import os
import pytest
import asyncio
from typing import AsyncGenerator, Generator
from fastapi.testclient import TestClient
from httpx import AsyncClient
from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession
from sqlalchemy.orm import sessionmaker
from sqlalchemy.pool import StaticPool
from dotenv import load_dotenv
from pathlib import Path

# Load test environment variables
test_env_path = Path(__file__).parent / "test.env"
load_dotenv(test_env_path)

from app.db.database import Base, get_db
from app.main import app
from app.core.config import settings

# Use SQLite for testing
SQLALCHEMY_DATABASE_URL = "sqlite+aiosqlite:///:memory:"

engine = create_async_engine(
    SQLALCHEMY_DATABASE_URL,
    connect_args={"check_same_thread": False},
    poolclass=StaticPool,
)

TestingSessionLocal = sessionmaker(
    engine,
    class_=AsyncSession,
    expire_on_commit=False,
)

@pytest.fixture(scope="session")
def event_loop() -> Generator:
    """Create an instance of the default event loop for each test case."""
    try:
        loop = asyncio.get_event_loop()
    except RuntimeError:
        loop = asyncio.new_event_loop()
    yield loop
    loop.close()

@pytest.fixture(scope="session")
async def test_app():
    """Create tables for testing and clean up afterward."""
    # Create test upload directories
    os.makedirs("./test_uploads/documents", exist_ok=True)
    os.makedirs("./test_uploads/images", exist_ok=True)
    
    # Create tables
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.drop_all)  # Ensure clean state
        await conn.run_sync(Base.metadata.create_all)
    
    yield app
    
    # Cleanup
    async with engine.begin() as conn:
        await conn.run_sync(Base.metadata.drop_all)

@pytest.fixture
async def db_session() -> AsyncGenerator[AsyncSession, None]:
    """Get a test database session."""
    async with TestingSessionLocal() as session:
        yield session
        # Rollback any changes made in the test
        await session.rollback()

@pytest.fixture
async def client(test_app) -> AsyncGenerator[AsyncClient, None]:
    """Get a test client with database session override."""
    async def override_get_db():
        async with TestingSessionLocal() as session:
            yield session

    app.dependency_overrides[get_db] = override_get_db

    async with AsyncClient(app=app, base_url="http://test") as client:
        yield client
    
    app.dependency_overrides.clear()