<?php
namespace Misuzu\Forum;

use InvalidArgumentException;
use RuntimeException;
use stdClass;
use Index\DateTime;
use Index\Colour\Colour;
use Index\Data\DbStatementCache;
use Index\Data\DbTools;
use Index\Data\IDbConnection;
use Index\Net\IPAddress;
use Misuzu\Pagination;
use Misuzu\Users\UserInfo;

class Forum {
    private IDbConnection $dbConn;
    private DbStatementCache $cache;

    public function __construct(IDbConnection $dbConn) {
        $this->dbConn = $dbConn;
        $this->cache = new DbStatementCache($dbConn);
    }

    public static function convertCategoryListToTree(
        array $catInfos,
        ForumCategoryInfo|string|null $parentInfo = null,
        ?Colour $colour = null
    ): array {
        $colour ??= Colour::none();
        $tree = [];
        $predicate = $parentInfo
            ? fn($catInfo) => $catInfo->isDirectChildOf($parentInfo)
            : fn($catInfo) => !$catInfo->hasParent();

        foreach($catInfos as $catInfo) {
            if(!$predicate($catInfo))
                continue;

            $tree[$catInfo->getId()] = $item = new stdClass;
            $item->info = $catInfo;
            $item->colour = $catInfo->hasColour() ? $catInfo->getColour() : $colour;
            $item->children = self::convertCategoryListToTree($catInfos, $catInfo, $item->colour);
            $item->childIds = [];
            foreach($item->children as $child) {
                $item->childIds[] = $child->info->getId();
                $item->childIds += $child->childIds;
            }
        }

        return $tree;
    }

    public function countCategories(
        ForumCategoryInfo|string|null|false $parentInfo = false,
        string|int|null $type = null,
        ?bool $hidden = null
    ): array {
        if($parentInfo instanceof ForumCategoryInfo)
            $parentInfo = $parentInfo->getId();

        $hasParentInfo = $parentInfo !== false;
        $hasType = $type !== null;
        $hasHidden = $hidden !== null;

        $args = 0;
        $query = 'SELECT COUNT(*) FROM msz_forum_categories';
        if($hasParentInfo) {
            ++$args;
            $isRootParent = $parentInfo === null;
            if($isRootParent) { // make a migration that makes the field DEFAULT NULL and update all 0s to NULL
                $query .= 'WHERE (forum_parent IS NULL OR forum_parent = 0)';
            } else {
                $query .= 'WHERE forum_parent = ?';
            }
        }
        if($hasType) {
            if(is_string($type)) {
                if(!array_key_exists($type, ForumCategoryInfo::TYPE_ALIASES))
                    throw new InvalidArgumentException('$type is not a valid alias.');
                $type = ForumCategoryInfo::TYPE_ALIASES[$type];
            }

            $query .= sprintf(' %s forum_type = ?', ++$args > 1 ? 'AND' : 'WHERE');
        }
        if($hasHidden)
            $query .= sprintf(' %s forum_hidden %s 0', ++$args > 1 ? 'AND' : 'WHERE', $hidden ? '<>' : '=');

        $args = 0;
        $stmt = $this->cache->get($query);
        if($hasParentInfo && !$isRootParent)
            $stmt->addParameter(++$args, $parentInfo->getId());
        if($hasType)
            $stmt->addParameter(++$args, $type);
        $stmt->execute();

        $result = $stmt->getResult();
        return $result->next() ? $result->getInteger(0) : 0;
    }

    public function getCategories(
        ForumCategoryInfo|string|null|false $parentInfo = false,
        string|int|null $type = null,
        ?bool $hidden = null,
        bool $asTree = false,
        ?Pagination $pagination = null
    ): array {
        $hasParentInfo = $parentInfo !== false;
        $hasType = $type !== null;
        $hasHidden = $hidden !== null;
        $hasPagination = $pagination !== null;

        if($hasParentInfo && $asTree)
            throw new InvalidArgumentException('$asTree can only be used with $parentInfo set to false.');

        $args = 0;
        $query = 'SELECT forum_id, forum_order, forum_parent, forum_name, forum_type, forum_description, forum_icon, forum_colour, forum_link, forum_link_clicks, UNIX_TIMESTAMP(forum_created), forum_archived, forum_hidden, forum_count_topics, forum_count_posts FROM msz_forum_categories';
        if($hasParentInfo) {
            ++$args;
            $isRootParent = $parentInfo === null;
            if($isRootParent) { // make a migration that makes the field DEFAULT NULL and update all 0s to NULL
                $query .= ' WHERE (forum_parent IS NULL OR forum_parent = 0)';
            } else {
                $query .= ' WHERE forum_parent = ?';
            }
        }
        if($hasType) {
            if(is_string($type)) {
                if(!array_key_exists($type, ForumCategoryInfo::TYPE_ALIASES))
                    throw new InvalidArgumentException('$type is not a valid alias.');
                $type = ForumCategoryInfo::TYPE_ALIASES[$type];
            }

            $query .= sprintf(' %s forum_type = ?', ++$args > 1 ? 'AND' : 'WHERE');
        }
        if($hasHidden)
            $query .= sprintf(' %s forum_hidden %s 0', ++$args > 1 ? 'AND' : 'WHERE', $hidden ? '<>' : '=');
        $query .= ' ORDER BY forum_parent, forum_type <> 1, forum_order';
        if($hasPagination)
            $query .= ' LIMIT ? OFFSET ?';

        $args = 0;
        $stmt = $this->cache->get($query);
        if($hasParentInfo && !$isRootParent) {
            if($parentInfo instanceof ForumCategoryInfo)
                $stmt->addParameter(++$args, $parentInfo->getId());
            else
                $stmt->addParameter(++$args, $parentInfo);
        }
        if($hasType)
            $stmt->addParameter(++$args, $type);
        if($hasPagination) {
            $stmt->addParameter(++$args, $pagination->getRange());
            $stmt->addParameter(++$args, $pagination->getOffset());
        }
        $stmt->execute();

        $result = $stmt->getResult();
        $cats = [];

        while($result->next())
            $cats[] = new ForumCategoryInfo($result);

        if($asTree)
            $cats = self::convertCategoryListToTree($cats);

        return $cats;
    }

    public function getCategory(
        ?string $categoryId = null,
        ForumTopicInfo|string|null $topicInfo = null,
        ForumPostInfo|string|null $postInfo = null
    ): ForumCategoryInfo {
        $hasCategoryId = $categoryId !== null;
        $hasTopicInfo = $topicInfo !== null;
        $hasPostInfo = $postInfo !== null;

        if(!$hasCategoryId && !$hasTopicInfo && !$hasPostInfo)
            throw new InvalidArgumentException('You must specify an argument.');
        if(($hasCategoryId && ($hasTopicInfo || $hasPostInfo))
            || ($hasTopicInfo && ($hasCategoryId || $hasPostInfo))
            || ($hasPostInfo && ($hasCategoryId || $hasTopicInfo)))
            throw new InvalidArgumentException('Only one argument may be specified.');

        $value = null;
        $query = 'SELECT forum_id, forum_order, forum_parent, forum_name, forum_type, forum_description, forum_icon, forum_colour, forum_link, forum_link_clicks, UNIX_TIMESTAMP(forum_created), forum_archived, forum_hidden, forum_count_topics, forum_count_posts FROM msz_forum_categories';
        if($hasCategoryId) {
            $query .= ' WHERE forum_id = ?';
            $value = $categoryId;
        }
        if($hasTopicInfo) {
            if($topicInfo instanceof ForumTopicInfo) {
                $query .= ' WHERE forum_id = ?';
                $value = $topicInfo->getCategoryId();
            } else {
                $query .= ' WHERE forum_id = (SELECT forum_id FROM msz_forum_topics WHERE topic_id = ?)';
                $value = $topicInfo;
            }
        }
        if($hasPostInfo) {
            if($postInfo instanceof ForumPostInfo) {
                $query .= ' WHERE forum_id = ?';
                $value = $postInfo->getCategoryId();
            } else {
                $query .= ' WHERE forum_id = (SELECT forum_id FROM msz_forum_posts WHERE post_id = ?)';
                $value = $postInfo;
            }
        }

