<?php
/**
 * WBEvent_Handler_TableLoadRealtion
 *
 *
 * $Id: TableLoadRelation.php 1511 2013-11-13 10:27:27Z gerd $
 *
 * @author gERD Schaufelberger <gerd@php-tools.net>
 * @license PHP License
 * @package Wombat
 * @subpackage base
 */

WBClass::load('WBEvent_Handler');

/**
 * WBEvent_Handler_TableLoadRealtion
 *
 * Load list of n:m relations from foreign table
 *
 * @version 0.1.0
 * @package Wombat
 * @subpackage base
 */
class WBEvent_Handler_TableLoadRelation extends WBEvent_Handler
{
    /**
     * handler config
     *
     * - field column to select and add to event data
     * - relationkey id to load data from relation table
     * - relationtable table to load data from
     * - relationfield column in relation table
     *
     * @var array
     */
    protected $config   =   array(
                                'field'         =>  '',
                                'relationkey'   =>  '',
                                'relationtable' =>  '',
                                'relationfield' =>  ''
                                );

    /**
     * Update data in table using data from related table
     *
     * Update exactly one column in one table for one row using primary key
     * Hence primary key is required, as well as column and table name.
     *
     * @param WBEvent $e
     * @return bool true to continue, false to stop processing
     * @throws Exception in case of error
     */
    public function process(WBEvent $e)
    {
        foreach ($this->config as $k => $v) {
            if (empty($v)) {
                WBClass::load('WBException_Config');
                throw new WBException_Config('Config parameter "' . $k . '" must not be empty!', 1, __CLASS__);
            }
        }

        // if column is already set, we are done already
        $old    =   $e->get($this->config['field']);
        if (!empty($old)) {
            return;
        }

        $table      =   WBClass::create('WBDatasource_Table');
        $clause     =   array();
        $clause[]   =   array(
                            'field' =>  $this->config['relationfield'],
                            'value' =>  $e->get($this->config['relationkey'])
                        );
        $list       =   $table->get($this->config['relationtable'], null, null, $clause, $options);
        if (empty($list)) {
            return true;
        }

        $value  =   array();
        foreach ($list as $l) {
            $value[]    =   $l[$this->config['field']];
        }

        $e->set($this->config['field'], $value);
        return true;
    }
}