<?php
/**
 * Kunena Component
 * @package Kunena.Framework
 * @subpackage Forum.Topic.User
 *
 * @copyright (C) 2008 - 2014 Kunena Team. All rights reserved.
 * @license http://www.gnu.org/copyleft/gpl.html GNU/GPL
 * @link http://www.kunena.org
 **/
defined ( '_JEXEC' ) or die ();

/**
 * Kunena Forum Topic User Helper Class
 */
abstract class KunenaForumTopicUserHelper {
	/**
	 * @var array|KunenaForumTopicUser[]
	 */
	protected static $_instances = array();
	/**
	 * @var array|KunenaForumTopicUser[]
	 */
	protected static $_topics = array();

	/**
	 * Returns KunenaForumTopicUser object.
	 *
	 * @param KunenaForumTopic|int|null $topic
	 * @param mixed $user
	 * @param bool $reload
	 *
	 * @return KunenaForumTopicUser
	 */
	static public function get($topic = null, $user = null, $reload = false) {
		if ($topic instanceof KunenaForumTopic) {
			$topic = $topic->id;
		}
		$topic = intval ( $topic );
		$user = KunenaUserHelper::get($user);

		if ($topic < 1)
			return new KunenaForumTopicUser (null, $user);

		if ($reload || empty ( self::$_instances [$user->userid][$topic] )) {
			$topics = self::getTopics ( $topic, $user );
			self::$_instances [$user->userid][$topic] = self::$_topics [$topic][$user->userid] = array_pop($topics);
		}

		return self::$_instances [$user->userid][$topic];
	}

	/**
	 * @param bool|array $ids
	 * @param mixed $user
	 *
	 * @return KunenaForumTopicUser[]
	 */
	static public function getTopics($ids = false, $user=null) {
		$user = KunenaUserHelper::get($user);
		if ($ids === false) {
			return isset(self::$_instances[$user->userid]) ? self::$_instances[$user->userid] : array();
		} elseif (!is_array ($ids) ) {
			$ids = array($ids);
		}
		// Convert topic objects into ids
		foreach ($ids as $i=>$id) {
			if ($id instanceof KunenaForumTopic) $ids[$i] = $id->id;
		}
		$ids = array_unique($ids);
		self::loadTopics($ids, $user);

		$list = array ();
		foreach ( $ids as $id ) {
			if (!empty(self::$_instances [$user->userid][$id])) {
				$list [$id] = self::$_instances [$user->userid][$id];
			}
		}

		return $list;
	}

	/**
	 * Get all user ids who have participated to the given topics.
	 *
	 * @param array|KunenaForumTopic[] $topics
	 * @param string $value  Row to pick up as value.
	 * @return array List of [topic][userid] = value.
	 */
	static public function getUserIds(array $topics, $value = 'user_id') {
		// Convert topic objects into ids
		$ids = array();
		foreach ($topics as $id) {
			if ($id instanceof KunenaForumTopic) $ids[(int) $id->id] = (int) $id->id;
			else $ids[(int) $id] = (int) $id;
		}
		$idlist = implode(',', $ids);

		$db = JFactory::getDbo();
		$query = $db->getQuery(true);
		$query->select('topic_id, user_id')
			->from($db->quoteName('#__kunena_user_topics'))
			->where("topic_id IN ({$idlist})")
			->where('posts>0');

		$query->select($db->quoteName($value));

		$db->setQuery($query);
		$results = (array) $db->loadRowList();
		KunenaError::checkDatabaseError();

		$list = array();
		foreach ($results as $result) {
			$list[$result->topic_id][$result->user_id] = $result->{$value};
		}

		return $list;
	}

	/**
	 * @param KunenaForumTopic $old
	 * @param KunenaForumTopic $new
	 *
	 * @return bool
	 */
	public static function move($old, $new) {
		// Update database
		$db = JFactory::getDBO ();
		$query ="UPDATE #__kunena_user_topics SET topic_id={$db->quote($new->id)}, category_id={$db->quote($new->category_id)} WHERE topic_id={$db->quote($old->id)}";
		$db->setQuery($query);
		$db->execute();
		if (KunenaError::checkDatabaseError ())
			return false;

		// Update internal state
		if (isset(self::$_topics [$old->id])) {
			if ($new->id != $old->id) {
				self::$_topics [$new->id] = self::$_topics [$old->id];
				unset(self::$_topics [$old->id]);
			}
			foreach (self::$_topics [$new->id] as &$instance) {
				$instance->topic_id = $new->id;
				$instance->category_id = $new->category_id;
			}
		}

		return true;
	}

	/**
	 * @param KunenaForumTopic $old
	 * @param KunenaForumTopic $new
	 *
	 * @return bool
	 */
	public static function merge($old, $new) {
		$db = JFactory::getDBO ();

		// Move all user topics which do not exist in new topic
		$queries[] = "UPDATE #__kunena_user_topics AS ut
			INNER JOIN #__kunena_user_topics AS o ON o.user_id = ut.user_id
			SET ut.topic_id={$db->quote($new->id)}, ut.category_id={$db->quote($new->category_id)}
			WHERE o.topic_id={$db->quote($old->id)} AND ut.topic_id IS NULL";

		// Merge user topics information that exists in both topics
		$queries[] = "UPDATE #__kunena_user_topics AS ut
			INNER JOIN #__kunena_user_topics AS o ON o.user_id = ut.user_id
			SET ut.posts = o.posts + ut.posts,
				ut.last_post_id = GREATEST( o.last_post_id, ut.last_post_id ),
				ut.owner = GREATEST( o.owner, ut.owner ),
				ut.favorite = GREATEST( o.favorite, ut.favorite ),
				ut.subscribed = GREATEST( o.subscribed, ut.subscribed )
				WHERE ut.topic_id = {$db->quote($new->id)}
				AND o.topic_id = {$db->quote($old->id)}";

