<?php
namespace Misuzu\Forum;

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

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

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

    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,
        ForumPostInfo|string|null $afterPostInfo = null,
        ?int $newerThanDays = null,
        ?array $searchQuery = null,
        ?bool $deleted = null,
        ?Pagination $pagination = null
    ): iterable {
        // remove this hack when search server
        $hasSearchQuery = $searchQuery !== null;
        $doSearchOrder = false;
        if($hasSearchQuery) {
            if(!empty($searchQuery['type'])
                && $searchQuery['type'] !== 'forum'
                && $searchQuery['type'] !== 'forum:post')
                return [];

            $userInfo = null;
            $deleted = false;
            $pagination = null;
            $doSearchOrder = true;
            $afterPostInfo = null;
            $newerThanDays = null;

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

            if(!empty($searchQuery['after']))
                $afterPostInfo = $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 = $upToPostInfo->getId();
        if($afterPostInfo instanceof ForumPostInfo)
            $afterPostInfo = $afterPostInfo->getId();

        $hasCategoryInfo = $categoryInfo !== null;
        $hasTopicInfo = $topicInfo !== null;
        $hasUserInfo = $userInfo !== null;
        $hasUpToPostInfo = $upToPostInfo !== null;
        $hasAfterPostInfo = $afterPostInfo !== null;
        $hasNewerThanDays = $newerThanDays !== 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($hasAfterPostInfo)
            $query .= sprintf(' %s post_id > ?', ++$args > 1 ? 'AND' : 'WHERE');
        if($hasNewerThanDays)
            $query .= sprintf(' %s post_created > NOW() - INTERVAL ? DAY', ++$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, $upToPostInfo);
        if($hasAfterPostInfo)
            $stmt->addParameter(++$args, $afterPostInfo);
        if($hasNewerThanDays)
            $stmt->addParameter(++$args, $newerThanDays);
        if($hasSearchQuery)
            $stmt->addParameter(++$args, $searchQuery);
        if($hasPagination) {
            $stmt->addParameter(++$args, $pagination->getRange());
            $stmt->addParameter(++$args, $pagination->getOffset());
        }
        $stmt->execute();

        return $stmt->getResult()->getIterator(ForumPostInfo::fromResult(...));
    }

    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 ForumPostInfo::fromResult($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;
    }
}