from datetime import datetime

from django.db import models

# M2M described on one of the models

class Person(models.Model):

    name = models.CharField(max_length=128)

    class Meta:

        ordering = ("name",)

class PersonChild(Person):

    pass

class Group(models.Model):

    name = models.CharField(max_length=128)

    members = models.ManyToManyField(Person, through="Membership")

    custom_members = models.ManyToManyField(

        Person, through="CustomMembership", related_name="custom"

    )

    nodefaultsnonulls = models.ManyToManyField(

        Person,

        through="TestNoDefaultsOrNulls",

        related_name="testnodefaultsnonulls",

    )

    class Meta:

        ordering = ("name",)

class Membership(models.Model):

    person = models.ForeignKey(Person, models.CASCADE)

    group = models.ForeignKey(Group, models.CASCADE)

    date_joined = models.DateTimeField(default=datetime.now)

    invite_reason = models.CharField(max_length=64, null=True)

    class Meta:

        ordering = ("date_joined", "invite_reason", "group")

    def __str__(self):

        return "%s is a member of %s" % (self.person.name, self.group.name)

class CustomMembership(models.Model):

    person = models.ForeignKey(

        Person,

        models.CASCADE,

        db_column="custom_person_column",

        related_name="custom_person_related_name",

    )

    group = models.ForeignKey(Group, models.CASCADE)

    weird_fk = models.ForeignKey(Membership, models.SET_NULL, null=True)

    date_joined = models.DateTimeField(default=datetime.now)

    class Meta:

        db_table = "test_table"

        ordering = ["date_joined"]

    def __str__(self):

        return "%s is a member of %s" % (self.person.name, self.group.name)

class TestNoDefaultsOrNulls(models.Model):

    person = models.ForeignKey(Person, models.CASCADE)

    group = models.ForeignKey(Group, models.CASCADE)

    nodefaultnonull = models.IntegerField()

class PersonSelfRefM2M(models.Model):

    name = models.CharField(max_length=5)

    friends = models.ManyToManyField("self", through="Friendship", symmetrical=False)

    sym_friends = models.ManyToManyField(

        "self", through="SymmetricalFriendship", symmetrical=True

    )

class Friendship(models.Model):

    first = models.ForeignKey(

        PersonSelfRefM2M, models.CASCADE, related_name="rel_from_set"

    )

    second = models.ForeignKey(

        PersonSelfRefM2M, models.CASCADE, related_name="rel_to_set"

    )

    date_friended = models.DateTimeField()

class SymmetricalFriendship(models.Model):

    first = models.ForeignKey(PersonSelfRefM2M, models.CASCADE)

    second = models.ForeignKey(PersonSelfRefM2M, models.CASCADE, related_name="+")

    date_friended = models.DateField()

# Custom through link fields

class Event(models.Model):

    title = models.CharField(max_length=50)

    invitees = models.ManyToManyField(

        to=Person,

        through="Invitation",

        through_fields=["event", "invitee"],

        related_name="events_invited",

    )

class Invitation(models.Model):

    event = models.ForeignKey(Event, models.CASCADE, related_name="invitations")

    # field order is deliberately inverted. the target field is "invitee".

    inviter = models.ForeignKey(Person, models.CASCADE, related_name="invitations_sent")

    invitee = models.ForeignKey(Person, models.CASCADE, related_name="invitations")

class Employee(models.Model):

    name = models.CharField(max_length=5)

    subordinates = models.ManyToManyField(

        "self",

        through="Relationship",

        through_fields=("source", "target"),

        symmetrical=False,

    )

    class Meta:

        ordering = ("pk",)

class Relationship(models.Model):

    # field order is deliberately inverted.

    another = models.ForeignKey(

        Employee, models.SET_NULL, related_name="rel_another_set", null=True

    )

    target = models.ForeignKey(Employee, models.CASCADE, related_name="rel_target_set")

    source = models.ForeignKey(Employee, models.CASCADE, related_name="rel_source_set")

class Ingredient(models.Model):

    iname = models.CharField(max_length=20, unique=True)

    class Meta:

        ordering = ("iname",)

class Recipe(models.Model):

    rname = models.CharField(max_length=20, unique=True)

    ingredients = models.ManyToManyField(

        Ingredient,

        through="RecipeIngredient",

        related_name="recipes",

    )

    class Meta:

        ordering = ("rname",)

class RecipeIngredient(models.Model):

    ingredient = models.ForeignKey(Ingredient, models.CASCADE, to_field="iname")

    recipe = models.ForeignKey(Recipe, models.CASCADE, to_field="rname")