#ifndef _XOPEN_SOURCE_EXTENDED
#define _XOPEN_SOURCE_EXTENDED
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <dirent.h>
#include <sys/stat.h>
#include <locale.h>
#include <ncurses.h>
#include <lua/lua.h>
#include <lua/lauxlib.h>
#include <lua/lualib.h>

extern const char main_luac[];
extern const unsigned int main_luac_len;

static lua_State        *G_L      = NULL;
static volatile int      g_resize = 0;

static void on_sigwinch(int sig) { (void)sig; g_resize = 1; }

static int push_error(lua_State *L, const char *msg) {
    lua_pushnil(L);
    lua_pushstring(L, msg);
    return 2;
}

static int l_init_ncurses(lua_State *L) {
    (void)L;
    setlocale(LC_ALL, "");
    initscr();
    cbreak();
    raw();
    noecho();
    keypad(stdscr, TRUE);
    nodelay(stdscr, FALSE);
    curs_set(0);
    start_color();
    use_default_colors();
    init_pair(1, COLOR_BLACK, COLOR_WHITE);
    signal(SIGWINCH, on_sigwinch);
    return 0;
}

static int l_end_ncurses(lua_State *L) {
    (void)L;
    endwin();
    return 0;
}

static int l_resize_terminal(lua_State *L) {
    (void)L;
    if (g_resize) {
        g_resize = 0;
        endwin();
        refresh();
        clearok(stdscr, TRUE);
    }
    return 0;
}

static int l_refresh_screen(lua_State *L) {
    (void)L;
    wrefresh(stdscr);
    return 0;
}

static int l_get_wchar(lua_State *L) {
    wint_t ch;
    int res = wget_wch(stdscr, &ch);
    if (res == ERR)
        lua_pushinteger(L, -1);
    else
        lua_pushinteger(L, (lua_Integer)ch);
    return 1;
}

static int l_set_title(lua_State *L) {
    const char *title = luaL_checkstring(L, 1);
    printf("\033]0;%s\007", title);
    fflush(stdout);
    return 0;
}

static int l_get_screen_size(lua_State *L) {
    int rows, cols;
    getmaxyx(stdscr, rows, cols);
    lua_pushinteger(L, rows);
    lua_pushinteger(L, cols + 1);
    return 2;
}

static int l_clear_screen(lua_State *L) {
    (void)L;
    clear();
    return 0;
}

static int l_move_cursor(lua_State *L) {
    int y = (int)luaL_checkinteger(L, 1);
    int x = (int)luaL_checkinteger(L, 2);
    move(y, x);
    return 0;
}

static int l_print_at(lua_State *L) {
    int         y   = (int)luaL_checkinteger(L, 1);
    int         x   = (int)luaL_checkinteger(L, 2);
    const char *str = luaL_checkstring(L, 3);
    mvprintw(y, x, "%s", str);
    return 0;
}

static int l_set_reverse(lua_State *L) {
    if (lua_toboolean(L, 1)) attron(A_REVERSE); else attroff(A_REVERSE);
    return 0;
}

static int l_set_bold(lua_State *L) {
    if (lua_toboolean(L, 1)) attron(A_BOLD); else attroff(A_BOLD);
    return 0;
}

static int l_set_color(lua_State *L) {
    int pair   = (int)luaL_checkinteger(L, 1);
    int enable = lua_toboolean(L, 2);
    if (enable) attron(COLOR_PAIR(pair)); else attroff(COLOR_PAIR(pair));
    return 0;
}

static int l_init_color_pair(lua_State *L) {
    int pair = (int)luaL_checkinteger(L, 1);
    int fg   = (int)luaL_checkinteger(L, 2);
    int bg   = (int)luaL_checkinteger(L, 3);
    init_pair((short)pair, (short)fg, (short)bg);
    return 0;
}

static int l_save_file(lua_State *L) {
    const char *fname   = luaL_checkstring(L, 1);
    const char *content = luaL_checkstring(L, 2);
    FILE *f = fopen(fname, "w");
    if (!f) return push_error(L, "Open failed");
    size_t len = strlen(content);
    if (len > 0 && fwrite(content, 1, len, f) != len) {
        fclose(f);
        return push_error(L, "Write failed");
    }
    fclose(f);
    lua_pushboolean(L, 1);
    return 1;
}