        $stmt = $this->cache->get($query);
        $stmt->addParameter(1, $value);
        $stmt->execute();

        $result = $stmt->getResult();
        if(!$result->next())
            throw new RuntimeException('Forum category info not found.');

        return new ForumCategoryInfo($result);
    }

    public function updateCategory(
        ForumCategoryInfo|string $categoryInfo
    ): void {
        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();
    }

    public function deleteCategory(ForumCategoryInfo|string $categoryInfo): void {
        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();
    }

    public function incrementCategoryClicks(ForumCategoryInfo|string $categoryInfo): void {
        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();

        // previous implementation also WHERE'd for forum_type = link but i don't think there's any other way to get here anyhow
        $stmt = $this->cache->get('UPDATE msz_forum_categories SET forum_link_clicks = forum_link_clicks + 1 WHERE forum_id = ? AND forum_link_clicks IS NOT NULL');
        $stmt->addParameter(1, $categoryInfo);
        $stmt->execute();
    }

    public function incrementCategoryTopics(ForumCategoryInfo|string $categoryInfo): void {
        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();

        $stmt = $this->cache->get('UPDATE msz_forum_categories SET forum_count_topics = forum_count_topics + 1 WHERE forum_id = ?');
        $stmt->addParameter(1, $categoryInfo);
        $stmt->execute();
    }

    public function incrementCategoryPosts(ForumCategoryInfo|string $categoryInfo): void {
        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();

        $stmt = $this->cache->get('UPDATE msz_forum_categories SET forum_count_posts = forum_count_posts + 1 WHERE forum_id = ?');
        $stmt->addParameter(1, $categoryInfo);
        $stmt->execute();
    }

    public function getCategoryAncestry(
        ForumCategoryInfo|ForumTopicInfo|ForumPostInfo|string $categoryInfo
    ): array {
        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();
        elseif($categoryInfo instanceof ForumTopicInfo || $categoryInfo instanceof ForumPostInfo)
            $categoryInfo = $categoryInfo->getCategoryId();

        $query = 'WITH RECURSIVE msz_cte_ancestry AS ('
            . 'SELECT forum_id, forum_order, forum_parent, forum_name, forum_type, forum_description, forum_icon, forum_colour, forum_link, forum_link_clicks, UNIX_TIMESTAMP(forum_created), forum_archived, forum_hidden, forum_count_topics, forum_count_posts FROM msz_forum_categories WHERE forum_id = ?'
            . ' UNION ALL'
            . ' SELECT fc.forum_id, fc.forum_order, fc.forum_parent, fc.forum_name, fc.forum_type, fc.forum_description, fc.forum_icon, fc.forum_colour, fc.forum_link, fc.forum_link_clicks, UNIX_TIMESTAMP(fc.forum_created), fc.forum_archived, fc.forum_hidden, fc.forum_count_topics, fc.forum_count_posts FROM msz_forum_categories AS fc JOIN msz_cte_ancestry AS ca ON fc.forum_id = ca.forum_parent'
            . ') SELECT * FROM msz_cte_ancestry';

        $stmt = $this->cache->get($query);
        $stmt->addParameter(1, $categoryInfo);
        $stmt->execute();

        $result = $stmt->getResult();
        $cats = [];

        while($result->next())
            $cats[] = new ForumCategoryInfo($result);

        return $cats;
    }

    public function getCategoryChildren(
        ForumCategoryInfo|string $parentInfo,
        bool $includeSelf = false,
        ?bool $hidden = null,
        bool $asTree = false
    ): array {
        if($parentInfo instanceof ForumCategoryInfo)
            $parentInfo = $parentInfo->getId();

        $hasHidden = $hidden !== null;

        $query = 'WITH RECURSIVE msz_cte_children AS ('
            . 'SELECT forum_id, forum_order, forum_parent, forum_name, forum_type, forum_description, forum_icon, forum_colour, forum_link, forum_link_clicks, UNIX_TIMESTAMP(forum_created), forum_archived, forum_hidden, forum_count_topics, forum_count_posts FROM msz_forum_categories WHERE forum_id = ?'
            . ' UNION ALL'
            . ' SELECT fc.forum_id, fc.forum_order, fc.forum_parent, fc.forum_name, fc.forum_type, fc.forum_description, fc.forum_icon, fc.forum_colour, fc.forum_link, fc.forum_link_clicks, UNIX_TIMESTAMP(fc.forum_created), fc.forum_archived, fc.forum_hidden, fc.forum_count_topics, fc.forum_count_posts FROM msz_forum_categories AS fc JOIN msz_cte_children AS cc ON fc.forum_parent = cc.forum_id'
            . ') SELECT * FROM msz_cte_children';

        $args = 0;
        if(!$includeSelf) {
            ++$args;
            $query .= ' WHERE forum_id <> ?';
        }
        if($hasHidden)
            $query .= sprintf(' %s forum_hidden %s 0', ++$args > 1 ? 'AND' : 'WHERE', $hidden ? '<>' : '=');
        $query .= ' ORDER BY forum_parent, forum_order';

        $args = 0;
        $stmt = $this->cache->get($query);
        $stmt->addParameter(++$args, $parentInfo);
        if(!$includeSelf)
            $stmt->addParameter(++$args, $parentInfo);
        $stmt->execute();

        $result = $stmt->getResult();
        $cats = [];

        while($result->next())
            $cats[] = new ForumCategoryInfo($result);

        if($asTree)
            $cats = self::convertCategoryListToTree($cats, $parentInfo);

        return $cats;
    }

    public function checkCategoryUnread(
        ForumCategoryInfo|string|array $categoryInfos,
        UserInfo|string|null $userInfo
    ): bool {
        if($userInfo === null)
            return false;

        if(!is_array($categoryInfos))
            $categoryInfos = [$categoryInfos];
        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();

        $args = 0;
        $stmt = $this->cache->get(sprintf(
            'SELECT COUNT(*) FROM msz_forum_topics AS ft LEFT JOIN msz_forum_topics_track AS ftt ON ftt.topic_id = ft.topic_id AND ftt.user_id = ? WHERE ft.forum_id IN (%s) AND ft.topic_deleted IS NULL AND ft.topic_bumped >= NOW() - INTERVAL 1 MONTH AND (ftt.track_last_read IS NULL OR ftt.track_last_read < ft.topic_bumped)',
            DbTools::prepareListString($categoryInfos)
        ));
        $stmt->addParameter(++$args, $userInfo);
        foreach($categoryInfos as $categoryInfo) {
            if($categoryInfo instanceof ForumCategoryInfo)
                $stmt->addParameter(++$args, $categoryInfo->getId());
            elseif(is_string($categoryInfo) || is_int($categoryInfo))
                $stmt->addParameter(++$args, $categoryInfo);
            else
                throw new InvalidArgumentException('Invalid item in $categoryInfos.');
        }
        $stmt->execute();

        $result = $stmt->getResult();
        return $result->next() && $result->getInteger(0) > 0;
    }

    public function updateUserReadCategory(
        UserInfo|string|null $userInfo,
        ForumCategoryInfo|string $categoryInfo
    ): void {
        if($userInfo === null)
            return;

        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();
        if($categoryInfo instanceof $categoryInfo)
            $categoryInfo = $categoryInfo->getId();

