<?php
/**
 * WBEvent_Handler_TableAddRealtion
 *
 *
 * $Id$
 *
 * @author gERD Schaufelberger <gerd@php-tools.net>
 * @license PHP License
 * @package Wombat
 * @subpackage base
 */

WBClass::load('WBEvent_Handler');

/**
 * WBEvent_Handler_TableAddRealtion
 *
 * Update a column in table
 *
 * @version 0.1.0
 * @package Wombat
 * @subpackage base
 */
class WBEvent_Handler_TableAddRelation extends WBEvent_Handler
{
    /**
     * handler config
     *
     * - table name of table to update
     * - field name of column to update
     * - key id of data to update
     * - relationkey id to load data from relation table
     * - relationtable table to load data from
     * - relationfield column in relation table
     *
     * @var array
     */
    protected $config   =   array(
                                'table'         =>  '',
                                'field'         =>  '',
                                'key'           =>  '',
                                '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)
    {
        $id =   $e->get($this->config['key']);
        if (empty($id) || '__new' == $id) {
            WBClass::load('WBException_Datasource');
            throw new WBException_Config('Id must neither be "__new" nor empty', 1, __CLASS__);
        }
        foreach ($this->config as $k => $v) {
            if (empty($v)) {
                WBClass::load('WBException_Config');
                throw new WBException_Config('Config parameter "' . $k . '" must not be empty!', 2, __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['relationkey'],
                            'value' =>  $e->get($this->config['relationkey'])
                        );
        $options    =   array(
                            'limit' =>  1
                        );
        $list       =   $table->get($this->config['relationtable'], null, null, $clause, $options);
        if (empty($list)) {
            return true;
        }
        $save   =   array(
                            $this->config['relationfield']  =>  $list[0][$this->config['relationfield']]
                        );
        $table->save($this->config['table'], $id, $save);
        return true;
    }
}