<?php

define('WIKIPEDIA_SUBJECT_TFA', 0); // Today's featured article
define('WIKIPEDIA_SUBJECT_DYK', 1); // Did you know...

class WikipediaBridge extends BridgeAbstract {
	const MAINTAINER = 'logmanoriginal';
	const NAME = 'Wikipedia bridge for many languages';
	const URI = 'https://www.wikipedia.org/';
	const DESCRIPTION = 'Returns articles for a language of your choice';

	const PARAMETERS = array( array(
		'language' => array(
			'name' => 'Language',
			'type' => 'list',
			'title' => 'Select your language',
			'exampleValue' => 'English',
			'values' => array(
				'English' => 'en',
				'Dutch' => 'nl',
				'Esperanto' => 'eo',
				'French' => 'fr',
				'German' => 'de',
			)
		),
		'subject' => array(
			'name' => 'Subject',
			'type' => 'list',
			'title' => 'What subject are you interested in?',
			'exampleValue' => 'Today\'s featured article',
			'values' => array(
				'Today\'s featured article' => 'tfa',
				'Did you know…' => 'dyk'
			)
		),
		'fullarticle' => array(
			'name' => 'Load full article',
			'type' => 'checkbox',
			'title' => 'Activate to always load the full article'
		)
	));

	public function getURI(){
		if(!is_null($this->getInput('language'))) {
			return 'https://'
			. strtolower($this->getInput('language'))
			. '.wikipedia.org';
		}

		return parent::getURI();
	}

	public function getName(){
		switch($this->getInput('subject')) {
			case 'tfa':
				$subject = WIKIPEDIA_SUBJECT_TFA;
				break;
			case 'dyk':
				$subject = WIKIPEDIA_SUBJECT_DYK;
				break;
			default: return parent::getName();
		}

		switch($subject) {
			case WIKIPEDIA_SUBJECT_TFA:
				$name = 'Today\'s featured article from '
				. strtolower($this->getInput('language'))
				. '.wikipedia.org';
				break;
			case WIKIPEDIA_SUBJECT_DYK:
				$name = 'Did you know? - articles from '
				. strtolower($this->getInput('language'))
				. '.wikipedia.org';
				break;
			default:
				$name = 'Articles from '
				. strtolower($this->getInput('language'))
				. '.wikipedia.org';
				break;
		}
		return $name;
	}

	public function collectData(){

		switch($this->getInput('subject')) {
			case 'tfa':
				$subject = WIKIPEDIA_SUBJECT_TFA;
				break;
			case 'dyk':
				$subject = WIKIPEDIA_SUBJECT_DYK;
				break;
			default:
				$subject = WIKIPEDIA_SUBJECT_TFA;
				break;
		}

		$fullArticle = $this->getInput('fullarticle');

		// This will automatically send us to the correct main page in any language (try it!)
		$html = getSimpleHTMLDOM($this->getURI() . '/wiki');

		if(!$html)
			returnServerError('Could not load site: ' . $this->getURI() . '!');

		/*
		* Now read content depending on the language (make sure to create one function per language!)
		* We build the function name automatically, just make sure you create a private function ending
		* with your desired language code, where the language code is upper case! (en -> getContentsEN).
		*/
		$function = 'getContents' . ucfirst(strtolower($this->getInput('language')));

		if(!method_exists($this, $function))
			returnServerError('A function to get the contents for your language is missing (\'' . $function . '\')!');

		/*
		* The method takes care of creating all items.
		*/
		$this->$function($html, $subject, $fullArticle);
	}

	/**
	* Replaces all relative URIs with absolute ones
	* @param $element A simplehtmldom element
	* @return The $element->innertext with all URIs replaced
	*/
	private function replaceUriInHtmlElement($element){
		return str_replace('href="/', 'href="' . $this->getURI() . '/', $element->innertext);
	}

	/*
	* Adds a new item to $items using a generic operation (should work for most
	* (all?) wikis) $anchorText can be specified if the wiki in question doesn't
	* use '...' (like Dutch, French and Italian) $anchorFallbackIndex can be
	* used to specify a different fallback link than the first
	* (e.g., -1 for the last)
	*/
	private function addTodaysFeaturedArticleGeneric($element,
	$fullArticle,
	$anchorText = '...',
	$anchorFallbackIndex = 0){
		// Clean the bottom of the featured article
		if ($element->find('ul', -1))
			$element->find('ul', -1)->outertext = '';
		elseif ($element->find('div', -1)) {
			$element->find('div', -1)->outertext = '';
		}

		// The title and URI of the article can be found in an anchor containing
		// the string '...' in most wikis ('full article ...')
		$target = $element->find('p a', $anchorFallbackIndex);
		foreach($element->find('//a') as $anchor) {
			if(strpos($anchor->innertext, $anchorText) !== false) {
				$target = $anchor;
				break;
			}
		}

