<?
class Subscriptions {
	/**
	 * Parse a post/comment body for quotes and notify all quoted users that have quote notifications enabled.
	 * @param string $Body
	 * @param int $PostID
	 * @param string $Page
	 * @param int $PageID
	 */
	public static function quote_notify($Body, $PostID, $Page, $PageID) {
		$QueryID = G::$DB->get_query_id();
		/*
		 * Explanation of the parameters PageID and Page: Page contains where
		 * this quote comes from and can be forums, artist, collages, requests
		 * or torrents. The PageID contains the additional value that is
		 * necessary for the users_notify_quoted table. The PageIDs for the
		 * different Page are: forums: TopicID artist: ArtistID collages:
		 * CollageID requests: RequestID torrents: GroupID
		 */
		$Matches = array();
		preg_match_all('/\[quote(?:=(.*)(?:\|.*)?)?]|\[\/quote]/iU', $Body, $Matches, PREG_SET_ORDER);

		if (count($Matches)) {
			$Usernames = array();
			$Level = 0;
			foreach ($Matches as $M) {
				if ($M[0] != '[/quote]') {
					if ($Level == 0 && isset($M[1]) && strlen($M[1]) > 0 && preg_match(USERNAME_REGEX, $M[1])) {
						$Usernames[] = preg_replace('/(^[.,]*)|([.,]*$)/', '', $M[1]); // wut?
					}
					++$Level;
				} else {
					--$Level;
				}
			}
		}
		// remove any dupes in the array (the fast way)
		$Usernames = array_flip(array_flip($Usernames));


		G::$DB->query("
			SELECT m.ID
			FROM users_main AS m
				LEFT JOIN users_info AS i ON i.UserID = m.ID
			WHERE m.Username IN ('" . implode("', '", $Usernames) . "')
				AND i.NotifyOnQuote = '1'
				AND i.UserID != " . G::$LoggedUser['ID']);


		$Results = G::$DB->to_array();
		foreach ($Results as $Result) {
			$UserID = db_string($Result['ID']);
			$QuoterID = db_string(G::$LoggedUser['ID']);
			$Page = db_string($Page);
			$PageID = db_string($PageID);
			$PostID = db_string($PostID);

			G::$DB->query("
				INSERT IGNORE INTO users_notify_quoted
					(UserID, QuoterID, Page, PageID, PostID, Date)
				VALUES
					('$UserID', '$QuoterID', '$Page', '$PageID', '$PostID', '" . sqltime() . "')");
			G::$Cache->delete_value("notify_quoted_$UserID");

		}
		G::$DB->set_query_id($QueryID);
	}

	/**
	 * (Un)subscribe from a forum thread.
	 * If UserID == 0, G::$LoggedUser[ID] is used
	 * @param int $TopicID
	 * @param int $UserID
	 */
	public static function subscribe($TopicID, $UserID = 0) {
		if ($UserID == 0) {
			$UserID = G::$LoggedUser['ID'];
		}
		$QueryID = G::$DB->get_query_id();
		$UserSubscriptions = self::get_subscriptions();
		$Key = self::has_subscribed($TopicID);
		if ($Key !== false) {
			G::$DB->query('
				DELETE FROM users_subscriptions
				WHERE UserID = ' . db_string($UserID) . '
					AND TopicID = ' . db_string($TopicID));
			unset($UserSubscriptions[$Key]);
		} else {
			G::$DB->query("
				INSERT IGNORE INTO users_subscriptions (UserID, TopicID)
				VALUES ($UserID, " . db_string($TopicID) . ")");
			array_push($UserSubscriptions, $TopicID);
		}
		G::$Cache->replace_value("subscriptions_user_$UserID", $UserSubscriptions, 0);
		G::$Cache->delete_value("subscriptions_user_new_$UserID");
		G::$DB->set_query_id($QueryID);
	}