        $stmt = $this->cache->get('REPLACE INTO msz_forum_topics_track (user_id, topic_id, forum_id, track_last_read) SELECT ?, topic_id, forum_id, NOW() FROM msz_forum_topics WHERE forum_id = ? AND topic_bumped >= NOW() - INTERVAL 1 MONTH');
        $stmt->addParameter(1, $userInfo);
        $stmt->addParameter(2, $categoryInfo);
        $stmt->execute();
    }

    public function getCategoryColour(
        ForumCategoryInfo|ForumTopicInfo|ForumPostInfo|string $categoryInfo
    ): Colour {
        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();
        elseif($categoryInfo instanceof ForumTopicInfo || $categoryInfo instanceof ForumPostInfo)
            $categoryInfo = $categoryInfo->getCategoryId();

        $query = 'WITH RECURSIVE msz_cte_colours AS ('
            . 'SELECT forum_id, forum_parent, forum_colour FROM msz_forum_categories WHERE forum_id = ?'
            . ' UNION ALL'
            . ' SELECT fc.forum_id, fc.forum_parent, fc.forum_colour FROM msz_forum_categories AS fc JOIN msz_cte_colours AS cc ON fc.forum_id = cc.forum_parent'
            . ') SELECT forum_colour FROM msz_cte_colours WHERE forum_colour IS NOT NULL';

        $stmt = $this->cache->get($query);
        $stmt->addParameter(1, $categoryInfo);
        $stmt->execute();

        $result = $stmt->getResult();
        return $result->next() ? Colour::fromMisuzu($result->getInteger(0)) : Colour::none();
    }

    public function getMostActiveCategoryInfo(
        UserInfo|string $userInfo,
        array $exceptCategoryInfos = [],
        array $exceptTopicInfos = [],
        ?bool $deleted = null
    ): object {
        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();

        $hasExceptCategoryInfos = !empty($exceptCategoryInfos);
        $hasExceptTopicInfos = !empty($exceptTopicInfos);
        $hasDeleted = $deleted !== null;

        $query = 'SELECT forum_id, COUNT(*) AS post_count FROM msz_forum_posts WHERE user_id = ?';
        if($hasDeleted)
            $query .= sprintf(' AND post_deleted %s NULL', $deleted ? 'IS NOT' : 'IS');
        if($hasExceptCategoryInfos)
            $query .= sprintf(' AND forum_id NOT IN (%s)', DbTools::prepareListString($exceptCategoryInfos));
        if($hasExceptTopicInfos)
            $query .= sprintf(' AND topic_id NOT IN (%s)', DbTools::prepareListString($exceptTopicInfos));
        $query .= ' GROUP BY forum_id ORDER BY post_count DESC LIMIT 1';

        $args = 0;
        $stmt = $this->cache->get($query);
        $stmt->addParameter(++$args, $userInfo);
        foreach($exceptCategoryInfos as $categoryInfo) {
            if($categoryInfo instanceof ForumCategoryInfo)
                $stmt->addParameter(++$args, $categoryInfo->getId());
            elseif(is_string($categoryInfo) || is_int($categoryInfo))
                $stmt->addParameter(++$args, (string)$categoryInfo);
            else
                throw new InvalidArgumentException('$exceptCategoryInfos may only contain string ids or instances of ForumCategoryInfo.');
        }
        foreach($exceptTopicInfos as $topicInfo) {
            if($topicInfo instanceof ForumTopicInfo)
                $stmt->addParameter(++$args, $topicInfo->getId());
            elseif(is_string($topicInfo) || is_int($topicInfo))
                $stmt->addParameter(++$args, (string)$topicInfo);
            else
                throw new InvalidArgumentException('$exceptTopicInfos may only contain string ids or instances of ForumTopicInfo.');
        }
        $stmt->execute();

        $result = $stmt->getResult();
        $info = new stdClass;
        $info->success = $result->next();
        if($info->success) {
            $info->categoryId = $result->getString(0);
            $info->postCount = $result->getInteger(1);
        }

        return $info;
    }

    public function syncForumCounters(
        ForumCategoryInfo|string|null $categoryInfo = null,
        bool $updateCounters = true
    ): object {
        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();
        elseif($categoryInfo === null)
            $categoryInfo = '0';

        $counters = new stdClass;

        $stmt = $this->cache->get('SELECT ? AS target_category_id, (SELECT COUNT(*) FROM msz_forum_topics WHERE forum_id = target_category_id AND topic_deleted IS NULL) AS count_topics, (SELECT COUNT(*) FROM msz_forum_posts WHERE forum_id = target_category_id AND post_deleted IS NULL) AS count_posts');
        $stmt->addParameter(1, $categoryInfo);
        $stmt->execute();

        $result = $stmt->getResult();
        if(!$result->next())
            throw new RuntimeException('Failed to fetch forum category counters.');

        $counters->topics = $result->getInteger(1);
        $counters->posts = $result->getInteger(2);

        $stmt = $this->cache->get('SELECT forum_id FROM msz_forum_categories WHERE forum_parent = ?');
        $stmt->addParameter(1, $categoryInfo);
        $stmt->execute();

        $children = [];
        $result = $stmt->getResult();
        while($result->next())
            $children[] = $result->getString(0);

        foreach($children as $childId) {
            $childCounters = $this->syncForumCounters($childId, $updateCounters);
            $counters->topics += $childCounters->topics;
            $counters->posts += $childCounters->posts;
        }

        if($updateCounters && $categoryInfo !== '0') {
            $stmt = $this->cache->get('UPDATE msz_forum_categories SET forum_count_topics = ?, forum_count_posts = ? WHERE forum_id = ?');
            $stmt->addParameter(1, $counters->topics);
            $stmt->addParameter(2, $counters->posts);
            $stmt->addParameter(3, $categoryInfo);
            $stmt->execute();
        }

        return $counters;
    }

    public function countTopics(
        ForumCategoryInfo|string|array|null $categoryInfo = null,
        UserInfo|string|null $userInfo = null,
        ?bool $global = null,
        ?bool $deleted = null
    ): int {
        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();
        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();

        $hasCategoryInfo = $categoryInfo !== null;
        $hasUserInfo = $userInfo !== null;
        $hasGlobal = $global !== null;
        $hasDeleted = $deleted !== null;

        $args = 0;
        $query = 'SELECT COUNT(*) FROM msz_forum_topics';
        if($hasCategoryInfo || $hasGlobal) {
            ++$args;

            // wow this sucks
            $hasGlobalAndCategory = $hasCategoryInfo && $hasGlobal;
            $query .= ' WHERE ';
            if($hasGlobalAndCategory)
                $query .= '(';

            if($hasCategoryInfo) {
                if(is_array($categoryInfo))
                    $query .= sprintf('forum_id IN (%s)', DbTools::prepareListString($categoryInfo));
                else
                    $query .= 'forum_id = ?';
            }

            if($hasGlobalAndCategory)
                $query .= ' OR ';

            if($hasGlobal) // not sure why you would ever set this to false, but consistency!
                $query .= sprintf('topic_type %s %d', $global ? '=' : '<>', ForumTopicInfo::TYPE_GLOBAL);

            if($hasGlobalAndCategory)
                $query .= ')';
        }
        if($hasUserInfo)
            $query .= sprintf(' %s user_id = ?', ++$args > 1 ? 'AND' : 'WHERE');
        if($hasDeleted)
            $query .= sprintf(' %s topic_deleted %s NULL', ++$args > 1 ? 'AND' : 'WHERE', $deleted ? 'IS NOT' : 'IS');

        $args = 0;
        $stmt = $this->cache->get($query);
        if($hasCategoryInfo) {
            if(is_array($categoryInfo)) {
                foreach($categoryInfo as $categoryInfoEntry)
                    $stmt->addParameter(++$args, $categoryInfoEntry instanceof ForumCategoryInfo ? $categoryInfoEntry->getId() : (string)$categoryInfoEntry);
            } else
                $stmt->addParameter(++$args, $categoryInfo);
        }
        if($hasUserInfo)
            $stmt->addParameter(++$args, $userInfo);
        $stmt->execute();

