<?php
class SoundCloudBridge extends BridgeAbstract {
	const MAINTAINER = 'kranack, Roliga';
	const NAME = 'Soundcloud Bridge';
	const URI = 'https://soundcloud.com/';
	const CACHE_TIMEOUT = 600; // 10min
	const DESCRIPTION = 'Returns 10 newest music from user profile';

	const PARAMETERS = array(array(
		'u' => array(
			'name' => 'username',
			'required' => true
		),
		't' => array(
			'name' => 'Content',
			'type' => 'list',
			'defaultValue' => 'tracks',
			'values' => array(
				'All (except likes)' => 'all',
				'Tracks' => 'tracks',
				'Albums' => 'albums',
				'Playlists' => 'playlists',
				'Reposts' => 'reposts',
				'Likes' => 'likes'
			)
		)
	));

	private $apiUrl = 'https://api-v2.soundcloud.com/';
	// Without url=http, player URL returns a 404
	private $playerUrl = 'https://w.soundcloud.com/player/?url=http';
	private $widgetUrl = 'https://widget.sndcdn.com/';

	private $feedTitle = null;
	private $feedIcon = null;
	private $clientIDCache = null;

	private $clientIdRegex = '/client_id.*?"(.+?)"/';
	private $widgetRegex = '/widget-.+?\.js/';

	public function collectData() {
		$res = $this->getUser($this->getInput('u'));

		$this->feedTitle = $res->username;
		$this->feedIcon = $res->avatar_url;

		$apiItems = $this->getUserItems($res->id, $this->getInput('t'))
			or returnServerError('No results for ' . $this->getInput('t'));

		$hasTrackObject = array('all', 'reposts', 'likes');

		foreach ($apiItems->collection as $index => $apiItem) {
			if (in_array($this->getInput('t'), $hasTrackObject) === true) {
				$apiItem = $apiItem->track;
			}

			$item = array();
			$item['author'] = $apiItem->user->username;
			$item['title'] = $apiItem->user->username . ' - ' . $apiItem->title;
			$item['timestamp'] = strtotime($apiItem->created_at);

			$description = nl2br($apiItem->description);

			$item['content'] = <<<HTML
				<p>{$description}</p>
HTML;

			if (isset($apiItem->tracks) && $apiItem->track_count > 0) {
				$list = $this->getTrackList($apiItem->tracks);

				$item['content'] .= <<<HTML
					<p><strong>Tracks ({$apiItem->track_count})</strong></p>
					{$list}
HTML;
			}

			$item['enclosures'][] = $apiItem->artwork_url;
			$item['id'] = $apiItem->permalink_url;
			$item['uri'] = $apiItem->permalink_url;
			$this->items[] = $item;

			if (count($this->items) >= 10) {
				break;
			}
		}
	}

	public function getIcon(){
		if ($this->feedIcon) {
			return $this->feedIcon;
		}

		return parent::getIcon();
	}

	public function getURI() {
		if ($this->getInput('u')) {
			return self::URI . $this->getInput('u') . '/' . $this->getInput('t');
		}

		return parent::getURI();
	}

	public function getName() {
		if($this->feedTitle) {
			return $this->feedTitle . ' - ' . ucfirst($this->getInput('t')) . ' - ' . self::NAME;
		}

		return parent::getName();
	}

	private function initClientIDCache(){
		if($this->clientIDCache !== null)
			return;

		$cacheFac = new CacheFactory();
		$cacheFac->setWorkingDir(PATH_LIB_CACHES);
		$this->clientIDCache = $cacheFac->create(Configuration::getConfig('cache', 'type'));
		$this->clientIDCache->setScope(get_called_class());
		$this->clientIDCache->setKey(array('client_id'));
	}

	private function getClientID(){
		$this->initClientIDCache();

		$clientID = $this->clientIDCache->loadData();

		if($clientID == null) {
			return $this->refreshClientID();
		} else {
			return $clientID;
		}
	}

	private function refreshClientID(){
		$this->initClientIDCache();

		$playerHTML = getContents($this->playerUrl);

		// Extract widget JS filenames from player page
		if(preg_match_all($this->widgetRegex, $playerHTML, $matches) == false)
			returnServerError('Unable to find widget JS URL.');

		$clientID = '';

		// Loop widget js files and extract client ID
		foreach ($matches[0] as $widgetFile) {
			$widgetURL = $this->widgetUrl . $widgetFile;

			$widgetJS = getContents($widgetURL);

			if(preg_match($this->clientIdRegex, $widgetJS, $matches)) {
				$clientID = $matches[1];
				$this->clientIDCache->saveData($clientID);

				return $clientID;
			}
		}

		if (empty($clientID)) {
			returnServerError('Unable to find client ID.');
		}
	}

	private function buildApiUrl($endpoint, $parameters) {
		return $this->apiUrl
			. $endpoint
			. '?'
			. http_build_query($parameters);
	}

	private function getUser($username) {
		$parameters = array('url' => self::URI . $username);

		return $this->getApi('resolve', $parameters);
	}

	private function getUserItems($userId, $type) {
		$parameters = array('limit' => 10);
		$endpoint = 'users/' . $userId . '/' . $type;

		if ($type === 'playlists') {
			$endpoint = 'users/' . $userId . '/playlists_without_albums';
		}

		if ($type === 'all') {
			$endpoint = 'stream/users/' . $userId;
		}

		if ($type === 'reposts') {
			$endpoint = 'stream/users/' . $userId . '/' . $type;
		}

		return $this->getApi($endpoint, $parameters);
	}

	private function getApi($endpoint, $parameters) {
		$parameters['client_id'] = $this->getClientID();
		$url = $this->buildApiUrl($endpoint, $parameters);

		try {
			return json_decode(getContents($url));
		} catch (Exception $e) {
			// Retry once with refreshed client ID
			$parameters['client_id'] = $this->refreshClientID();
			$url = $this->buildApiUrl($endpoint, $parameters);

			return json_decode(getContents($url));
		}
	}

	private function getTrackList($tracks) {
		$trackids = '';

		foreach ($tracks as $track) {
			$trackids .= $track->id . ',';
		}

		$apiItems = $this->getApi(
			'tracks', array('ids' => $trackids)
		);

		$list = '';
		foreach($apiItems as $track) {
			$list .= <<<HTML
				<li>{$track->user->username} — <a href="{$track->permalink_url}">{$track->title}</a></li>
HTML;
		}

		$html = <<<HTML
			<ul>{$list}</ul>
HTML;

		return $html;
	}
}