	/**
	 * (Un)subscribe from comments.
	 * If UserID == 0, G::$LoggedUser[ID] is used
	 * @param string $Page 'artist', 'collages', 'requests' or 'torrents'
	 * @param int $PageID ArtistID, CollageID, RequestID or GroupID
	 * @param int $UserID
	 */
	public static function subscribe_comments($Page, $PageID, $UserID = 0) {
		if ($UserID == 0) {
			$UserID = G::$LoggedUser['ID'];
		}
		$QueryID = G::$DB->get_query_id();
		$UserCommentSubscriptions = self::get_comment_subscriptions();
		$Key = self::has_subscribed_comments($Page, $PageID);
		if ($Key !== false) {
			G::$DB->query("
				DELETE FROM users_subscriptions_comments
				WHERE UserID = " . db_string($UserID) . "
					AND Page = '" . db_string($Page) . "'
					AND PageID = " . db_string($PageID));
			unset($UserCommentSubscriptions[$Key]);
		} else {
			G::$DB->query("
				INSERT IGNORE INTO users_subscriptions_comments
					(UserID, Page, PageID)
				VALUES
					($UserID, '" . db_string($Page) . "', " . db_string($PageID) . ")");
			array_push($UserCommentSubscriptions, array($Page, $PageID));
		}
		G::$Cache->replace_value("subscriptions_comments_user_$UserID", $UserCommentSubscriptions, 0);
		G::$Cache->delete_value("subscriptions_comments_user_new_$UserID");
		G::$DB->set_query_id($QueryID);
	}

	/**
	 * Read $UserID's subscriptions. If the cache key isn't set, it gets filled.
	 * If UserID == 0, G::$LoggedUser[ID] is used
	 * @param int $UserID
	 * @return array Array of TopicIDs
	 */
	public static function get_subscriptions($UserID = 0) {
		if ($UserID == 0) {
			$UserID = G::$LoggedUser['ID'];
		}
		$QueryID = G::$DB->get_query_id();
		$UserSubscriptions = G::$Cache->get_value("subscriptions_user_$UserID");
		if ($UserSubscriptions === false) {
			G::$DB->query('
				SELECT TopicID
				FROM users_subscriptions
				WHERE UserID = ' . db_string($UserID));
			$UserSubscriptions = G::$DB->collect(0);
			G::$Cache->cache_value("subscriptions_user_$UserID", $UserSubscriptions, 0);
		}
		G::$DB->set_query_id($QueryID);
		return $UserSubscriptions;
	}

	/**
	 * Same as self::get_subscriptions, but for comment subscriptions
	 * @param int $UserID
	 * @return array Array of ($Page, $PageID)
	 */
	public static function get_comment_subscriptions($UserID = 0) {
		if ($UserID == 0) {
			$UserID = G::$LoggedUser['ID'];
		}
		$QueryID = G::$DB->get_query_id();
		$UserCommentSubscriptions = G::$Cache->get_value("subscriptions_comments_user_$UserID");
		if ($UserCommentSubscriptions === false) {
			G::$DB->query('
				SELECT Page, PageID
				FROM users_subscriptions_comments
				WHERE UserID = ' . db_string($UserID));
			$UserCommentSubscriptions = G::$DB->to_array(false, MYSQLI_NUM);
			G::$Cache->cache_value("subscriptions_comments_user_$UserID", $UserCommentSubscriptions, 0);
		}
		G::$DB->set_query_id($QueryID);
		return $UserCommentSubscriptions;
	}

	/**
	 * Returns whether or not the current user has new subscriptions. This handles both forum and comment subscriptions.
	 * @return int Number of unread subscribed threads/comments
	 */
	public static function has_new_subscriptions() {
		$QueryID = G::$DB->get_query_id();

		$NewSubscriptions = G::$Cache->get_value('subscriptions_user_new_' . G::$LoggedUser['ID']);
		if ($NewSubscriptions === false) {
			// forum subscriptions
			G::$DB->query("
					SELECT COUNT(1)
					FROM users_subscriptions AS s
						LEFT JOIN forums_last_read_topics AS l ON l.UserID = s.UserID AND l.TopicID = s.TopicID
						JOIN forums_topics AS t ON t.ID = s.TopicID
						JOIN forums AS f ON f.ID = t.ForumID
					WHERE " . Forums::user_forums_sql() . "
						AND IF(t.IsLocked = '1' AND t.IsSticky = '0'" . ", t.LastPostID, IF(l.PostID IS NULL, 0, l.PostID)) < t.LastPostID
						AND s.UserID = " . G::$LoggedUser['ID']);
			list($NewForumSubscriptions) = G::$DB->next_record();

