_OK; }
static int cmd_isearch_forward(ecex_t *ed) { ecex_request_prompt(ed, ECEX_PROMPT_ISEARCH_FORWARD, "I-search: "); return ECEX_OK; }
static int cmd_isearch_backward(ecex_t *ed) { ecex_request_prompt(ed, ECEX_PROMPT_ISEARCH_BACKWARD, "I-search backward: "); return ECEX_OK; }

static int cmd_find_file(ecex_t *ed) {
    ecex_request_prompt(ed, ECEX_PROMPT_FIND_FILE, "Find file: ");
    return ECEX_OK;
}

static int cmd_write_file(ecex_t *ed) {
    ecex_request_prompt(ed, ECEX_PROMPT_WRITE_FILE, "Write file: ");
    return ECEX_OK;
}

static int cmd_save_buffer(ecex_t *ed) {
    if (!ed) return ECEX_ERR;

    buffer_t *buf = ecex_current_buffer(ed);
    if (!buf) return ECEX_ERR;

    if (!buf->path) {
        ecex_request_prompt(ed, ECEX_PROMPT_WRITE_FILE, "Write file: ");
        return ECEX_OK;
    }

    return ecex_save_current_buffer(ed);
}

static int cmd_eval_buffer(ecex_t *ed) {
    return ecex_eval_current_buffer(ed);
}

static int cmd_eval_line(ecex_t *ed) {
    return ecex_eval_current_line(ed);
}

static int cmd_eval_region(ecex_t *ed) {
    return ecex_eval_current_region(ed);
}

static int cmd_eval_file(ecex_t *ed) {
    ecex_request_prompt(ed, ECEX_PROMPT_EVAL_FILE, "Eval file: ");
    return ECEX_OK;
}

static int cmd_eval_rerun_last(ecex_t *ed) {
    return ecex_eval_rerun_last(ed);
}

static int cmd_quit_window(ecex_t *ed) {
    if (!ed) return ECEX_ERR;
    if (ecex_window_count(ed) > 1) return ecex_delete_window(ed);
    return ecex_previous_buffer(ed);
}

static int cmd_reload_config(ecex_t *ed) {
    return ecex_reload_config(ed);
}

static int ecex_register_builtins(ecex_t *ed) {
    ECEX_COMMAND("quit", cmd_quit);
    ECEX_COMMAND("find-file", cmd_find_file);
    ECEX_COMMAND("save-buffer", cmd_save_buffer);
    ECEX_COMMAND("write-file", cmd_write_file);
    ECEX_COMMAND("eval-buffer", cmd_eval_buffer);
    ECEX_COMMAND("eval-line", cmd_eval_line);
    ECEX_COMMAND("eval-region", cmd_eval_region);
    ECEX_COMMAND("eval-selection", cmd_eval_region);
    ECEX_COMMAND("eval-file", cmd_eval_file);
    ECEX_COMMAND("eval-rerun-last", cmd_eval_rerun_last);
    ECEX_COMMAND("revert-eval-buffer", cmd_eval_rerun_last);
    ECEX_COMMAND("quit-window", cmd_quit_window);
    ECEX_COMMAND("reload-config", cmd_reload_config);
    ECEX_COMMAND("list-commands", cmd_list_commands);
    ECEX_COMMAND("list-buffers", cmd_list_buffers);
    ECEX_COMMAND("switch-buffer", cmd_switch_buffer);
    ECEX_COMMAND("kill-buffer", cmd_kill_buffer_command);
    ECEX_COMMAND("compile", cmd_compile);
    ECEX_COMMAND("recompile", cmd_recompile);
    ECEX_COMMAND("grep", cmd_grep);
    ECEX_COMMAND("regrep", cmd_regrep);
    ECEX_COMMAND("next-error", cmd_next_error);
    ECEX_COMMAND("previous-error", cmd_previous_error);
    ECEX_COMMAND("comment-region", cmd_comment_region);
    ECEX_COMMAND("uncomment-region", cmd_uncomment_region);
    ECEX_COMMAND("toggle-line-numbers", cmd_toggle_line_numbers);
    ECEX_COMMAND("toggle-current-line", cmd_toggle_current_line);
    ECEX_COMMAND("isearch-forward", cmd_isearch_forward);
    ECEX_COMMAND("isearch-backward", cmd_isearch_backward);

    ECEX_COMMAND("next-buffer", cmd_next_buffer);
    ECEX_COMMAND("previous-buffer", cmd_previous_buffer);
    ECEX_COMMAND("split-window-right", cmd_split_window_right);
    ECEX_COMMAND("split-window-vertically", cmd_split_window_right);
    ECEX_COMMAND("split-window-below", cmd_split_window_below);
    ECEX_COMMAND("split-window-horizontally", cmd_split_window_below);
    ECEX_COMMAND("other-window", cmd_other_window);
    ECEX_COMMAND("previous-window", cmd_previous_window);
    ECEX_COMMAND("delete-window", cmd_delete_window);
    ECEX_COMMAND("delete-other-windows", cmd_delete_other_windows);
    ECEX_COMMAND("balance-windows", cmd_balance_windows);

    ECEX_COMMAND("move-left", cmd_move_left);
    ECEX_COMMAND("move-right", cmd_move_right);
    ECEX_COMMAND("move-up", cmd_move_up);
    ECEX_COMMAND("move-down", cmd_move_down);
    ECEX_COMMAND("move-word-left", cmd_move_word_left);
    ECEX_COMMAND("move-word-right", cmd_move_word_right);
    ECEX_COMMAND("beginning-of-line", cmd_beginning_of_line);
    ECEX_COMMAND("end-of-line", cmd_end_of_line);
    ECEX_COMMAND("beginning-of-buffer", cmd_beginning_of_buffer);
    ECEX_COMMAND("end-of-buffer", cmd_end_of_buffer);

    ECEX_COMMAND("undo", cmd_undo);
    ECEX_COMMAND("redo", cmd_redo);
    ECEX_COMMAND("backspace", cmd_backspace);
    ECEX_COMMAND("delete-forward", cmd_delete_forward);
    ECEX_COMMAND("newline", cmd_newline);
    ECEX_COMMAND("kill-line", cmd_kill_line);
    ECEX_COMMAND("clear-buffer", cmd_clear_buffer);
    ECEX_COMMAND("set-mark", cmd_set_mark);
    ECEX_COMMAND("clear-mark", cmd_clear_mark);
    ECEX_COMMAND("yank", cmd_yank);
    ECEX_COMMAND("paste", cmd_yank);
    ECEX_COMMAND("copy-region", cmd_copy_region);
    ECEX_COMMAND("copy-region-as-kill", cmd_copy_region);
    ECEX_COMMAND("kill-region", cmd_kill_region);

    ECEX_BIND("LEFT", "move-left");
    ECEX_BIND("RIGHT", "move-right");
    ECEX_BIND("UP", "move-up");
    ECEX_BIND("DOWN", "move-down");