        $result = $stmt->getResult();
        return $result->next() ? $result->getInteger(0) : 0;
    }

    public function getTopics(
        ForumCategoryInfo|string|array|null $categoryInfo = null,
        UserInfo|string|null $userInfo = null,
        ?array $searchQuery = null,
        ?bool $global = null,
        ?bool $deleted = null,
        ?Pagination $pagination = null
    ): array {
        // remove this hack when search server
        $hasSearchQuery = $searchQuery !== null;
        $hasAfterTopicId = false;
        $doSearchOrder = false;
        if($hasSearchQuery) {
            if(!empty($searchQuery['type'])
                && $searchQuery['type'] !== 'forum'
                && $searchQuery['type'] !== 'forum:topic')
                return [];

            $deleted = false;
            $pagination = null;
            $doSearchOrder = true;

            if(!empty($searchQuery['author']))
                $userInfo = $searchQuery['author'];

            if(!empty($searchQuery['after'])) {
                $hasAfterTopicId = true;
                $afterTopicId = $searchQuery['after'];
            }

            $searchQuery = $searchQuery['query_string'];
            $hasSearchQuery = !empty($searchQuery);
        }

        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();
        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();

        $hasCategoryInfo = $categoryInfo !== null;
        $hasUserInfo = $userInfo !== null;
        $hasGlobal = $global !== null;
        $hasDeleted = $deleted !== null;
        $hasPagination = $pagination !== null;

        $args = 0;
        $query = 'SELECT topic_id, forum_id, user_id, topic_type, topic_title, topic_count_views, UNIX_TIMESTAMP(topic_created), UNIX_TIMESTAMP(topic_bumped), UNIX_TIMESTAMP(topic_deleted), UNIX_TIMESTAMP(topic_locked), (SELECT COUNT(*) FROM msz_forum_posts WHERE topic_id = ft.topic_id AND post_deleted IS NULL) AS topic_count_posts, (SELECT COUNT(*) FROM msz_forum_posts WHERE topic_id = ft.topic_id AND post_deleted IS NOT NULL) AS topic_count_posts_deleted FROM msz_forum_topics AS ft';
        if($hasCategoryInfo || $hasGlobal) {
            ++$args;

            // wow this sucks
            $hasGlobalAndCategory = $hasCategoryInfo && $hasGlobal;
            $query .= ' WHERE ';
            if($hasGlobalAndCategory)
                $query .= '(';

            if($hasCategoryInfo) {
                if(is_array($categoryInfo))
                    $query .= sprintf('forum_id IN (%s)', DbTools::prepareListString($categoryInfo));
                else
                    $query .= 'forum_id = ?';
            }

            if($hasGlobalAndCategory)
                $query .= ' OR ';

            if($hasGlobal) // not sure why you would ever set this to false, but consistency!
                $query .= sprintf('topic_type %s %d', $global ? '=' : '<>', ForumTopicInfo::TYPE_GLOBAL);

            if($hasGlobalAndCategory)
                $query .= ')';
        }
        if($hasUserInfo)
            $query .= sprintf(' %s user_id = ?', ++$args > 1 ? 'AND' : 'WHERE');
        if($hasAfterTopicId)
            $query .= sprintf(' %s topic_id > ?', ++$args > 1 ? 'AND' : 'WHERE');
        if($hasSearchQuery)
            $query .= sprintf(' %s MATCH(topic_title) AGAINST (? IN NATURAL LANGUAGE MODE)', ++$args > 1 ? 'AND' : 'WHERE');
        if($hasDeleted)
            $query .= sprintf(' %s topic_deleted %s NULL', ++$args > 1 ? 'AND' : 'WHERE', $deleted ? 'IS NOT' : 'IS');
        if($doSearchOrder) {
            $query .= ' ORDER BY topic_id ASC LIMIT 20';
        } else {
            $query .= ' ORDER BY topic_type DESC, topic_bumped DESC';
            if($hasPagination)
                $query .= ' LIMIT ? OFFSET ?';
        }

        $args = 0;
        $stmt = $this->cache->get($query);
        if($hasCategoryInfo) {
            if(is_array($categoryInfo)) {
                foreach($categoryInfo as $categoryInfoEntry)
                    $stmt->addParameter(++$args, $categoryInfoEntry instanceof ForumCategoryInfo ? $categoryInfoEntry->getId() : (string)$categoryInfoEntry);
            } else
                $stmt->addParameter(++$args, $categoryInfo);
        }
        if($hasUserInfo)
            $stmt->addParameter(++$args, $userInfo);
        if($hasAfterTopicId)
            $stmt->addParameter(++$args, $afterTopicId);
        if($hasSearchQuery)
            $stmt->addParameter(++$args, $searchQuery);
        if($hasPagination) {
            $stmt->addParameter(++$args, $pagination->getRange());
            $stmt->addParameter(++$args, $pagination->getOffset());
        }
        $stmt->execute();

        $result = $stmt->getResult();
        $topics = [];

        while($result->next())
            $topics[] = new ForumTopicInfo($result);

        return $topics;
    }

    public function getTopic(
        ?string $topicId = null,
        ForumPostInfo|string|null $postInfo = null
    ): ForumTopicInfo {
        $hasTopicId = $topicId !== null;
        $hasPostInfo = $postInfo !== null;

        if(!$hasTopicId && !$hasPostInfo)
            throw new InvalidArgumentException('At least one argument must be specified.');
        if($hasTopicId && $hasPostInfo)
            throw new InvalidArgumentException('Only one argument may be specified.');

        $value = null;
        $query = 'SELECT topic_id, forum_id, user_id, topic_type, topic_title, topic_count_views, UNIX_TIMESTAMP(topic_created), UNIX_TIMESTAMP(topic_bumped), UNIX_TIMESTAMP(topic_deleted), UNIX_TIMESTAMP(topic_locked), (SELECT COUNT(*) FROM msz_forum_posts WHERE topic_id = ft.topic_id AND post_deleted IS NULL) AS topic_count_posts, (SELECT COUNT(*) FROM msz_forum_posts WHERE topic_id = ft.topic_id AND post_deleted IS NOT NULL) AS topic_count_posts_deleted FROM msz_forum_topics AS ft';
        if($hasTopicId) {
            $query .= ' WHERE topic_id = ?';
            $value = $topicId;
        }
        if($hasPostInfo) {
            if($postInfo instanceof ForumPostInfo) {
                $query .= ' WHERE topic_id = ?';
                $value = $postInfo->getTopicId();
            } else {
                $query .= ' WHERE topic_id = (SELECT topic_id FROM msz_forum_posts WHERE post_id = ?)';
                $value = $postInfo;
            }
        }

        $stmt = $this->cache->get($query);
        $stmt->addParameter(1, $value);
        $stmt->execute();

        $result = $stmt->getResult();
        if(!$result->next())
            throw new RuntimeException('Forum topic not found.');

        return new ForumTopicInfo($result);
    }

    public function createTopic(
        ForumCategoryInfo|string $categoryInfo,
        UserInfo|string|null $userInfo,
        string $title,
        string|int $type = ForumTopicInfo::TYPE_DISCUSSION
    ): ForumTopicInfo {
        if(is_string($type)) {
            if(!array_key_exists($type, ForumTopicInfo::TYPE_ALIASES))
                throw new InvalidArgumentException('$type is not a valid alias.');
            $type = ForumTopicInfo::TYPE_ALIASES[$type];
        }
        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();
        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();

        $stmt = $this->cache->get('INSERT INTO msz_forum_topics (forum_id, user_id, topic_type, topic_title) VALUES (?, ?, ?, ?)');
        $stmt->addParameter(1, $categoryInfo);
        $stmt->addParameter(2, $userInfo);
        $stmt->addParameter(3, $type);
        $stmt->addParameter(4, $title);
        $stmt->execute();

        return $this->getTopic(topicId: (string)$this->dbConn->getLastInsertId());
    }

    public function updateTopic(
        ForumTopicInfo|string $topicInfo,
        ?string $title = null,
        string|int|null $type = null
    ): void {
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();

