import os

import pytest
from httpx import ASGITransport, AsyncClient
from sqlalchemy.ext.asyncio import async_sessionmaker, create_async_engine

import app.models  # noqa: F401 — ensures all models register with Base.metadata
from app.core.database import Base, get_session
from app.main import app

TEST_DATABASE_URL = os.getenv(
    "TEST_DATABASE_URL",
    "postgresql+asyncpg://postgres:postgres@localhost:5433/nuzlocke_test",
)


@pytest.fixture(scope="session")
async def engine():
    """Create the test engine and schema once for the entire session."""
    eng = create_async_engine(TEST_DATABASE_URL, echo=False)
    async with eng.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)
    yield eng
    async with eng.begin() as conn:
        await conn.run_sync(Base.metadata.drop_all)
    await eng.dispose()


@pytest.fixture
async def db_session(engine):
    """
    Provide a database session for a single test.

    Overrides the FastAPI get_session dependency so endpoint handlers use the
    same session. Truncates all tables after the test to isolate state.
    """
    session_factory = async_sessionmaker(engine, expire_on_commit=False)
    session = session_factory()

    async def override_get_session():
        yield session

    app.dependency_overrides[get_session] = override_get_session

    yield session

    await session.close()
    app.dependency_overrides.clear()

    async with engine.begin() as conn:
        for table in reversed(Base.metadata.sorted_tables):
            await conn.execute(table.delete())


@pytest.fixture
async def client(db_session):
    """Async HTTP client wired to the FastAPI app with the test database session."""
    async with AsyncClient(
        transport=ASGITransport(app=app), base_url="http://test"
    ) as ac:
        yield ac