<?php
/**
 * Rate everything
 *
 * $Id$
 *
 * @author gERD Schaufelberger <gerd@php-tools.net>
 * @license PHP License
 * @package WB
 * @subpackage db
 */

WBClass::load('WBDatasource_XReference');

/**
 * Rate everything
 *
 * Manage storage of ratings for anything related to other tables. Hence, this allows
 * to comment blog entries as well as users or uploaded files
 *
 * @version 0.1.0
 * @package WB
 * @subpackage db
 */
class WBDatasource_Rate extends WBDatasource_XReference
{
    /**
     * anonymous user
     */
    const GROUP_ANON = '__anonymous';

    /**
     * Session
     * @param
     */
    private $sess;

    /**
     * Simple query
     * @var WBDatasource_SimpleQuery
     */
    private $query;

    /**
     * static constructor
     *
     * Load configuration into static property and merge it with
     * default values.
     */
    static public function staticConstruct()
    {
        $conf = array(
                    'default'       =>  array(
                                            'requiredgroup' =>  self::GROUP_ANON,
                                            'values'        =>  array(1, 2, 3, 4, 5),
                                            'minrates'      =>  5
                                    ),
                    'namespaces'    =>  array()
                    );

        parent::staticConstructLoader($conf, 'rate');
    }

    /**
     * Constructor
     *
     * Call parent's constructor and start session.
     * @param array $parameter
     */
    public function __construct($parameter = array())
    {
        parent::__construct($parameter);
        $this->query    =   WBClass::create('WBDatasource_SimpleQuery');
        $this->sess     =   WBClass::create('patSession');
    }

    /**
     * Add rating for current record
     *
     * Store rating value for selected namespace and xid. The actual rating value must be one of the
     * configured values, Also permissions are checked to prevent ratings from wrong users or
     * duplicates.
     *
     * @param int value
     * @return bool
     */
    public function add($value)
    {
        $data   =   array(
                            'value'                 =>  $value,
                            $this->uPrimary         =>  $this->uid,
                            'namespace'             =>  $this->clause[0]['value'],
                            'xid'                   =>  $this->clause[1]['value'],
                            );

        $values =   self::$conf['namespaces'][$data['namespace']]['values'];
        if (!in_array($value, $values)) {
            return false;
        }

        if (!$this->isAllowed(true)) {
            return false;
        }

        $this->table->save('rating', '__new', $data);
        return true;
    }

    /**
     * Check wheather current use may rate
     *
     * First check in session wheather current record was rated already.
     * If not, access control is check for user according namespace settings.
     * Return true if user may rate, false otherwise.
     *
     * @param bool $updateSess wheather to update in session
     * @return bool
     */
    public function isAllowed($updateSess = false)
    {
        $ns     =   $this->clause[0]['value'];
        $xid    =   $this->clause[1]['value'];
        $rgroup =   self::$conf['namespaces'][$ns]['requiredgroup'];

        // see wheather user already voted in this session
        $sess   =   $this->sess->get(__CLASS__ . ':rated:' . $this->uid);
        if (!is_array($sess)) {
            $sess   =   array();
        }
        if (!isset($sess[$ns])) {
            $sess[$ns]  =   array();
        }
        if (isset($sess[$ns][$xid])) {
            return false;
        }

        $sess[$ns][$xid]    =   true;
        if ($updateSess) {
            $this->sess->set(__CLASS__ . ':rated:' . $this->uid, $sess);
        }

        // check permissions
        if (self::GROUP_ANON == $rgroup) {
            return true;
        }

        if (0 == $this->uid) {
            return false;
        }

        // check database for old ratings
        $old    =   $this->table->get('rating', null, $this->uid, $this->clause);
        if (!empty($old)) {
            return false;
        }

        if (empty($rgroup)) {
            return true;
        }

        if (in_array($rgroup, $this->uGroups)) {
            return true;
        }
        return false;
    }

    /**
     * Get rating of item
     *
     * Get total number of rates, average as well as min and max created timestamp
     * @return array
     */
    public function get()
    {
        $table      =   $this->query->getTableInfo('rating');
        $where      =   array();
        $this->query->clause2Where('rating', $this->clause, $where);
        $query      =   array('SELECT count(*) AS total, avg(value) AS average, min(created) AS createdmin, max(created) AS createdmax');
        $query[]    =   'FROM ' . $table['table'];
        $query[]    =   'WHERE ' . implode(' AND ', $where);

        $rating =   $this->query->query($query);
        if (empty($rating)) {
            $rating =   array(
                            array(
                                'total'         =>  0,
                                'average'       =>  0,
                                'createdmin'    =>  '0000-00-00 00:00:00',
                                'createdmax'    =>  '0000-00-00 00:00:00'
                                )
                            );
        }
        return $rating[0];
    }

    /**
     * Get best rated records for namespace
     *
     * Select items from table defined by namespace. Select only records with a minimum
     * number of rates. Also order by average rating value to get the best 10 records.
     *
     * The optional clause allows to e.g. select the best blog article of a specific category
     * or whatsoever.
     *
     * @param array $clause
     * @param int $limit
     * @return array
     */
    public function getBest($clause = array(), $limit = 10)
    {
        if (empty($this->clause[0]['value'])) {
            WBClass::load('WBException_Call');
            throw new WBException_Call('There is no namespace set, yet. Use setNamespace() first.', 1, __CLASS__);
        }

        $namespace  =   $this->clause[0]['value'];
        $clause[]   =   array(
                            'field' =>  $this->clause[0]['field'],
                            'table' =>  'rating',
                            'value' =>  $namespace
                            );

        $options    =   array(
                            'join'  =>  array(
                                            array(
                                                    'table'     =>  'rating',
                                                    'onleft'    =>  $this->table->getIdentifier($namespace),
                                                    'onright'   =>  'xid'
                                                )
                                        ),
                            'order' =>  array(
                                            array(
                                                    'table'     =>  'rating',
                                                    'field'     =>  'value',
                                                    'function'  =>  'avg',
                                                    'asc'       =>  0
                                                ),
                                            array(
                                                    'table'     =>  'rating',
                                                    'field'     =>  'value',
                                                    'function'  =>  'count',
                                                    'asc'       =>  0
                                                ),
                                        ),
                            'groupby' =>  array(
                                            array(
                                                'table'     =>  'rating',
                                                'field'     =>  'xid',
                                                'having'    =>  'count(xid) >= ' . intval(self::$conf['namespaces'][$namespace]['minrates'])
                                                )
                                            ),
                            'limit' =>  10
                            );
        return $this->table->get($namespace, null, null, $clause, $options);
    }
}