<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\web;

use yii\base\Object;

/**
 * Link represents a link object as defined in [JSON Hypermedia API Language](https://tools.ietf.org/html/draft-kelly-json-hal-03).
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class Link extends Object
{
	/**
	 * The self link.
	 */
	const REL_SELF = 'self';

	/**
	 * @var string a URI [RFC3986](https://tools.ietf.org/html/rfc3986) or
	 * URI template [RFC6570](https://tools.ietf.org/html/rfc6570). This property is required.
	 */
	public $href;
	/**
	 * @var string a secondary key for selecting Link Objects which share the same relation type
	 */
	public $name;
	/**
	 * @var string a hint to indicate the media type expected when dereferencing the target resource
	 */
	public $type;
	/**
	 * @var boolean a value indicating whether [[href]] refers to a URI or URI template.
	 */
	public $templated = false;
	/**
	 * @var string a URI that hints about the profile of the target resource.
	 */
	public $profile;
	/**
	 * @var string a label describing the link
	 */
	public $title;
	/**
	 * @var string the language of the target resource
	 */
	public $hreflang;


	/**
	 * Serializes a list of links into proper array format.
	 * @param array $links the links to be serialized
	 * @return array the proper array representation of the links.
	 */
	public static function serialize(array $links)
	{
		foreach ($links as $rel => $link) {
			if (is_array($link)) {
				foreach ($link as $i => $l) {
					$link[$i] = $l instanceof self ? array_filter((array)$l) : ['href' => $l];
				}
				$links[$rel] = $link;
			} elseif (!$link instanceof self) {
				$links[$rel] = ['href' => $link];
			}
		}
		return $links;
	}
}