#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# SPDX-FileCopyrightText: 2009,2010,2012,2019 kaliko <kaliko@azylum.org>
# SPDX-License-Identifier: GPL-3.0-or-later

import sys
import argparse

from time import sleep
from os.path import basename

import musicpd

VERSION = '0.2'


class Nalbum(musicpd.MPDClient):
    script_info = dict({
        'prog': basename(__file__),
        'description': 'Jump to next album in playlist.',
        'epilog': 'Set MPD host/port in env. var'
    })

    def __init__(self):
        musicpd.MPDClient.__init__(self)
        self.args = self._get_args()
        self._run()

    def _get_args(self):
        parser = argparse.ArgumentParser(**self.__class__.script_info)
        parser.add_argument('--version', action='version',
                            version='v%s' % VERSION)
        parser.add_argument('-c', '--cross-fade', type=int, dest='time',
                            help='fade out/fade in over t seconds.',)
        args = parser.parse_args()
        return args

    def _setvol(self, vol):
        """
        Sometimes while fading in on next album, MPD fails.
        Log shows :
        "exception: Failed to set mixer for 'My Pulse Output': disconnected"
        python-musicpd then raises "[52@0] {setvol} problems setting volume"
        """
        try:
            self.setvol(int(vol))
        except musicpd.CommandError as err:
            print('MPD raised "%s"' % err)
            print('Try to set the output with \'always_on    "yes"\'')
            if 'problems setting volume' in str(err):
                sleep(.1)
                self._setvol(int(vol))

    def _fade(self, mpd_vol, io='out'):
        """
        end_volum => End volume value
        start_vol   => Start volume value
        """
        if io == 'out':
            end_volum = mpd_vol // 10
            start_vol = mpd_vol
        if io == 'in':
            end_volum = mpd_vol
            start_vol = mpd_vol // 10
        # print(start_vol, end_volum)
        span = float(end_volum - start_vol)
        step = span / float(10*self.args.time)
        if step == 0:
            return True
        while True:
            start_vol += step
            self._setvol(int(start_vol))
            if abs(start_vol - end_volum) < 1.1*abs(step):
                self._setvol(end_volum)
                return True
            sleep(0.1)

    def _get_next(self):
        """Retrieve playlist from current song to the end."""
        if 'song' not in self.status():
            print('No current song set in MPD!')
            self.disconnect()
            sys.exit(0)
        current_album = str(self.currentsong().get('album', 'TAG MISSING'))
        current_song_pos = int(self.currentsong().get('pos'))
        print('Current album: "%s"' % current_album)
        next_album_pos = current_song_pos
        album = current_album
        while album == current_album:
            next_album_pos += 1
            pl_length = int(self.status().get('playlistlength')) - 1
            if pl_length < next_album_pos:
                print('Next album not found in the playlitst!')
                self.disconnect()
                sys.exit(0)
            album = self.playlistinfo(next_album_pos)[
                0].get('album', 'TAG MISSING')
        print('Next album appears to be: "%s"' % album)
        return next_album_pos

    def _run(self):
        self.connect()
        nalbum = self._get_next()
        init_vol = int(self.status().get('volume', 0))
        if self.args.time:
            print('Cross fading next album')
            self._fade(init_vol)
        self.play(nalbum)
        if self.args.time:
            self._fade(init_vol, io='in')
        self.disconnect()
        sys.exit(0)


# Script starts here
if __name__ == '__main__':
    try:
        Nalbum()
    except KeyboardInterrupt:
        sys.stdout.write('exit')

# VIM MODLINE
# vim: ai ts=4 sw=4 sts=4 expandtab