from typing import List, Optional

import databases
import sqlalchemy
from sqlalchemy import create_engine

import ormar
import pytest

from tests.settings import DATABASE_URL

db = databases.Database(DATABASE_URL)
metadata = sqlalchemy.MetaData()


class User(ormar.Model):
    class Meta:
        metadata = metadata
        database = db
        tablename = "test_users"

    id: int = ormar.Integer(primary_key=True)
    name: str = ormar.String(max_length=50)


class Signup(ormar.Model):
    class Meta:
        metadata = metadata
        database = db
        tablename = "test_signup"

    id: int = ormar.Integer(primary_key=True)


class Session(ormar.Model):
    class Meta:
        metadata = metadata
        database = db
        tablename = "test_sessions"

    id: int = ormar.Integer(primary_key=True)
    name: str = ormar.String(max_length=255, index=True)
    some_text: str = ormar.Text()
    some_other_text: Optional[str] = ormar.Text(nullable=True)
    teacher: Optional[User] = ormar.ForeignKey(
        User, nullable=True, related_name="teaching"
    )
    students: Optional[List[User]] = ormar.ManyToMany(
        User, through=Signup, related_name="attending"
    )


@pytest.fixture(autouse=True, scope="module")
def create_test_database():
    engine = create_engine(DATABASE_URL)
    metadata.create_all(engine)
    yield
    metadata.drop_all(engine)


@pytest.mark.asyncio
async def test_add_students():
    async with db:
        for user_id in [1, 2, 3, 4, 5]:
            await User.objects.create(name=f"User {user_id}")

        for name, some_text, some_other_text in [
            ("Session 1", "Some text 1", "Some other text 1"),
            ("Session 2", "Some text 2", "Some other text 2"),
            ("Session 3", "Some text 3", "Some other text 3"),
            ("Session 4", "Some text 4", "Some other text 4"),
            ("Session 5", "Some text 5", "Some other text 5"),
        ]:
            await Session(
                name=name, some_text=some_text, some_other_text=some_other_text
            ).save()

        s1 = await Session.objects.get(pk=1)
        s2 = await Session.objects.get(pk=2)

        users = {}
        for i in range(1, 6):
            user = await User.objects.get(pk=i)
            users[f"user_{i}"] = user
            if i % 2 == 0:
                await s1.students.add(user)
            else:
                await s2.students.add(user)

        assert len(s1.students) > 0
        assert len(s2.students) > 0

        user = await User.objects.select_related("attending").get(pk=1)

        assert user.attending is not None
        assert len(user.attending) > 0

        query = Session.objects.prefetch_related(["students", "teacher",])
        sessions = await query.all()
        assert len(sessions) == 5