from django.db import models
from django.db.models.signals import pre_save
from django.dispatch.dispatcher import receiver
from django.template.defaultfilters import slugify


class Artist(models.Model):
    """ An Artist of the label. """

    name = models.CharField(max_length = 64)
    slug = models.SlugField()
    image = models.ImageField(upload_to = "artists")
    url_bandcamp = models.URLField(blank = True)
    url_soundcloud = models.URLField(blank = True)
    genre = models.CharField(max_length = 256)
    description = models.TextField(blank = True)

    def __str__(self):
        return self.name

    class Meta(object):
        ordering = ("name",)

@receiver(pre_save, sender = Artist)
def _artist_pre_save(sender, instance, **kwargs):
    instance.slug = slugify(instance.name)


REL_TYPES_HINT = "full-length (0), EP (1), Split (2), Démo (3)"

class Release(models.Model):
    """ A release (album, EP, ...) of the label.

    Each release has an associated number "ident" to use in the catalog. It has
    of course a title, several possible artists, and other informations.

    Attributes:
        ident: catalog number
        title: release title
        contributors: list of Artists who contributed to this release
        release_type: see below
        year: year of release
        cover: image file associated to this release
    """

    ident = models.IntegerField()
    title = models.CharField(max_length = 256)
    contributors = models.ManyToManyField(Artist)
    release_type = models.IntegerField(default = 0, help_text = REL_TYPES_HINT)
    cover = models.ImageField(upload_to = "releases")
    year = models.IntegerField()
    embed = models.TextField(blank = True)
    description = models.TextField(blank = True)

    def __str__(self):
        return self.title

    class Meta(object):
        ordering = ("ident", "title")