			// comment subscriptions
			G::$DB->query("
					SELECT COUNT(1)
					FROM users_subscriptions_comments AS s
						LEFT JOIN users_comments_last_read AS lr ON lr.UserID = s.UserID AND lr.Page = s.Page AND lr.PageID = s.PageID
						LEFT JOIN comments AS c ON c.ID = (SELECT MAX(ID) FROM comments WHERE Page = s.Page AND PageID = s.PageID)
						LEFT JOIN collages AS co ON s.Page = 'collages' AND co.ID = s.PageID
					WHERE s.UserID = " . G::$LoggedUser['ID'] . "
						AND (s.Page != 'collages' OR co.Deleted = '0')
						AND IF(lr.PostID IS NULL, 0, lr.PostID) < c.ID");
			list($NewCommentSubscriptions) = G::$DB->next_record();

			$NewSubscriptions = $NewForumSubscriptions + $NewCommentSubscriptions;
			G::$Cache->cache_value('subscriptions_user_new_' . G::$LoggedUser['ID'], $NewSubscriptions, 0);
		}
		G::$DB->set_query_id($QueryID);
		return (int)$NewSubscriptions;
	}

	/**
	 * Returns whether or not the current user has new quote notifications.
	 * @return int Number of unread quote notifications
	 */
	public static function has_new_quote_notifications() {
		$QuoteNotificationsCount = G::$Cache->get_value('notify_quoted_' . G::$LoggedUser['ID']);
		if ($QuoteNotificationsCount === false) {
			$sql = "
				SELECT COUNT(1)
				FROM users_notify_quoted AS q
					LEFT JOIN forums_topics AS t ON t.ID = q.PageID
					LEFT JOIN forums AS f ON f.ID = t.ForumID
					LEFT JOIN collages AS c ON q.Page = 'collages' AND c.ID = q.PageID
				WHERE q.UserID = " . G::$LoggedUser['ID'] . "
					AND q.UnRead
					AND (q.Page != 'forums' OR " . Forums::user_forums_sql() . ")
					AND (q.Page != 'collages' OR c.Deleted = '0')";
			$QueryID = G::$DB->get_query_id();
			G::$DB->query($sql);
			list($QuoteNotificationsCount) = G::$DB->next_record();
			G::$DB->set_query_id($QueryID);
			G::$Cache->cache_value('notify_quoted_' . G::$LoggedUser['ID'], $QuoteNotificationsCount, 0);
		}
		return (int)$QuoteNotificationsCount;
	}

	/**
	 * Returns the key which holds this $TopicID in the subscription array.
	 * Use type-aware comparison operators with this! (ie. if (self::has_subscribed($TopicID) !== false) { ... })
	 * @param int $TopicID
	 * @return bool|int
	 */
	public static function has_subscribed($TopicID) {
		$UserSubscriptions = self::get_subscriptions();
		return array_search($TopicID, $UserSubscriptions);
	}

	/**
	 * Same as has_subscribed, but for comment subscriptions.
	 * @param string $Page 'artist', 'collages', 'requests' or 'torrents'
	 * @param int $PageID
	 * @return bool|int
	 */
	public static function has_subscribed_comments($Page, $PageID) {
		$UserCommentSubscriptions = self::get_comment_subscriptions();
		return array_search(array($Page, $PageID), $UserCommentSubscriptions);
	}

	/**
	 * Clear the subscription cache for all subscribers of a forum thread or artist/collage/request/torrent comments.
	 * @param type $Page 'forums', 'artist', 'collages', 'requests' or 'torrents'
	 * @param type $PageID TopicID, ArtistID, CollageID, RequestID or GroupID, respectively
	 */
	public static function flush_subscriptions($Page, $PageID) {
		$QueryID = G::$DB->get_query_id();
		if ($Page == 'forums') {
			G::$DB->query("
				SELECT UserID
				FROM users_subscriptions
				WHERE TopicID = '$PageID'");
		} else {
			G::$DB->query("
				SELECT UserID
				FROM users_subscriptions_comments
				WHERE Page = '$Page'
					AND PageID = '$PageID'");
		}
		$Subscribers = G::$DB->collect('UserID');
		foreach ($Subscribers as $Subscriber) {
			G::$Cache->delete_value("subscriptions_user_new_$Subscriber");
		}
		G::$DB->set_query_id($QueryID);
	}

