from django.db import models

class City(models.Model):

    id = models.BigAutoField(primary_key=True)

    name = models.CharField(max_length=50)

class Country(models.Model):

    id = models.SmallAutoField(primary_key=True)

    name = models.CharField(max_length=50)

class District(models.Model):

    city = models.ForeignKey(City, models.CASCADE, primary_key=True)

    name = models.CharField(max_length=50)

class Reporter(models.Model):

    first_name = models.CharField(max_length=30)

    last_name = models.CharField(max_length=30)

    email = models.EmailField()

    facebook_user_id = models.BigIntegerField(null=True)

    raw_data = models.BinaryField(null=True)

    small_int = models.SmallIntegerField()

    interval = models.DurationField()

    class Meta:

        unique_together = ("first_name", "last_name")

class Article(models.Model):

    headline = models.CharField(max_length=100)

    pub_date = models.DateField()

    body = models.TextField(default="")

    reporter = models.ForeignKey(Reporter, models.CASCADE)

    response_to = models.ForeignKey("self", models.SET_NULL, null=True)

    unmanaged_reporters = models.ManyToManyField(

        Reporter, through="ArticleReporter", related_name="+"

    )

    class Meta:

        ordering = ("headline",)

        index_together = [

            ["headline", "pub_date"],

            ["headline", "response_to", "pub_date", "reporter"],

        ]

class ArticleReporter(models.Model):

    article = models.ForeignKey(Article, models.CASCADE)

    reporter = models.ForeignKey(Reporter, models.CASCADE)

    class Meta:

        managed = False

class Comment(models.Model):

    ref = models.UUIDField(unique=True)

    article = models.ForeignKey(Article, models.CASCADE, db_index=True)

    email = models.EmailField()

    pub_date = models.DateTimeField()

    body = models.TextField()

    class Meta:

        constraints = [

            models.UniqueConstraint(

                fields=["article", "email", "pub_date"],

                name="article_email_pub_date_uniq",

            ),

        ]

        indexes = [

            models.Index(fields=["email", "pub_date"], name="email_pub_date_idx"),

        ]

class CheckConstraintModel(models.Model):

    up_votes = models.PositiveIntegerField()

    voting_number = models.PositiveIntegerField(unique=True)

    class Meta:

        required_db_features = {

            "supports_table_check_constraints",

        }

        constraints = [

            models.CheckConstraint(

                name="up_votes_gte_0_check", check=models.Q(up_votes__gte=0)

            ),

        ]

class UniqueConstraintConditionModel(models.Model):

    name = models.CharField(max_length=255)

    color = models.CharField(max_length=32, null=True)

    class Meta:

        required_db_features = {"supports_partial_indexes"}

        constraints = [

            models.UniqueConstraint(

                fields=["name"],

                name="cond_name_without_color_uniq",

                condition=models.Q(color__isnull=True),

            ),

        ]