static int l_load_file(lua_State *L) {
    const char *fname = luaL_checkstring(L, 1);
    FILE *f = fopen(fname, "r");
    if (!f) return push_error(L, "Open failed");
    fseek(f, 0, SEEK_END);
    long size = ftell(f);
    fseek(f, 0, SEEK_SET);
    if (size < 0) { fclose(f); return push_error(L, "Seek failed"); }
    char *buf = malloc((size_t)size + 1);
    if (!buf) { fclose(f); return push_error(L, "Alloc failed"); }
    size_t r = fread(buf, 1, (size_t)size, f);
    buf[r] = '\0';
    fclose(f);
    lua_pushlstring(L, buf, r);
    free(buf);
    return 1;
}

static int l_list_dir(lua_State *L) {
    const char *path = luaL_checkstring(L, 1);
    DIR *d = opendir(path);
    if (!d) { lua_pushnil(L); return 1; }
    lua_newtable(L);
    int idx = 1;
    struct dirent *ent;
    while ((ent = readdir(d)) != NULL) {
        lua_pushstring(L, ent->d_name);
        lua_rawseti(L, -2, idx++);
    }
    closedir(d);
    return 1;
}

static int l_stat_file(lua_State *L) {
    const char *path = luaL_checkstring(L, 1);
    struct stat st;
    if (stat(path, &st) != 0) { lua_pushnil(L); return 1; }
    if      (S_ISREG(st.st_mode)) lua_pushstring(L, "file");
    else if (S_ISDIR(st.st_mode)) lua_pushstring(L, "dir");
    else                           lua_pushstring(L, "other");
    return 1;
}

static int l_lua_eval(lua_State *L) {
    const char *code     = luaL_checkstring(L, 1);
    int         top_before = lua_gettop(G_L);

    if (luaL_loadstring(G_L, code) != LUA_OK) {
        const char *err = lua_tostring(G_L, -1);
        lua_pop(G_L, 1);
        lua_pushstring(L, err ? err : "compile error");
        return 1;
    }
    if (lua_pcall(G_L, 0, LUA_MULTRET, 0) != LUA_OK) {
        const char *err = lua_tostring(G_L, -1);
        lua_pop(G_L, 1);
        lua_pushstring(L, err ? err : "runtime error");
        return 1;
    }
    int nret = lua_gettop(G_L) - top_before;
    if (nret > 0) {
        const char *res = lua_tostring(G_L, -1);
        lua_pushstring(L, res ? res : "(non-string result)");
        lua_settop(G_L, top_before);
    } else {
        lua_pushstring(L, "ok");
    }
    return 1;
}

static const struct { const char *name; lua_CFunction func; } bindings[] = {
    {"init_ncurses",    l_init_ncurses},
    {"end_ncurses",     l_end_ncurses},
    {"resize_terminal", l_resize_terminal},
    {"refresh_screen",  l_refresh_screen},
    {"get_wchar",       l_get_wchar},
    {"set_title",       l_set_title},
    {"get_screen_size", l_get_screen_size},
    {"clear_screen",    l_clear_screen},
    {"move_cursor",     l_move_cursor},
    {"print_at",        l_print_at},
    {"set_reverse",     l_set_reverse},
    {"set_bold",        l_set_bold},
    {"set_color",       l_set_color},
    {"init_color_pair", l_init_color_pair},
    {"save_file",       l_save_file},
    {"load_file",       l_load_file},
    {"list_dir",        l_list_dir},
    {"stat_file",       l_stat_file},
    {"lua_eval",        l_lua_eval},
    {NULL, NULL}
};

int main(int argc, char *argv[]) {
    lua_State *L = luaL_newstate();
    if (!L) { fprintf(stderr, "Lua init failed\n"); return 1; }
    G_L = L;
    luaL_openlibs(L);

    for (int i = 0; bindings[i].name; i++) {
        lua_pushcfunction(L, bindings[i].func);
        lua_setglobal(L, bindings[i].name);
    }

    lua_newtable(L);
    for (int i = 1; i < argc; i++) {
        lua_pushstring(L, argv[i]);
        lua_rawseti(L, -2, i);
    }
    lua_setglobal(L, "arg");

    if (luaL_loadbuffer(L, main_luac, main_luac_len, "main.lua") ||
        lua_pcall(L, 0, 0, 0)) {
        fprintf(stderr, "Lume: %s\n", lua_tostring(L, -1));
        lua_pop(L, 1);
        lua_close(L);
        return 1;
    }

    lua_close(L);
    return 0;
}