        $fields = [];
        $values = [];

        if($title !== null) {
            $fields[] = 'topic_title = ?';
            $values[] = $title;
        }

        if($type !== null) {
            if(is_string($type)) {
                if(!array_key_exists($type, ForumTopicInfo::TYPE_ALIASES))
                    throw new InvalidArgumentException('$type is not a valid type alias.');

                $type = ForumTopicInfo::TYPE_ALIASES[$type];
            }

            $fields[] = 'topic_type = ?';
            $values[] = $type;
        }

        if(empty($fields))
            return;

        $args = 0;
        $stmt = $this->cache->get(sprintf('UPDATE msz_forum_topics SET %s WHERE topic_id = ?', implode(', ', $fields)));
        foreach($values as $value)
            $stmt->addParameter(++$args, $value);
        $stmt->addParameter(++$args, $topicInfo);
        $stmt->execute();
    }

    public function incrementTopicView(ForumTopicInfo|string $topicInfo): void {
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();

        $stmt = $this->cache->get('UPDATE msz_forum_topics SET topic_count_views = topic_count_views + 1 WHERE topic_id = ?');
        $stmt->addParameter(1, $topicInfo);
        $stmt->execute();
    }

    public function bumpTopic(ForumTopicInfo|string $topicInfo): void {
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();

        $stmt = $this->cache->get('UPDATE msz_forum_topics SET topic_bumped = NOW() WHERE topic_id = ?');
        $stmt->addParameter(1, $topicInfo);
        $stmt->execute();
    }

    public function lockTopic(ForumTopicInfo|string $topicInfo): void {
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();

        $stmt = $this->cache->get('UPDATE msz_forum_topics SET topic_locked = NOW() WHERE topic_id = ?');
        $stmt->addParameter(1, $topicInfo);
        $stmt->execute();
    }

    public function unlockTopic(ForumTopicInfo|string $topicInfo): void {
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();

        $stmt = $this->cache->get('UPDATE msz_forum_topics SET topic_locked = NULL WHERE topic_id = ?');
        $stmt->addParameter(1, $topicInfo);
        $stmt->execute();
    }

    public function deleteTopic(ForumTopicInfo|string $topicInfo): void {
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();

        $stmt = $this->cache->get('UPDATE msz_forum_topics SET topic_deleted = COALESCE(topic_deleted, NOW()) WHERE topic_id = ? AND topic_deleted IS NULL');
        $stmt->addParameter(1, $topicInfo);
        $stmt->execute();

        $stmt = $this->cache->get('UPDATE msz_forum_posts AS fp SET post_deleted = (SELECT topic_deleted FROM msz_forum_topics WHERE topic_id = fp.topic_id) WHERE topic_id = ? AND post_deleted = NULL');
        $stmt->addParameter(1, $topicInfo);
        $stmt->execute();
    }

    public function restoreTopic(ForumTopicInfo|string $topicInfo): void {
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();

        $stmt = $this->cache->get('UPDATE msz_forum_posts AS fp SET post_deleted = NULL WHERE topic_id = ? AND post_deleted = (SELECT topic_deleted FROM msz_forum_topics WHERE topic_id = fp.topic_id)');
        $stmt->addParameter(1, $topicInfo);
        $stmt->execute();

        $stmt = $this->cache->get('UPDATE msz_forum_topics SET topic_deleted = NULL WHERE topic_id = ?');
        $stmt->addParameter(1, $topicInfo);
        $stmt->execute();
    }

    public function nukeTopic(ForumTopicInfo|string $topicInfo): void {
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();

        $stmt = $this->cache->get('DELETE FROM msz_forum_topics WHERE topic_id = ?');
        $stmt->addParameter(1, $topicInfo);
        $stmt->execute();
    }

    public function checkTopicParticipated(
        ForumTopicInfo|string $topicInfo,
        UserInfo|string|null $userInfo
    ): bool {
        if($userInfo === null)
            return false;
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();
        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();

        $stmt = $this->cache->get('SELECT COUNT(*) FROM msz_forum_posts WHERE topic_id = ? AND user_id = ?');
        $stmt->addParameter(1, $topicInfo);
        $stmt->addParameter(2, $userInfo);
        $stmt->execute();
        $result = $stmt->getResult();

        return $result->next() && $result->getInteger(0) > 0;
    }

    public function checkTopicUnread(
        ForumTopicInfo|string $topicInfo,
        UserInfo|string|null $userInfo
    ): bool {
        if($userInfo === null)
            return false;

        $topicInfoIsInstance = $topicInfo instanceof ForumTopicInfo;
        if($topicInfoIsInstance && !$topicInfo->isActive())
            return false;

        $query = 'SELECT UNIX_TIMESTAMP(track_last_read) FROM msz_forum_topics_track AS ftt WHERE user_id = ? AND topic_id = ?';
        if(!$topicInfoIsInstance)
            $query .= ' AND track_last_read = (SELECT topic_bumped FROM msz_forum_topics WHERE topic_id = ftt.topic_id AND topic_bumped >= NOW() - INTERVAL 1 MONTH)';

        $stmt = $this->cache->get($query);
        $stmt->addParameter(1, $userInfo instanceof UserInfo ? $userInfo->getId() : $userInfo);
        $stmt->addParameter(2, $topicInfoIsInstance ? $topicInfo->getId() : $topicInfo);
        $stmt->execute();
        $result = $stmt->getResult();

        // user has never read this topic, return unread
        if(!$result->next())
            return true;

        return $result->getInteger(0) < $topicInfo->getBumpedTime();
    }

    public function getMostActiveTopicInfo(
        UserInfo|string $userInfo,
        array $exceptCategoryInfos = [],
        array $exceptTopicInfos = [],
        ?bool $deleted = null
    ): object {
        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();

        $hasExceptCategoryInfos = !empty($exceptCategoryInfos);
        $hasExceptTopicInfos = !empty($exceptTopicInfos);
        $hasDeleted = $deleted !== null;

        $query = 'SELECT topic_id, forum_id, COUNT(*) AS post_count FROM msz_forum_posts WHERE user_id = ?';
        if($hasDeleted)
            $query .= sprintf(' AND post_deleted %s NULL', $deleted ? 'IS NOT' : 'IS');
        if($hasExceptCategoryInfos)
            $query .= sprintf(' AND forum_id NOT IN (%s)', DbTools::prepareListString($exceptCategoryInfos));
        if($hasExceptTopicInfos)
            $query .= sprintf(' AND topic_id NOT IN (%s)', DbTools::prepareListString($exceptTopicInfos));
        $query .= ' GROUP BY topic_id ORDER BY post_count DESC LIMIT 1';

        $args = 0;
        $stmt = $this->cache->get($query);
        $stmt->addParameter(++$args, $userInfo);
        foreach($exceptCategoryInfos as $categoryInfo) {
            if($categoryInfo instanceof ForumCategoryInfo)
                $stmt->addParameter(++$args, $categoryInfo->getId());
            elseif(is_string($categoryInfo) || is_int($categoryInfo))
                $stmt->addParameter(++$args, (string)$categoryInfo);
            else
                throw new InvalidArgumentException('$exceptCategoryInfos may only contain string ids or instances of ForumCategoryInfo.');
        }
        foreach($exceptTopicInfos as $topicInfo) {
            if($topicInfo instanceof ForumTopicInfo)
                $stmt->addParameter(++$args, $topicInfo->getId());
            elseif(is_string($topicInfo) || is_int($topicInfo))
                $stmt->addParameter(++$args, (string)$topicInfo);
            else
                throw new InvalidArgumentException('$exceptTopicInfos may only contain string ids or instances of ForumTopicInfo.');
        }
        $stmt->execute();

