/*
 * melisma - extensible and scriptable audio engine
 * Copyright (C) 2026  Ludvig Gunne Lindström
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <string.h>
#include <errno.h>
#include <dirent.h>
#include <lauxlib.h>

static const char *dirent_typestr(struct dirent *de)
{
	switch (de->d_type)
	{
	case DT_BLK:  return "b";
	case DT_CHR:  return "c";
	case DT_DIR:  return "d";
	case DT_FIFO: return "p";
	case DT_REG:  return "f";
	case DT_LNK:  return "l";
	case DT_SOCK: return "s";
	default:      return "?";
	}
}

static void push_dirent(lua_State *s, struct dirent *de)
{
	lua_newtable(s);
	int tbl = lua_gettop(s);

	lua_pushstring(s,de->d_name);
	lua_setfield(s,tbl,"name");

	lua_pushstring(s,dirent_typestr(de));
	lua_setfield(s,tbl,"type");

	lua_settop(s,tbl);
}

static int l_readdir(lua_State *s)
{
	const char *path = luaL_checkstring(s,1);
	DIR *dirp = opendir(path);

	if (dirp == NULL)
	{
		luaL_error(s,strerror(errno));
	}

	lua_newtable(s);
	int tbl = lua_gettop(s);

	int i = 1;
	struct dirent *de;
	while ((de = readdir(dirp)) != NULL)
	{
		push_dirent(s,de);
		lua_rawseti(s,tbl,i++);
	}

	closedir(dirp);
	lua_settop(s,tbl);
	return 1;
}

int luaopen_melisma_fs(lua_State *s)
{
/*** File system utilities.
@module fs
*/
	lua_newtable(s);
	int tbl = lua_gettop(s);

/*** List directory contents.
@function readdir
@tparam string path Directory path.
@treturn table Directory contents.
@usage
local fs = require 'melisma.fs'
local contents = fs.readdir('.')
for _,entry in ipairs(contents) do
	print(entry.name, entry.type)
end
*/
	lua_pushcfunction(s,l_readdir);
	lua_setfield(s,tbl,"readdir");

	lua_settop(s,tbl);
	return 1;
}