<?php
/* vim:set tabstop=8 softtabstop=8 shiftwidth=8 noexpandtab: */
/**
 *
 * LICENSE: GNU General Public License, version 2 (GPLv2)
 * Copyright 2001 - 2013 Ampache.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License v2
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

/**
 * Rating class
 *
 * This tracks ratings for songs, albums and artists.
 *
 */
class Rating extends database_object {

	// Public variables
	public $id;		// The ID of the object rated
	public $type;		// The type of object we want

	/**
	 * Constructor
	 * This is run every time a new object is created, and requires
	 * the id and type of object that we need to pull the rating for
	 */
	public function __construct($id, $type) {
		$id = intval($id);
		$type = Dba::escape($type);

		$this->id = $id;
		$this->type = $type;

		return true;

	} // Constructor

	/**
	 * gc
	 *
	 * Remove ratings for items that no longer exist.
	 */
	public static function gc() {
		foreach(array('song', 'album', 'artist', 'video') as $object_type) {
			Dba::write("DELETE FROM `rating` USING `rating` LEFT JOIN `$object_type` ON `$object_type`.`id` = `rating`.`object_type` WHERE `object_type` = '$object_type` AND `$object_type`.`id` IS NULL");
		}
	}

	/**
 	 * build_cache
	 * This attempts to get everything we'll need for this page load in a 
	 * single query, saving on connection overhead
	 */
	public static function build_cache($type, $ids) {

		if (!is_array($ids) OR !count($ids)) { return false; }

		$user_id = intval($GLOBALS['user']->id);
		$ratings = array();
		$user_ratings = array();

		$idlist = '(' . implode(',', $ids) . ')';
		$sql = "SELECT `rating`, `object_id` FROM `rating` " .
			"WHERE `user`='$user_id' AND `object_id` IN $idlist " .
			"AND `object_type`='$type'";
		$db_results = Dba::read($sql);

		while ($row = Dba::fetch_assoc($db_results)) {
			$user_ratings[$row['object_id']] = $row['rating'];
		}

		$sql = "SELECT AVG(`rating`) as `rating`, `object_id` FROM " .
			"`rating` WHERE `object_id` IN $idlist AND " .
			"`object_type`='$type' GROUP BY `object_id`";
		$db_results = Dba::read($sql);

		while ($row = Dba::fetch_assoc($db_results)) {
			$ratings[$row['object_id']] = $row['rating'];
  		}

		foreach ($ids as $id) {
			// First store the user-specific rating
			if (!isset($user_ratings[$id])) {
				$rating = 0;
			}
			else {
				$rating = intval($user_ratings[$id]);
			}
			parent::add_to_cache('rating_' . $type . '_user' . $user_id, $id, $rating);

			// Then store the average
			if (!isset($ratings[$id])) {
				$rating = 0;
			}
			else {
				$rating = round($ratings[$id]['rating'], 1);
			}
			parent::add_to_cache('rating_' . $type . '_all', $id, $rating);
		}

		return true;

	} // build_cache

	/**
	 * get_user_rating
	 * Get a user's rating.  If no userid is passed in, we use the currently
	 * logged in user.
	 */
	 public function get_user_rating($user_id = null) {

		$id = intval($this->id);
		$type = Dba::escape($this->type);
		if (is_null($user_id)) {
			$user_id = $GLOBALS['user']->id;
		}
		$user_id = intval($user_id);
		
		$key = 'rating_' . $type . '_user' . $user_id;
		if (parent::is_cached($key, $id)) {
			return parent::get_from_cache($key, $id);
		}

		$sql = "SELECT `rating` FROM `rating` WHERE `user`='$user_id' ".
			"AND `object_id`='$id' AND `object_type`='$type'";
		$db_results = Dba::read($sql);

		$rating = 0;

		if ($results = Dba::fetch_assoc($db_results)) {
			$rating = $results['rating'];
		}

		parent::add_to_cache($key, $id, $rating);
		return $rating;

	} // get_user_rating

	/**
	 * get_average_rating
	 * Get the floored average rating of what everyone has rated this object
	 * as. This is shown if there is no personal rating.
	 */
	public function get_average_rating() {

		$id = intval($this->id);
		$type = Dba::escape($this->type);

		if (parent::is_cached('rating_' . $type . '_all', $id)) {
			return parent::get_from_cache('rating_' . $type . '_user', $id);
		}

		$sql = "SELECT AVG(`rating`) as `rating` FROM `rating` WHERE " .
			"`object_id`='$id' AND `object_type`='$type'";
		$db_results = Dba::read($sql);

		$results = Dba::fetch_assoc($db_results);
		
		parent::add_to_cache('rating_' . $type . '_all', $id, $results['rating']);
		return $results['rating'];

	} // get_average_rating

	/**
	 * set_rating
	 * This function sets the rating for the current object.
	 * If no userid is passed in, we use the currently logged in user.
	 */
	public function set_rating($rating, $user_id = null) {
		$id = intval($this->id);
		$type = Dba::escape($this->type);
		$rating = intval($rating);
		if (is_null($user_id)) {
			$user_id = $GLOBALS['user']->id;
		}
		$user_id = intval($user_id);

		debug_event('Rating', "Setting rating for $type $id to $rating", 5);

		// If score is -1, then remove rating
		if ($rating == '-1') {
			$sql = "DELETE FROM `rating` WHERE " .
				"`object_id`='$this->id' AND " .
				"`object_type`='$this->type' AND " .
				"`user`='$user_id'";
		}
		else {
			$sql = "REPLACE INTO `rating` " .
			"(`object_id`, `object_type`, `rating`, `user`) " .
			"VALUES ('$id', '$type', '$rating', '$user_id')";
		}
		$db_results = Dba::write($sql);

		parent::add_to_cache('rating_' . $type . '_user' . $user_id, $id, $rating);

		foreach (Plugin::get_plugins('save_rating') as $plugin_name) {
			$plugin = new Plugin($plugin_name);
			if ($plugin->load()) {
				$plugin->_plugin->save_rating($this, $rating);
			}
		}

		return true;

	} // set_rating

	/**
	 * show
	 * This takes an id and a type and displays the rating if ratings are 
	 * enabled.  If $static is true, the rating won't be editable.
	 */
	public static function show($object_id, $type, $static=false) {

		// If ratings aren't enabled don't do anything
		if (!Config::get('ratings')) { return false; }

		$rating = new Rating($object_id, $type);

		if ($static) {
			require Config::get('prefix') . '/templates/show_static_object_rating.inc.php';
		}
		else {
			require Config::get('prefix') . '/templates/show_object_rating.inc.php';
		}

	} // show

} //end rating class
?>