        $result = $stmt->getResult();
        $info = new stdClass;
        $info->success = $result->next();
        if($info->success) {
            $info->topicId = $result->getString(0);
            $info->categoryId = $result->getString(1);
            $info->postCount = $result->getInteger(2);
        }

        return $info;
    }

    public function checkUserHasReadTopic(
        UserInfo|string|null $userInfo,
        ForumTopicInfo|string $topicInfo
    ): bool {
        // this method is primarily used to check if we should increment the view count
        // guests shouldn't increment it so we just
        if($userInfo === null)
            return true;

        $stmt = $this->cache->get('SELECT COUNT(*) FROM msz_forum_topics_track WHERE topic_id = ? AND user_id = ?');
        $stmt->addParameter(1, $topicInfo instanceof ForumTopicInfo ? $topicInfo->getId() : $topicInfo);
        $stmt->addParameter(2, $userInfo instanceof UserInfo ? $userInfo->getId() : $userInfo);
        $stmt->execute();
        $result = $stmt->getResult();

        return $result->next() && $result->getInteger(0) > 0;
    }

    public function updateUserReadTopic(
        UserInfo|string|null $userInfo,
        ForumTopicInfo|string $topicInfo,
        ForumCategoryInfo|string|null $categoryInfo = null
    ): void {
        if($userInfo === null)
            return;

        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();

        if($topicInfo instanceof ForumTopicInfo) {
            $categoryInfo = $topicInfo->getCategoryId();
            $topicInfo = $topicInfo->getId();
        } else {
            if($categoryInfo === null)
                throw new InvalidArgumentException('$categoryInfo must be specified if $topicInfo is not an instance of ForumTopicInfo.');
            if($categoryInfo instanceof ForumCategoryInfo)
                $categoryInfo = $categoryInfo->getId();
        }

        $stmt = $this->cache->get('REPLACE INTO msz_forum_topics_track (user_id, topic_id, forum_id, track_last_read) VALUES (?, ?, ?, NOW())');
        $stmt->addParameter(1, $userInfo);
        $stmt->addParameter(2, $topicInfo);
        $stmt->addParameter(3, $categoryInfo);
        $stmt->execute();
    }

    public function countTopicRedirects(
        UserInfo|string|null $userInfo = null
    ): int {
        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();

        $hasUserInfo = $userInfo !== null;

        $query = 'SELECT COUNT(*) FROM msz_forum_topics_redirects';
        if($hasUserInfo)
            $query .= ' WHERE user_id = ?';

        $stmt = $this->cache->get($query);
        if($hasUserInfo)
            $stmt->addParameter(1, $userInfo);
        $stmt->execute();

        $result = $stmt->getResult();
        return $result->next() ? $result->getInteger(0) : 0;
    }

    public function getTopicRedirects(
        UserInfo|string|null $userInfo = null,
        ?Pagination $pagination = null
    ): array {
        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();

        $hasUserInfo = $userInfo !== null;
        $hasPagination = $pagination !== null;

        $query = 'SELECT topic_id, user_id, topic_redir_url, UNIX_TIMESTAMP(topic_redir_created) FROM msz_forum_topics_redirects';
        if($hasUserInfo)
            $query .= ' WHERE user_id = ?';
        if($hasPagination)
            $query .= ' LIMIT ? OFFSET ?';

        $args = 0;
        $stmt = $this->cache->get($query);
        if($hasUserInfo)
            $stmt->addParameter(++$args, $userInfo);
        if($hasPagination) {
            $stmt->addParameter(++$args, $pagination->getRange());
            $stmt->addParameter(++$args, $pagination->getOffset());
        }
        $stmt->execute();

        $result = $stmt->getResult();
        $redirs = [];

        while($result->next())
            $redirs[] = new ForumTopicRedirectInfo($result);

        return $redirs;
    }

    public function hasTopicRedirect(ForumTopicInfo|string $topicInfo): bool {
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();

        $stmt = $this->cache->get('SELECT COUNT(*) FROM msz_forum_topics_redirects WHERE topic_id = ?');
        $stmt->addParameter(1, $topicInfo);
        $stmt->execute();

        $result = $stmt->getResult();
        if(!$result->next())
            throw new RuntimeException('Was unable to check if a redirect exists.');

        return $result->getInteger(0) > 0;
    }

    public function getTopicRedirect(ForumTopicInfo|string $topicInfo): ForumTopicRedirectInfo {
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();

        $stmt = $this->cache->get('SELECT topic_id, user_id, topic_redir_url, UNIX_TIMESTAMP(topic_redir_created) FROM msz_forum_topics_redirects WHERE topic_id = ?');
        $stmt->addParameter(1, $topicInfo);
        $stmt->execute();

        $result = $stmt->getResult();
        if(!$result->next())
            throw new RuntimeException('Could not find that forum topic redirect.');

        return new ForumTopicRedirectInfo($result);
    }

    public function createTopicRedirect(
        ForumTopicInfo|string $topicInfo,
        UserInfo|string|null $userInfo,
        string $linkTarget
    ): ForumTopicRedirectInfo {
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();
        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();

        $stmt = $this->cache->get('INSERT INTO msz_forum_topics_redirects (topic_id, user_id, topic_redir_url) VALUES (?, ?, ?)');
        $stmt->addParameter(1, $topicInfo);
        $stmt->addParameter(2, $userInfo);
        $stmt->addParameter(3, $linkTarget);
        $stmt->execute();

        return $this->getTopicRedirect($topicInfo);
    }

    public function deleteTopicRedirect(ForumTopicRedirectInfo|ForumTopicInfo|string $topicInfo): void {
        if($topicInfo instanceof ForumTopicRedirectInfo)
            $topicInfo = $topicInfo->getTopicId();
        elseif($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();

        $stmt = $this->cache->get('DELETE FROM msz_forum_topics_redirects WHERE topic_id = ?');
        $stmt->addParameter(1, $topicInfo);
        $stmt->execute();
    }

    public function countPosts(
        ForumCategoryInfo|string|null $categoryInfo = null,
        ForumTopicInfo|string|null $topicInfo = null,
        UserInfo|string|null $userInfo = null,
        ForumPostInfo|string|null $upToPostInfo = null,
        ?bool $deleted = null
    ): int {
        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();
        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();
        if($upToPostInfo instanceof ForumPostInfo)
            $upToPostInfo = $upToPostInfo->getId();

        $hasCategoryInfo = $categoryInfo !== null;
        $hasTopicInfo = $topicInfo !== null;
        $hasUserInfo = $userInfo !== null;
        $hasUpToPostInfo = $upToPostInfo !== null;
        $hasDeleted = $deleted !== null;

        $args = 0;
        $query = 'SELECT COUNT(*) FROM msz_forum_posts';
        if($hasCategoryInfo) {
            ++$args;
            $query .= ' WHERE forum_id = ?';
        }
        if($hasTopicInfo)
            $query .= sprintf(' %s topic_id = ?', ++$args > 1 ? 'AND' : 'WHERE');
        if($hasUserInfo)
            $query .= sprintf(' %s user_id = ?', ++$args > 1 ? 'AND' : 'WHERE');
        if($hasUpToPostInfo)
            $query .= sprintf(' %s post_id < ?', ++$args > 1 ? 'AND' : 'WHERE');
        if($hasDeleted)
            $query .= sprintf(' %s post_deleted %s NULL', ++$args > 1 ? 'AND' : 'WHERE', $deleted ? 'IS NOT' : 'IS');

        $args = 0;
        $stmt = $this->cache->get($query);
        if($hasCategoryInfo)
            $stmt->addParameter(++$args, $categoryInfo);
        if($hasTopicInfo)
            $stmt->addParameter(++$args, $topicInfo);
        if($hasUserInfo)
            $stmt->addParameter(++$args, $userInfo);
        if($hasUpToPostInfo)
            $stmt->addParameter(++$args, $upToPostInfo);
        $stmt->execute();

