from django.db import models
from django.contrib.auth.models import User
from django.core.validators import MaxValueValidator, MinValueValidator


class Movie(models.Model):
    title = models.CharField(max_length=32)
    description = models.TextField(max_length=360)

    def no_of_ratings(self):
        ratings = Rating.objects.filter(movie=self)
        return len(ratings)

    def average_ratings(self):
        ratings = Rating.objects.filter(movie=self)
        average = 0
        for rating in ratings:
            average += rating.stars
        if len(ratings) > 0:
            return average / len(ratings)
        return 0

    def __str__(self):
        return self.title


class Rating(models.Model):
    movie = models.ForeignKey(Movie, on_delete=models.CASCADE)
    user = models.ForeignKey(User, on_delete=models.CASCADE)
    stars = models.IntegerField(
        validators=[MinValueValidator(1), MaxValueValidator(5)])

    class Meta:
        unique_together = (('user'), 'movie')
        index_together = (('user'), 'movie')

    def __str__(self):
        return f"{self.movie.title} - {self.stars}"