	/**
	 * Move all $Page subscriptions from $OldPageID to $NewPageID (for example when merging torrent groups).
	 * Passing $NewPageID = null will delete the subscriptions.
	 * @param string $Page 'forums', 'artist', 'collages', 'requests' or 'torrents'
	 * @param int $OldPageID TopicID, ArtistID, CollageID, RequestID or GroupID, respectively
	 * @param int|null $NewPageID As $OldPageID, or null to delete the subscriptions
	 */
	public static function move_subscriptions($Page, $OldPageID, $NewPageID) {
		self::flush_subscriptions($Page, $OldPageID);
		$QueryID = G::$DB->get_query_id();
		if ($Page == 'forums') {
			if ($NewPageID !== null) {
				G::$DB->query("
					UPDATE IGNORE users_subscriptions
					SET TopicID = '$NewPageID'
					WHERE TopicID = '$OldPageID'");
				// explanation see below
				G::$DB->query("
					UPDATE IGNORE forums_last_read_topics
					SET TopicID = $NewPageID
					WHERE TopicID = $OldPageID");
				G::$DB->query("
					SELECT UserID, MIN(PostID)
					FROM forums_last_read_topics
					WHERE TopicID IN ($OldPageID, $NewPageID)
					GROUP BY UserID
					HAVING COUNT(1) = 2");
				$Results = G::$DB->to_array(false, MYSQLI_NUM);
				foreach ($Results as $Result) {
					G::$DB->query("
						UPDATE forums_last_read_topics
						SET PostID = $Result[1]
						WHERE TopicID = $NewPageID
							AND UserID = $Result[0]");
				}
			}
			G::$DB->query("
				DELETE FROM users_subscriptions
				WHERE TopicID = '$OldPageID'");
			G::$DB->query("
				DELETE FROM forums_last_read_topics
				WHERE TopicID = $OldPageID");
		} else {
			if ($NewPageID !== null) {
				G::$DB->query("
					UPDATE IGNORE users_subscriptions_comments
					SET PageID = '$NewPageID'
					WHERE Page = '$Page'
						AND PageID = '$OldPageID'");
				// last read handling
				// 1) update all rows that have no key collisions (i.e. users that haven't previously read both pages or if there are only comments on one page)
				G::$DB->query("
					UPDATE IGNORE users_comments_last_read
					SET PageID = '$NewPageID'
					WHERE Page = '$Page'
						AND PageID = $OldPageID");
				// 2) get all last read records with key collisions (i.e. there are records for one user for both PageIDs)
				G::$DB->query("
					SELECT UserID, MIN(PostID)
					FROM users_comments_last_read
					WHERE Page = '$Page'
						AND PageID IN ($OldPageID, $NewPageID)
					GROUP BY UserID
					HAVING COUNT(1) = 2");
				$Results = G::$DB->to_array(false, MYSQLI_NUM);
				// 3) update rows for those people found in 2) to the earlier post
				foreach ($Results as $Result) {
					G::$DB->query("
						UPDATE users_comments_last_read
						SET PostID = $Result[1]
						WHERE Page = '$Page'
							AND PageID = $NewPageID
							AND UserID = $Result[0]");
				}
			}
			G::$DB->query("
				DELETE FROM users_subscriptions_comments
				WHERE Page = '$Page'
					AND PageID = '$OldPageID'");
			G::$DB->query("
				DELETE FROM users_comments_last_read
				WHERE Page = '$Page'
					AND PageID = '$OldPageID'");
		}
		G::$DB->set_query_id($QueryID);
	}

	/**
	 * Clear the quote notification cache for all subscribers of a forum thread or artist/collage/request/torrent comments.
	 * @param string $Page 'forums', 'artist', 'collages', 'requests' or 'torrents'
	 * @param int $PageID TopicID, ArtistID, CollageID, RequestID or GroupID, respectively
	 */
	public static function flush_quote_notifications($Page, $PageID) {
		$QueryID = G::$DB->get_query_id();
		G::$DB->query("
			SELECT UserID
			FROM users_notify_quoted
			WHERE Page = '$Page'
				AND PageID = $PageID");
		$Subscribers = G::$DB->collect('UserID');
		foreach ($Subscribers as $Subscriber) {
			G::$Cache->delete_value("notify_quoted_$Subscriber");
		}
		G::$DB->set_query_id($QueryID);
	}
}