<?
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");
      if ($Page == 'forums') {
        $URL = site_url() . "forums.php?action=viewthread&postid=$PostID";
      } else {
        $URL = site_url() . "comments.php?action=jump&postid=$PostID";
      }
      NotificationsManager::send_push($UserID, 'New Quote!', 'Quoted by ' . G::$LoggedUser['Username'] . " $URL", $URL, NotificationsManager::QUOTES);
    }
    G::$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);
  }
}
