<?php
/*
 * Gallery - a web based photo album viewer and editor
 * Copyright (C) 2000-2007 Bharat Mediratta
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or (at
 * your option) any later version.
 *
 * 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., 51 Franklin Street - Fifth Floor, Boston, MA  02110-1301, USA.
 */

/**
 * Retrieves information for ratings.
 * @package Rating
 * @subpackage Classes
 * @author  Don Seiler <don@seiler.us>
 * @version $Revision: 15513 $
 * @static
 */
class RatingHelper {

    /**
     * Return the average rating of the given itemId
     *
     * @param int $itemIds GalleryItem id
     * @param int $userId User id to fetch rating of
     * @return array object GalleryStatus a status code
     *               array  double  latest average rating
     *                      int     count of total ratings
     */
    function fetchRatings($itemIds, $userId) {
	global $gallery;

	list ($ret, $searchResults) = GalleryCoreApi::getMapEntry('RatingCacheMap',
	    array('itemId', 'averageRating', 'voteCount'),
	    array('itemId' => $itemIds));
	if ($ret) {
	    return array($ret, null);
	}

	$data = array();
	while ($result = $searchResults->nextResult()) {
	    $rating = $result[1] / 1000;
	    $data[(int)$result[0]] = array('itemId' => (int)$result[0],
		    'rating' => GalleryUtilities::roundToString($rating, 3),
		    'votes' => (int)$result[2],
		    'averagePercent' => GalleryUtilities::roundToString(($rating * 100 / 5), 3),
		    'stars' => round($rating * 2)
		    );

	    if ($rating == 0) {
		$data[(int)$result[0]]['stars'] = 1;
	    }
	}

	/* Set defaults if a requested ID isn't found. */
	foreach ($itemIds as $itemId) {
	    if (!isset($data[$itemId])) {
		$data[$itemId] = array('itemId' => $itemId, 'rating' => 0, 'votes' => 0,
				       'userRating' => 'N/A', 'userStars' => 0, 'stars' => 0,
				       'averagePercent' => 0);
	    }
	}

	/* Check for existing votes from this user! */
	$session =& $gallery->getSession();
	/*
	 * If the user doesn't have a persistent session yet, it's a guest user without a session
	 * and since we create a persistent session when a guest rates, we know that this guest
	 * user hasn't rated any item yet
	 */
	if ($session->isPersistent()) {
	    $searchParams = array('itemId' => $itemIds, 'userId' => (int)$userId);

	    /* Handle extra checks for anonymous users */
	    list ($ret, $isAnonymous) = GalleryCoreApi::isAnonymousUser($userId);
	    if ($ret) {
		return array($ret, null);
	    }
	    if ($isAnonymous) {
		$sessionId = $session->getId();
		$remoteId = $session->getRemoteIdentifier();
		$searchParams['sessionId'] = $sessionId;
		$searchParams['remoteIdentifier'] = implode(':', $remoteId);
	    }

	    list ($ret, $searchResults) = GalleryCoreApi::getMapEntry('RatingMap',
		array('itemId', 'rating'), $searchParams);
	    if ($ret) {
		return array($ret, null);
	    }

	    while ($result = $searchResults->nextResult()) {
		if (isset($data[$result[0]])) {
		    $data[(int)$result[0]]['userRating'] = (int)$result[1];
		    $data[(int)$result[0]]['userStars'] = round((int)$result[1] * 2);
		} else {
		    $data[(int)$result[0]]['userRating'] = 'N/A';
		    $data[(int)$result[0]]['userStars'] = 0;
		}
	    }
	}

	return array(null, $data);
    }

    /**
     * Sets rating in database, returns new ratings.
     *
     * @param int $itemId GalleryItem id
     * @param int $rating Rating score
     * @param int $userId
     * @return array object GalleryStatus a status code
     *               array  double  new avg rating for itemId
     *                      int     total votes for itemId
     */
    function rateItem($itemId, $rating, $userId) {
	global $gallery;

	/* Make sure the user isn't a search engine crawler */
	$botId = GalleryUtilities::identifySearchEngine();
	if (isset($botId)) {
	    return array(null, null);
	}

	/* Make sure the item really exists */
	list ($ret, $entity) = GalleryCoreApi::loadEntitiesById($itemId);
	if ($ret) {
	    return array($ret, null);
	}

	/* Use this to get new IDs and check affected rows for updates */
	$storage = $gallery->getStorage();

	$session =& $gallery->getSession();
	if (!$session->isPersistent()) {
	    /*
	     * To show what this user has rated we need a persistent session
	     * Add some session data to force the creation of a persistent session (sends a cookie)
	     */
	    $session->put('rating', 1);
	    $ret = $session->start();
	    if ($ret) {
		return array($ret, null);
	    }
	}

	$sessionId = $session->getId();
	$remoteId = $session->getRemoteIdentifier();

	/* Handle extra checks for anonymous users */
	list ($ret, $isAnonymous) = GalleryCoreApi::isAnonymousUser($userId);
	if ($ret) {
	    return array($ret, null);
	}

	/* Update existing user vote for this item */
	$matchParams = array(	'itemId' => (int)$itemId,
				'userId' => (int)$userId);
	if ($isAnonymous) {
	    $matchParams['sessionId'] = $sessionId;
	    $matchParams['remoteIdentifier'] = implode(':', $remoteId);
	}

	$ret = GalleryCoreApi::removeMapEntry('RatingMap', $matchParams);
	if ($ret) {
	    return array($ret, null);
	}

	/* Insert record */
	list ($ret, $ratingId) = $storage->getUniqueId();
	if ($ret) {
	    return array($ret, null);
	}

	$ret = GalleryCoreApi::addMapEntry('RatingMap',
	    array(  'ratingId' => $ratingId,
		    'itemId' => $itemId,
		    'userId' => $userId,
		    'rating' => $rating,
		    'sessionId' => $sessionId,
		    'remoteIdentifier' => implode(':', $remoteId) ));
	if ($ret) {
	    return array($ret, null);
	}

	/* Compute average and update cache table */
	list ($ret, $avg) = $storage->getFunctionSql('AVG', array('[RatingMap::rating]'));
	if ($ret) {
	    return array($ret, null);
	}
	$query = '
	    SELECT
	    ' . $avg . ',
	    COUNT([RatingMap::rating])
		FROM
		[RatingMap]
		WHERE
		[RatingMap::itemId] = ?
	';
	list ($ret, $searchResults) = $gallery->search($query, array((int)$itemId));
	if ($ret) {
	    return array($ret, null);
	}

	$data = array();
	if ($searchResults->resultCount() > 0) {
	    /* Update cache */
	    $result = $searchResults->nextResult();
	    $averageRating = round($result[0], 3)*1000;
	    $voteCount = $result[1];

	    $ret = GalleryCoreApi::removeMapEntry('RatingCacheMap', array('itemId' => $itemId));
	    if ($ret) {
		return array($ret, null);
	    }

	    $ret = GalleryCoreApi::addMapEntry('RatingCacheMap',
			array(  'itemId' => $itemId,
				'averageRating' => $averageRating,
				'voteCount' => $voteCount));
	    if ($ret) {
		return array($ret, null);
	    }

	    $data['itemId'] = (int)$itemId;
	    $data['rating'] = $averageRating / 1000;
	    $data['votes'] = (int)$voteCount;
	    $data['userRating'] = (int)$rating;
	}

	return array(null, $data);
    }
}
?>