<?php

// (c) Copyright by authors of the Tiki Wiki CMS Groupware Project
//
// All Rights Reserved. See copyright.txt for details and a complete list of authors.
// Licensed under the GNU LESSER GENERAL PUBLIC LICENSE. See license.txt for details.
// $Id$

class Tiki_Formula_Function_Attribute extends Math_Formula_Function
{
    public function evaluate($element)
    {
        $allowed = [ 'object', 'default', 'property' ];

        if ($extra = $element->getExtraValues($allowed)) {
            $this->error(tr('Unexpected values: %0', implode(', ', $extra)));
        }

        $object = $element->object;

        if (! $object || count($object) != 2) {
            $this->error(tra('Object must be provided and contain two arguments: type and object'));
        }

        $type = $this->evaluateChild($object[0]);
        $object = $this->evaluateChild($object[1]);

        if (( $property = $element->property ) && count($property) == 1) {
            $property = $property[0];
        } else {
            $this->error(tra('Invalid property.'));
        }

        if ($property instanceof Math_Formula_Element) {
            $property = $this->evaluateChild($property);
        }

        if ($type == 'wiki page' && is_numeric($object)) {
            $tikilib = TikiLib::lib('tiki');
            $object = $tikilib->get_page_name_from_id($object);
        }

        $attributelib = TikiLib::lib('attribute');
        $values = $attributelib->get_attributes($type, $object);

        // Attributes are always lowercase
        $property = strtolower($property);

        if (isset($values[$property])) {
            return $values[$property];
        } elseif (( $default = $element->default ) && count($default) == 1) {
            return $this->evaluateChild($default[0]);
        } else {
            return 0;
        }
    }
}