#
#    Copyright (C) 2010 Anton Khirnov <wyskas@gmail.com>
#
#    Nephilim is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    Nephilim is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with Nephilim.  If not, see <http://www.gnu.org/licenses/>.
#

from PyQt5 import QtCore, QtNetwork
from PyQt5.QtCore import pyqtSignal as Signal, pyqtSlot as Slot
import logging
import os.path

from .song import Song
from .mpdsocket import MPDSocket

class AudioOutput(QtCore.QObject):
    """
    This class represents an MPD audio output.
    Instances of this class are generated by MPClient, do not
    instantiate directly.
    """

    #### PUBLIC ####
    # constants
    name     = None

    # read-only
    state    = None

    # SIGNALS
    state_changed = Signal(bool)

    #### public ####
    def __init__(self, data, set_state, parent = None):
        QtCore.QObject.__init__(self, parent)

        self.name     = data['outputname']
        self.state    = int(data['outputenabled'])

        self.set_state = set_state

    @Slot(bool)
    def set_state(self, state):
        pass

    def update(self, data):
        """
        This is called by mpclient to inform about output state change.
        """
        if int(data['outputenabled']) != self.state:
            self.state = not self.state
            self.state_changed.emit(self.state)

class MPDStatus(dict):
    """
    This class represent MPD status with a dict-like interface.
    Instances of this class are generated by MPClient, do not
    instantiate directly.
    """

    #### PRIVATE ####
    """All standard status items."""
    _status = {'volume'       : 0,      'repeat'       : 0,     'single'         : 0,
               'consume'      : 0,      'playlist'     : '-1',  'playlistlength' : 0,
               'state'        : 'stop', 'song'         : -1,    'songid'         : '-1',
               'nextsong'     : -1,     'nextsongid'   : '-1',  'time'           : '0:0',
               'elapsed'      : .0,     'bitrate'      : 0,     'xfade'          : 0,
               'mixrampdb'    : .0,     'mixrampdelay' : .0,    'audio'          : '0:0:0',
               'updatings_db' : -1,     'error'        : u'',   'random'         : 0 }

    def __init__(self, data = {}):
        dict.__init__(self, MPDStatus._status)
        for key in data:
            if key in self._status:
                self[key] = type(self._status[key])(data[key])
            else:
                self[key] = data[key]
        try:
            self['time']  = list(map(int, self['time'].split(':')))
        except ValueError:
            self['time']  = [0, 0]
        try:
            self['audio'] = tuple(map(int, self['audio'].split(':')))
        except ValueError:
            self['audio'] = (0, 0, 0)

class MPClient(QtCore.QObject):
    """
    A high-level MPD interface. It is mostly asynchronous -- all responses from
    MPD are read via callbacks. A callback may be None, in which case the data
    is silently discarded. Callbacks that take iterators must ensure that the
    iterator is exhausted.
    """

    #### PUBLIC ####
    # these don't change while we are connected
    """A list of AudioOutputs available."""
    outputs     = None
    """A set of supported tags (valid indices for Song)."""
    tagtypes    = None
    """A list of supported URL handlers."""
    urlhandlers = None

    # read-only
    """An MPDStatus object representing current status."""
    status      = None
    """A Song object representing current song."""
    cur_song    = None
    """
    A dictionary of Song objects representing all songs currently in the database,
    indexed by their paths.
    Changes when db_updated() signal is emitted.
    """
    db          = None
    """
    A list of Song objects representing current playlist
    """
    #playlist    = None

    # SIGNALS
    connect_changed   = Signal(bool)
    db_updated        = Signal()
    time_changed      = Signal(int)
    song_changed      = Signal(object)
    songpos_changed   = Signal(object)          # this one's emitted when only current song's position changed
    state_changed     = Signal(str)
    volume_changed    = Signal(int)
    repeat_changed    = Signal(bool)
    random_changed    = Signal(bool)
    single_changed    = Signal(bool)
    consume_changed   = Signal(bool)
    crossfade_changed = Signal(int)
    playlist_changed  = Signal()
    sticker_changed   = Signal()


    #### PRIVATE ####
    # const
    _sup_ver     = (0, 16, 0)
    _logger      = None
    _timer       = None

    # these don't change while we are connected
    _commands    = None
    _socket      = None
    _password    = None

    #### PUBLIC ####

    ## internals ##
    def __init__(self, parent = None):
        QtCore.QObject.__init__(self, parent)
        self._logger     = logging.getLogger('%smpclient'%(str(parent) + "." if parent else ""))
        self._timer      = QtCore.QTimer(self)
        self._timer.setInterval(1000)
        self._timer.timeout.connect(self._update_timer)
        self._socket     = MPDSocket(self)
        self._commands   = []
        self.status      = MPDStatus()
        self.cur_song    = Song()
        self.db          = {}
        #self.playlist    = []

        self.outputs     = []
        self.urlhandlers = []
        self.tagtypes    = set()
    def __str__(self):
        return self._logger.name

