/*
 * 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>


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

const char *host;
int port;

void
ircd(void)
{
	size_t i, schedulei, connected, pid;
	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);
	for (connected = 0;;schedulei = 0)
	{
		pfd[connected] = (struct pollfd){ .fd = sfd, .events = POLLIN };
		for (i = 0; i < connected; ++i)
			pfd[i] = (struct pollfd)
			{
				.fd = peers[i].fd,
				.events = POLLIN,
			};
		res = poll(pfd, (passed = connected) + 1, -1);
		if (res == -1)
			err(1, "poll()");

		if (pfd[connected].revents & POLLIN)
		{
			client = accept(sfd, (void *)&clientaddr, &(int){sizeof(clientaddr)});
			if (client == -1)
			{
				warn("accept(sfd)");
			}
			else if (connected == PEERS_MAX)
			{
				/*
				 * TODO: maybe send 005 or smth?
				 */
				close(client);
			}
			else
			{
				peers[connected++] = (struct Peer){ .fd = client };
				strlcpy(
					peers[connected - 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]))
				remove_schedule[schedulei++] = i;
		}
		for (i = 0; i < schedulei; ++i)
		{
			pid = remove_schedule[i];
			/* TODO: announce_quit(&peers[pid]); */
			writef(peers[pid].fd, "ERROR :Closing Link: %s", peers[pid].host);
			close(peers[pid].fd);
			peers[pid] = peers[--connected];
		}
		schedulei = 0;
	}
}