mcg/mcg/client.py

#!/usr/bin/env python3


import concurrent.futures
import configparser
import logging
import os
import queue
import re
import socket
import threading

from mcg.utils import SortOrder
from mcg.utils import Utils




class MPDException(Exception):
    def __init__(self, error):
        super(MPDException, self).__init__(self._parse_error(error))
        self._error = error


    def _parse_error(self, error):
        if error:
            parts = re.match("\[(\d+)@(\d+)\]\s\{(\w+)\}\s(.*)", error)
            if parts:
                self._error_number = int(parts.group(1))
                self._command_number = int(parts.group(2))
                self._command_name = parts.group(3)
                return parts.group(4)
        return error


    def get_error(self):
        return self._error


    def get_error_number(self):
        return self._error_number


    def get_command_number(self):
        return self._command_number


    def get_command_name(self):
        return self._command_name


class ConnectionException(MPDException):
    pass


class ProtocolException(MPDException):
    pass


class CommandException(MPDException):
    pass




class Future(concurrent.futures.Future):
    def __init__(self, signal):
        concurrent.futures.Future.__init__(self)
        self._signal = signal


    def get_signal(self):
        return self._signal




class Base():
    def __init__(self):
        self._callbacks = {}


    def connect_signal(self, signal, callback):
        """Connect a callback function to a signal (event)."""
        self._callbacks[signal] = callback


    def disconnect_signal(self, signal):
        """Disconnect a callback function from a signal (event)."""
        if self._has_callback(signal):
            del self._callbacks[signal]


    def _has_callback(self, signal):
        """Check if there is a registered callback function for a signal."""
        return signal in self._callbacks


    def _callback(self, signal, *data):
        if signal in self._callbacks:
            callback = self._callbacks[signal]
            callback(*data)


    def _callback_future(self, future):
        self._callback(future.get_signal(), *future.result())




class Client(Base):
    """Client library for handling the connection to the Music Player Daemon.

    This class implements an album-based MPD client. It offers a non-blocking
    threaded worker model for use in graphical environments.
    """
    # Protocol: greeting mark
    PROTOCOL_GREETING = 'OK MPD '
    # Protocol: completion mark
    PROTOCOL_COMPLETION = 'OK'
    # Protocol: error mark
    PROTOCOL_ERROR = 'ACK '
    # Protocol: error: permission
    PROTOCOL_ERROR_PERMISSION = 4
    # Protocol: error: no exists
    PROTOCOL_ERROR_NOEXISTS = 50
    # Signal: connection status
    SIGNAL_CONNECTION = 'connection'
    # Signal: status
    SIGNAL_STATUS = 'status'
    # Signal: stats
    SIGNAL_STATS = 'stats'
    # Signal: init loading of albums
    SIGNAL_INIT_ALBUMS = 'init-albums'
    # Signal: pulse loading of albums
    SIGNAL_PULSE_ALBUMS = 'pulse-albums'
    # Signal: load albums
    SIGNAL_LOAD_ALBUMS = 'load-albums'
    # Signal: load playlist
    SIGNAL_LOAD_PLAYLIST = 'load-playlist'
    # Signal: load audio output devices
    SIGNAL_LOAD_OUTPUT_DEVICES = 'load-output-devices'
    # Signal: load albumart
    SIGNAL_LOAD_ALBUMART = 'albumart'
    # Signal: custom (dummy) event to trigger callback
    SIGNAL_CUSTOM = 'custom'
    # Signal: error
    SIGNAL_ERROR = 'error'
    # Buffer size for reading from socket
    SOCKET_BUFSIZE = 4096



    def __init__(self):
        """Set class variables and instantiates the Client."""
        Base.__init__(self)
        self._logger = logging.getLogger(__name__)
        self._sock = None
        self._buffer = bytearray()
        self._sock_write = None
        self._stop = threading.Event()
        self._actions = queue.Queue()
        self._worker = None
        self._idling = False
        self._host = None
        self._albums = {}
        self._playlist = []
        self._state = None