        $result = $stmt->getResult();
        return $result->next() ? $result->getInteger(0) : 0;
    }

    public function getPosts(
        ForumCategoryInfo|string|array|null $categoryInfo = null,
        ForumTopicInfo|string|null $topicInfo = null,
        UserInfo|string|null $userInfo = null,
        ForumPostInfo|string|null $upToPostInfo = null,
        ?array $searchQuery = null,
        ?bool $deleted = null,
        ?Pagination $pagination = null
    ): array {
        // remove this hack when search server
        $hasSearchQuery = $searchQuery !== null;
        $hasAfterPostId = false;
        $doSearchOrder = false;
        if($hasSearchQuery) {
            if(!empty($searchQuery['type'])
                && $searchQuery['type'] !== 'forum'
                && $searchQuery['type'] !== 'forum:post')
                return [];

            $deleted = false;
            $pagination = null;
            $doSearchOrder = true;

            if(!empty($searchQuery['author']))
                $userInfo = $searchQuery['author'];

            if(!empty($searchQuery['after'])) {
                $hasAfterPostId = true;
                $afterPostId = $searchQuery['after'];
            }

            $searchQuery = $searchQuery['query_string'];
            $hasSearchQuery = !empty($searchQuery);
        }

        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();
        if($topicInfo instanceof ForumTopicInfo)
            $topicInfo = $topicInfo->getId();
        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();
        if($upToPostInfo instanceof ForumPostInfo)
            $upToPostInfo = $upToPostInfo->getId();

        $hasCategoryInfo = $categoryInfo !== null;
        $hasTopicInfo = $topicInfo !== null;
        $hasUserInfo = $userInfo !== null;
        $hasUpToPostInfo = $upToPostInfo !== null;
        $hasDeleted = $deleted !== null;
        $hasPagination = $pagination !== null;

        $args = 0;
        $query = 'SELECT post_id, topic_id, forum_id, user_id, INET6_NTOA(post_ip), post_text, post_parse, post_display_signature, UNIX_TIMESTAMP(post_created), UNIX_TIMESTAMP(post_edited), UNIX_TIMESTAMP(post_deleted) FROM msz_forum_posts';
        if($hasCategoryInfo) {
            ++$args;
            if(is_array($categoryInfo))
                $query .= sprintf(' WHERE forum_id IN (%s)', DbTools::prepareListString($categoryInfo));
            else
                $query .= ' WHERE forum_id = ?';
        }
        if($hasTopicInfo)
            $query .= sprintf(' %s topic_id = ?', ++$args > 1 ? 'AND' : 'WHERE');
        if($hasUserInfo)
            $query .= sprintf(' %s user_id = ?', ++$args > 1 ? 'AND' : 'WHERE');
        if($hasUpToPostInfo)
            $query .= sprintf(' %s post_id < ?', ++$args > 1 ? 'AND' : 'WHERE');
        if($hasAfterPostId)
            $query .= sprintf(' %s post_id > ?', ++$args > 1 ? 'AND' : 'WHERE');
        if($hasSearchQuery)
            $query .= sprintf(' %s MATCH(post_text) AGAINST (? IN NATURAL LANGUAGE MODE)', ++$args > 1 ? 'AND' : 'WHERE');
        if($hasDeleted)
            $query .= sprintf(' %s post_deleted %s NULL', ++$args > 1 ? 'AND' : 'WHERE', $deleted ? 'IS NOT' : 'IS');
        if($doSearchOrder) {
            $query .= ' ORDER BY post_id ASC LIMIT 20';
        } else {
            $query .= ' ORDER BY post_id ASC';
            if($hasPagination)
                $query .= ' LIMIT ? OFFSET ?';
        }

        $args = 0;
        $stmt = $this->cache->get($query);
        if($hasCategoryInfo) {
            if(is_array($categoryInfo)) {
                foreach($categoryInfo as $categoryInfoEntry)
                    $stmt->addParameter(++$args, $categoryInfoEntry instanceof ForumCategoryInfo ? $categoryInfoEntry->getId() : (string)$categoryInfoEntry);
            } else
                $stmt->addParameter(++$args, $categoryInfo);
        }
        if($hasTopicInfo)
            $stmt->addParameter(++$args, $topicInfo);
        if($hasUserInfo)
            $stmt->addParameter(++$args, $userInfo);
        if($hasUpToPostInfo)
            $stmt->addParameter(++$args, $upToPostInfo);
        if($hasAfterPostId)
            $stmt->addParameter(++$args, $afterPostId);
        if($hasSearchQuery)
            $stmt->addParameter(++$args, $searchQuery);
        if($hasPagination) {
            $stmt->addParameter(++$args, $pagination->getRange());
            $stmt->addParameter(++$args, $pagination->getOffset());
        }
        $stmt->execute();

        $result = $stmt->getResult();
        $posts = [];

        while($result->next())
            $posts[] = new ForumPostInfo($result);

        return $posts;
    }

    public function getPost(
        ?string $postId = null,
        ForumTopicInfo|string|null $topicInfo = null,
        ForumCategoryInfo|string|array|null $categoryInfos = null,
        UserInfo|string|null $userInfo = null,
        bool $getLast = false,
        ?bool $deleted = null
    ): ForumPostInfo {
        $hasPostId = $postId !== null;
        $hasTopicInfo = $topicInfo !== null;
        $hasCategoryInfos = $categoryInfos !== null;
        $hasUserInfo = $userInfo !== null;
        $hasDeleted = $deleted !== null;

        if(!$hasPostId && !$hasTopicInfo && !$hasCategoryInfos && !$hasUserInfo)
            throw new InvalidArgumentException('At least one of the four first arguments must be specified.');

        $values = [];
        $query = 'SELECT post_id, topic_id, forum_id, user_id, INET6_NTOA(post_ip), post_text, post_parse, post_display_signature, UNIX_TIMESTAMP(post_created), UNIX_TIMESTAMP(post_edited), UNIX_TIMESTAMP(post_deleted) FROM msz_forum_posts';
        if($hasPostId) {
            $query .= ' WHERE post_id = ?';
            $values[] = $postId;
        } elseif($hasUserInfo) {
            $query .= ' WHERE user_id = ?';
            $values[] = $userInfo instanceof UserInfo ? $userInfo->getId() : $userInfo;
            $query .= sprintf(' ORDER BY post_id %s', $getLast ? 'DESC' : 'ASC');
        } elseif($hasTopicInfo) {
            if($topicInfo instanceof ForumTopicInfo)
                $topicInfo = $topicInfo->getId();

            $query .= sprintf(' WHERE post_id = (SELECT %s(post_id) FROM msz_forum_posts WHERE topic_id = ?', $getLast ? 'MAX' : 'MIN');
            if($hasDeleted)
                $query .= sprintf(' AND post_deleted %s NULL', $deleted ? 'IS NOT' : 'IS');
            $query .= ')';

            $values[] = $topicInfo;
        } elseif($hasCategoryInfos) {
            if(!is_array($categoryInfos))
                $categoryInfos = [$categoryInfos];

            $query .= sprintf(
                ' WHERE post_id = (SELECT %s(post_id) FROM msz_forum_posts WHERE forum_id IN (%s)',
                $getLast ? 'MAX' : 'MIN',
                DbTools::prepareListString($categoryInfos)
            );
            if($hasDeleted)
                $query .= sprintf(' AND post_deleted %s NULL', $deleted ? 'IS NOT' : 'IS');
            $query .= ')';

            foreach($categoryInfos as $categoryInfo) {
                if($categoryInfo instanceof ForumCategoryInfo)
                    $values[] = $categoryInfo->getId();
                elseif(is_string($categoryInfo) || is_int($categoryInfo))
                    $values[] = (string)$categoryInfo;
                else
                    throw new InvalidArgumentException('$categoryInfos contains an invalid item.');
            }
        }