    ECEX_BIND("C-b", "move-left");
    ECEX_BIND("C-f", "move-right");
    ECEX_BIND("C-p", "move-up");
    ECEX_BIND("C-n", "move-down");
    ECEX_BIND("C-a", "beginning-of-line");
    ECEX_BIND("C-e", "end-of-line");
    ECEX_BIND("C-k", "kill-line");
    ECEX_BIND("C-SPC", "set-mark");
    ECEX_BIND("C-y", "yank");
    ECEX_BIND("C-v", "paste");
    ECEX_BIND("M-w", "copy-region-as-kill");
    ECEX_BIND("C-w", "kill-region");
    ECEX_BIND("C-s", "isearch-forward");
    ECEX_BIND("C-r", "isearch-backward");
    ECEX_BIND("C-/", "undo");
    ECEX_BIND("C-z", "undo");
    ECEX_BIND("C-S-z", "redo");

    ECEX_BIND("C-x C-f", "find-file");
    ECEX_BIND("C-x C-s", "save-buffer");
    ECEX_BIND("C-x C-w", "write-file");
    ECEX_BIND("C-x C-b", "list-buffers");
    ECEX_BIND("C-x b", "switch-buffer");
    ECEX_BIND("C-x k", "kill-buffer");
    ECEX_BIND("C-x 2", "split-window-below");
    ECEX_BIND("C-x 3", "split-window-right");
    ECEX_BIND("C-x o", "other-window");
    ECEX_BIND("C-x O", "previous-window");
    ECEX_BIND("C-x 0", "delete-window");
    ECEX_BIND("C-x 1", "delete-other-windows");
    ECEX_BIND("C-x +", "balance-windows");
    ECEX_BIND("C-x e b", "eval-buffer");
    ECEX_BIND("C-x e l", "eval-line");
    ECEX_BIND("C-x C-e", "eval-line");
    ECEX_BIND("C-x e r", "eval-region");
    ECEX_BIND("C-x e f", "eval-file");
    ECEX_BIND("C-x C-r", "reload-config");
    ECEX_BIND("F5", "reload-config");
    ECEX_BIND("M-g n", "next-error");
    ECEX_BIND("M-g p", "previous-error");
    ECEX_BIND("M-;", "comment-region");

    ECEX_BIND("BACKSPACE", "backspace");
    ECEX_BIND("DELETE", "delete-forward");
    ECEX_BIND("ENTER", "newline");

    ecex_define_major_mode(ed, "fundamental-mode");
    ecex_define_major_mode(ed, "c-mode");
    ecex_define_major_mode(ed, "eval-output-mode");
    ecex_define_major_mode(ed, "special-mode");
    ecex_bind_mode_key(ed, "eval-output-mode", "g", "eval-rerun-last");
    ecex_bind_mode_key(ed, "eval-output-mode", "q", "quit-window");
    ecex_bind_mode_key(ed, "eval-output-mode", "r", "eval-rerun-last");
    ecex_bind_mode_key(ed, "special-mode", "q", "quit-window");
    ecex_bind_mode_key(ed, "special-mode", "g", "recompile");
    ecex_bind_mode_key(ed, "special-mode", "n", "next-error");
    ecex_bind_mode_key(ed, "special-mode", "p", "previous-error");

    return ECEX_OK;
}

#undef ECEX_COMMAND
#undef ECEX_BIND
#undef CURRENT_BUFFER_OR_ERR

ecex_t *ecex_new(void) {
    ecex_t *ed = calloc(1, sizeof(*ed));
    if (!ed) return NULL;

    ecex_theme_set_defaults(ed);

    buffer_t *scratch = buffer_new("*scratch*", NULL, 0);
    if (!scratch || ecex_add_buffer(ed, scratch) != ECEX_OK) {
        buffer_free(scratch);
        ecex_free(ed);
        return NULL;
    }

    ed->current_buffer_index = 0;
    ed->current_buffer = scratch;
    ed->next_major_mode_id = 1;

    ed->window_cap = ECEX_INITIAL_WINDOW_CAP;
    ed->windows = calloc(ed->window_cap, sizeof(*ed->windows));
    if (!ed->windows) {
        ecex_free(ed);
        return NULL;
    }
    ed->window_count = 1;
    ed->current_window_index = 0;
    ed->windows[0].buffer = scratch;
    ed->windows[0].x = 0.0f;
    ed->windows[0].y = 0.0f;
    ed->windows[0].w = 1.0f;
    ed->windows[0].h = 1.0f;

    if (ecex_register_builtins(ed) != ECEX_OK) {
        ecex_free(ed);
        return NULL;
    }

    ecex_buffer_set_major_mode_by_name(ed, scratch, "fundamental-mode");

    return ed;
}

void ecex_free(ecex_t *ed) {
    if (!ed) return;

    for (size_t i = 0; i < ed->jit_module_count; i++) {
        ccdjit_module_free((ccdjit_module *)ed->jit_modules[i]);
    }

    for (size_t i = 0; i < ed->buffer_count; i++) {
        buffer_free(ed->buffers[i]);
    }

    for (size_t i = 0; i < ed->command_count; i++) {
        free(ed->commands[i].name);
    }

    for (size_t i = 0; i < ed->keybind_count; i++) {
        free(ed->keybinds[i].key);
        free(ed->keybinds[i].command);
    }

    for (size_t i = 0; i < ed->mode_keybind_count; i++) {
        free(ed->mode_keybinds[i].key);
        free(ed->mode_keybinds[i].command);
    }

    for (size_t i = 0; i < ed->major_mode_count; i++) {
        free(ed->major_modes[i].name);
    }

    free(ed->jit_modules);
    free(ed->windows);
    free(ed->buffers);
    free(ed->commands);
    free(ed->keybinds);
    free(ed->mode_keybinds);
    free(ed->major_modes);
    free(ed->last_eval_source);
    free(ed->last_eval_filename);
    free(ed->last_compile_command);
    free(ed->last_grep_command);
    free(ed->config_path);
    free(ed->theme.font_path);
    free(ed);
}

int ecex_reserve_buffers(ecex_t *ed, size_t needed) {
    ECEX_RETURN_ERR_IF_NULL(ed);
    if (needed <= ed->buffer_cap) return ECEX_OK;

    while (ed->buffer_cap < needed) {
        if (ECEX_GROW_ARRAY(ed->buffers,
                            ed->buffer_count,
                            ed->buffer_cap,
                            ECEX_INITIAL_BUFFER_CAP) != ECEX_OK) {
            return ECEX_ERR;
        }
    }

    return ECEX_OK;
}

int ecex_add_buffer(ecex_t *ed, buffer_t *buffer) {
    if (!ed || !buffer) return ECEX_ERR;

    if (ecex_reserve_buffers(ed, ed->buffer_count + 1) != ECEX_OK) return ECEX_ERR;

    ed->buffers[ed->buffer_count++] = buffer;

    if (!ed->current_buffer) {
        ed->current_buffer_index = 0;
        ed->current_buffer = buffer;
    }

