/*
 * Copyright (c) 2026 Nakidai Perumenei <nakidai at disroot dot org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "ircd.h"

#include <string.h>

#include <err.h>
#include <poll.h>
#include <signal.h>
#include <unistd.h>

#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/types.h>


static struct pollfd pfd[PEERS_MAX + 1];
struct Peer peers[PEERS_MAX];
size_t peers_c;

const char *host;
int port;

void
ircd(void)
{
	size_t i, j, k;
	struct sockaddr_in addr, clientaddr;
	int res, sfd, client;
	nfds_t passed;
	ssize_t recvd;

	addr.sin_family = PF_INET;
	addr.sin_port = htons(port);

	res = inet_pton(AF_INET, host, &addr.sin_addr);
	if (res == -1)
		err(1, "inet_pton()");
	sfd = socket(AF_INET, SOCK_STREAM, 0); if (sfd == -1)
		err(1, "socket()");

	res = setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &(int){1}, sizeof(int));
	if (res == -1)
		err(1, "setsockopt(SO_REUSEADDR)");

	res = bind(sfd, (void *)&addr, sizeof(addr));
	if (res == -1)
		err(1, "bind()");

	res = listen(sfd, 128);
	if (res == -1)
		err(1, "listen()");

	signal(SIGPIPE, SIG_IGN);
loop:
	pfd[peers_c] = (struct pollfd){ .fd = sfd, .events = POLLIN };
	for (i = 0; i < peers_c; ++i)
		pfd[i] = (struct pollfd)
		{
			.fd = peers[i].fd,
			.events = POLLIN,
		};
	res = poll(pfd, (passed = peers_c) + 1, -1);
	if (res == -1)
		err(1, "poll()");

	if (pfd[peers_c].revents & POLLIN)
	{
		client = accept(sfd, (void *)&clientaddr, &(int){sizeof(clientaddr)});
		if (client == -1)
		{
			warn("accept(%d)", sfd);
		}
		else if (peers_c == PEERS_MAX)
		{
			/*
			 * TODO: maybe send 005 or smth?
			 */
			close(client);
		}
		else
		{
			peers[peers_c++] = (struct Peer){ .fd = client };
			strlcpy(
				peers[peers_c - 1].host,
				inet_ntoa(clientaddr.sin_addr),
				sizeof(peers->host)
			);
		}
	}

	for (i = 0; i < passed; ++i)
	{
		if (!(pfd[i].revents & POLLIN))
			continue;

		recvd = read(
			peers[i].fd,
			peers[i].buf + peers[i].recvd,
			sizeof(peers[i].buf) - peers[i].recvd
		);
		peers[i].recvd += recvd;
		if (recvd == -1 || !recvd || handle(&peers[i]))
			peers[i].flags |= DELETE;
	}
	for (i = 0; i < peers_c; ++i)
	{
		if (!(peers[i].flags & DELETE))
			continue;

		if (!peers[i].type)
			goto skip;
		writef(
			peers[i].fd,
			":%s!%s@%s QUIT",
			getnick(&peers[i]),
			peers[i].user,
			peers[i].host
		);
		for (j = 0; j < peers[i].channels_c; ++j)
		{
			channel_exit(peers[i].channels[j], &peers[i]);
			for (k = 0; k < peers[i].channels[j]->users_c; ++k)
				peers[i].channels[j]->users[k]->flags |= ANNOUNCE;
		}
		for (j = 0; j < peers_c; ++j)
			if (peers[j].flags & ANNOUNCE)
			{
				writef(
					peers[j].fd,
					"%s!%s@%s QUIT",
					getnick(&peers[i]),
					peers[i].user,
					peers[i].host
				);
				peers[j].flags &= ~ANNOUNCE;
			}
skip:
		writef(peers[i].fd, "ERROR :Closing Link: %s", peers[i].host);
		close(peers[i].fd);
		peers[i] = peers[--peers_c];
		i = 0;
	}
	goto loop;
}