from django.db import models

class ArtistManager(models.Manager):
    def from_json(self, json):
        try:
            return Artist.objects.get(pk=json["id"])
        except Artist.DoesNotExist:
            keys = [f.name for f in Artist._meta.get_fields()]
            subset = {key:json[key] for key in set(keys) & set(json.keys())}
            artist = self.create(**subset)
            return artist

class Artist(models.Model):
    def __str__(self):
        return self.name
    id = models.CharField(primary_key=True, max_length=128)
    name = models.CharField(max_length=255)
    popularity = models.SmallIntegerField(null=True, blank=True)
    genres = models.JSONField(null=True)

    objects = ArtistManager()

class AlbumManager(models.Manager):
    def from_json(self, json):
        try:
            return Album.objects.get(pk=json["id"])
        except Album.DoesNotExist:
            artists = []
            for artist in json["artists"]:
                artists.append(Artist.objects.from_json(artist))
            del json["artists"]
            keys = [f.name for f in Album._meta.get_fields()]
            subset = {key:json[key] for key in set(keys) & set(json.keys())}
            album = self.create(**subset)
            for artist in artists:
                album.artists.add(artist)
            return album

class Album(models.Model):
    def __str__(self):
        return self.name
    id = models.CharField(primary_key=True, max_length=128)
    name = models.CharField(max_length=255)
    artists = models.ManyToManyField(Artist)
    album_type = models.CharField(max_length=255)
    total_tracks = models.PositiveSmallIntegerField(null=True)
    image = models.ImageField(upload_to="albums/")

    objects = AlbumManager()

class TrackManager(models.Manager):
    def get_queryset(self):
        return super().get_queryset().filter(old=False)
    def from_json(self, json):
        artists = []
        for artist in json["artists"]:
            artists.append(Artist.objects.from_json(artist))
        del json["artists"]

        album = Album.objects.from_json(json["album"])
        del json["album"]

        keys = [f.name for f in Track._meta.get_fields()]
        subset = {key:json[key] for key in set(keys) & set(json.keys())}
        track = self.create(**subset)
        track.album = album
        for artist in artists:
            track.artists.add(artist)
        track.save()
        return track

class Track(models.Model):
    def __str__(self):
        s = f"'{self.name}'"
        if self.artists.count() > 0:
            artists = list(map(lambda a:a.name, self.artists.all()))
            s += " by "
            s += " & ".join(artists)
            
        if self.explicit:
            s += " PARENTAL ADVISORY"
        return s
    id = models.CharField(primary_key=True, max_length=128)
    name = models.CharField(max_length=255)
    artists = models.ManyToManyField(Artist)
    album = models.ForeignKey(Album, null=True, on_delete=models.SET_NULL)

    explicit = models.BooleanField(default=False)
    duration_ms = models.PositiveIntegerField(null=True)
    popularity = models.PositiveIntegerField(null=True)

    banter = models.TextField(blank=True)

    old = models.BooleanField(default=False)

    objects = TrackManager()

#class TrackFeatures(models.Model):