    ## connection functions ##
    def connect_mpd(self, host = "localhost", port = 6600, password = None):
        """
        Connect to MPD at host:port optionally using a password. A Unix domain
        socket is used if port is omitted.
        """
        self._logger.info('Connecting to MPD...')

        if self.is_connected():
            self._logger.warning('Already connected.')

        self._socket.connect_changed.connect(lambda val: self._handle_connected() if val else self._handle_disconnected())
        self._socket.connect_mpd(host, port)
        self._password = password
    def disconnect_mpd(self):
        """
        Disconnect from MPD.
        """
        self._logger.info('Disconnecting from MPD.')
        if self.is_connected():
            self._socket.write_command('close')
    def is_connected(self):
        """
        Returns True if connected to MPD, False otherwise.
        """
        return self._socket.state() == QtNetwork.QAbstractSocket.ConnectedState

    ## playlists ##
    def playlist(self, callback):
        """
        Request current playlist from MPD. Callback will be called with an
        iterator over Songs in current playlist as the argument.
        """
        self._command('playlistinfo', callback = lambda data: callback(self._parse_songs(data)))
    def delete(self, ids):
        """
        Delete songs with specified ids from playlist.
        """
        for id in ids:
            self._command('deleteid', id)
    def clear(self):
        """
        Clear current playlist.
        """
        self._command('clear')
    def add(self, paths, pos = -1):
        """
        Add specified songs to specified position in current playlist.
        """
        # start playback of the first added song if MPD is stopped
        if self.status['state'] == 'stop':
            cb = lambda data: [self.play(sid) for sid in self._parse_list(data) ]
        else:
            cb = None

        args = ['addid', '']
        if pos >= 0:
            args.append(pos)
        for path in paths:
            args[1] = path
            if cb:
                self._command(*args, callback = cb)
                cb = None
            else:
                self._command(*args)
            if pos >= 0:
                args[2] += 1
    def move(self, src, dst):
        """
        Move a song with given src id to position dst.
        """
        self._command('moveid', src, dst)
    def shuffle(self):
        """
        Shuffle the current playlist.
        """
        self._command('shuffle')

    ## database ##
    def update_database(self):
        """
        Initiates a database update.
        """
        self._command('update')
    def rescan_database(self):
        """
        Initiase a rebuild of database from scratch.
        """
        self._command('rescan')

    ## searching ##
    def find(self, callback, *args):
        """
        Request a search on MPD. Callback will be called with an iterator over
        all found songs. For allowed values of args, see MPD protocol documentation.
        """
        self._command('find', args, callback = lambda data: callback(self._parse_songs(data)))
    def findadd(self, *args):
        """
        Request a search on MPD and add found songs to current playlist. Allowed values
        of args are same as for find.
        """
        self._command('findadd', *args)

    ## playback options ##
    def set_volume(self, volume):
        """
        Set MPD volume level.
        """
        volume = min(100, max(0, volume))
        self._command('setvol', volume)
    def repeat(self, val):
        """
        Enable/disable repeat.
        """
        val = '1' if val else '0'
        self._command('repeat', val)
    def random(self, val):
        """
        Enable/disable random.
        """
        val = '1' if val else '0'
        self._command('random', val)
    def consume(self, val):
        """
        Enable/disable consume.
        """
        val = '1' if val else '0'
        self._command('consume', val)
    def single(self, val):
        """
        Enable/disable single.
        """
        val = '1' if val else '0'
        self._command('single', val)
    def crossfade(self, time):
        """
        Set crossfade to specified time.
        """
        self._command('crossfade', time)

    ## controlling playback ##
    def play(self, id = None):
        """
        Start playback of song with a specified id. If no id is given, then
        start on current song/beginning.
        """
        args = ['playid']
        if id:
            args.append(id)
        self._command(*args)
    def pause(self):
        """
        Pause playback.
        """
        self._command('pause', 1)
    def resume(self):
        """
        Resume paused playback.
        """
        self._command('pause', 0)
    def next(self):
        """
        Move on to next song.
        """
        self._command('next')
    def previous(self):
        """
        Move back to previous song.
        """
        self._command('previous')
    def stop(self):
        """
        Stop playback.
        """
        self._command('stop')
    def seek(self, time):
        """
        Seek to specified time in current song.
        """
        self._command('seekid', self.status['songid'], time)