    def get_logger(self):
        return self._logger


    # Client commands

    def connect(self, host, port, password=None):
        """Connect to MPD with the given host, port and password or with
        standard values.
        """
        self._logger.info("connect")
        self._host = host
        self._add_action(self._connect, host, port, password)
        self._stop.clear()
        self._start_worker()


    def is_connected(self):
        """Return the connection status."""
        return self._worker is not None and self._worker.is_alive()


    def disconnect(self):
        """Disconnect from the connected MPD."""
        self._logger.info("disconnect")
        self._stop.set()
        self._add_action(self._disconnect)


    def join(self):
        self._actions.join()


    def get_status(self):
        """Determine the current status."""
        self._logger.info("get status")
        self._add_action_signal(Client.SIGNAL_STATUS, self._get_status)


    def get_stats(self):
        """Load statistics."""
        self._logger.info("get stats")
        self._add_action_signal(Client.SIGNAL_STATS, self._get_stats)


    def get_output_devices(self):
        """Determine the list of audio output devices."""
        self._logger.info("get output devices")
        self._add_action_signal(Client.SIGNAL_LOAD_OUTPUT_DEVICES, self._get_output_devices)


    def enable_output_device(self, device, enabled):
        """Enable/disable an audio output device."""
        self._logger.info("enable output device")
        self._add_action(self._enable_output_device, device, enabled)



    def load_albums(self):
        self._logger.info("load albums")
        self._add_action_signal(Client.SIGNAL_LOAD_ALBUMS, self._load_albums)


    def update(self):
        self._logger.info("update")
        self._add_action(self._update)


    def load_playlist(self):
        self._logger.info("load playlist")
        self._add_action_signal(Client.SIGNAL_LOAD_PLAYLIST, self._load_playlist)


    def clear_playlist(self):
        """Clear the current playlist"""
        self._logger.info("clear playlist")
        self._add_action(self._clear_playlist)


    def remove_album_from_playlist(self, album):
        """Remove the given album from the playlist."""
        self._logger.info("remove album from playlist")
        self._add_action(self._remove_album_from_playlist, album)


    def remove_albums_from_playlist(self, albums):
        """Remove multiple albums from the playlist in one step."""
        self._logger.info("remove multiple albums from playlist")
        self._add_action(self._remove_albums_from_playlist, albums)


    def play_album_from_playlist(self, album):
        """Play the given album from the playlist."""
        self._logger.info("play album from playlist")
        self._add_action(self._play_album_from_playlist, album)


    def playpause(self):
        """Play or pauses the current state."""
        self._logger.info("playpause")
        self._add_action(self._playpause)


    def play_album(self, album):
        """Add the given album to the queue and play it immediately."""
        self._logger.info("play album")
        self._add_action(self._play_album, album)


    def queue_album(self, album):
        """Add the given album to the queue."""
        self._logger.info("play album")
        self._add_action(self._queue_album, album)


    def queue_albums(self, albums):
        """Add the given albums to the queue."""
        self._logger.info("play albums")
        self._add_action(self._queue_albums, albums)


    def seek(self, pos, time):
        """Seeks to a song at a position"""
        self._logger.info("seek")
        self._add_action(self._seek, pos, time)


    def stop(self):
        self._logger.info("stop")
        self._add_action(self._stop)


    def set_volume(self, volume):
        self._logger.info("set volume")
        self._add_action(self._set_volume, volume)


    def get_albumart(self, album):
        self._logger.info("get albumart")
        self._add_action_signal(Client.SIGNAL_LOAD_ALBUMART, self._get_albumart, album)


    def get_albumart_now(self, album):
        self._logger.info("get albumart now")
        future = concurrent.futures.Future()
        self._add_action_future(future, self._get_albumart, album)
        (_, albumart) = future.result()
        return albumart


    def get_custom(self, name):
        self._logger.info("get custom \"%s\"", name)
        self._add_action_signal(Client.SIGNAL_CUSTOM, self._get_custom, name)


