from django.db import models


class Dinosaur(models.Model):
    ERA_CHOICES = [
        ('triassic', 'Triassic'),
        ('jurassic', 'Jurassic'),
        ('cretaceous', 'Cretaceous'),
    ]

    DIET_CHOICES = [
        ('herbivore', 'Herbivore'),
        ('carnivore', 'Carnivore'),
        ('omnivore', 'Omnivore'),
    ]

    name = models.CharField(max_length=120)
    era = models.CharField(max_length=32, choices=ERA_CHOICES, default='jurassic')
    diet = models.CharField(max_length=32, choices=DIET_CHOICES, default='herbivore')
    description = models.TextField(blank=True)
    image = models.ImageField(upload_to='dinosaurs/', blank=True, null=True)

    # Top-trump style stats (0-100)
    speed = models.PositiveSmallIntegerField(default=50)
    weight = models.PositiveSmallIntegerField(default=50)
    intelligence = models.PositiveSmallIntegerField(default=50)
    height = models.PositiveSmallIntegerField(default=50)

    created_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['-created_at', 'name']

    def __str__(self):
        return self.name


class BackgroundImage(models.Model):
    """Background images used behind card renders.

    Admins can upload multiple backgrounds and mark one as active. Templates
    will use BackgroundImage.get_active() to obtain the active background.
    """
    title = models.CharField(max_length=200, blank=True)
    image = models.ImageField(upload_to='backgrounds/')
    is_active = models.BooleanField(default=False, help_text='Mark as the active background')
    uploaded_at = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ['-is_active', '-uploaded_at']

    def __str__(self):
        return self.title or f"Background #{self.pk}"

    @classmethod
    def get_active(cls):
        """Return the active BackgroundImage if set, otherwise the most recent one or None."""
        active = cls.objects.filter(is_active=True).order_by('-uploaded_at').first()
        if active:
            return active
        return cls.objects.order_by('-uploaded_at').first()