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


ART_GENRE_HINT = 'lowercase please!'
ART_DESC_HINT = 'Markdown or HTML formatting supported'
ART_TYPES_HINT = 'main roster (0), side project (1)'


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, help_text=ART_GENRE_HINT)
    description = models.TextField(blank=True, help_text=ART_DESC_HINT)
    artist_type = models.IntegerField(default=0, help_text=ART_TYPES_HINT)

    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)


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 TYPE_HINT
        year: year of release
        cover: image file associated to this release
    """

    TYPE_HINT = 'full-length (0), EP (1), Split (2), Démo (3)'
    EMBED_HINT = 'HTML iframe -- for Bandcamp, add the whole tracklist'

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

    def __str__(self):
        return self.title

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