    # Private methods

    def _connect(self, host, port, password):
        self._logger.info("connecting to host %r, port %r", host, port)
        if self._sock is not None:
            return
        try:
            self._sock = self._connect_socket(host, port)
            self._sock_write = self._sock.makefile("w", encoding="utf-8")
            self._greet()
            self._logger.info("connected")
            if password:
                self._logger.info("setting password")
                self._call("password", password)
            self._set_connection_status(True)
        except OSError as e:
            raise ConnectionException("connection failed: {}".format(e))


    def _connect_socket(self, host, port):
        sock = None
        error = None
        for res in socket.getaddrinfo(host, port, socket.AF_UNSPEC, socket.SOCK_STREAM, socket.IPPROTO_TCP):
            af, socktype, proto, canonname, sa = res
            try:
                sock = socket.socket(af, socktype, proto)
                sock.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1)
                sock.connect(sa)
                return sock
            except Exception as e:
                error = e
                if sock is not None:
                    sock.close()
                break
        if error is not None:
            raise ConnectionException("connection failed: {}".format(error))
        else:
            raise ConnectionException("no suitable socket")


    def _greet(self):
        greeting = self._read_line()
        self._logger.debug("greeting: %s", greeting.strip())
        if not greeting.startswith(Client.PROTOCOL_GREETING):
            self._disconnect_socket()
            raise ProtocolException("invalid greeting: {}".format(greeting))
        self._protocol_version = greeting[len(Client.PROTOCOL_GREETING):].strip()
        self._logger.debug("protocol version: %s", self._protocol_version)


    def _disconnect(self):
        self._logger.info("disconnecting")
        self._disconnect_socket()


    def _disconnect_socket(self):
        if self._sock_write is not None:
            self._sock_write.close()
        self._sock_write = None
        if self._sock is not None:
            self._sock.close()
        self._sock = None
        self._logger.info("disconnected")
        self._set_connection_status(False)


    def _idle(self):
        """React to idle events from MPD."""
        self._logger.info("idle")
        self._idling = True
        subsystems = self._parse_dict(self._call("idle"))
        self._idling = False
        self._logger.info("idle subsystems: %r", subsystems)
        if subsystems:
            if subsystems['changed'] == 'player':
                self.load_playlist()
                self.get_status()
            if subsystems['changed'] == 'mixer':
                self.get_status()
            if subsystems['changed'] == 'playlist':
                self.load_playlist()
            if subsystems['changed'] == 'database':
                self.load_albums()
                self.load_playlist()
                self.get_status()
            if subsystems['changed'] == 'update':
                self.load_albums()
                self.load_playlist()
                self.get_status()
            if subsystems['changed'] == 'output':
                self.get_output_devices()
                self.get_status()


    def _noidle(self):
        if self._idling:
            self._logger.debug("noidle")
            self._write("noidle")


    def _get_status(self):
        """Action: Perform the real status determination."""
        self._logger.info("getting status")
        status = self._parse_dict(self._call("status"))
        self._logger.debug("status: %r", status)

        # State
        state = None
        if 'state' in status:
            state = status['state']
        self._state = state
        # Time
        time = 0
        if 'time' in status:
            time = int(status['time'].split(':')[0])
        # Volume
        volume = 0
        if 'volume' in status:
            volume = int(status['volume'])
        # Error
        error = None
        if 'error' in status:
            error = status['error']
        # Album
        file = None
        album = None
        pos = 0
        song = self._parse_dict(self._call("currentsong"))
        if song:
            # File
            if 'file' in song:
                file = song['file']
            # Track
            track = self._extract_playlist_track(song)
            if track:
                # Album
                album = self._extract_album(song)
                # Position
                pos = track.get_pos()
                for palbum in self._playlist:
                    if palbum == album and len(palbum.get_tracks()) >= pos:
                        album = palbum
                        break
                    pos = pos - len(palbum.get_tracks())
        # Audio
        audio = None
        if 'audio' in status:
            audio = status['audio']
        # Bitrate
        bitrate = None
        if 'bitrate' in status:
            bitrate = status['bitrate']
        return (state, album, pos, time, volume, file, audio, bitrate, error)


    def _get_stats(self):
        """Action: Perform the real statistics gathering."""
        self._logger.info("getting statistics")
        stats = self._parse_dict(self._call("stats"))
        self._logger.debug("stats: %r", stats)

