<?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_TrackerField extends Math_Formula_Function
{
    public function evaluate($element)
    {
        $default = 0;
        $allowed = [ 'object', 'field' ];

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

        $object = $element->object;

        if (! $object || count($object) != 2) {
            $this->error(tra('Item must be provided and contain one argument: type, object-id'));
        }

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

        $field = $element->field;

        if (! $field || count($field) != 1) {
            $this->error(tra('Field must be provided and contain one argument: field permanent name'));
        }
        $field = $field[0];

        if ($type != 'trackeritem') {
            return $default;
        }

        return $this->fetchValue($object, $field, $default);
    }

    protected function fetchValue($object, $field, $default)
    {
        $trklib = TikiLib::lib('trk');
        $item = $trklib->get_tracker_item($object);

        if (! $item) {
            return $default;
        }

        if (! $definition = Tracker_Definition::get($item['trackerId'])) {
            return $default;
        }

        if (! $field = $definition->getFieldFromPermName($field)) {
            return $default;
        }

        $fieldId = $field['fieldId'];

        if (! isset($item[$fieldId])) {
            return $default;
        }

        return $item[$fieldId];
    }
}