<?php

class Rss {

	private $document, $channel;

	private function element($name, $value = null, $attributes = array()) {
		$element = $this->document->createElement($name);

		if(is_null($value) === false) {
			$text = $this->document->createTextNode($value);
			$element->appendChild($text);
		}

		foreach($attributes as $key => $val) {
			$element->setAttribute($key, $val);
		}

		return $element;
	}

	public function __construct($name, $description, $url, $language) {
		// create a dom xml object
		$this->document = new DOMDocument('1.0', 'UTF-8');

		// create our rss feed
		$rss = $this->element('rss', null, array('version' => '2.0', 'xmlns:atom' => 'http://www.w3.org/2005/Atom'));
		$this->document->appendChild($rss);

		// create channel
		$this->channel = $this->element('channel');
		$rss->appendChild($this->channel);

		// title
		$title = $this->element('title', $name);
		$this->channel->appendChild($title);

		// link
		$link = $this->element('link', $url);
		$this->channel->appendChild($link);

		// description
		$description = $this->element('description', $description);
		$this->channel->appendChild($description);

		// laguage
		// http://www.rssboard.org/rss-language-codes
		$language = $this->element('language', $language);
		$this->channel->appendChild($language);

		$ttl = $this->element('ttl', 60);
		$this->channel->appendChild($ttl);

		$docs = $this->element('docs', 'http://blogs.law.harvard.edu/tech/rss');
		$this->channel->appendChild($docs);

		$copyright = $this->element('copyright', $name);
		$this->channel->appendChild($copyright);

		// atom self link
		$atom = $this->element('atom:link', null, array(
			'href' => $url,
			'rel' => 'self',
			'type' => 'application/rss+xml'
		));
		$this->channel->appendChild($atom);
	}

	public function item($title, $url, $description, $date) {
		$item = $this->element('item');
		$this->channel->appendChild($item);

		// title
		$title = $this->element('title', $title);
		$item->appendChild($title);

		// link
		$link = $this->element('link', $url);
		$item->appendChild($link);

		// description
		$description = $this->element('description', $description);
		$item->appendChild($description);

		// date
		$date = $this->element('pubDate', date(DATE_RSS, strtotime($date)));
		$item->appendChild($date);
	}

	public function output() {
		// dump xml tree
		return $this->document->saveXML();
	}

}