/*
 * 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 <string.h>

#include <err.h>


struct Channel channels[CHANNELS_MAX];
size_t channels_c;

int
channel_join(struct Channel *channel, struct Peer *peer)
{
	if (channel->peers_c == lengthof(channel->peers)
	 || peer->channels_c == lengthof(peer->channels))
		return 1;

	peer->channels[peer->channels_c++] = channel;
	channel->peers[channel->peers_c++].p = peer;
	writechanf(
		0,
		channel,
		":%s!%s@%s JOIN %s",
		getnick(peer),
		peer->user,
		peer->host,
		channel->name
	);
	return 0;
}

int
channel_exit(struct Channel *channel, struct Peer *peer)
{
	size_t i;

	for (i = 0; i < channel->peers_c; ++i)
		if (channel->peers[i].p == peer)
			break;
	ensure(i != channel->peers_c, (void)0, 1);
	channel->peers[i] = channel->peers[--channel->peers_c];

	for (i = 0; i < peer->channels_c; ++i)
		if (!strcmp(peer->channels[i]->name, channel->name))
			break;
	ensure(i != peer->channels_c, warnx(
		"channel_exit(): channel had user, but user hadn't channel"
	), 1)
	peer->channels[i] = peer->channels[--peer->channels_c];

	if (!channel->peers_c)
	{
		for (i = 0; i < channels_c; ++i)
			if (!strcmp(channels[i].name, channel->name))
				break;
		ensure(i != channels_c, warnx(
			"channel_exit(): couldn't find empty channel"
		), 1);
		channel_remove(i);
	}

	return 0;
}

const struct ChannelModeParam *
channel_modes_parse(const struct Message *msg)
{
	static struct ChannelModeParam modes[MESSAGE_MAX];
	size_t i, modes_c, queue_l, queue_r;
	char *m, queue[PARAM_MAX];
	int set = 1;

	memset(modes, 0, sizeof(modes));
	for (modes_c = queue_l = queue_r = 0, i = 1; msg->params[i]; ++i, set = 1) switch (*msg->params[i])
	{
	case '-':
		set = 0;
	case '+':
	{
		for (m = msg->params[i]+1; *m; ++m) switch (*m)
		{
		break; case 'o': case 'v':
			/* since all flags are ASCII (< 128) bit 7
			 * can be and is abused for the set flag */
			if (queue_r == lengthof(queue))
			{
				modes[modes_c].mode = *m;
				return modes;
			}
			queue[queue_r++] = (set << 7) | *m;
		break; case 'm': case 'n': case 's': case 't':
			modes[modes_c].mode = *m;
			modes[modes_c++].set = set;
		break; default:
			modes[modes_c].mode = *m;
			modes[modes_c++].set = set;
			return modes;
		}
	} break;
	default:
	{
		modes[modes_c].param = msg->params[i];

		if (queue_l == queue_r)
		{
			return modes;
		}
		else
		{
			modes[modes_c].set = !!(queue[queue_l] & (1 << 7));
			modes[modes_c++].mode = queue[queue_l++] & ~(1 << 7);
		}
	} break;
	}

	return modes;
}

void
channel_remove(size_t cid)
{
	struct Channel *tofix;
	size_t i, j;

	tofix = &channels[channels_c-1];
	for (i = 0; i < tofix->peers_c; ++i)
	{
		for (j = 0; j < tofix->peers[i].p->channels_c; ++j)
			if (!strcmp(tofix->peers[i].p->channels[j]->name, tofix->name))
				break;
		if (j == tofix->peers[i].p->channels_c)
		{
			warnx(
				"channel_remove(): %s doesn't belong to %s@%s, "
				"though they believe in the opposite",
				tofix->name,
				getnick(tofix->peers[i].p),
				tofix->peers[i].p->host
			);
			continue;
		}

		tofix->peers[i].p->channels[j] = &channels[cid];
	}

	channels[cid] = channels[--channels_c];
}