    return ECEX_OK;
}

buffer_t *ecex_create_buffer(ecex_t *ed,
                             const char *name,
                             const char *path,
                             int read_only) {
    if (!ed || !name) return NULL;

    buffer_t *buffer = buffer_new(name, path, read_only);
    if (!buffer) return NULL;

    if (ecex_add_buffer(ed, buffer) != ECEX_OK) {
        buffer_free(buffer);
        return NULL;
    }

    return buffer;
}

buffer_t *ecex_find_buffer(ecex_t *ed, const char *name) {
    if (!ed || !name) return NULL;

    for (size_t i = 0; i < ed->buffer_count; i++) {
        if (strcmp(ed->buffers[i]->name, name) == 0) {
            return ed->buffers[i];
        }
    }

    return NULL;
}


static int ecex_set_current_buffer_index(ecex_t *ed, size_t index) {
    if (!ed || index >= ed->buffer_count) return ECEX_ERR;
    ed->current_buffer_index = index;
    ed->current_buffer = ed->buffers[index];
    ecex_window_t *win = ecex_current_window(ed);
    if (win) win->buffer = ed->current_buffer;
    return ECEX_OK;
}

int ecex_sync_current_buffer(ecex_t *ed) {
    if (!ed) return ECEX_ERR;
    ecex_window_t *win = ecex_current_window(ed);
    if (!win || !win->buffer) return ECEX_ERR;

    ed->current_buffer = win->buffer;
    for (size_t i = 0; i < ed->buffer_count; i++) {
        if (ed->buffers[i] == win->buffer) {
            ed->current_buffer_index = i;
            return ECEX_OK;
        }
    }
    return ECEX_ERR;
}

int ecex_switch_buffer(ecex_t *ed, const char *name) {
    if (!ed || !name) return ECEX_ERR;

    for (size_t i = 0; i < ed->buffer_count; i++) {
        if (strcmp(ed->buffers[i]->name, name) == 0) {
            return ecex_set_current_buffer_index(ed, i);
        }
    }

    return ECEX_ERR;
}

buffer_t *ecex_current_buffer(ecex_t *ed) {
    if (!ed) return NULL;
    ecex_window_t *win = ecex_current_window(ed);
    if (win && win->buffer) return win->buffer;
    return ed->current_buffer;
}

ecex_window_t *ecex_current_window(ecex_t *ed) {
    if (!ed || ed->window_count == 0 || ed->current_window_index >= ed->window_count) return NULL;
    return &ed->windows[ed->current_window_index];
}

size_t ecex_window_count(ecex_t *ed) {
    return ed ? ed->window_count : 0;
}

static int ecex_reserve_windows(ecex_t *ed, size_t needed) {
    if (!ed) return ECEX_ERR;
    if (needed <= ed->window_cap) return ECEX_OK;
    while (ed->window_cap < needed) {
        if (ECEX_GROW_ARRAY(ed->windows,
                            ed->window_count,
                            ed->window_cap,
                            ECEX_INITIAL_WINDOW_CAP) != ECEX_OK) {
            return ECEX_ERR;
        }
    }
    return ECEX_OK;
}

static int ecex_add_window(ecex_t *ed, ecex_window_t win) {
    if (!ed || !win.buffer) return ECEX_ERR;
    if (ecex_reserve_windows(ed, ed->window_count + 1) != ECEX_OK) return ECEX_ERR;
    ed->windows[ed->window_count++] = win;
    return ECEX_OK;
}

int ecex_split_window_vertically(ecex_t *ed) {
    ecex_window_t *active = ecex_current_window(ed);
    if (!active || !active->buffer || active->w < 0.08f) return ECEX_ERR;

    ecex_window_t new_win = *active;
    float half = active->w * 0.5f;
    active->w = half;
    new_win.x = active->x + half;
    new_win.w = half;

    if (ecex_add_window(ed, new_win) != ECEX_OK) return ECEX_ERR;
    ed->current_window_index = ed->window_count - 1;
    return ecex_sync_current_buffer(ed);
}

int ecex_split_window_horizontally(ecex_t *ed) {
    ecex_window_t *active = ecex_current_window(ed);
    if (!active || !active->buffer || active->h < 0.08f) return ECEX_ERR;

    ecex_window_t new_win = *active;
    float half = active->h * 0.5f;
    active->h = half;
    new_win.y = active->y + half;
    new_win.h = half;

    if (ecex_add_window(ed, new_win) != ECEX_OK) return ECEX_ERR;
    ed->current_window_index = ed->window_count - 1;
    return ecex_sync_current_buffer(ed);
}

int ecex_other_window(ecex_t *ed) {
    if (!ed || ed->window_count == 0) return ECEX_ERR;
    ed->current_window_index = (ed->current_window_index + 1) % ed->window_count;
    return ecex_sync_current_buffer(ed);
}

int ecex_previous_window(ecex_t *ed) {
    if (!ed || ed->window_count == 0) return ECEX_ERR;
    if (ed->current_window_index == 0) ed->current_window_index = ed->window_count - 1;
    else ed->current_window_index--;
    return ecex_sync_current_buffer(ed);
}

int ecex_delete_window(ecex_t *ed) {
    if (!ed || ed->window_count <= 1 || ed->current_window_index >= ed->window_count) return ECEX_ERR;

    size_t index = ed->current_window_index;
    for (size_t i = index; i + 1 < ed->window_count; i++) {
        ed->windows[i] = ed->windows[i + 1];
    }
    ed->window_count--;
    if (ed->current_window_index >= ed->window_count) ed->current_window_index = ed->window_count - 1;
    return ecex_sync_current_buffer(ed);
}

int ecex_delete_other_windows(ecex_t *ed) {
    ecex_window_t *active = ecex_current_window(ed);
    if (!ed || !active) return ECEX_ERR;
    ecex_window_t keep = *active;
    keep.x = 0.0f; keep.y = 0.0f; keep.w = 1.0f; keep.h = 1.0f;
    ed->windows[0] = keep;
    ed->window_count = 1;
    ed->current_window_index = 0;
    return ecex_sync_current_buffer(ed);
}

int ecex_balance_windows(ecex_t *ed) {
    if (!ed || ed->window_count == 0) return ECEX_ERR;
    size_t n = ed->window_count;
    size_t cols = 1;
    while (cols * cols < n) cols++;
    size_t rows = (n + cols - 1) / cols;
    for (size_t i = 0; i < n; i++) {
        size_t row = i / cols;
        size_t col = i % cols;
        ed->windows[i].x = (float)col / (float)cols;
        ed->windows[i].y = (float)row / (float)rows;
        ed->windows[i].w = 1.0f / (float)cols;
        ed->windows[i].h = 1.0f / (float)rows;
    }
    return ecex_sync_current_buffer(ed);
}

int ecex_next_buffer(ecex_t *ed) {
    if (!ed || ed->buffer_count == 0) return ECEX_ERR;
    ecex_sync_current_buffer(ed);
    return ecex_set_current_buffer_index(ed, (ed->current_buffer_index + 1) % ed->buffer_count);
}