        # Artists
        artists = 0
        if 'artists' in stats:
            artists = int(stats['artists'])
         # Albums
        albums = 0
        if 'albums' in stats:
            albums = int(stats['albums'])
        # Songs
        songs = 0
        if 'songs' in stats:
            songs = int(stats['songs'])
        # Database playtime
        dbplaytime = 0
        if 'db_playtime' in stats:
            dbplaytime = stats['db_playtime']
        # Playtime
        playtime = 0
        if 'playtime' in stats:
            playtime = stats['playtime']
        # Uptime
        uptime = 0
        if 'uptime' in stats:
            uptime = stats['uptime']
        return (artists, albums, songs, dbplaytime, playtime, uptime)


    def _get_output_devices(self):
        """Action: Perform the real loading of output devices."""
        devices = []
        for output in self._parse_list(self._call('outputs'), ['outputid']):
            device = OutputDevice(output['outputid'], output['outputname'])
            device.set_enabled(int(output['outputenabled']) == 1)
            devices.append(device)
        return (devices, )


    def _enable_output_device(self, device, enabled):
        """Action: Perform the real enabling/disabling of an output device."""
        if enabled:
            self._call('enableoutput ', device.get_id())
        else:
            self._call('disableoutput ', device.get_id())


    def _load_albums(self):
        """Action: Perform the real update."""
        self._callback(Client.SIGNAL_INIT_ALBUMS)
        self._albums = {}
        # Albums
        for album in self._parse_list(self._call('list album'), ['album']):
            self._callback(Client.SIGNAL_PULSE_ALBUMS)

            # Album
            album = self._extract_album(album)
            self._logger.debug("album: %r", album)
            # Tracks
            for song in self._parse_list(self._call('find album ', album.get_title()), ['file']):
                track = self._extract_track(song)
                if track:
                    self._logger.debug("track: %r", track)
                    album.add_track(track)
        return (self._albums, )


    def _update(self):
        self._call('update')


    def _load_playlist(self):
        self._playlist = []
        for song in self._parse_list(self._call('playlistinfo'), ['file', 'playlist']):
            self._logger.debug("song: %r", song)
            # Track
            track = self._extract_playlist_track(song)
            self._logger.debug("track: %r", track)
            # Album
            album = self._extract_album(song, lookup=False)
            if len(self._playlist) == 0 or self._playlist[len(self._playlist)-1] != album:
                self._playlist.append(album)
            else:
                album = self._playlist[len(self._playlist)-1]
            self._logger.debug("album: %r", album)
            if track:
                album.add_track(track)
        return (self._playlist, )


    def _clear_playlist(self):
        """Action: Perform the real clearing of the current playlist."""
        self._call('clear')


    def _remove_album_from_playlist(self, album):
        self._call_list('command_list_begin')
        for track in album.get_tracks():
            self._call_list('deleteid', track.get_id())
        self._call('command_list_end')


    def _remove_albums_from_playlist(self, albums):
        self._call_list('command_list_begin')
        for album in albums:
            for track in album.get_tracks():
                self._call_list('deleteid', track.get_id())
        self._call('command_list_end')


    def _play_album_from_playlist(self, album):
        if album.get_tracks():
            self._call('playid', album.get_tracks()[0].get_id())


    def _playpause(self):
        """Action: Perform the real play/pause command."""
        #status = self._parse_dict(self._call('status'))
        #if 'state' in status:
        if self._state == 'play':
            self._call('pause')
        else:
            self._call('play')


    def _play_album(self, album):
        track_ids = self._queue_album(album)
        if track_ids:
            self._logger.info("play track %d", track_ids[0])
            self._call('playid', track_ids[0])


    def _queue_album(self, album):
        track_ids = []
        if album in self._albums:
            self._logger.info("add album %s", album)
            for track in self._albums[album].get_tracks():
                self._logger.info("addid: %r", track.get_file())
                track_id = None
                track_id_response = self._parse_dict(self._call('addid', track.get_file()))
                if 'id' in track_id_response:
                    track_id = track_id_response['id']
                self._logger.debug("track id: %r", track_id)
                if track_id is not None:
                    track_ids.append(track_id)
        return track_ids


