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

WBClass::load('WBEvent_Handler');

/**
 * WBEvent_Handler_TableOrderPos
 *
 * Add order pos for table record
 *
 * @version 0.1.0
 * @package Wombat
 * @subpackage base
 */
class WBEvent_Handler_TableOrderPos extends WBEvent_Handler
{
    /**
     * handler config
     *
     * - table name of table to update
     * - column name of column to update
     * - value new value
     * - valueindex data index where to load the value from
     * - key primary key of row to update
     * - keyindex data index where to achieve the primary key from
     *
     * @var array
     */
    protected $config   =   array(
                                'table'         =>  '',
                                'column'        =>  'orderpos',
                                );


    /**
     * Table access
     * @var WBDatasource_Table
     */
    private $table;

    /**
     * Table access via SQL
     * @var WBDatasource_SimpleQuery
     */
    private $query;

    /**
     * Init order position
     *
     * In case
     *
     * @param WBEvent $e
     * @return bool true to continue, false to stop processing
     * @throws Exception in case of error
     */
    public function process(WBEvent $e)
    {
        $table  =   $this->config['table'];
        if (empty($this->config['table'])) {
            $table  =   $e->get('table');
        }
        if (empty($this->config['column'])) {
            WBClass::load('WBException_Config');
            throw new WBException_Config('Column must not be empty!', 2, __CLASS__);
        }

        // if someone just update the order position column, nothing
        $save   =   $e->get('save');
        if (isset($save[$this->config['column']]) && 0 < $save[$this->config['column']]) {
            return true;
        }

        $this->table    =   WBClass::create('WBDatasource_Table');
        $this->table->switchTranslation(false);

        $id =   $e->get('id');
        if (empty($id) || $id == '__new') {
            WBClass::load('WBException_Argument');
            throw new WBException_Argument('Id may not be empty or "__new"', 1, __CLASS__);
        }

        // find out, whether orderpos is set
        $old    =   $this->table->get($table, $id);
        if (1 != count($old)) {
            WBClass::load('WBException_Datasource');
            throw new WBException_Datasource('Select by id expected a single row.', 1, __CLASS__);
        }
        $old    =   $old[0];
        if (!isset($old[$this->config['column']])) {
            WBClass::load('WBException_Config');
            throw new WBException_Config('Order position column does not exist', 2, __CLASS__);
        }

        // order position was already set.
        if (0 < $old[$this->config['column']]) {
            return true;
        }

        $info           =   $this->table->getTableInfo($table);
        $sql            =   'SELECT max(%1$s.%2$s) + 1 AS m FROM %1$s';
        $sql            =   sprintf($sql, $info['table'], $this->config['column']);
        $this->query    =   WBClass::create('WBDatasource_SimpleQuery');
        $value          =   $this->query->query($sql);
        if (1 != count($value)) {
            $value  =   array(array('m' => $id));
        }

        // update
        $save   =   array(
                        $this->config['column'] => $value[0]['m']
                    );

        $this->table->save($table, $id, $save);
        return true;
    }
}
?>