int ecex_previous_buffer(ecex_t *ed) {
    if (!ed || ed->buffer_count == 0) return ECEX_ERR;
    ecex_sync_current_buffer(ed);

    if (ed->current_buffer_index == 0) {
        ed->current_buffer_index = ed->buffer_count - 1;
    } else {
        ed->current_buffer_index--;
    }

    return ecex_set_current_buffer_index(ed, ed->current_buffer_index);
}

int ecex_kill_buffer(ecex_t *ed, const char *name) {
    if (!ed || !name || ed->buffer_count == 0) return ECEX_ERR;

    size_t index = ed->buffer_count;
    for (size_t i = 0; i < ed->buffer_count; i++) {
        if (strcmp(ed->buffers[i]->name, name) == 0) {
            index = i;
            break;
        }
    }

    if (index == ed->buffer_count) return ECEX_ERR;

    buffer_t *victim = ed->buffers[index];

    for (size_t i = index; i + 1 < ed->buffer_count; i++) {
        ed->buffers[i] = ed->buffers[i + 1];
    }

    ed->buffer_count--;

    buffer_t *fallback = ed->buffer_count > 0 ? ed->buffers[0] : NULL;
    for (size_t i = 0; i < ed->window_count; i++) {
        if (ed->windows[i].buffer == victim) {
            ed->windows[i].buffer = fallback;
        }
    }

    buffer_free(victim);

    if (ed->buffer_count == 0) {
        ed->current_buffer = NULL;
        ed->current_buffer_index = 0;
        ed->window_count = 0;
        ed->current_window_index = 0;
        return ECEX_OK;
    }

    if (ed->current_window_index >= ed->window_count) {
        ed->current_window_index = ed->window_count ? ed->window_count - 1 : 0;
    }

    return ecex_sync_current_buffer(ed);
}

int ecex_keep_jit_module(ecex_t *ed, void *module) {
    if (!ed || !module) return ECEX_ERR;

    if (ECEX_GROW_ARRAY(ed->jit_modules,
                        ed->jit_module_count,
                        ed->jit_module_cap,
                        8) != ECEX_OK) {
        return ECEX_ERR;
    }

    ed->jit_modules[ed->jit_module_count++] = module;
    return ECEX_OK;
}

int ecex_set_config_path(ecex_t *ed, const char *path) {
    if (!ed) return ECEX_ERR;

    char *copy = NULL;
    if (path && path[0]) {
        copy = ecex_strdup(path);
        if (!copy) return ECEX_ERR;
    }

    free(ed->config_path);
    ed->config_path = copy;
    return ECEX_OK;
}

const char *ecex_config_path(ecex_t *ed) {
    if (!ed) return NULL;
    return ed->config_path;
}

static void ecex_clear_commands(ecex_t *ed) {
    if (!ed) return;

    for (size_t i = 0; i < ed->command_count; i++) {
        free(ed->commands[i].name);
    }
    ed->command_count = 0;
}

static void ecex_clear_keybinds(ecex_t *ed) {
    if (!ed) return;

    for (size_t i = 0; i < ed->keybind_count; i++) {
        free(ed->keybinds[i].key);
        free(ed->keybinds[i].command);
    }
    ed->keybind_count = 0;
}

static void ecex_clear_mode_keybinds(ecex_t *ed) {
    if (!ed) return;

    for (size_t i = 0; i < ed->mode_keybind_count; i++) {
        free(ed->mode_keybinds[i].key);
        free(ed->mode_keybinds[i].command);
    }
    ed->mode_keybind_count = 0;
}

int ecex_reload_config(ecex_t *ed) {
    if (!ed || !ed->config_path || !ed->config_path[0]) {
        fprintf(stderr, "ecex: no config file to reload; start with --config path/to/ecexrc.c\n");
        return ECEX_ERR;
    }

    char *path = ecex_strdup(ed->config_path);
    if (!path) return ECEX_ERR;

    ecex_clear_commands(ed);
    ecex_clear_keybinds(ed);
    ecex_clear_mode_keybinds(ed);

    if (ecex_register_builtins(ed) != ECEX_OK) {
        free(path);
        return ECEX_ERR;
    }

    int result = ecex_load_c_config(ed, path);
    free(path);
    return result;
}

int ecex_register_command(ecex_t *ed, const char *name, ecex_command_fn fn) {
    if (!ed || !name || !fn) return ECEX_ERR;

    for (size_t i = 0; i < ed->command_count; i++) {
        if (strcmp(ed->commands[i].name, name) == 0) {
            ed->commands[i].fn = fn;
            return ECEX_OK;
        }
    }

    if (ECEX_GROW_ARRAY(ed->commands,
                        ed->command_count,
                        ed->command_cap,
                        ECEX_INITIAL_COMMAND_CAP) != ECEX_OK) {
        return ECEX_ERR;
    }

    char *copy = ecex_strdup(name);
    if (!copy) return ECEX_ERR;

    ed->commands[ed->command_count].name = copy;
    ed->commands[ed->command_count].fn = fn;
    ed->command_count++;
    return ECEX_OK;
}

int ecex_execute_command(ecex_t *ed, const char *name) {
    if (!ed || !name) return ECEX_ERR;

    for (size_t i = 0; i < ed->command_count; i++) {
        if (strcmp(ed->commands[i].name, name) == 0) {
            return ed->commands[i].fn(ed);
        }
    }

    return ECEX_ERR;
}

void ecex_set_clipboard_callbacks(ecex_t *ed,
                                  ecex_clipboard_get_fn get_fn,
                                  ecex_clipboard_set_fn set_fn,
                                  void *userdata) {
    if (!ed) return;
    ed->clipboard_get = get_fn;
    ed->clipboard_set = set_fn;
    ed->clipboard_userdata = userdata;
}

const char *ecex_clipboard_get(ecex_t *ed) {
    if (!ed || !ed->clipboard_get) return NULL;
    return ed->clipboard_get(ed->clipboard_userdata);
}

int ecex_clipboard_set(ecex_t *ed, const char *text) {
    if (!ed || !ed->clipboard_set || !text) return ECEX_ERR;
    ed->clipboard_set(ed->clipboard_userdata, text);
    return ECEX_OK;
}

int ecex_bind_key(ecex_t *ed, const char *key, const char *command) {
    if (!ed || !key || !command) return ECEX_ERR;

    for (size_t i = 0; i < ed->keybind_count; i++) {
        if (strcmp(ed->keybinds[i].key, key) == 0) {
            char *new_command = ecex_strdup(command);
            if (!new_command) return ECEX_ERR;

            free(ed->keybinds[i].command);
            ed->keybinds[i].command = new_command;
            return ECEX_OK;
        }
    }

    if (ECEX_GROW_ARRAY(ed->keybinds,
                        ed->keybind_count,
                        ed->keybind_cap,
                        ECEX_INITIAL_KEYBIND_CAP) != ECEX_OK) {
        return ECEX_ERR;
    }

