"""

The lookup API

This demonstrates features of the database API.

"""

from django.db import models

from django.db.models.lookups import IsNull

class Alarm(models.Model):

    desc = models.CharField(max_length=100)

    time = models.TimeField()

    def __str__(self):

        return "%s (%s)" % (self.time, self.desc)

class Author(models.Model):

    name = models.CharField(max_length=100)

    alias = models.CharField(max_length=50, null=True, blank=True)

    class Meta:

        ordering = ("name",)

class Article(models.Model):

    headline = models.CharField(max_length=100)

    pub_date = models.DateTimeField()

    author = models.ForeignKey(Author, models.SET_NULL, blank=True, null=True)

    slug = models.SlugField(unique=True, blank=True, null=True)

    class Meta:

        ordering = ("-pub_date", "headline")

    def __str__(self):

        return self.headline

class Tag(models.Model):

    articles = models.ManyToManyField(Article)

    name = models.CharField(max_length=100)

    class Meta:

        ordering = ("name",)

class NulledTextField(models.TextField):

    def get_prep_value(self, value):

        return None if value == "" else value

@NulledTextField.register_lookup

class NulledTransform(models.Transform):

    lookup_name = "nulled"

    template = "NULL"

@NulledTextField.register_lookup

class IsNullWithNoneAsRHS(IsNull):

    lookup_name = "isnull_none_rhs"

    can_use_none_as_rhs = True

class Season(models.Model):

    year = models.PositiveSmallIntegerField()

    gt = models.IntegerField(null=True, blank=True)

    nulled_text_field = NulledTextField(null=True)

    class Meta:

        constraints = [

            models.UniqueConstraint(fields=["year"], name="season_year_unique"),

        ]

    def __str__(self):

        return str(self.year)

class Game(models.Model):

    season = models.ForeignKey(Season, models.CASCADE, related_name="games")

    home = models.CharField(max_length=100)

    away = models.CharField(max_length=100)

class Player(models.Model):

    name = models.CharField(max_length=100)

    games = models.ManyToManyField(Game, related_name="players")

class Product(models.Model):

    name = models.CharField(max_length=80)

    qty_target = models.DecimalField(max_digits=6, decimal_places=2)

class Stock(models.Model):

    product = models.ForeignKey(Product, models.CASCADE)

    short = models.BooleanField(default=False)

    qty_available = models.DecimalField(max_digits=6, decimal_places=2)

class Freebie(models.Model):

    gift_product = models.ForeignKey(Product, models.CASCADE)

    stock_id = models.IntegerField(blank=True, null=True)

    stock = models.ForeignObject(

        Stock,

        from_fields=["stock_id", "gift_product"],

        to_fields=["id", "product"],

        on_delete=models.CASCADE,

    )