        $args = 0;
        $stmt = $this->cache->get($query);
        foreach($values as $value)
            $stmt->addParameter(++$args, $value);
        $stmt->execute();

        $result = $stmt->getResult();
        if(!$result->next())
            throw new RuntimeException('Forum post not found.');

        return new ForumPostInfo($result);
    }

    public function createPost(
        ForumTopicInfo|string $topicInfo,
        UserInfo|string|null $userInfo,
        IPAddress|string $remoteAddr,
        string $body,
        int $bodyParser,
        bool $displaySignature,
        ForumCategoryInfo|string|null $categoryInfo = null
    ): ForumPostInfo {
        if($categoryInfo instanceof ForumCategoryInfo)
            $categoryInfo = $categoryInfo->getId();

        if($topicInfo instanceof ForumTopicInfo) {
            $categoryInfo ??= $topicInfo->getCategoryId();
            $topicInfo = $topicInfo->getId();
        } elseif($categoryInfo === null)
            throw new InvalidArgumentException('$categoryInfo may only be null if $topicInfo is an instance of ForumTopicInfo.');

        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();

        if($remoteAddr instanceof IPAddress)
            $remoteAddr = (string)$remoteAddr;

        $stmt = $this->cache->get('INSERT INTO msz_forum_posts (topic_id, forum_id, user_id, post_ip, post_text, post_parse, post_display_signature) VALUES (?, ?, ?, INET6_ATON(?), ?, ?, ?)');
        $stmt->addParameter(1, $topicInfo);
        $stmt->addParameter(2, $categoryInfo);
        $stmt->addParameter(3, $userInfo);
        $stmt->addParameter(4, $remoteAddr);
        $stmt->addParameter(5, $body);
        $stmt->addParameter(6, $bodyParser);
        $stmt->addParameter(7, $displaySignature ? 1 : 0);
        $stmt->execute();

        return $this->getPost(postId: (string)$this->dbConn->getLastInsertId());
    }

    public function updatePost(
        ForumPostInfo|string $postInfo,
        IPAddress|string|null $remoteAddr = null,
        ?string $body = null,
        ?int $bodyParser = null,
        ?bool $displaySignature = null,
        bool $bumpEdited = true
    ): void {
        if($postInfo instanceof ForumPostInfo)
            $postInfo = $postInfo->getId();

        $fields = [];
        $values = [];

        if($remoteAddr !== null) {
            if($remoteAddr instanceof IPAddress)
                $remoteAddr = (string)$remoteAddr;

            $fields[] = 'post_ip = INET6_ATON(?)';
            $values[] = $remoteAddr;
        }

        if($body !== null) {
            $fields[] = 'post_text = ?';
            $values[] = $body;
        }

        if($bodyParser !== null) {
            $fields[] = 'post_parse = ?';
            $values[] = $bodyParser;
        }

        if($displaySignature !== null) {
            $fields[] = 'post_display_signature = ?';
            $values[] = $displaySignature ? 1 : 0;
        }

        if(empty($fields))
            return;

        if($bumpEdited)
            $fields[] = 'post_edited = NOW()';

        $args = 0;
        $stmt = $this->cache->get(sprintf('UPDATE msz_forum_posts SET %s WHERE post_id = ?', implode(', ', $fields)));
        foreach($values as $value)
            $stmt->addParameter(++$args, $value);
        $stmt->addParameter(++$args, $postInfo);
        $stmt->execute();
    }

    public function deletePost(ForumPostInfo|string $postInfo): void {
        if($postInfo instanceof ForumPostInfo)
            $postInfo = $postInfo->getId();

        $stmt = $this->cache->get('UPDATE msz_forum_posts SET post_deleted = COALESCE(post_deleted, NOW()) WHERE post_id = ?');
        $stmt->addParameter(1, $postInfo);
        $stmt->execute();
    }

    public function restorePost(ForumPostInfo|string $postInfo): void {
        if($postInfo instanceof ForumPostInfo)
            $postInfo = $postInfo->getId();

        $stmt = $this->cache->get('UPDATE msz_forum_posts SET post_deleted = NULL WHERE post_id = ?');
        $stmt->addParameter(1, $postInfo);
        $stmt->execute();
    }

    public function nukePost(ForumPostInfo|string $postInfo): void {
        if($postInfo instanceof ForumPostInfo)
            $postInfo = $postInfo->getId();

        $stmt = $this->cache->get('DELETE FROM msz_forum_posts WHERE post_id = ?');
        $stmt->addParameter(1, $postInfo);
        $stmt->execute();
    }

    public function getUserLastPostCreatedTime(UserInfo|string $userInfo): int {
        if($userInfo instanceof UserInfo)
            $userInfo = $userInfo->getId();

        // intentionally including deleted posts
        $stmt = $this->cache->get('SELECT UNIX_TIMESTAMP(MAX(post_created)) FROM msz_forum_posts WHERE user_id = ?');
        $stmt->addParameter(1, $userInfo);
        $stmt->execute();

        $result = $stmt->getResult();
        if(!$result->next())
            return 0;

        return $result->getInteger(0);
    }

    public function getUserLastPostCreatedAt(UserInfo|string $userInfo): DateTime {
        return DateTime::fromUnixTimeSeconds($this->getUserLastPostCreatedTime($userInfo));
    }

    public function generatePostRankings(
        int $year = 0,
        int $month = 0,
        array $exceptCategoryInfos = [],
        array $exceptTopicInfos = []
    ): array {
        $hasYear = $year > 0;
        $hasMonth = $hasYear && $month > 0;
        $hasExcludedCategoryInfos = !empty($exceptCategoryInfos);
        $hasExcludedTopicInfos = !empty($exceptTopicInfos);

        $query = 'SELECT user_id, COUNT(*) AS posts_count FROM msz_forum_posts WHERE post_deleted IS NULL';
        if($hasYear)
            $query .= sprintf(
                ' AND DATE(post_created) BETWEEN "%1$04d-%2$02d-01" AND "%1$04d-%3$02d-31"',
                $year,
                $hasMonth ? $month : 1,
                $hasMonth ? $month : 12
            );
        if($hasExcludedCategoryInfos)
            $query .= sprintf(' AND forum_id NOT IN (%s)', DbTools::prepareListString($exceptCategoryInfos));
        if($hasExcludedTopicInfos)
            $query .= sprintf(' AND topic_id NOT IN (%s)', DbTools::prepareListString($exceptTopicInfos));
        $query .= ' GROUP BY user_id HAVING posts_count > 0 ORDER BY posts_count DESC';

        $args = 0;
        $stmt = $this->cache->get($query);
        foreach($exceptCategoryInfos as $exceptCategoryInfo)
            $stmt->addParameter(++$args, $exceptCategoryInfo instanceof ForumCategoryInfo ? $exceptCategoryInfo->getId() : $exceptCategoryInfo);
        foreach($exceptTopicInfos as $exceptTopicInfo)
            $stmt->addParameter(++$args, $exceptTopicInfo instanceof ForumTopicInfo ? $exceptTopicInfo->getId() : $exceptTopicInfo);
        $stmt->execute();

        $result = $stmt->getResult();
        $rankings = [];
        $rankNo = 0;
        $lastPostsCount = PHP_INT_MAX;

        while($result->next()) {
            $rankings[] = $ranking = new stdClass;
            $ranking->userId = $result->getString(0);
            $ranking->postsCount = $result->getInteger(1);

            if($lastPostsCount > $ranking->postsCount) {
                ++$rankNo;
                $lastPostsCount = $ranking->postsCount;
            }

            $ranking->position = $rankNo;
        }

        return $rankings;
    }
}