    char *key_copy = ecex_strdup(key);
    char *command_copy = ecex_strdup(command);
    if (!key_copy || !command_copy) {
        free(key_copy);
        free(command_copy);
        return ECEX_ERR;
    }

    ed->keybinds[ed->keybind_count].key = key_copy;
    ed->keybinds[ed->keybind_count].command = command_copy;
    ed->keybind_count++;
    return ECEX_OK;
}

const char *ecex_lookup_key(ecex_t *ed, const char *key) {
    if (!ed || !key) return NULL;

    for (size_t i = 0; i < ed->keybind_count; i++) {
        if (strcmp(ed->keybinds[i].key, key) == 0) {
            return ed->keybinds[i].command;
        }
    }

    return NULL;
}

int ecex_define_major_mode(ecex_t *ed, const char *name) {
    if (!ed || !name || !name[0]) return 0;

    for (size_t i = 0; i < ed->major_mode_count; i++) {
        if (strcmp(ed->major_modes[i].name, name) == 0) {
            return ed->major_modes[i].id;
        }
    }

    if (ECEX_GROW_ARRAY(ed->major_modes,
                        ed->major_mode_count,
                        ed->major_mode_cap,
                        ECEX_INITIAL_MODE_CAP) != ECEX_OK) {
        return 0;
    }

    char *copy = ecex_strdup(name);
    if (!copy) return 0;

    int id = ed->next_major_mode_id++;
    ed->major_modes[ed->major_mode_count].id = id;
    ed->major_modes[ed->major_mode_count].name = copy;
    ed->major_mode_count++;
    return id;
}

int ecex_major_mode_by_name(ecex_t *ed, const char *name) {
    if (!ed || !name) return 0;
    for (size_t i = 0; i < ed->major_mode_count; i++) {
        if (strcmp(ed->major_modes[i].name, name) == 0) return ed->major_modes[i].id;
    }
    return 0;
}

const char *ecex_major_mode_name(ecex_t *ed, int mode) {
    if (!ed || mode == 0) return "fundamental-mode";
    for (size_t i = 0; i < ed->major_mode_count; i++) {
        if (ed->major_modes[i].id == mode) return ed->major_modes[i].name;
    }
    return "unknown-mode";
}

int ecex_buffer_set_major_mode(buffer_t *buffer, int mode) {
    if (!buffer) return ECEX_ERR;
    buffer->major_mode = mode;
    return ECEX_OK;
}

int ecex_buffer_set_major_mode_by_name(ecex_t *ed, buffer_t *buffer, const char *name) {
    if (!ed || !buffer || !name) return ECEX_ERR;
    int mode = ecex_define_major_mode(ed, name);
    if (!mode) return ECEX_ERR;
    return ecex_buffer_set_major_mode(buffer, mode);
}

const char *ecex_buffer_major_mode_name(ecex_t *ed, buffer_t *buffer) {
    if (!buffer) return "fundamental-mode";
    return ecex_major_mode_name(ed, buffer->major_mode);
}

int ecex_bind_mode_key(ecex_t *ed, const char *mode_name, const char *key, const char *command) {
    if (!ed || !mode_name || !key || !command) return ECEX_ERR;

    int mode = ecex_define_major_mode(ed, mode_name);
    if (!mode) return ECEX_ERR;

    for (size_t i = 0; i < ed->mode_keybind_count; i++) {
        if (ed->mode_keybinds[i].mode == mode && strcmp(ed->mode_keybinds[i].key, key) == 0) {
            char *new_command = ecex_strdup(command);
            if (!new_command) return ECEX_ERR;
            free(ed->mode_keybinds[i].command);
            ed->mode_keybinds[i].command = new_command;
            return ECEX_OK;
        }
    }

    if (ECEX_GROW_ARRAY(ed->mode_keybinds,
                        ed->mode_keybind_count,
                        ed->mode_keybind_cap,
                        ECEX_INITIAL_MODE_KEYBIND_CAP) != ECEX_OK) {
        return ECEX_ERR;
    }

    char *key_copy = ecex_strdup(key);
    char *command_copy = ecex_strdup(command);
    if (!key_copy || !command_copy) {
        free(key_copy);
        free(command_copy);
        return ECEX_ERR;
    }

    ed->mode_keybinds[ed->mode_keybind_count].mode = mode;
    ed->mode_keybinds[ed->mode_keybind_count].key = key_copy;
    ed->mode_keybinds[ed->mode_keybind_count].command = command_copy;
    ed->mode_keybind_count++;
    return ECEX_OK;
}

const char *ecex_lookup_key_for_buffer(ecex_t *ed, buffer_t *buffer, const char *key) {
    if (!ed || !key) return NULL;

    int mode = buffer ? buffer->major_mode : 0;
    if (mode) {
        for (size_t i = 0; i < ed->mode_keybind_count; i++) {
            if (ed->mode_keybinds[i].mode == mode && strcmp(ed->mode_keybinds[i].key, key) == 0) {
                return ed->mode_keybinds[i].command;
            }
        }
    }

    return ecex_lookup_key(ed, key);
}

int ecex_key_sequence_has_prefix_for_buffer(ecex_t *ed, buffer_t *buffer, const char *prefix) {
    if (!ed || !prefix) return 0;
    size_t prefix_len = strlen(prefix);
    int mode = buffer ? buffer->major_mode : 0;

    if (mode) {
        for (size_t i = 0; i < ed->mode_keybind_count; i++) {
            const char *key = ed->mode_keybinds[i].key;
            if (ed->mode_keybinds[i].mode == mode &&
                strncmp(key, prefix, prefix_len) == 0 && key[prefix_len] == ' ') {
                return 1;
            }
        }
    }

    for (size_t i = 0; i < ed->keybind_count; i++) {
        const char *key = ed->keybinds[i].key;
        if (strncmp(key, prefix, prefix_len) == 0 && key[prefix_len] == ' ') return 1;
    }

    return 0;
}

int ecex_auto_set_major_mode(ecex_t *ed, buffer_t *buffer) {
    if (!ed || !buffer) return ECEX_ERR;

    const char *name = "fundamental-mode";
    const char *path = buffer->path ? buffer->path : buffer->name;
    const char *dot = path ? strrchr(path, '.') : NULL;

    if (dot && (strcmp(dot, ".c") == 0 || strcmp(dot, ".h") == 0 ||
                strcmp(dot, ".cc") == 0 || strcmp(dot, ".cpp") == 0 ||
                strcmp(dot, ".hpp") == 0)) {
        name = "c-mode";
    }

    if (buffer_is_interactive(buffer) && buffer->name && buffer->name[0] == '*') {
        name = "special-mode";
    }

    return ecex_buffer_set_major_mode_by_name(ed, buffer, name);
}

int ecex_list_commands(ecex_t *ed) {
    if (!ed) return ECEX_ERR;