    def _queue_albums(self, albums):
        track_ids = []
        for album in albums:
            track_ids.extend(self._queue_album(album))


    def _seek(self, pos, time):
        self._call('seek', pos, time)


    def _stop(self):
        self._call('stop')


    def _set_volume(self, volume):
        self._call('setvol', volume)


    def _get_albumart(self, album):
        data = None
        if album in self._albums:
            album = self._albums[album]
            if not album.get_tracks():
                return None
            self._logger.debug("get albumart for album \"%s\"", album.get_title())
            size = 1
            offset = 0
            index = 0

            # Read data until size is reached
            try:
                while offset < size:
                    self._write('albumart', args=[album.get_tracks()[0].get_file(), offset])

                    # Read first line which tells us whether there is an albumart
                    line = self._read_line()
                    if line.startswith(Client.PROTOCOL_ERROR):
                        error = line[len(Client.PROTOCOL_ERROR):].strip()
                        self._logger.debug("command failed: %r", error)
                        raise CommandException(error)
                    # First line is the file size
                    size = int(self._parse_dict([line])['size'])
                    self._logger.debug("size: %d", size)
                    # Second line is the count of bytes read
                    binary = int(self._parse_dict([self._read_line()])['binary'])
                    self._logger.debug("binary: %d", binary)

                    # Create new data array on the first iteration
                    if not data:
                        data = bytearray(size)
                    # Create a view for the current chunk of data
                    data_view = memoryview(data)[offset:offset+binary]
                    # Read actual bytes
                    self._read_bytes(data_view, binary)
                    offset += binary
                    # Read line break to complete previous repsonse
                    self._read_line()
                    # Read command completion
                    end = self._read_line()
                    if not end.startswith(Client.PROTOCOL_COMPLETION):
                        self._logger.debug("albumart not completed")
                        data = None
                        break
            except CommandException as e:
                # If no albumart can be found, do not throw an exception
                if e.get_error_number() == Client.PROTOCOL_ERROR_NOEXISTS:
                    data = None
                else:
                    raise e
        return (album, data)


    def _get_custom(self, name):
        return (name, )


    def _start_worker(self):
        """Start the worker thread which waits for action to be performed."""
        self._logger.debug("start worker")
        self._worker = threading.Thread(target=self._run, name='mcg-worker', args=())
        self._worker.setDaemon(True)
        self._worker.start()
        self._logger.debug("worker started")


    def _run(self):
        while not self._stop.is_set() or not self._actions.empty():
            if self._sock is not None and self._actions.empty():
                self._add_action(self._idle)
            action = self._actions.get()
            self._logger.debug("next action: %r", action)
            self._work(action)
            self._actions.task_done()
            self._logger.debug("action done")
        self._logger.debug("worker finished")


    def _add_action(self, method, *args):
        """Add an action to the action list."""
        self._logger.debug("add action %r (%r)", method.__name__, args)
        future = concurrent.futures.Future()
        action = (future, method, args)
        self._actions.put(action)
        self._noidle()

        return future


    def _add_action_signal(self, signal, method, *args):
        """Add an action to the action list that triggers a callback."""
        self._logger.debug("add action signal %r: %r (%r)", signal, method.__name__, args)
        future = Future(signal)
        future.add_done_callback(self._callback_future)
        self._add_action_future(future, method, *args)

        return future


    def _add_action_future(self, future, method, *args):
        """Add an action to the action list based on a futre."""
        self._logger.debug("add action future %r (%r)", method.__name__, args)
        action = (future, method, args)
        self._actions.put(action)
        self._noidle()


    def _work(self, action):
        (future, method, args) = action
        self._logger.debug("work: %r", method.__name__)
        try:
            result = method(*args)
            future.set_result(result)
        except ConnectionException as e:
            self._logger.exception(e)
            future.set_exception(e)
            self._callback(Client.SIGNAL_ERROR, e)
            self._disconnect_socket()
        except Exception as e:
            self._logger.exception(e)
            future.set_exception(e)
            self._callback(Client.SIGNAL_ERROR, e)


