<?php
define('MSZ_PERM_FORUM_MANAGE_FORUMS', 1);

define('MSZ_FORUM_PERM_LIST_FORUM', 1); // can see stats, but will get error when trying to view
define('MSZ_FORUM_PERM_VIEW_FORUM', 1 << 1);

define('MSZ_FORUM_PERM_CREATE_TOPIC', 1 << 10);
define('MSZ_FORUM_PERM_DELETE_TOPIC', 1 << 11); // how is this different from MSZ_FORUM_PERM_DELETE_ANY_POST?
define('MSZ_FORUM_PERM_MOVE_TOPIC', 1 << 12);
define('MSZ_FORUM_PERM_LOCK_TOPIC', 1 << 13);
define('MSZ_FORUM_PERM_STICKY_TOPIC', 1 << 14);
define('MSZ_FORUM_PERM_ANNOUNCE_TOPIC', 1 << 15);
define('MSZ_FORUM_PERM_GLOBAL_ANNOUNCE_TOPIC', 1 << 16);

define('MSZ_FORUM_PERM_CREATE_POST', 1 << 20);
define('MSZ_FORUM_PERM_EDIT_POST', 1 << 21);
define('MSZ_FORUM_PERM_EDIT_ANY_POST', 1 << 22);
define('MSZ_FORUM_PERM_DELETE_POST', 1 << 23);
define('MSZ_FORUM_PERM_DELETE_ANY_POST', 1 << 24);

// shorthands, never use these to SET!!!!!!!
define('MSZ_FORUM_PERM_SET_READ', MSZ_FORUM_PERM_LIST_FORUM | MSZ_FORUM_PERM_VIEW_FORUM);
define(
    'MSZ_FORUM_PERM_SET_WRITE',
    MSZ_FORUM_PERM_CREATE_TOPIC
    | MSZ_FORUM_PERM_DELETE_TOPIC
    | MSZ_FORUM_PERM_MOVE_TOPIC
    | MSZ_FORUM_PERM_LOCK_TOPIC
    | MSZ_FORUM_PERM_STICKY_TOPIC
    | MSZ_FORUM_PERM_ANNOUNCE_TOPIC
    | MSZ_FORUM_PERM_GLOBAL_ANNOUNCE_TOPIC
    | MSZ_FORUM_PERM_CREATE_POST
    | MSZ_FORUM_PERM_EDIT_POST
    | MSZ_FORUM_PERM_EDIT_ANY_POST
    | MSZ_FORUM_PERM_DELETE_POST
    | MSZ_FORUM_PERM_DELETE_ANY_POST
);

define('MSZ_FORUM_TYPE_DISCUSSION', 0);
define('MSZ_FORUM_TYPE_CATEGORY', 1);
define('MSZ_FORUM_TYPE_LINK', 2);
define('MSZ_FORUM_TYPES', [
    MSZ_FORUM_TYPE_DISCUSSION,
    MSZ_FORUM_TYPE_CATEGORY,
    MSZ_FORUM_TYPE_LINK,
]);

define('MSZ_FORUM_MAY_HAVE_CHILDREN', [
    MSZ_FORUM_TYPE_DISCUSSION,
    MSZ_FORUM_TYPE_CATEGORY,
]);

define('MSZ_FORUM_MAY_HAVE_TOPICS', [
    MSZ_FORUM_TYPE_DISCUSSION,
]);

define('MSZ_FORUM_ROOT', 0);
define('MSZ_FORUM_ROOT_DATA', [ // should be compatible with the data fetched in forum_get_root_categories
    'forum_id' => 0,
    'forum_name' => 'Forums',
    'forum_children' => 0,
    'forum_type' => MSZ_FORUM_TYPE_CATEGORY,
    'forum_colour' => null,
]);

function forum_is_valid_type(int $type): bool
{
    return in_array($type, MSZ_FORUM_TYPES, true);
}

function forum_may_have_children(int $forumType): bool
{
    return in_array($forumType, MSZ_FORUM_MAY_HAVE_CHILDREN);
}

function forum_may_have_topics(int $forumType): bool
{
    return in_array($forumType, MSZ_FORUM_MAY_HAVE_TOPICS);
}

function forum_fetch(int $forumId): array
{
    $getForum = db_prepare('
        SELECT
            `forum_id`, `forum_name`, `forum_type`, `forum_link`,
            `forum_link_clicks`, `forum_parent`, `forum_colour`,
            (
                SELECT COUNT(`topic_id`)
                FROM `msz_forum_topics`
                WHERE `forum_id` = f.`forum_id`
            ) as `forum_topic_count`
        FROM `msz_forum_categories` as f
        WHERE `forum_id` = :forum_id
    ');
    $getForum->bindValue('forum_id', $forumId);
    $getForum->execute();
    $forums = $getForum->fetch();