    buffer_t *buf = ecex_find_buffer(ed, "*commands*");
    if (!buf) {
        buf = ecex_create_buffer(ed, "*commands*", NULL, 0);
        if (!buf) return ECEX_ERR;
    }

    if (buffer_clear(buf) != ECEX_OK) return ECEX_ERR;
    buffer_append(buf, "Commands:\n\n");

    for (size_t i = 0; i < ed->command_count; i++) {
        const char *command_name = ed->commands[i].name;
        int first_key = 1;

        buffer_append(buf, "  ");
        buffer_append(buf, command_name);

        for (size_t j = 0; j < ed->keybind_count; j++) {
            if (strcmp(ed->keybinds[j].command, command_name) == 0) {
                buffer_append(buf, first_key ? "    [" : ", ");
                buffer_append(buf, ed->keybinds[j].key);
                first_key = 0;
            }
        }

        for (size_t j = 0; j < ed->mode_keybind_count; j++) {
            if (strcmp(ed->mode_keybinds[j].command, command_name) == 0) {
                buffer_append(buf, first_key ? "    [" : ", ");
                buffer_append(buf, ecex_major_mode_name(ed, ed->mode_keybinds[j].mode));
                buffer_append(buf, ":");
                buffer_append(buf, ed->mode_keybinds[j].key);
                first_key = 0;
            }
        }

        if (!first_key) buffer_append(buf, "]");
        buffer_append(buf, "\n");
    }

    buf->point = 0;
    buf->modified = 0;
    return ecex_switch_buffer(ed, "*commands*");
}



static int ecex_interactive_switch_buffer_action(ecex_t *ed,
                                                 buffer_t *buffer,
                                                 size_t line,
                                                 const char *payload,
                                                 void *userdata) {
    (void)buffer;
    (void)line;
    (void)userdata;

    if (!ed || !payload) return ECEX_ERR;
    return ecex_switch_buffer(ed, payload);
}

int ecex_list_buffers(ecex_t *ed) {
    if (!ed) return ECEX_ERR;

    buffer_t *buf = ecex_find_buffer(ed, "*buffers*");
    if (!buf) {
        buf = ecex_create_interactive_buffer(ed, "*buffers*");
        if (!buf) return ECEX_ERR;
    }

    buffer_set_interactive(buf, 1);
    if (buffer_clear(buf) != ECEX_OK) return ECEX_ERR;
    buffer_set_interactive(buf, 1);

    buffer_append(buf, "Buffers:\n");
    buffer_append(buf, "Press ENTER on a buffer to switch to it.\n\n");

    for (size_t i = 0; i < ed->buffer_count; i++) {
        buffer_t *b = ed->buffers[i];
        char line[1024];

        snprintf(line,
                 sizeof(line),
                 "%s %s %-24s %-18s size:%zu%s%s",
                 b == ed->current_buffer ? "*" : " ",
                 b->modified ? "+" : " ",
                 b->name ? b->name : "(unnamed)",
                 ecex_buffer_major_mode_name(ed, b),
                 b->len,
                 b->path ? "    " : "",
                 b->path ? b->path : "");

        if (ecex_interactive_append_line(ed,
                                         buf,
                                         line,
                                         ecex_interactive_switch_buffer_action,
                                         b->name,
                                         NULL) != ECEX_OK) {
            return ECEX_ERR;
        }
    }

    buf->point = 0;
    buf->modified = 0;
    return ecex_switch_buffer(ed, "*buffers*");
}

buffer_t *ecex_create_interactive_buffer(ecex_t *ed, const char *name) {
    if (!ed || !name) return NULL;

    buffer_t *buffer = ecex_find_buffer(ed, name);
    if (!buffer) {
        buffer = ecex_create_buffer(ed, name, NULL, 0);
        if (!buffer) return NULL;
    }

    buffer_set_interactive(buffer, 1);
    if (buffer->major_mode == 0) ecex_buffer_set_major_mode_by_name(ed, buffer, "special-mode");
    return buffer;
}

int ecex_interactive_append_line(ecex_t *ed,
                                 buffer_t *buffer,
                                 const char *text,
                                 ecex_interactive_line_fn fn,
                                 const char *payload,
                                 void *userdata) {
    (void)ed;

    if (!buffer || !text) return ECEX_ERR;

    size_t line = buffer_line_count(buffer);
    if (line > 0) line--;

    if (fn) {
        if (buffer_add_interactive_action(buffer, line, fn, payload, userdata) != ECEX_OK) {
            return ECEX_ERR;
        }
    }

    if (buffer_append(buffer, text) != ECEX_OK) return ECEX_ERR;
    if (buffer_append(buffer, "\n") != ECEX_OK) return ECEX_ERR;

    buffer_set_interactive(buffer, 1);
    return ECEX_OK;
}

int ecex_interactive_activate_current_line(ecex_t *ed) {
    if (!ed) return ECEX_ERR;

    buffer_t *buffer = ecex_current_buffer(ed);
    if (!buffer || !buffer_is_interactive(buffer)) return ECEX_ERR;

    size_t line = buffer_current_line_number(buffer);
    if (line > 0) line--;

    ecex_interactive_line_action_t *action =
        buffer_interactive_action_at_line(buffer, line);

    if (!action || !action->fn) return ECEX_ERR;
    return action->fn(ed, buffer, line, action->payload, action->userdata);
}

static const char *ecex_basename(const char *path) {
    if (!path || !path[0]) return "untitled";

    const char *last_slash = strrchr(path, '/');
    if (last_slash && last_slash[1]) return last_slash + 1;
    if (last_slash && last_slash == path) return "/";
    return path;
}

static int ecex_buffer_path_equal(buffer_t *buffer, const char *path) {
    return buffer && buffer->path && path && strcmp(buffer->path, path) == 0;
}

int ecex_find_file(ecex_t *ed, const char *path) {
    if (!ed || !path || !path[0]) return ECEX_ERR;

    for (size_t i = 0; i < ed->buffer_count; i++) {
        if (ecex_buffer_path_equal(ed->buffers[i], path)) {
            return ecex_set_current_buffer_index(ed, i);
        }
    }

    const char *name = ecex_basename(path);
    buffer_t *buf = ecex_create_buffer(ed, name, NULL, 0);
    if (!buf) return ECEX_ERR;

    if (ecex_file_exists(path)) {
        if (buffer_load_file(buf, path) != ECEX_OK) {
            ecex_kill_buffer(ed, buf->name);
            return ECEX_ERR;
        }
    } else {
        char *new_path = ecex_strdup(path);
        if (!new_path) {
            ecex_kill_buffer(ed, buf->name);
            return ECEX_ERR;
        }

        free(buf->path);
        buf->path = new_path;
        buf->modified = 0;
    }

    ecex_auto_set_major_mode(ed, buf);
    return ecex_set_current_buffer_index(ed, ed->buffer_count ? ed->buffer_count - 1 : 0);
}

int ecex_save_current_buffer(ecex_t *ed) {
    buffer_t *buf = ecex_current_buffer(ed);
    if (!buf) return ECEX_ERR;
    return buffer_save(buf);
}