    ## stickers ##
    def sticker_list(self, song, callback):
        """
        Get a list of stickers for specified song. callback is called with an
        iterator over (key, value) tuples as argument.
        """
        self._command('sticker', 'list', 'song', song, callback = lambda data: callback(self._parse_stickers(data)))
    def sticker_set(self, song, key, value):
        """
        Set a sticker associated with song.
        """
        self._command('sticker', 'set', 'song', song, key, value)
    def sticker_get(self, song, key, callback):
        """
        Get a sticker with the given key associated with song.
        Callback is called with the sticker's value as argument.
        """
        self._command('sticker', 'get', 'song', song, key,
                      callback = lambda data: callback(self._parse_sticker(data)), report_errors = False)

    #### PRIVATE ####

    ## connection functions ##
    # these functions are called during connection process #
    # XXX: maybe use a generator?
    @Slot()
    def _handle_connected(self):
        """
        Called when a connection is established. Send a password and
        start getting locally stored values.
        """
        self._logger.debug('Connection established.')

        # check if protocol version is supported
        v = self._socket.version
        if v[0] != self._sup_ver[0]:
            self._logger.error('Server reported unsupported major protocol version %d, disconnecting.'%v[0])
            return self.disconnect_mpd()
        if v[1] < self._sup_ver[1]:
            self._logger.warning('Server reported too low minor protocol version %d. Continuing, but things might break.'%v[1])

        if self._password:
            self._socket.write_command('password', self._password)

        self._socket.write_command('commands', callback = self._parse_commands)

    def _parse_commands(self, data):
        """
        Receive a list of available commands and update
        the other locally stored values.
        """
        self._logger.debug('Receiving command list.')
        self._commands = list(self._parse_list(data))

        if not 'listallinfo' in self._commands:
            self._logger.error('Don\'t have MPD read permission, diconnecting.')
            return self.disconnect_mpd()

        # update cached values
        self._command('outputs',     callback = self._parse_outputs)
        self._command('tagtypes',    callback = self._parse_tagtypes)
        self._command('urlhandlers', callback = self._parse_urlhandlers)

    def _parse_outputs(self, data):
        """
        Update a list of outputs.
        """
        self._logger.debug('Receiving outputs.')
        self.outputs = []
        for output in self._parse_objects(data, ['outputid']):
            self.outputs.append(AudioOutput(output, lambda val, outid = output['outputid']: self._set_output(outid, val), self))

    def _parse_tagtypes(self, data):
        """
        Update a list of tag types.
        """
        self._logger.debug('Receiving tag types.')
        self.tagtypes = set(self._parse_list(data))
        self.tagtypes.add('file')
    def _parse_urlhandlers(self, data):
        """
        Update a list of URL handlers and finish connection.
        """
        self._logger.debug('Receiving URL handlers.')
        self.urlhandlers = list(self._parse_list(data))

        # done initializing data, finish connecting
        return self._finish_connect()

    def _finish_connect(self):
        """
        Called when connecting is completely done. Emit all signals.
        """
        self._logger.info('Successfully connected to MPD.')

        self._socket.subsystems_changed.connect(self._mpd_changed)
        self.connect_changed.emit(True)
        self._mpd_changed()

    @Slot()
    def _handle_disconnected(self):
        """
        Called when connection is closed. Clear all cached data and emit
        corresponding signals.
        """
        self._logger.info('Disconnected from MPD.')
        self._commands   = []
        self.outputs     = {}
        self.tagtypes    = set()
        self.urlhandlers = []

        self._mpd_changed()
        self.connect_changed.emit(False)

     ################################

    @Slot(list)
    def _mpd_changed(self, subsystems = None):
        """
        Called when MPD signals a change in some subsystems.
        """
        if not subsystems:
            subsystems = ['database', 'update', 'stored_playlist', 'playlist', 'output',
                          'player', 'mixer', 'options', 'sticker']

        if ('player'          in subsystems or
            'mixer'           in subsystems or
            'options'         in subsystems):
            self._command('status', callback = self._update_status)
        if 'database'        in subsystems:
            self._command('listallinfo', callback = lambda data: self._update_db(self._parse_songs(data)))
        if 'sticker'         in subsystems:
            self.sticker_changed.emit()
        if 'update'          in subsystems:
            pass                    # just list for completeness
        if 'stored_playlist' in subsystems:
            pass
        if 'playlist'        in subsystems:
            self.playlist_changed.emit()
            self._command('currentsong', callback = self._update_cur_song)
        if 'output'          in subsystems:
            self._command('outputs', callback = self._update_outputs)

    def _update_outputs(self, data):
        """
        Update outputs states.
        """
        for output in self._parse_objects(data, ['outputid']):
            self.outputs[int(output['outputid'])].update(output)

    def _update_status(self, data):
        """
        Called when something in status has changed. Check what was it and emit
        corresponding signals.
        """
        status      = self.status
        try:
            self.status = MPDStatus(list(self._parse_objects(data, ''))[0])
        except IndexError:
            self.status = MPDStatus()