    def _call(self, command, *args):
        try:
            self._write(command, args)
            return self._read()
        except MPDException as e:
            if command == 'idle' and e.get_error_number() == Client.PROTOCOL_ERROR_PERMISSION:
                self.disconnect()
            self._callback(Client.SIGNAL_ERROR, e)


    def _call_list(self, command, *args):
        try:
            self._write(command, args)
        except MPDException as e:
            if command == 'idle' and e.get_error_number() == Client.PROTOCOL_ERROR_PERMISSION:
                self.disconnect()
            self._callback(Client.SIGNAL_ERROR, e)


    def _write(self, command, args=None):
        if args is not None and len(args) > 0:
            line = '{} "{}"\n'.format(command, '" "'.join(str(x).replace('"', '\\\"') for x in args))
        else:
            line = '{}\n'.format(command)
        self._logger.debug("write: %r", line)
        self._sock_write.write(line)
        self._sock_write.flush()


    def _read(self):
        self._logger.debug("reading response")
        response = []
        line = self._read_line()
        while not line.startswith(Client.PROTOCOL_COMPLETION) and not line.startswith(Client.PROTOCOL_ERROR):
            response.append(line.strip())
            line = self._read_line()
        if line.startswith(Client.PROTOCOL_COMPLETION):
            self._logger.debug("response complete")
        if line.startswith(Client.PROTOCOL_ERROR):
            error = line[len(Client.PROTOCOL_ERROR):].strip()
            self._logger.debug("command failed: %r", error)
            raise CommandException(error)
        self._logger.debug("response: %r", response)
        return response


    def _read_line(self):
        self._logger.debug("reading line")

        # Read from the buffer
        data = self._buffer_get_char(b'\x0A')
        if not data.endswith(b'\x0A'):
            # Read more from socket until next line break
            while b'\x0A' not in data:
                buf = self._sock.recv(Client.SOCKET_BUFSIZE)
                if buf:
                    data += buf
                else:
                    break

            # Get first line from data, add rest to buffer
            if data:
                lines = data.split(b'\x0A', 1)
                data = lines[0]
                self._buffer_set(lines[1])
        if data:
            return data.decode('utf-8')
        return None


    def _read_bytes(self, buf, nbytes):
        self._logger.debug("reading bytes")
        # Use already buffered data
        buf_read = self._buffer_get_size(nbytes)
        nbytes_read = len(buf_read)
        buf[0:nbytes_read] = buf_read
        # Read additional data from socket
        nbytes = nbytes - nbytes_read
        if nbytes > 0:
            buf_view = memoryview(buf)[nbytes_read:]
            nbytes_read += self._sock.recv_into(buf_view, nbytes)
        return nbytes_read


    def _buffer_get_char(self, char):
        pos = self._buffer.find(char)
        if pos < 0:
            pos = len(self._buffer)-1
        buf = self._buffer[0:pos+1]
        self._buffer = self._buffer[pos+1:]
        return buf


    def _buffer_get_size(self, size):
        buf = self._buffer[0:size]
        self._logger.debug("get %d bytes from buffer", len(buf))
        self._buffer = self._buffer[size:]
        self._logger.debug("leaving %d in the buffer", len(self._buffer))
        return buf


    def _buffer_set(self, buf):
        self._logger.debug("set %d %s as buffer", len(buf), type(buf))
        self._buffer = buf


    def _parse_dict(self, response):
        dict = {}
        if response:
            for line in response:
                key, value = self._split_line(line)
                dict[key] = value
        return dict


    def _parse_list(self, response, delimiters):
        entry = {}
        if response:
            for line in response:
                key, value = self._split_line(line)
                if entry and key in delimiters:
                    yield entry
                    entry = {}
                #if key in entry.keys():
                #    if entry[key] is not list:
                #        entry[key] = [entry[key]]
                #    entry[key].append(value)
                #else:
                entry[key] = value
        if entry:
            yield entry


    def _split_line(self, line):
        parts = line.split(':')
        return parts[0].lower(), ':'.join(parts[1:]).lstrip()