		// Delete all user topics from the shadow topic
		$queries[] = "DELETE FROM #__kunena_user_topics WHERE topic_id={$db->quote($old->id)}";

		foreach ($queries as $query) {
			$db->setQuery($query);
			$db->execute();
			if (KunenaError::checkDatabaseError ())
				return false;
		}

		// Update internal state
		self::reloadTopic($old->id);
		self::reloadTopic($new->id);

		return true;
	}

	/**
	 * Free up memory by cleaning up all cached items.
	 */
	public static function cleanup() {
		self::$_instances = array();
		self::$_topics = array();
	}

	/**
	 * @param bool|array|int $topicids
	 * @param int  $start
	 * @param int  $end
	 *
	 * @return bool|int
	 */
	public static function recount($topicids=false, $start=0, $end=0) {
		$db = JFactory::getDBO ();

		if (is_array($topicids)) {
			$where = 'AND m.thread IN ('.implode(',', $topicids).')';
			$where2 = 'AND ut.topic_id IN ('.implode(',', $topicids).')';
		} elseif ((int)$topicids) {
			$where = 'AND m.thread='.(int)$topicids;
			$where2 = 'AND ut.topic_id='.(int)$topicids;
		} else {
			$where = '';
			$where2 = '';
		}
		if ($end) {
			$where .= " AND (m.thread BETWEEN {$start} AND {$end})";
			$where2 .= " AND (ut.topic_id BETWEEN {$start} AND {$end})";
		}

		// Create missing user topics and update post count and last post if there are posts by that user
		$query ="INSERT INTO #__kunena_user_topics (user_id, topic_id, category_id, posts, last_post_id, owner)
					SELECT m.userid AS user_id, m.thread AS topic_id, m.catid AS category_id, SUM(m.hold=0) AS posts, MAX(IF(m.hold=0,m.id,0)) AS last_post_id, MAX(IF(m.parent=0,1,0)) AS owner
					FROM #__kunena_messages AS m
					WHERE m.userid>0 AND m.moved=0 {$where}
					GROUP BY m.userid, m.thread
				ON DUPLICATE KEY UPDATE category_id=VALUES(category_id), posts=VALUES(posts), last_post_id=VALUES(last_post_id)";
		$db->setQuery($query);
		$db->execute();
		if (KunenaError::checkDatabaseError ())
			return false;
		$rows = $db->getAffectedRows ();

		// Find user topics where last post doesn't exist and reset values in it
		$query ="UPDATE #__kunena_user_topics AS ut
			LEFT JOIN #__kunena_messages AS m ON ut.last_post_id=m.id AND m.hold=0
			SET posts=0, last_post_id=0
			WHERE m.id IS NULL {$where2}";
		$db->setQuery($query);
		$db->execute();
		if (KunenaError::checkDatabaseError ())
			return false;
		$rows += $db->getAffectedRows ();

		// Delete entries that have default values
		$query ="DELETE ut FROM #__kunena_user_topics AS ut WHERE ut.posts=0 AND ut.owner=0 AND ut.favorite=0 AND ut.subscribed=0 AND ut.params='' {$where2}";
		$db->setQuery($query);
		$db->execute();
		if (KunenaError::checkDatabaseError ())
			return false;
		$rows += $db->getAffectedRows ();
		return $rows;
	}

	// Internal functions

	/**
	 * @param array      $ids
	 * @param KunenaUser $user
	 */
	static protected function loadTopics(array $ids, KunenaUser $user) {
		foreach ($ids as $i=>$id) {
			$id = intval($id);
			if (!$id || isset(self::$_instances [$user->userid][$id]))
				unset($ids[$i]);
		}
		if (empty($ids))
			return;

		$idlist = implode(',', $ids);
		$db = JFactory::getDBO ();
		$query = "SELECT * FROM #__kunena_user_topics WHERE user_id={$db->quote($user->userid)} AND topic_id IN ({$idlist})";
		$db->setQuery ( $query );
		$results = (array) $db->loadAssocList ('topic_id');
		KunenaError::checkDatabaseError ();

		foreach ( $ids as $id ) {
			if (isset($results[$id])) {
				$instance = new KunenaForumTopicUser ();
				$instance->bind ( $results[$id] );
				$instance->exists(true);
				self::$_instances [$user->userid][$id] = self::$_topics [$id][$user->userid] = $instance;
			} else {
				self::$_instances [$user->userid][$id] = self::$_topics [$id][$user->userid] = new KunenaForumTopicUser ($id, $user->userid);
			}
		}
		unset ($results);
	}

	/**
	 * @param int $id
	 */
	static protected function reloadTopic($id) {
		if (empty(self::$_topics [$id])) return;

		$idlist = implode(',', array_keys(self::$_topics [$id]));
		$db = JFactory::getDBO ();
		$query = "SELECT * FROM #__kunena_user_topics WHERE user_id IN ({$idlist}) AND topic_id={$id}";
		$db->setQuery ( $query );
		$results = (array) $db->loadAssocList ('user_id');
		KunenaError::checkDatabaseError ();

		// TODO: Is there a bug?
		foreach (self::$_topics[$id] as $instance) {
			if (isset($results[$instance->user_id])) {
				$instance->bind ( $results[$instance->user_id] );
				$instance->exists(true);
			} else {
				$instance->reset();
			}
		}
		unset ($results);
	}
}
