from django.db import models
from django.db.models import Q
from django.conf import settings
from django.utils import timezone

from songs.models import Song

class Playlist(models.Model):
    def __str__(self):
        return 'Playlist #' + str(self.id)


class PlaylistSong(models.Model):
    playlist = models.ForeignKey(
        Playlist,
        on_delete=models.SET_NULL,
        blank=True,
        null=True,
    )
    song = models.ForeignKey(
        Song,
        on_delete=models.SET_NULL,
        blank=True,
        null=True,
    )
    user = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        blank=True,
        null=True,
        db_index=True,
    )
    played_at = models.DateTimeField(blank=True, null=True)

    # 0: Queued.
    # 1: Playing.
    # 2: Played.
    # 3: Cancelled.
    STATECHOICE = (
        (0, 'Queued'),
        (1, 'Playing'),
        (2, 'Played'),
        (3, 'Cancelled'),
    )
    state = models.IntegerField(default=0, db_index=True, choices=STATECHOICE)


    def move_down(self):
        other_song = PlaylistSong.objects.filter(playlist=self.playlist, id__gt=self.id).first()
        old_id = self.id
        self.id = other_song.id
        other_song.id = old_id
        self.save()
        other_song.save()

    def __str__(self):
        return 'Playlist #' + str(self.playlist_id) + ': ' + str(self.song)


class Queue(models.Model):
    class Meta:
        permissions = (
            ('can_skip', 'Can skip the currently playing song'),
            ('can_move', 'Can move all songs in the queue'),
            ('can_cancel', 'Can cancel all songs in the queue'),
            ('can_control_volume', 'Can control the volume of Marietje'),
            ('unlimited_queue_length', 'Is unlimited by maximum queue length'),
        )

    name = models.TextField()
    playlist = models.ForeignKey(
        Playlist,
        on_delete=models.SET_NULL,
        blank=True,
        null=True,
    )
    random_playlist = models.ForeignKey(
        Playlist,
        on_delete=models.SET_NULL,
        blank=True,
        null=True,
        related_name='random_playlist_set'
    )
    started_at = models.DateTimeField(blank=True, null=True)
    songs = None
    player_token = models.TextField(blank=True, null=True)

    def get_songs(self):
        if self.songs is None:
            self.fill_random_queue()
            self.songs = PlaylistSong.objects\
                .filter(Q(playlist=self.playlist_id) | Q(playlist_id=self.random_playlist_id),
                        Q(state=0) | Q(state=1))\
                .order_by('-state', 'playlist_id', 'id')\
                .select_related('song', 'user')
        return self.songs

    def current_song(self):
        songs = self.get_songs()
        if not songs:
            return None
        song = songs[0]
        if song.state != 1:
            song.state = 1
            song.save()
        return song

    def queue(self):
        songs = self.get_songs()
        if len(songs) < 2:
            return []
        return songs[1:]

    def request(self, song, user):
        if not user.has_perm('queues.unlimited_queue_length'):
            playlist_songs = PlaylistSong.objects.filter(playlist=self.playlist, state=0).order_by('id')

            seconds_in_a_row = sum(ps.song.duration for ps in playlist_songs if ps.user == user)
            msg = 'You cannot request more than ' + str(settings.MAX_MINUTES_IN_A_ROW) + ' minutes in a row.'
            if settings.LIMIT_ALWAYS:
                if seconds_in_a_row > settings.MAX_MINUTES_IN_A_ROW * 60:
                    return msg
            else:
                now = timezone.now()
                if seconds_in_a_row > 0 and \
                        seconds_in_a_row + song.duration > settings.MAX_MINUTES_IN_A_ROW * 60 and \
                        settings.LIMIT_HOURS[0] <= now.hour < settings.LIMIT_HOURS[1]:
                    return msg

            if {ps for ps in playlist_songs if ps.song == song}:
                return 'This song is already in the queue.'

        playlist_song = PlaylistSong(playlist=self.playlist, song=song, user=user)
        playlist_song.save()

        # If the song was auto-queue'd, then remove it from the auto-queue
        autolist_songs = PlaylistSong.objects.filter(playlist=self.random_playlist, state=0, song=song)
        autolist_songs.delete()

        return None

    def fill_random_queue(self):
        song_count = PlaylistSong.objects.filter(playlist_id=self.random_playlist_id, state=0).count()
        while song_count < 5:
            song = Song.objects.filter(deleted=False).order_by('?').first()
            if song is None:
                return
            playlist_song = PlaylistSong(playlist=self.random_playlist, song=song, user=None)
            playlist_song.save()
            song_count += 1

    def __str__(self):
        return str(self.name)


class QueueCommand(models.Model):
    queue = models.ForeignKey(
        Queue,
        on_delete=models.CASCADE,
        db_index=True,
    )
    command = models.TextField()

    def __str__(self):
        return str(self.command)