<?php
/**
 * Populate form element's attribute
 *
 * $Id$
 *
 * @author gERD Schaufelberger <gerd@php-tools.net>
 * @license PHP License
 * @package WB
 * @subpackage db
 */

/**
 * Populate form element's attribute
 *
 * Generic class to populate element's attribute. The template method is
 * implemented here, the child class is required to actually receive proper
 * attribute values.
 *
 * @version 0.2.1
 * @package WB
 * @subpackage db
 */
class WBDatasource_FormAttribute extends WBStdClass
{
    /**
     * configuration values
     * @var array
     */
    protected $config   =   array(
                                'ajaxupdate'    =>  '',
                                    );

    /**
     * form element to set values to
     * @var patForms_Element
     */
    protected $element;

    /**
     * session storage container
     * @var patSession_Storage
     */
    protected $sess;

    /**
     * set form element
     *
     * Tell which element to manipulate
     *
     * @param patForms_Element $element
     */
    private function setElement($element)
    {
        $this->element  =   $element;
    }

    /**
     * set configuration
     *
     * @param array $config
     */
    private function setConfig($config)
    {
        // usually we are going to populate the values attriubte
        if (!isset($this->config['attribute'])) {
            $this->config['attribute']  =   'values';
        }
        $this->config   =   array_merge($this->config, $config);

        // generic config
        if (!isset($this->config['ajaxupdate'])) {
            $this->config['ajaxupdate'] =   '';
        }
    }

    /**
     * populate elements attribute(s)
     *
     * Template method that does the whole thing.
     *
     * @param patForms_Element $element
     * @param array $config
     */
    final public function populate($element, $config)
    {
        $this->setElement($element);
        $this->setConfig($config);

        // load JavaScript classes
        if (!empty($this->config['ajaxupdate'])) {
            WBHtml_JS::add('WB/Ajax');
            WBHtml_JS::add('WB/Ajax/Form');
            WBHtml_JS::add('WB/Ajax/Form/Element');
        }

        $value  =   $this->element->getAttribute($this->config['attribute']);
        $value  =   $this->getAttributeValue($value);
        $this->element->setAttribute($this->config['attribute'], $value);

        $name   =   'form:element:update:config:' . $this->element->getAttribute('name');
        $this->sess =   WBClass::create('patSession');
        if (empty($this->config['ajaxupdate'])) {
            $this->sess->clear($name);
            return;
        }
        $this->sess->set($name, $this->config);
    }

    /**
     * get attribute's value
     *
     * Implement this method in actual child classes
     *
     * @param mixed $current actual attribute value
     * @return mixed
     */
    protected function getAttributeValue($current)
    {
        return '';
    }

    /**
     * custom compare function
     *
     * Comparision function for value lists with label
     *
     * @see usort()
     * @param array $a
     * @param array $b
     * @return int -1, 0 or 1
     */
    protected function compareValuesByLabel($a, $b)
    {
        if ($a['label'] == $b['label']) {
            return 0;
        }

        if ($a['label'] > $b['label']) {
            return 1;
        }

        return -1;
    }
}