    def _extract_album(self, song, lookup=True):
        album = None
        if 'album' not in song:
            song['album'] = MCGAlbum.DEFAULT_ALBUM
        id = Utils.generate_id(song['album'])
        if lookup and id in self._albums.keys():
            album = self._albums[id]
        else:
            album = MCGAlbum(song['album'], self._host)
        if lookup:
            self._albums[id] = album
        return album


    def _extract_track(self, song):
        track = None
        if 'artist' in song and 'title' in song and 'file' in song:
            track = MCGTrack(song['artist'], song['title'], song['file'])
            if 'track' in song:
                track.set_track(song['track'])
            if 'time' in song:
                track.set_length(song['time'])
            if 'date' in song:
                track.set_date(song['date'])
            if 'albumartist' in song:
                track.set_albumartists(song['albumartist'])
        return track


    def _extract_playlist_track(self, song):
        track = self._extract_track(song)
        if track and 'id' in song and 'pos' in song:
            track = MCGPlaylistTrack(track, song['id'], song['pos'])
        return track


    def _set_connection_status(self, status):
        self._callback(Client.SIGNAL_CONNECTION, status)




class OutputDevice:


    def __init__(self, id, name):
        self._id = id
        self._name = name
        self._enabled = None


    def get_id(self):
        return self._id


    def get_name(self):
        return self._name


    def set_enabled(self, enabled):
        self._enabled = enabled


    def is_enabled(self):
        return self._enabled




class MCGAlbum:
    DEFAULT_ALBUM = 'Various'
    _FILE_NAMES = ['cover', 'folder']
    _FILE_EXTS = ['jpg', 'png', 'jpeg']
    _FILTER_DELIMITER = ' '


    def __init__(self, title, host):
        self._artists = []
        self._albumartists = []
        self._pathes = []
        if type(title) is list:
            title = title[0]
        self._title = title
        self._dates = []
        self._host = host
        self._tracks = []
        self._length = 0
        self._id = Utils.generate_id(title)


    def __eq__(self, other):
        return (other and self.get_id() == other.get_id())


    def __hash__(self):
        return hash(self._title)


    def get_id(self):
        return self._id


    def get_artists(self):
        if self._albumartists:
            return [artist for artist in self._artists if artist not in self._albumartists]
        return self._artists


    def get_albumartists(self):
        if self._albumartists:
            return self._albumartists
        return self._artists


    def get_title(self):
        return self._title


    def get_dates(self):
        return self._dates


    def get_date(self):
        if len(self._dates) == 0:
            return None
        return self._dates[0]


    def get_path(self):
        return self._path


    def add_track(self, track):
        self._tracks.append(track)
        self._length = self._length + track.get_length()
        for artist in track.get_artists():
            if artist not in self._artists:
                self._artists.append(artist)
        for artist in track.get_albumartists():
            if artist not in self._albumartists:
                self._albumartists.append(artist)
        if track.get_date() is not None and track.get_date() not in self._dates:
            self._dates.append(track.get_date())
        path = os.path.dirname(track.get_file())
        if path not in self._pathes:
            self._pathes.append(path)


    def get_tracks(self):
        return self._tracks


    def get_length(self):
        return self._length


    def filter(self, filter_string):
        if len(filter_string) == 0:
            return True
        keywords = filter_string.split(MCGAlbum._FILTER_DELIMITER)
        for keyword in keywords:
            if len(keyword) == 0:
                continue
            result = False
            keyword = keyword.lower()
            # Search in album data
            for value in self._artists + [self._title] + self._dates:
                if keyword in value.lower():
                    result = True
                    break
            if result:
                continue
            # Search in track data
            for track in self._tracks:
                if keyword in track.get_title().lower() or keyword in track.get_file().lower():
                    result = True
                    break
            if not result:
                return False
        return True


    def compare(album1, album2, criterion=None):
        if criterion == None:
            criterion = SortOrder.TITLE
        if criterion == SortOrder.ARTIST:
            value_function = "get_artists"
        elif criterion == SortOrder.TITLE:
            value_function = "get_title"
        elif criterion == SortOrder.YEAR:
            value_function = "get_date"

