/*
 * 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/>.
 */

#ifndef MUTIL_H
#define MUTIL_H

/* TODO: Move to main repo? */

#include "melisma.h"
#include <lauxlib.h>

#define MUTIL_OUTPUT_CHANNEL_FUNCTION "__ml_out"

static ml_channel *mutil_get_optchannel(lua_State *s, int i)
{
	ml_channel **c;

	if ((c = luaL_testudata(s,i,MELISMA_OUTPUT_CHANNEL_TYPENAME)) != NULL)
	{
		return *c;
	}

	lua_getfield(s,i,MUTIL_OUTPUT_CHANNEL_FUNCTION);

	if (!lua_isfunction(s,-1))
	{
		lua_pop(s,1);
		return NULL;
	}

	lua_pushvalue(s,i);
	lua_call(s,1,1);

	if ((c = luaL_testudata(s,-1,MELISMA_OUTPUT_CHANNEL_TYPENAME)) != NULL)
	{
		lua_pop(s,1);
		return *c;
	}

	lua_pop(s,1);
	return NULL;
}

static ml_channel *mutil_get_channel(lua_State *s, int i)
{
	ml_channel *c = mutil_get_optchannel(s,i);
	if (c == NULL)
	{
		luaL_argerror(s,i,"expected output channel");
	}
	return c;
}

#endif