    return $forums ? $forums : [];
}

function forum_get_root_categories(int $userId): array
{
    $getCategories = db_prepare(sprintf(
        "
            SELECT
                f.`forum_id`, f.`forum_name`, f.`forum_type`, f.`forum_colour`,
                (
                    SELECT COUNT(`forum_id`)
                    FROM `msz_forum_categories` as sf
                    WHERE sf.`forum_parent` = f.`forum_id`
                ) as `forum_children`
            FROM `msz_forum_categories` as f
            WHERE f.`forum_parent` = 0
            AND f.`forum_type` = %d
            AND f.`forum_hidden` = 0
            AND (%s & %d) > 0
            ORDER BY f.`forum_order`
        ",
        MSZ_FORUM_TYPE_CATEGORY,
        forum_perms_get_user_sql('forum', 'f.`forum_id`'),
        MSZ_FORUM_PERM_SET_READ
    ));
    $getCategories->bindValue('perm_user_id_user', $userId);
    $getCategories->bindValue('perm_user_id_role', $userId);
    $categories = $getCategories->execute() ? $getCategories->fetchAll(PDO::FETCH_ASSOC) : [];
    $categories = array_merge([MSZ_FORUM_ROOT_DATA], $categories);

    $getRootForumCount = db_prepare(sprintf(
        "
            SELECT COUNT(`forum_id`)
            FROM `msz_forum_categories`
            WHERE `forum_parent` = %d
            AND `forum_type` != %d
            AND (%s & %d) > 0
        ",
        MSZ_FORUM_ROOT,
        MSZ_FORUM_TYPE_CATEGORY,
        forum_perms_get_user_sql('forum', '`forum_id`'),
        MSZ_FORUM_PERM_SET_READ
    ));
    $getRootForumCount->bindValue('perm_user_id_user', $userId);
    $getRootForumCount->bindValue('perm_user_id_role', $userId);
    $getRootForumCount->execute();

    $categories[0]['forum_children'] = (int)$getRootForumCount->fetchColumn();

    return $categories;
}

function forum_get_breadcrumbs(
    int $forumId,
    string $linkFormat = '/forum/forum.php?f=%d',
    array $indexLink = ['Forums' => '/forum/']
): array {
    $breadcrumbs = [];
    $getBreadcrumbs = db_prepare('
        WITH RECURSIVE breadcrumbs(forum_id, forum_name, forum_parent) as (
            SELECT c.`forum_id`, c.`forum_name`, c.`forum_parent`
            FROM `msz_forum_categories` as c
            WHERE `forum_id` = :forum_id
            UNION ALL
            SELECT p.`forum_id`, p.`forum_name`, p.`forum_parent`
            FROM `msz_forum_categories` as p
            INNER JOIN breadcrumbs
            ON p.`forum_id` = breadcrumbs.forum_parent
        )
        SELECT * FROM breadcrumbs
    ');
    $getBreadcrumbs->bindValue('forum_id', $forumId);
    $breadcrumbsDb = $getBreadcrumbs->execute() ? $getBreadcrumbs->fetchAll(PDO::FETCH_ASSOC) : [];

    if (!$breadcrumbsDb) {
        return [$indexLink];
    }

    foreach ($breadcrumbsDb as $breadcrumb) {
        $breadcrumbs[$breadcrumb['forum_name']] = sprintf($linkFormat, $breadcrumb['forum_id']);
    }

    return array_reverse($breadcrumbs + $indexLink);
}

function forum_get_colour(int $forumId): int
{
    $getColours = db_prepare('
        WITH RECURSIVE breadcrumbs(forum_id, forum_parent, forum_colour) as (
            SELECT c.`forum_id`, c.`forum_parent`, c.`forum_colour`
            FROM `msz_forum_categories` as c
            WHERE `forum_id` = :forum_id
            UNION ALL
            SELECT p.`forum_id`, p.`forum_parent`, p.`forum_colour`
            FROM `msz_forum_categories` as p
            INNER JOIN breadcrumbs
            ON p.`forum_id` = breadcrumbs.forum_parent
        )
        SELECT * FROM breadcrumbs
    ');
    $getColours->bindValue('forum_id', $forumId);
    $colours = $getColours->execute() ? $getColours->fetchAll(PDO::FETCH_ASSOC) : [];

    if ($colours) {
        foreach ($colours as $colour) {
            if ($colour['forum_colour'] !== null) {
                return $colour['forum_colour'];
            }
        }
    }

    return colour_none();
}

function forum_increment_clicks(int $forumId): void
{
    $incrementLinkClicks = db_prepare(sprintf('
        UPDATE `msz_forum_categories`
        SET `forum_link_clicks` = `forum_link_clicks` + 1
        WHERE `forum_id` = :forum_id
        AND `forum_type` = %d
        AND `forum_link_clicks` IS NOT NULL
    ', MSZ_FORUM_TYPE_LINK));
    $incrementLinkClicks->bindValue('forum_id', $forumId);
    $incrementLinkClicks->execute();
}

