"""Pytest fixtures for async tests."""

import asyncio
from typing import AsyncGenerator

import fakeredis.aioredis
import pytest
import pytest_asyncio
from httpx import ASGITransport, AsyncClient
from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine

import app.cache as cache_module
from app.database import Base, get_db
from app.main import app


@pytest.fixture(scope="session")
def event_loop():
    """Create a single event loop for all tests."""
    loop = asyncio.new_event_loop()
    yield loop
    loop.close()


@pytest_asyncio.fixture
async def test_engine():
    """Create a fresh in-memory SQLite engine for each test."""
    engine = create_async_engine("sqlite+aiosqlite:///:memory:", echo=False)
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.create_all)
    yield engine
    await engine.dispose()


@pytest_asyncio.fixture
async def db_session(test_engine) -> AsyncGenerator[AsyncSession, None]:
    """Yield a DB session bound to the test engine."""
    session_factory = async_sessionmaker(test_engine, class_=AsyncSession, expire_on_commit=False)
    async with session_factory() as session:
        yield session


@pytest_asyncio.fixture
async def fake_redis():
    """Provide a fakeredis instance and patch the cache module global."""
    fake = fakeredis.aioredis.FakeRedis(decode_responses=True)
    cache_module._cache_client = fake
    yield fake
    cache_module._cache_client = None
    await fake.flushall()


@pytest_asyncio.fixture
async def client(test_engine, fake_redis) -> AsyncGenerator[AsyncClient, None]:
    """Provide an async HTTP client with test DB and fake Redis."""
    session_factory = async_sessionmaker(test_engine, class_=AsyncSession, expire_on_commit=False)

    async def override_get_db() -> AsyncGenerator[AsyncSession, None]:
        async with session_factory() as session:
            yield session

    app.dependency_overrides[get_db] = override_get_db

    transport = ASGITransport(app=app)
    async with AsyncClient(transport=transport, base_url="http://test") as ac:
        yield ac

    app.dependency_overrides.clear()