/*
 * 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 <stddef.h>
#include <stdio.h>
#include <string.h>


#define ensure(cond, iffalse, doexit) if (!(cond)) { iffalse; if (doexit >= 0) return doexit; }

static int
nick(struct Message *msg, struct Peer *peer)
{
	ensure(msg->params[0] && msg->params[0], writef(
		peer->fd,
		":%s 431 %s :No nickname given",
		hostname,
		getnick(peer)
	), 0);

	user_reg(peer, msg->params[0], NULL, NULL);

	return 0;
}

static int
privmsg(struct Message *msg, struct Peer *peer)
{
	size_t i;

	ensure(peer->type, writef(
		peer->fd,
		":%s 451 %s :You have not registered",
		hostname,
		getnick(peer)
	), 0);
	ensure(msg->params[0] && *msg->params[0], writef(
		peer->fd,
		":%s 411 %s :No recipient given (PRIVMSG)",
		hostname,
		getnick(peer)
	), 0);
	ensure(msg->params[1] && *msg->params[1], writef(
		peer->fd,
		":%s 412 %s :No text to send",
		hostname,
		getnick(peer)
	), 0);

	/* TODO: implement channels */
	ensure(!strchr("!+#&", *msg->params[0]), writef(
		peer->fd,
		":%s 421 %s :Channels are not supported yet",
		hostname,
		getnick(peer)
	), 0);

	/* TODO: implement server-to-server communication */
	for (i = 0; i < PEERS_MAX; ++i)
		if (peers[i].type == CLIENT && !strcmp(peers[i].nick, msg->params[0]))
			writef(
				peers[i].fd,
				":%s!%s@%s PRIVMSG %s :%s",
				peer->nick,
				peer->user,
				peer->host,
				peer->nick,
				msg->params[1]
			);
	return 0;
}

static int
quit(struct Message *msg, struct Peer *peer)
{
	return 1;
}

static int
user(struct Message *msg, struct Peer *peer)
{
	size_t i;

	ensure(!peer->type, writef(
		peer->fd,
		":%s 462 %s :Unauthorized command (already registered)",
		hostname,
		getnick(peer)
	), 0);
	for (i = 0; i < 4; ++i)
		ensure(msg->params[i] && *msg->params[i], writef(
			peer->fd,
			":%s 461 %s %s :Not enough parameters",
			hostname,
			getnick(peer),
			msg->command
		), 0);

	user_reg(peer, NULL, msg->params[0], msg->params[3]);

	return 0;
}

static int
default_handler(struct Message *msg, struct Peer *peer)
{
	ensure(peer->type, 0, 0);

	writef(peer->fd, ":%s 421 %s %s :Unknown command", hostname, getnick(peer), msg->command);
	return 0;
}

static struct Handler {
	const char *name;
	Handler *handler;
} handlers[] =
{
	{ "nick", nick },
	{ "privmsg", privmsg },
	{ "quit", quit },
	{ "user", user },
};

Handler *
find(const char *command)
{
	struct Handler *l, *m, *r;
	int res;

	l = handlers;
	r = handlers + lengthof(handlers) - 1;
	while (l <= r)
	{
		m = l + (r - l) / 2;
		res = strcmp(command, m->name);
		if (res > 0)
			l = ++m;
		else if (res < 0)
			r = --m;
		else
			return m->handler;
	}

	return default_handler;
}