function forum_read_status_sql(
    string $topic_id_param,
    string $user_param_sub,
    string $forum_id_param = 'f.`forum_id`',
    string $user_param = '`target_user_id`'
): string {
    return sprintf(
        '
            SELECT
                %1$s > 0
            AND
                %2$s IS NOT NULL
            AND (
                SELECT COUNT(ti.`topic_id`)
                FROM `msz_forum_topics` AS ti
                LEFT JOIN `msz_forum_topics_track` AS tt
                ON tt.`topic_id` = ti.`topic_id` AND tt.`user_id` = %4$s
                WHERE ti.`forum_id` = %3$s
                AND ti.`topic_deleted` IS NULL
                AND ti.`topic_bumped` >= NOW() - INTERVAL 1 MONTH
                AND (
                    tt.`track_last_read` IS NULL
                    OR tt.`track_last_read` < ti.`topic_bumped`
                )
            )
        ',
        $user_param,
        $topic_id_param,
        $forum_id_param,
        $user_param_sub
    );
}

define(
    'MSZ_FORUM_GET_CHILDREN_QUERY_SMALL',
    '
        SELECT
            :user_id as `target_user_id`,
            f.`forum_id`, f.`forum_name`,
            (%1$s) as `forum_unread`
        FROM `msz_forum_categories` as f
        LEFT JOIN `msz_forum_topics` as t
        ON t.`topic_id` = (
            SELECT `topic_id`
            FROM `msz_forum_topics`
            WHERE `forum_id` = f.`forum_id`
            AND `topic_deleted` IS NULL
            ORDER BY `topic_bumped` DESC
            LIMIT 1
        )
        WHERE `forum_parent` = :parent_id
        AND `forum_hidden` = false
        AND (%4$s & %5$d) > 0
        ORDER BY f.`forum_order`
    '
);

define(
    'MSZ_FORUM_GET_CHILDREN_QUERY_STANDARD',
    '
        SELECT
            :user_id as `target_user_id`,
            f.`forum_id`, f.`forum_name`, f.`forum_description`, f.`forum_type`,
            f.`forum_link`, f.`forum_link_clicks`, f.`forum_archived`, f.`forum_colour`,
            t.`topic_id` as `recent_topic_id`, p.`post_id` as `recent_post_id`,
            t.`topic_title` as `recent_topic_title`, t.`topic_bumped` as `recent_topic_bumped`,
            p.`post_created` as `recent_post_created`,
            u.`user_id` as `recent_post_user_id`,
            u.`username` as `recent_post_username`,
            COALESCE(u.`user_colour`, r.`role_colour`) as `recent_post_user_colour`,
            (
                SELECT COUNT(`topic_id`)
                FROM `msz_forum_topics`
                WHERE `forum_id` = f.`forum_id`
            ) as `forum_topic_count`,
            (
                SELECT COUNT(`post_id`)
                FROM `msz_forum_posts`
                WHERE `forum_id` = f.`forum_id`
            ) as `forum_post_count`,
            (%1$s) as `forum_unread`
        FROM `msz_forum_categories` as f
        LEFT JOIN `msz_forum_topics` as t
        ON t.`topic_id` = (
            SELECT `topic_id`
            FROM `msz_forum_topics`
            WHERE `forum_id` = f.`forum_id`
            AND `topic_deleted` IS NULL
            ORDER BY `topic_bumped` DESC
            LIMIT 1
        )
        LEFT JOIN `msz_forum_posts` as p
        ON p.`post_id` = (
            SELECT `post_id`
            FROM `msz_forum_posts`
            WHERE `topic_id` = t.`topic_id`
            ORDER BY `post_id` DESC
            LIMIT 1
        )
        LEFT JOIN `msz_users` as u
        ON u.`user_id` = p.`user_id`
        LEFT JOIN `msz_roles` as r
        ON r.`role_id` = u.`display_role`
        WHERE f.`forum_parent` = :parent_id
        AND f.`forum_hidden` = 0
        AND (%4$s & %5$d) > 0
        AND (
            (f.`forum_parent` = %2$d AND f.`forum_type` != %3$d)
            OR f.`forum_parent` != %2$d
        )
        ORDER BY f.`forum_order`
    '
);

function forum_get_children_query(bool $small = false): string
{
    return sprintf(
        $small
            ? MSZ_FORUM_GET_CHILDREN_QUERY_SMALL
            : MSZ_FORUM_GET_CHILDREN_QUERY_STANDARD,
        forum_read_status_sql('t.`topic_id`', ':user_for_check'),
        MSZ_FORUM_ROOT,
        MSZ_FORUM_TYPE_CATEGORY,
        forum_perms_get_user_sql('forum', 'f.`forum_id`'),
        MSZ_FORUM_PERM_SET_READ
    );
}

function forum_get_children(int $parentId, int $userId, bool $small = false): array
{
    $getListing = db_prepare(forum_get_children_query($small));
    $getListing->bindValue('user_id', $userId);
    $getListing->bindValue('perm_user_id_user', $userId);
    $getListing->bindValue('perm_user_id_role', $userId);
    $getListing->bindValue('user_for_check', $userId);
    $getListing->bindValue('parent_id', $parentId);

    return $getListing->execute() ? $getListing->fetchAll() : [];
}