<?php

/**

* Copyright 2017 OpenStack Foundation

* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

* http://www.apache.org/licenses/LICENSE-2.0

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

**/

final class OrderParser

{

/**

* @param string $orders

* @param array $allowed_fields

* @return Order

*/

public static function parse($orders, array $allowed_fields = [])

{

$res = [];

$orders = explode(',', $orders);

//default ordering is asc

foreach($orders as $field)

{

$element = null;

if(strpos($field, '+') === 0)

{

$field = trim($field,'+');

if(!in_array($field, $allowed_fields)) continue;

$element = OrderElement::buildAscFor($field);

}

else if(strpos($field, '-') === 0)

{

$field = trim($field,'-');

if(!in_array($field, $allowed_fields)) continue;

$element = OrderElement::buildDescFor($field);

}

else

{

if(!in_array($field, $allowed_fields)) continue;

$element = OrderElement::buildAscFor($field);

}

$res[] = $element;

}

return new Order($res);

}

}