/*
 * 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 <stdbool.h>

#include "io.h"
#include "mem.h"

struct io
{
	ml_io_handler  hdl;
	void          *args;
	bool           removed;
};

static struct io     *ios;
static struct pollfd *pollfds;
static size_t         num_fds;

void ml_add_io_handler(int fd, int flags, ml_io_handler hdl, void *args)
{
	size_t i = num_fds++;
	ios = srealloc(ios,sizeof(*ios)*num_fds);
	pollfds = srealloc(pollfds,sizeof(*pollfds)*num_fds);

	ios[i] = (struct io) {
		.hdl = hdl,
		.args = args,
	};

	pollfds[i] = (struct pollfd) {
		.fd = fd,
		.events = flags,
	};
}

void ml_remove_io_handler(int fd)
{
	for (size_t i = 0; i < num_fds; i++)
	{
		if (pollfds[i].fd == fd)
		{
			ios[i].removed = true;
			return;
		}
	}
}

static bool remove_fds(void)
{
	for (size_t i = 0; i < num_fds; i++)
	{
		if (ios[i].removed)
		{
			num_fds--;
			ios[i] = ios[num_fds];
			pollfds[i] = pollfds[num_fds];
			return true;
		}
	}

	return false;
}

void io_loop(void)
{
	while (poll(pollfds,num_fds,-1) >= 0)
	{
		for (size_t i = 0; i < num_fds; i++)
		{
			struct pollfd *p = &pollfds[i];
			struct io *io = &ios[i];

			if ((p->revents & p->events) && io->hdl)
			{
				io->hdl(p->fd,p->revents,io->args);
			}
		}

		while (remove_fds())
			;
	}
}