		$item = array();
		$item['uri'] = $this->getURI() . $target->href;
		$item['title'] = $target->title;

		if(!$fullArticle)
			$item['content'] = strip_tags($this->replaceUriInHtmlElement($element), '<a><p><br><img>');
		else
			$item['content'] = $this->loadFullArticle($item['uri']);

		$this->items[] = $item;
	}

	/*
	* Adds a new item to $items using a generic operation (should work for most (all?) wikis)
	*/
	private function addDidYouKnowGeneric($element, $fullArticle){
		foreach($element->find('ul', 0)->find('li') as $entry) {
			$item = array();

			// We can only use the first anchor, there is no way of finding the 'correct' one if there are multiple
			$item['uri'] = $this->getURI() . $entry->find('a', 0)->href;
			$item['title'] = strip_tags($entry->innertext);

			if(!$fullArticle)
				$item['content'] = $this->replaceUriInHtmlElement($entry);
			else
				$item['content'] = $this->loadFullArticle($item['uri']);

			$this->items[] = $item;
		}
	}

	/**
	* Loads the full article from a given URI
	*/
	private function loadFullArticle($uri){
		$content_html = getSimpleHTMLDOMCached($uri);

		if(!$content_html)
			returnServerError('Could not load site: ' . $uri . '!');

		$content = $content_html->find('#mw-content-text', 0);

		if(!$content)
			returnServerError('Could not find content in page: ' . $uri . '!');

		// Let's remove a couple of things from the article
		$table = $content->find('#toc', 0); // Table of contents
		if(!$table === false)
			$table->outertext = '';

		foreach($content->find('ol.references') as $reference) // References
			$reference->outertext = '';

		return str_replace('href="/', 'href="' . $this->getURI() . '/', $content->innertext);
	}

	/**
	* Implementation for de.wikipedia.org
	*/
	private function getContentsDe($html, $subject, $fullArticle){
		switch($subject) {
			case WIKIPEDIA_SUBJECT_TFA:
				$element = $html->find('div[id=artikel] div.hauptseite-box-content', 0);
				$this->addTodaysFeaturedArticleGeneric($element, $fullArticle);
				break;
			case WIKIPEDIA_SUBJECT_DYK:
				$element = $html->find('div[id=wissenswertes]', 0);
				$this->addDidYouKnowGeneric($element, $fullArticle);
				break;
			default:
				break;
		}
	}

	/**
	* Implementation for fr.wikipedia.org
	*/
	private function getContentsFr($html, $subject, $fullArticle){
		switch($subject) {
			case WIKIPEDIA_SUBJECT_TFA:
				$element = $html->find('div[class=accueil_2017_cadre]', 0);
				$this->addTodaysFeaturedArticleGeneric($element, $fullArticle, 'Lire la suite');
				break;
			case WIKIPEDIA_SUBJECT_DYK:
				$element = $html->find('div[class=accueil_2017_cadre]', 2);
				$this->addDidYouKnowGeneric($element, $fullArticle);
				break;
			default:
				break;
		}
	}

	/**
	* Implementation for en.wikipedia.org
	*/
	private function getContentsEn($html, $subject, $fullArticle){
		switch($subject) {
			case WIKIPEDIA_SUBJECT_TFA:
				$element = $html->find('div[id=mp-tfa]', 0);
				$this->addTodaysFeaturedArticleGeneric($element, $fullArticle, -1);
				break;
			case WIKIPEDIA_SUBJECT_DYK:
				$element = $html->find('div[id=mp-dyk]', 0);
				$this->addDidYouKnowGeneric($element, $fullArticle);
				break;
			default:
				break;
		}
	}

	/**
	* Implementation for eo.wikipedia.org
	*/
	private function getContentsEo($html, $subject, $fullArticle){
		switch($subject) {
			case WIKIPEDIA_SUBJECT_TFA:
				$element = $html->find('div[id=mf-artikolo-de-la-monato]', 0);
				$element->find('div', -2)->outertext = '';
				$this->addTodaysFeaturedArticleGeneric($element, $fullArticle);
				break;
			case WIKIPEDIA_SUBJECT_DYK:
				$element = $html->find('div.hp', 1)->find('table', 4)->find('td', -1);
				$this->addDidYouKnowGeneric($element, $fullArticle);
				break;
			default:
				break;
		}
	}

	/**
	* Implementation for nl.wikipedia.org
	*/
	private function getContentsNl($html, $subject, $fullArticle){
		switch($subject) {
			case WIKIPEDIA_SUBJECT_TFA:
				$element = $html->find('td[id=segment-Uitgelicht] div', 0);
				$element->find('p', 1)->outertext = '';
				$this->addTodaysFeaturedArticleGeneric($element, $fullArticle, 'Lees verder');
				break;
			case WIKIPEDIA_SUBJECT_DYK:
				$element = $html->find('td[id=segment-Wist_je_dat] div', 0);
				$this->addDidYouKnowGeneric($element, $fullArticle);
				break;
			default:
				break;
		}
	}
}