<?php
/**
 * A class for calling the Last.fm API
 *
 * @package		LastFm
 * @version		1.1
 * @author		Koa Metter <koa@iamkoa.net>
 * @link		http://iamkoa.net
 * @license		http://www.opensource.org/licenses/bsd-license.php
 * @uses		SimpleXML
 */

class LastFm
{
	/**
	* LastFm API URL
	* @var string
	*/
	public $base_url = "http://ws.audioscrobbler.com/2.0/";
	
	/**
	* LastFm auth URL
	* @var string
	*/
	public $auth_url = "http://www.last.fm/api/auth/";
	
	/**
	* LastFm API key
	* @var string
	*/
	public $key = null;
	
	/**
	 * Magic function used to make API call
	 *
	 * @param string $method LastFm API method
	 * @param string $args LastFm API args
	 * @return obj XML data converted to a PHP object
	 * @uses SimpleXML
	 * ex:
	 *	$lastfm->user_getLovedTracks("user=iamkoa");
	 *		Calls API method "user.getLovedTracks" and sets
	 *		the "user" argument to "iamkoa".
	 */
	private function __call ($method, $args)
	{
		$this->url = $this->buildCall($method, $args);
		$this->xml = $this->makeCall($this->url);
		return simplexml_load_string($this->xml);
	}
	
	/**
	 * Gets the API key
	 *
	 * @param string $glue The character that precedes the API key
	 * @return string Formatted API key
	 */
	private function getKey ($glue = null)
	{
		if (is_null($this->key)) return false;
		return $glue."api_key=".$this->key;
	}
	
	/**
	 * Gets the API call
	 *
	 * @param string $method LastFm API method - append with "auth_" to require authentication
	 * @return string Formatted API method
	 */
	private function getMethod ($method)
	{
		$ex = explode("_",$method);
		if ($ex[0] == 'auth') {
			/* we've requested authentication */
			
			// build auth url
			$url = $this->auth_url.$this->getKey("?");
			
			// make call
			exit(print_r($this->makeCall($url)));
			$method = $ex[1].".".$ex[2];
		} else $method = str_replace('_','.',$method);
		
		$this->method = "?method=";
		$this->method .= $method;
		$this->method .= '&';
		return $this->method;
	}
	
	/**
	 * Gets the API arguments
	 *
	 * @param string $method LastFm API args
	 * @return string Formatted API args
	 */
	private function getArgs ($args)
	{
		if (is_array($args)) {
			$this->args = implode('&',$args);
			return $this->args;
		}
	}
	
	/**
	 * Builds the API call
	 *
	 * @param string $method LastFm API args
	 * @param string $args LastFm API args
	 * @return string Formatted API args
	 * @see getArgs()
	 */
	private function buildCall ($method, $args)
	{
		$this->call_url  = $this->base_url;
		$this->call_url .= $this->getMethod($method);
		$this->call_url .= $this->getArgs($args);
		$this->call_url .= $this->getKey("&");
		return $this->call_url;
	}
	
	/**
	 * Call the API
	 *
	 * @param string $url LastFm API url call
	 * @return xml Formatted API results
	 * @see buildCall()
	 */
	private function makeCall ($url)
	{
		$ch = curl_init();
		curl_setopt ($ch, CURLOPT_URL, $url);
		curl_setopt ($ch, CURLOPT_RETURNTRANSFER, true);
		curl_setopt ($ch, CURLOPT_CONNECTTIMEOUT, 8);
		$this->results = curl_exec($ch);
		curl_close($ch);
		return $this->results;
	}
}