<?php
/**
Last.fm Component 
Description: Class for interacting with the REST services on last.fm
			 This class provides a programatic interface for interacting
			 with the rest services on last.fm.  Adapted from the217.com's 
			 original source code.
Author: Troy Stanger <stanger@illinimedia.com>
 */
class LastfmComponent {
	
	var $url_base = "http://ws.audioscrobbler.com/1.0/";
	
	/*
	 * Artist Data 
	 */
	function topTracksForArtist($artist) {
		$url_form = $this->url_base.'artist/'.rawurlencode($artist).'/toptracks.xml';
		return $this->processRequest($url_form);
	}
	
	function topAlbumsForArtist($artist) {
		$url_form = $this->url_base.'artist/'.rawurlencode($artist).'/topalbums.xml';
		return $this->processRequest($url_form);

	}
	
	function topTagsForArtist($artist) {
		$url_form = $this->url_base.'artist/'.rawurlencode($artist).'/toptags.xml';
		return $this->processRequest($url_form);

	}
	
	function relatedArtistsForArtist($artist) {
		$url_form = $this->url_base.'artist/'.rawurlencode($artist).'/similar.xml';
		return $this->processRequest($url_form);
	} 
	
	/*
	 * Album Data
	 */
	function artistAlbum($artist,$album) {
		$url_form = $this->url_base.'album/'.rawurlencode($artist).'/'.rawurlencode($album).'/info.xml';
		return $this->processRequest($url_form);
	}
	
	/*
	 * User related functions.
	 * 
	 * These can be used to obtain information related to a specific
	 * users listening habits.
	 */
	 
	function topArtistsForUser($user,$span = null) {
		$url_form = $this->url_base.'user/'.rawurlencode($user).'/topartists.xml';
		return $this->processRequest($url_form);
	}
	
	function topAlbumsForUser($user,$span = null) {
		$url_form = $this->url_base.'user/'.rawurlencode($user).'/topalbums.xml';
		
		return $this->processRequest($url_form);
	}

	function topTrackForUser($user,$span = null) {
		$url_form = $this->url_base.'user/'.rawurlencode($user).'/toptracks.xml';
		return $this->processRequest($url_form);
		
	}
	
	function recentTracksForUser($user) {
		$url_form = $this->url_base.'user/'.rawurlencode($user).'/recenttracks.xml';
		return $this->processRequest($url_form);
		
	}
	
	/**
	 * Helper function to load the url of the requested lastfm information
	 * 
	 * This function takes the url of a valid lastfm REST request and returns 
	 * a simplexml object from the incoming xml.  This function will also optional
	 * cache the request.
	 * 
	 * @author Troy Stanger <stanger@illinimedia.com>
	 */
	private function processRequest($url, $use_cache = true) {
		$key = md5($url);
		$cache_name = "cache/lastfm.php?".$key; 
		$cache_expires = "+1 hour";
		
		// Load the data from cache
		//$cache_data = $use_cache ? cache($cache_name, null, $cache_expires) : null;
		$cache_data = array();
		
		if (empty($cache_data)) {
			
			// Big Hack to make sure we aren't making too many requests in a row
			// Last.fm only allows 1 request per second
			sleep(2);
			
			//fix requests for non-existant files
			$headers = get_headers($url);
			if($headers[0] != "HTTP/1.0 404 Not Found") {
				$data = file_get_contents($url);
			}
			else {
				$data = null;	
			}
				
			// Save the request unless told not to
			if ($use_cache) {
				//cache($cache_name, $data, $cache_expires);
			}
		} else {
			//$this->log("Cache Hit");
			$data = $cache_data;
		}
		
		$xml = simplexml_load_string($data);

		return $xml;
	}
	
}

?>