int ecex_write_current_buffer(ecex_t *ed, const char *path) {
    buffer_t *buf = ecex_current_buffer(ed);
    if (!buf || !path || !path[0]) return ECEX_ERR;
    int result = buffer_save_as(buf, path);
    if (result == ECEX_OK) ecex_auto_set_major_mode(ed, buf);
    return result;
}

void ecex_request_prompt(ecex_t *ed,
                         ecex_prompt_request_t request,
                         const char *message) {
    if (!ed) return;

    ed->prompt_request = request;
    snprintf(ed->prompt_message,
             sizeof(ed->prompt_message),
             "%s",
             message ? message : "");
}

void ecex_clear_prompt_request(ecex_t *ed) {
    if (!ed) return;
    ed->prompt_request = ECEX_PROMPT_NONE;
    ed->prompt_message[0] = '\0';
}

static int ecex_fuzzy_score(const char *candidate, const char *query) {
    if (!candidate || !query) return -1;
    if (query[0] == '\0') return 0;

    int score = 0;
    int consecutive = 0;
    int last_match = -1;
    size_t ci = 0;
    size_t qi = 0;

    while (candidate[ci] && query[qi]) {
        char c = candidate[ci];
        char q = query[qi];

        if (c >= 'A' && c <= 'Z') c = (char)(c - 'A' + 'a');
        if (q >= 'A' && q <= 'Z') q = (char)(q - 'A' + 'a');

        if (c == q) {
            score += 10;

            if ((int)ci == last_match + 1) {
                consecutive++;
                score += 5 * consecutive;
            } else {
                consecutive = 0;
            }

            if (ci == 0) score += 20;
            if (ci > 0 && (candidate[ci - 1] == '-' ||
                           candidate[ci - 1] == '_' ||
                           candidate[ci - 1] == ' ')) {
                score += 15;
            }

            last_match = (int)ci;
            qi++;
        }

        ci++;
    }

    if (query[qi] != '\0') return -1;

    score -= (int)strlen(candidate);
    if (strncmp(candidate, query, strlen(query)) == 0) score += 100;
    return score;
}

const char *ecex_complete_command(ecex_t *ed, const char *query) {
    if (!ed || !query || !ed->theme.completion_enabled) return NULL;

    const char *best = NULL;
    int best_score = -1;

    for (size_t i = 0; i < ed->command_count; i++) {
        const char *name = ed->commands[i].name;
        int score = ecex_fuzzy_score(name, query);

        if (score > best_score) {
            best_score = score;
            best = name;
        }
    }

    return best;
}


static int ecex_set_owned_string(char **slot, const char *value) {
    if (!slot) return ECEX_ERR;
    char *copy = NULL;
    if (value && value[0]) {
        copy = ecex_strdup(value);
        if (!copy) return ECEX_ERR;
    }
    free(*slot);
    *slot = copy;
    return ECEX_OK;
}

static int ecex_parse_file_line(const char *text, char *path, size_t path_size, size_t *out_line) {
    if (!text || !path || path_size == 0 || !out_line) return ECEX_ERR;
    const char *colon = strchr(text, ':');
    if (!colon || colon == text) return ECEX_ERR;
    char *end = NULL;
    long line = strtol(colon + 1, &end, 10);
    if (line <= 0 || end == colon + 1) return ECEX_ERR;
    size_t len = (size_t)(colon - text);
    if (len >= path_size) len = path_size - 1;
    memcpy(path, text, len);
    path[len] = '\0';
    *out_line = (size_t)line;
    return ECEX_OK;
}

static int ecex_goto_file_line_action(ecex_t *ed, buffer_t *buffer, size_t line, const char *payload, void *userdata) {
    (void)buffer;
    (void)line;
    (void)userdata;
    if (!ed || !payload) return ECEX_ERR;
    char path[1024];
    size_t target_line = 1;
    if (ecex_parse_file_line(payload, path, sizeof(path), &target_line) != ECEX_OK) return ECEX_ERR;
    if (ecex_find_file(ed, path) != ECEX_OK) return ECEX_ERR;
    buffer_t *buf = ecex_current_buffer(ed);
    if (!buf) return ECEX_ERR;
    size_t pos = 0;
    for (size_t l = 1; l < target_line && pos < buf->len; pos++) {
        if (buf->data[pos] == '\n') l++;
    }
    buffer_set_point(buf, pos);
    return ECEX_OK;
}

static int ecex_append_shell_output(ecex_t *ed, const char *name, const char *command) {
    if (!ed || !name || !command || !command[0]) return ECEX_ERR;
    buffer_t *buf = ecex_create_interactive_buffer(ed, name);
    if (!buf) return ECEX_ERR;
    buffer_set_interactive(buf, 1);
    if (buffer_clear(buf) != ECEX_OK) return ECEX_ERR;
    buffer_set_interactive(buf, 1);
    ecex_buffer_set_major_mode_by_name(ed, buf, "special-mode");

    char header[2048];
    snprintf(header, sizeof(header), "%s\n\nKeys: g/r rerun, n/p next/previous result, RET jump, q quit.\n\n", command);
    buffer_append(buf, header);

    char shell_command[4096];
    snprintf(shell_command, sizeof(shell_command), "%s 2>&1", command);
    FILE *pipe = popen(shell_command, "r");
    if (!pipe) {
        buffer_append(buf, "Failed to start command.\n");
        return ecex_switch_buffer(ed, name);
    }

    char line[4096];
    while (fgets(line, sizeof(line), pipe)) {
        size_t len = strlen(line);
        while (len > 0 && (line[len - 1] == '\n' || line[len - 1] == '\r')) line[--len] = '\0';
        char path[1024];
        size_t target = 0;
        ecex_interactive_line_fn fn = NULL;
        char payload[1200];
        payload[0] = '\0';
        if (ecex_parse_file_line(line, path, sizeof(path), &target) == ECEX_OK) {
            snprintf(payload, sizeof(payload), "%s:%zu", path, target);
            fn = ecex_goto_file_line_action;
        }
        ecex_interactive_append_line(ed, buf, line, fn, payload[0] ? payload : NULL, NULL);
    }

    int status = pclose(pipe);
    char footer[128];
    snprintf(footer, sizeof(footer), "\n[process exited: %d]\n", status);
    buffer_append(buf, footer);
    buf->point = 0;
    buf->modified = 0;
    return ecex_switch_buffer(ed, name);
}

int ecex_compile(ecex_t *ed, const char *command) {
    if (!ed || !command || !command[0]) return ECEX_ERR;
    if (ecex_set_owned_string(&ed->last_compile_command, command) != ECEX_OK) return ECEX_ERR;
    return ecex_append_shell_output(ed, "*compilation*", command);
}

int ecex_grep(ecex_t *ed, const char *command) {
    if (!ed || !command || !command[0]) return ECEX_ERR;
    if (ecex_set_owned_string(&ed->last_grep_command, command) != ECEX_OK) return ECEX_ERR;
    return ecex_append_shell_output(ed, "*grep*", command);
}