        value1 = getattr(album1, value_function)()
        value2 = getattr(album2, value_function)()
        if value1 is None and value2 is None:
            return 0
        elif value1 is None:
            return -1
        elif value2 is None:
            return 1
        if value1 < value2:
            return -1
        elif value1 == value2:
            return 0
        else:
            return 1




class MCGTrack:
    def __init__(self, artists, title, file):
        if type(artists) is not list:
            artists = [artists]
        self._artists = artists
        if type(title) is list:
            title = title[0]
        self._title = title
        if type(file) is list:
            file = file[0]
        self._file = file

        self._albumartists = []
        self._track = None
        self._length = 0
        self._date = None


    def __eq__(self, other):
        return self._file == other.get_file()


    def __hash__(self):
        return hash(self._file)


    def get_artists(self):
        if self._albumartists:
            return [artist for artist in self._artists if artist not in self._albumartists]
        return self._artists


    def set_albumartists(self, artists):
        if type(artists) is not list:
            artists = [artists]
        self._albumartists = artists


    def get_albumartists(self):
        if self._albumartists:
            return self._albumartists
        return self._artists


    def get_title(self):
        return self._title


    def get_track(self):
        return self._track


    def set_track(self, track):
        if type(track) is list:
            track = track[0]
        if type(track) is str and '/' in track:
            track = track[0: track.index('/')]
        if track is not None:
            try:
                track = int(track)
            except ValueError:
                track = 0
        self._track = track


    def get_length(self):
        return self._length


    def set_length(self, length):
        self._length = int(length)


    def get_date(self):
        return self._date


    def set_date(self, date):
        if type(date) is list:
            date = date[0]
        self._date = date


    def get_file(self):
        return self._file




class MCGPlaylistTrack(MCGTrack):
    def __init__(self, track, id, pos):
        MCGTrack.__init__(
            self,
            track.get_artists(),
            track.get_title(),
            track.get_file()
        )
        self.set_albumartists(track.get_albumartists())
        self.set_track(track.get_track())
        self.set_length(track.get_length())
        self.set_date(track.get_date())
        self._id = int(id)
        self._pos = int(pos)


    def get_id(self):
        return self._id


    def get_pos(self):
        return self._pos




class MCGConfig(configparser.ConfigParser):
    CONFIG_DIR = '~/.config/mcg/'


    def __init__(self, filename):
        configparser.ConfigParser.__init__(self)
        self._filename = os.path.expanduser(os.path.join(MCGConfig.CONFIG_DIR, filename))
        self._create_dir()


    def load(self):
        if os.path.isfile(self._filename):
            self.read(self._filename)


    def save(self):
        with open(self._filename, 'w') as configfile:
            self.write(configfile)


    def _create_dir(self):
        dirname = os.path.dirname(self._filename)
        if not os.path.exists(dirname):
            os.makedirs(dirname)




class MCGCache():
    DIRNAME = '~/.cache/mcg/'
    SIZE_FILENAME = 'size'
    _lock = threading.Lock()


    def __init__(self, host, size):
        self._host = host
        self._size = size
        self._dirname = os.path.expanduser(os.path.join(MCGCache.DIRNAME, host))
        if not os.path.exists(self._dirname):
            os.makedirs(self._dirname)
        self._read_size()


    def create_filename(self, album):
        return os.path.join(self._dirname, '-'.join([album.get_id()]))


    def _read_size(self):
        size = 100
        MCGCache._lock.acquire()
        # Read old size
        filename = os.path.join(self._dirname, MCGCache.SIZE_FILENAME)
        if os.path.exists(filename):
            with open(filename, 'r') as f:
                size = int(f.readline())
        # Clear cache if size has changed
        if size != self._size:
            self._clear()
        # Write new size
        with open(filename, 'w') as f:
            f.write(str(self._size))
        MCGCache._lock.release()


    def _clear(self):
        for filename in os.listdir(self._dirname):
            path = os.path.join(self._dirname, filename)
            if os.path.isfile(path):
                try:
                    os.unlink(path)
                except Exception as e:
                    print("clear:", e)