        if self.status['state'] == 'play':
            self._timer.start()
        else:
            self._timer.stop()

        if status['state']  != self.status['state']:
            self.state_changed.emit(self.status['state'])
        if status['time'][0] != self.status['time'][0]:
            self.time_changed.emit(self.status['time'][0])
        if status['volume'] != self.status['volume']:
            self.volume_changed.emit(self.status['volume'])
        if status['repeat'] != self.status['repeat']:
            self.repeat_changed.emit(self.status['repeat'])
        if status['random'] != self.status['random']:
            self.random_changed.emit(self.status['random'])
        if status['single'] != self.status['single']:
            self.single_changed.emit(self.status['single'])
        if status['consume'] != self.status['consume']:
            self.consume_changed.emit(self.status['consume'])
        if status['xfade'] != self.status['xfade']:
            self.crossfade_changed.emit(self.status['xfade'])
        if status['songid'] != self.status['songid']:
            self._command('currentsong', callback = self._update_cur_song)

    def _update_cur_song(self, data):
        song = self.cur_song
        try:
            self.cur_song = Song(list(self._parse_objects(data, ''))[0])
        except IndexError:
            self.cur_song = Song()
        if song['id'] != self.cur_song['id']:
            self.song_changed.emit(self.cur_song)
            if 'played' in song:
                self._update_playcount(song)
        else:
            self.songpos_changed.emit(self.cur_song)

    def _update_db(self, songs):
        for song in songs:
            self.db[song['file']] = song
        self.db_updated.emit()

    def _update_playcount(self, song):
        if not 'file' in song or os.path.isabs(song['file']):
            return
        self._logger.info('Incrementing the playcount for song %s.'%song['file'])
        self.sticker_get(song['file'], 'playcount', lambda val: self._update_playcount2(song, val))
    def _update_playcount2(self, song, playcount):
        try:
            playcount = int(playcount)
        except ValueError:
            playcount = 0
        playcount += 1
        self.sticker_set(song['file'], 'playcount', playcount)

    def _command(self, *cmd, **kwargs):
        """
        Send specified command to MPD asynchronously. kwargs must contain
        a callable 'callback' if the caller want to read a response. Otherwise
        any reponse from MPD is silently discarded.
        """
        if not self.is_connected():
            self._logger.debug('Not connected -- not running command: %s'%cmd[0])
            if 'callback' in kwargs:
                kwargs['callback']([])
        elif not cmd[0] in self._commands:
            self._logger.error('Command %s not allowed.'%cmd[0])
            if 'callback' in kwargs:
                kwargs['callback']([])
        else:
            self._socket.write_command(*cmd, **kwargs)

    def _set_output(self, out_id, val):
        """
        Enable/disable speciffied output. Called only by AudioOutput.
        """
        cmd = 'enableoutput' if val else 'disableoutput'
        self._command(cmd, out_id)

    def _update_timer(self):
        self.status['time'][0] += 1
        self.time_changed.emit(self.status['time'][0])
        if not 'played' in self.cur_song:
            if self.status['time'][0] / self.status['time'][1] > 0.75:
                self.cur_song['played'] = True

    ## MPD output parsing functions ##

    def _parse_list(self, data):
        """
        Parse a list of 'id_we_dont_care_about: useful_data'.
        """
        for line in data:
            parts = line.partition(': ')
            if not parts[1]:
                self._logger.error('Malformed line: %s.'%line)
                continue
            yield parts[2]

    def _parse_objects(self, data, delimiters):
        """
        Parse a list of object separated by specified delimiters.
        """
        cur = {}
        for line in data:
            parts = line.partition(': ')
            if not parts[1]:
                self._logger.error('Malformed line: %s.'%line)
                continue

            if parts[0] in delimiters and cur:
                yield cur
                cur = {}

            if parts[0] in cur:
                cur[parts[0]] += ',' + parts[2]
            else:
                cur[parts[0]] = parts[2]
        if cur:
            yield cur

    def _parse_songs(self, data):
        """
        Parse a list of songs -- output of playlistinfo/listallinfo.
        """
        for song in self._parse_objects(data, ['file', 'directory']):
            if 'file' in song:
                yield Song(song)

    def _parse_stickers(self, data):
        """
        Parse a list of stickers -- output of sticker list.
        Yields (key, value) tuples.
        """
        for sticker in self._parse_list(data):
            parts = sticker.partition('=')
            if not parts[1]:
                self._logger.error('Malformed sticker: %s.'%sticker)
                continue
            yield (parts[0], parts[2])
    def _parse_sticker(self, data):
        """
        Parse a single sticker -- output of sticker get.
        Returns the sticker's value.
        """
        sticker = list(self._parse_list(data))
        try:
            return sticker[0].partition('=')[2]
        except IndexError:
            return ""