int ecex_rerun_compile(ecex_t *ed) {
    if (!ed || !ed->last_compile_command) return ECEX_ERR;
    return ecex_append_shell_output(ed, "*compilation*", ed->last_compile_command);
}

int ecex_rerun_grep(ecex_t *ed) {
    if (!ed || !ed->last_grep_command) return ECEX_ERR;
    return ecex_append_shell_output(ed, "*grep*", ed->last_grep_command);
}

int ecex_next_interactive_action(ecex_t *ed) {
    buffer_t *buf = ecex_current_buffer(ed);
    if (!buf || !buffer_is_interactive(buf) || buf->interactive_action_count == 0) return ECEX_ERR;
    size_t current = buffer_current_line_number(buf);
    if (current > 0) current--;
    size_t best = (size_t)-1;
    for (size_t i = 0; i < buf->interactive_action_count; i++) {
        size_t line = buf->interactive_actions[i].line;
        if (line > current && (best == (size_t)-1 || line < best)) best = line;
    }
    if (best == (size_t)-1) best = buf->interactive_actions[0].line;
    size_t pos = 0;
    for (size_t l = 0; l < best && pos < buf->len; pos++) if (buf->data[pos] == '\n') l++;
    buffer_set_point(buf, pos);
    return ECEX_OK;
}

int ecex_previous_interactive_action(ecex_t *ed) {
    buffer_t *buf = ecex_current_buffer(ed);
    if (!buf || !buffer_is_interactive(buf) || buf->interactive_action_count == 0) return ECEX_ERR;
    size_t current = buffer_current_line_number(buf);
    if (current > 0) current--;
    size_t best = (size_t)-1;
    for (size_t i = 0; i < buf->interactive_action_count; i++) {
        size_t line = buf->interactive_actions[i].line;
        if (line < current && (best == (size_t)-1 || line > best)) best = line;
    }
    if (best == (size_t)-1) best = buf->interactive_actions[buf->interactive_action_count - 1].line;
    size_t pos = 0;
    for (size_t l = 0; l < best && pos < buf->len; pos++) if (buf->data[pos] == '\n') l++;
    buffer_set_point(buf, pos);
    return ECEX_OK;
}

static int ecex_region_lines(buffer_t *buf, size_t *out_start, size_t *out_end) {
    if (!buf || !buffer_has_selection(buf)) return ECEX_ERR;
    size_t start = 0, end = 0;
    buffer_selection_range(buf, &start, &end);
    start = buffer_line_start_at(buf, start);
    end = buffer_line_end_at(buf, end);
    if (end < buf->len) end++;
    if (out_start) *out_start = start;
    if (out_end) *out_end = end;
    return ECEX_OK;
}

int ecex_comment_region(ecex_t *ed) {
    buffer_t *buf = ecex_current_buffer(ed);
    size_t start = 0, end = 0;
    if (!buf || ecex_region_lines(buf, &start, &end) != ECEX_OK) return ECEX_ERR;
    size_t pos = start;
    while (pos <= end && pos <= buf->len) {
        if (buffer_insert_at(buf, pos, "// ") != ECEX_OK) return ECEX_ERR;
        pos += 3;
        end += 3;
        size_t eol = buffer_line_end_at(buf, pos);
        if (eol >= end || eol >= buf->len) break;
        pos = eol + 1;
    }
    return ECEX_OK;
}

int ecex_uncomment_region(ecex_t *ed) {
    buffer_t *buf = ecex_current_buffer(ed);
    size_t start = 0, end = 0;
    if (!buf || ecex_region_lines(buf, &start, &end) != ECEX_OK) return ECEX_ERR;
    size_t pos = start;
    while (pos < end && pos < buf->len) {
        if (pos + 2 <= buf->len && memcmp(buf->data + pos, "//", 2) == 0) {
            size_t del = (pos + 3 <= buf->len && buf->data[pos + 2] == ' ') ? 3 : 2;
            if (buffer_delete_range(buf, pos, pos + del) != ECEX_OK) return ECEX_ERR;
            end = end > del ? end - del : 0;
        }
        size_t eol = buffer_line_end_at(buf, pos);
        if (eol >= end || eol >= buf->len) break;
        pos = eol + 1;
    }
    return ECEX_OK;
}

int ecex_set_font(ecex_t *ed, const char *path) {
    if (!ed || !path) return ECEX_ERR;

    char *copy = ecex_strdup(path);
    if (!copy) return ECEX_ERR;

    free(ed->theme.font_path);
    ed->theme.font_path = copy;
    return ECEX_OK;
}

float ecex_get_font_size(ecex_t *ed) {
    if (!ed) return 0.0f;
    return ed->theme.font_size;
}

int ecex_set_font_size(ecex_t *ed, float size) {
    if (!ed) return ECEX_ERR;
    ed->theme.font_size = ECEX_CLAMP(size, 8.0f, 96.0f);
    return ECEX_OK;
}

int ecex_adjust_font_size(ecex_t *ed, float delta) {
    if (!ed) return ECEX_ERR;
    return ecex_set_font_size(ed, ed->theme.font_size + delta);
}

void ecex_set_bg_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.bg = ecex_color(r, g, b); }
void ecex_set_fg_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.fg = ecex_color(r, g, b); }
void ecex_set_status_bg_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.status_bg = ecex_color(r, g, b); }
void ecex_set_status_fg_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.status_fg = ecex_color(r, g, b); }
void ecex_set_status_border_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.status_border = ecex_color(r, g, b); }
void ecex_set_cursor_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.cursor = ecex_color(r, g, b); }
void ecex_set_region_bg_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.region_bg = ecex_color(r, g, b); }
void ecex_set_minibuffer_bg_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.minibuffer_bg = ecex_color(r, g, b); }
void ecex_set_minibuffer_fg_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.minibuffer_fg = ecex_color(r, g, b); }
void ecex_set_completion_fg_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.completion_fg = ecex_color(r, g, b); }
void ecex_set_completion_enabled(ecex_t *ed, int enabled) { if (ed) ed->theme.completion_enabled = enabled ? 1 : 0; }
void ecex_set_interactive_highlight_bg_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.interactive_highlight_bg = ecex_color(r, g, b); }
void ecex_set_interactive_highlight_fg_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.interactive_highlight_fg = ecex_color(r, g, b); }
void ecex_set_current_line_bg_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.current_line_bg = ecex_color(r, g, b); }
void ecex_set_search_bg_color(ecex_t *ed, float r, float g, float b) { if (ed) ed->theme.search_bg = ecex_color(r, g, b); }
void ecex_set_line_numbers_enabled(ecex_t *ed, int enabled) { if (ed) ed->theme.line_numbers_enabled = enabled ? 1 : 0; }
void ecex_set_current_line_enabled(ecex_t *ed, int enabled) { if (ed) ed->theme.current_line_enabled = enabled ? 1 : 0; }