import sys
import pytest
from pathlib import Path
from typing import Generator

# Add backend to path
sys.path.insert(0, str(Path(__file__).parent.parent))

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, Session

# NOTE: This import will fail until models are created in Task 2.1
# This is expected behavior - the models module doesn't exist yet
from app.models import Base


@pytest.fixture(scope="function")
def db_path(tmp_path):
    """临时数据库路径."""
    return tmp_path / "test.db"


@pytest.fixture(scope="function")
def db_engine(db_path):
    """临时数据库引擎."""
    engine = create_engine(f"sqlite:///{db_path}", connect_args={"check_same_thread": False})
    Base.metadata.create_all(engine)
    yield engine
    engine.dispose()


@pytest.fixture(scope="function")
def db_session(db_engine):
    """临时数据库会话."""
    SessionLocal = sessionmaker(bind=db_engine, autocommit=False, autoflush=False)
    session = SessionLocal()
    yield session
    session.close()


@pytest.fixture(scope="function")
def test_encrypt_key():
    """测试加密密钥."""
    import base64
    return base64.b64encode(b'test-key-32-bytes-long-123456789').decode()


@pytest.fixture(scope="function")
def test_env_vars(db_path, test_encrypt_key, monkeypatch):
    """设置测试环境变量."""
    # Clear global settings to ensure fresh config
    import app.config
    app.config._settings = None

    monkeypatch.setenv("GM_ENCRYPT_KEY", test_encrypt_key)
    monkeypatch.setenv("GM_API_TOKEN", "test-token")
    monkeypatch.setenv("GM_DATA_DIR", str(db_path.parent))
    return {
        "GM_ENCRYPT_KEY": test_encrypt_key,
        "GM_API_TOKEN": "test-token",
    }


@pytest.fixture(scope="function")
def client(db_session: Session, test_env_vars: dict, monkeypatch):
    """
    FastAPI test client fixture.

    Provides a test client for the FastAPI application with:
    - In-memory database session
    - Test environment variables
    - Disabled lifespan (for faster tests)

    Args:
        db_session: Database session fixture
        test_env_vars: Test environment variables fixture
        monkeypatch: Pytest monkeypatch fixture

    Yields:
        FastAPI test client

    Example:
        def test_create_ssh_key(client):
            response = client.post(
                "/api/ssh-keys",
                json={"name": "test-key", "private_key": "..."},
                headers={"Authorization": "Bearer test-token"}
            )
            assert response.status_code == 201
    """
    from fastapi.testclient import TestClient
    from unittest.mock import AsyncMock, patch

    # Mock the lifespan context manager
    async def mock_lifespan(app):  # noqa: ARG001 - Unused app parameter
        # Database is already initialized by db_session fixture
        yield

    # Import after setting env vars
    import app.database
    import app.config

    # Initialize database with test session
    app.database._engine = db_session.bind
    app.database._session_factory = sessionmaker(bind=db_session.bind, autocommit=False, autoflush=False)

    # Create app with mocked lifespan
    from app.main import create_app
    test_app = create_app(lifespan_handler=mock_lifespan)

    # Override get_db_session dependency to use test session
    from app.api import deps

    def override_get_db_session():
        try:
            yield db_session
        finally:
            pass

    test_app.dependency_overrides[deps.get_db_session] = override_get_db_session

    with TestClient(test_app) as test_client:
        yield test_client

    # Clean up
    test_app.dependency_overrides = {}
    app.database._engine = None
    app.database._session_factory = None
    app.config._settings = None