<?php
class LWNprevBridge extends BridgeAbstract{
	const MAINTAINER = 'Pierre Mazière';
	const NAME = 'LWN Free Weekly Edition';
	const URI = 'https://lwn.net/';
	const CACHE_TIMEOUT = 604800; // 1 week
	const DESCRIPTION = 'LWN Free Weekly Edition available one week late';

	function getURI(){
		return self::URI . 'free/bigpage';
	}

	private function jumpToNextTag(&$node){
		while($node && $node->nodeType === XML_TEXT_NODE){
			$nextNode = $node->nextSibling;
			if(!$nextNode){
				break;
			}
			$node = $nextNode;
		}
	}

	private function jumpToPreviousTag(&$node){
		while($node && $node->nodeType === XML_TEXT_NODE){
			$previousNode = $node->previousSibling;
			if(!$previousNode){
				break;
			}
			$node = $previousNode;
		}
	}

	public function collectData(){
		// Because the LWN page is written in loose HTML and not XHTML,
		// Simple HTML Dom is not accurate enough for the job
		$content = getContents($this->getURI())
			or returnServerError('No results for LWNprev');

		libxml_use_internal_errors(true);
		$html = new DOMDocument();
		$html->loadHTML($content);
		libxml_clear_errors();

		$cat1 = '';
		$cat2 = '';

		foreach($html->getElementsByTagName('a') as $a){
			if($a->textContent === 'Multi-page format'){
				break;
			}
		}
		$realURI = self::URI . $a->getAttribute('href');
		$URICounter = 0;

		$edition = $html->getElementsByTagName('h1')->item(0)->textContent;
		$editionTimeStamp = strtotime(
			substr($edition, strpos($edition, 'for ') + strlen('for '))
		);

		foreach($html->getElementsByTagName('h2') as $h2){
			if($h2->getAttribute('class') !== 'SummaryHL'){
				continue;
			}

			$item = array();

			$h2NextSibling = $h2->nextSibling;
			$this->jumpToNextTag($h2NextSibling);

			switch($h2NextSibling->getAttribute('class')){
			case 'FeatureByline':
				$item['author'] = $h2NextSibling->getElementsByTagName('b')->item(0)->textContent;
				break;
			case 'GAByline':
				$text = $h2NextSibling->textContent;
				$item['author'] = substr($text,strpos($text, 'by '));
				break;
			default:
				$item['author'] = 'LWN';
				break;
			};

			$h2FirstChild = $h2->firstChild;
			$this->jumpToNextTag($h2FirstChild);
			if($h2FirstChild->nodeName === 'a'){
				$item['uri'] = self::URI . $h2FirstChild->getAttribute('href');
			}else{
				$item['uri'] = $realURI . '#' . $URICounter;
			}
			$URICounter++;

			$item['timestamp'] = $editionTimeStamp + $URICounter;

			$h2PrevSibling = $h2->previousSibling;
			$this->jumpToPreviousTag($h2PrevSibling);
			switch($h2PrevSibling->getAttribute('class')){
			case 'Cat2HL':
				$cat2 = $h2PrevSibling->textContent;
				$h2PrevSibling = $h2PrevSibling->previousSibling;
				$this->jumpToPreviousTag($h2PrevSibling);
				if($h2PrevSibling->getAttribute('class') !== 'Cat1HL'){
					break;
				}
				$cat1 = $h2PrevSibling->textContent;
				break;
			case 'Cat1HL':
				$cat1 = $h2PrevSibling->textContent;
				$cat2 = '';
				break;
			default:
				break;
			}
			$h2PrevSibling = null;

			$item['title'] = '';
			if(!empty($cat1)){
				$item['title'] .= '[' . $cat1 . ($cat2 ? '/' . $cat2 : '') . '] ';
			}
			$item['title'] .= $h2->textContent;

			$node = $h2;
			$content = '';
			$contentEnd = false;
			while(!$contentEnd){
				$node = $node->nextSibling;
				if(!$node || (
						$node->nodeType !== XML_TEXT_NODE && (
							$node->nodeName === 'h2' || (
								!is_null($node->attributes) &&
								!is_null($class = $node->attributes->getNamedItem('class')) &&
								in_array($class->nodeValue, array('Cat1HL', 'Cat2HL'))
							)
						)
					)
				){
					$contentEnd = true;
				}else{
					$content .= $node->C14N();
				}
			}
			$item['content'] = $content;
			$this->items[] = $item;
		}
	}
}