<?php
    class AudioScrobbler {
        private $username = '',
            $raw = '',
            $data = array(), $tracks = array(),
            $cache = null; //  array('class' => '', 'time' => 60); // 1 min

        public function __construct($username, $cache = null) {
            $this->username = $username;
            $this->cache = $cache;

            if((is_string($cache) && !class_exists($cache)) || (is_array($cache) && !class_exists($cache['class'])))
                throw new AudioScrobblerException("invalid cache class " . (is_string($cache) ? ($cache) : ($cache['class'])));

            if(is_string($cache))
                $this->cache = array('class' => $cache, 'time' => 60);

            $this->cache = (object)$this->cache;

            if ($this->raw = $this->getData()) {
                $this->data = simplexml_load_string($this->raw);
                $this->initTracks();
            }
            else
                throw new AudioScrobblerException("unable to load tracks (does user {$this->username} exist?)");
        }

        private function getData() {
            if($this->cache !== null)
                $this->cache->instance = new $this->cache->class($this->username, $this->cache->time);

            if(!$this->cache->instance->check())
                $this->cache->instance->set(file_get_contents("http://ws.audioscrobbler.com/2.0/user/{$this->username}/recenttracks"));

            return $this->cache->instance->get();
        }

        private function initTracks() {
            foreach ($this->data->track as $track) {
                $this->tracks[] = new AudioScrobblerTrack($track);
            }
        }

        public function getLatestTrack() {
            return $this->tracks[0];
        }

        public function getTracks() {
            return $this->tracks;
        }

        public function getUser() {
            return $this->username;
        }
    }

    interface AudioScrobblerCacheInterface {
        public function __construct($name, $time = 60);
        public function get();
        public function set($data);
        public function check();
    }

    class AudioScrobblerCache implements AudioScrobblerCacheInterface {
        protected $name,
            $time = 60;

        public function __construct($name, $time = 60) {
            $this->name = $name;
            $this->time = (int)$time;
        }

        public function get() {}

        public function set($data) {}

        public function check() {}
    }

    class AudioScrobblerFileCache extends AudioScrobblerCache {
        public function get() {
            return file_get_contents("cache/{$this->name}.fm");
        }

        public function set($data) {
            file_put_contents("cache/{$this->name}.fm", $data);
        }

        public function check() {
            if(file_exists("cache/{$this->name}.fm") && (time() - filemtime("cache/{$this->name}.fm")) < $this->time)
                return true;

            return false;
        }

    }

    class AudioScrobblerTrack {
        private $data = array();

        public function __construct($track) {
            $this->data = (object)$track;
        }

        public function getTime() {
            return $this->data->date->attributes()->uts;
        }

        public function getTitle() {
            return $this->data->name;
        }

        public function getAlbum() {
            return $this->data->album;
        }

        public function getArtist() {
            return $this->data->artist;
        }
    }

    class AudioScrobblerException extends Exception {}