"""
Unit tests for BackgroundLoaderService database session handling.

This module tests that the background loader service properly uses async context
managers for database sessions, preventing TypeError with async for.
"""
import pytest
from unittest.mock import AsyncMock, MagicMock, patch
from datetime import datetime, timezone

from src.server.services.background_loader_service import (
    BackgroundLoaderService,
    SeriesLoadingTask,
    LoadingStatus,
)


@pytest.mark.asyncio
async def test_load_series_data_uses_async_with_not_async_for():
    """Test that _load_series_data uses 'async with' for database session.
    
    This test verifies the fix for the TypeError:
    'async for' requires an object with __aiter__ method, got _AsyncGeneratorContextManager
    
    The code should use 'async with get_db_session() as db:' not 'async for db in get_db_session():'
    """
    # Create a fake series app
    fake_series_app = MagicMock()
    fake_series_app.directory_to_search = "/fake/path"
    fake_series_app.loader = MagicMock()
    
    # Create fake websocket and anime services
    fake_websocket_service = AsyncMock()
    fake_anime_service = AsyncMock()
    
    # Create the service
    service = BackgroundLoaderService(
        websocket_service=fake_websocket_service,
        anime_service=fake_anime_service,
        series_app=fake_series_app
    )
    
    # Create a test task
    task = SeriesLoadingTask(
        key="test-anime",
        folder="Test Anime",
        name="Test Anime",
        year=2023,
        status=LoadingStatus.PENDING,
        progress={"episodes": False, "nfo": False, "logo": False, "images": False},
        started_at=datetime.now(timezone.utc),
    )
    
    # Mock the database session
    mock_db = AsyncMock()
    mock_series_db = MagicMock()
    mock_series_db.loading_status = "pending"
    
    # Mock database service
    with patch('src.server.database.connection.get_db_session') as mock_get_db:
        with patch('src.server.database.service.AnimeSeriesService') as mock_service:
            # Configure the async context manager
            mock_get_db.return_value.__aenter__ = AsyncMock(return_value=mock_db)
            mock_get_db.return_value.__aexit__ = AsyncMock(return_value=None)
            
            # Configure service methods
            mock_service.get_by_key = AsyncMock(return_value=mock_series_db)
            mock_db.commit = AsyncMock()
            
            # Mock helper methods
            service.check_missing_data = AsyncMock(return_value={
                "episodes": False,
                "nfo": False,
                "logo": False,
                "images": False
            })
            service._broadcast_status = AsyncMock()
            
            # Execute the method - this should not raise TypeError
            await service._load_series_data(task)
            
            # Verify the context manager was entered (proves we used 'async with')
            mock_get_db.return_value.__aenter__.assert_called_once()
            mock_get_db.return_value.__aexit__.assert_called_once()
            
            # Verify task was marked as completed
            assert task.status == LoadingStatus.COMPLETED
            assert task.completed_at is not None


@pytest.mark.asyncio
async def test_load_series_data_handles_database_errors():
    """Test that _load_series_data properly handles database errors."""
    # Create a fake series app
    fake_series_app = MagicMock()
    fake_series_app.directory_to_search = "/fake/path"
    fake_series_app.loader = MagicMock()
    
    # Create fake websocket and anime services
    fake_websocket_service = AsyncMock()
    fake_anime_service = AsyncMock()
    
    # Create the service
    service = BackgroundLoaderService(
        websocket_service=fake_websocket_service,
        anime_service=fake_anime_service,
        series_app=fake_series_app
    )
    
    # Create a test task
    task = SeriesLoadingTask(
        key="test-anime",
        folder="Test Anime",
        name="Test Anime",
        year=2023,
        status=LoadingStatus.PENDING,
        progress={"episodes": False, "nfo": False, "logo": False, "images": False},
        started_at=datetime.now(timezone.utc),
    )
    
    # Mock the database session to raise an error
    mock_db = AsyncMock()
    
    with patch('src.server.database.connection.get_db_session') as mock_get_db:
        with patch('src.server.database.service.AnimeSeriesService') as mock_service:
            # Configure the async context manager
            mock_get_db.return_value.__aenter__ = AsyncMock(return_value=mock_db)
            mock_get_db.return_value.__aexit__ = AsyncMock(return_value=None)
            
            # Make check_missing_data raise an error
            service.check_missing_data = AsyncMock(side_effect=Exception("Database error"))
            service._broadcast_status = AsyncMock()
            mock_service.get_by_key = AsyncMock(return_value=None)
            
            # Execute - should handle error gracefully
            await service._load_series_data(task)
            
            # Verify task was marked as failed
            assert task.status == LoadingStatus.FAILED
            assert task.error == "Database error"
            assert task.completed_at is not None


@pytest.mark.asyncio
async def test_load_series_data_loads_missing_episodes():
    """Test that _load_series_data loads episodes when missing."""
    # Create a fake series app
    fake_series_app = MagicMock()
    fake_series_app.directory_to_search = "/fake/path"
    fake_series_app.loader = MagicMock()
    
    # Create fake websocket and anime services
    fake_websocket_service = AsyncMock()
    fake_anime_service = AsyncMock()
    
    # Create the service
    service = BackgroundLoaderService(
        websocket_service=fake_websocket_service,
        anime_service=fake_anime_service,
        series_app=fake_series_app
    )
    
    # Create a test task
    task = SeriesLoadingTask(
        key="test-anime",
        folder="Test Anime",
        name="Test Anime",
        year=2023,
        status=LoadingStatus.PENDING,
        progress={"episodes": False, "nfo": False, "logo": False, "images": False},
        started_at=datetime.now(timezone.utc),
    )
    
    # Mock the database session
    mock_db = AsyncMock()
    mock_series_db = MagicMock()
    
    with patch('src.server.database.connection.get_db_session') as mock_get_db:
        with patch('src.server.database.service.AnimeSeriesService') as mock_service:
            # Configure the async context manager
            mock_get_db.return_value.__aenter__ = AsyncMock(return_value=mock_db)
            mock_get_db.return_value.__aexit__ = AsyncMock(return_value=None)
            
            # Configure service methods
            mock_service.get_by_key = AsyncMock(return_value=mock_series_db)
            mock_db.commit = AsyncMock()
            
            # Mock helper methods - episodes are missing
            service.check_missing_data = AsyncMock(return_value={
                "episodes": True,  # Episodes are missing
                "nfo": False,
                "logo": False,
                "images": False
            })
            service._load_episodes = AsyncMock()
            service._broadcast_status = AsyncMock()
            
            # Execute
            await service._load_series_data(task)
            
            # Verify _load_episodes was called
            service._load_episodes.assert_called_once_with(task, mock_db)
            
            # Verify task completed
            assert task.status == LoadingStatus.COMPLETED


@pytest.mark.asyncio
async def test_load_series_data_loads_nfo_and_images():
    """Test that _load_series_data loads NFO and images when missing."""
    # Create a fake series app
    fake_series_app = MagicMock()
    fake_series_app.directory_to_search = "/fake/path"
    fake_series_app.loader = MagicMock()
    
    # Create fake websocket and anime services
    fake_websocket_service = AsyncMock()
    fake_anime_service = AsyncMock()
    
    # Create the service
    service = BackgroundLoaderService(
        websocket_service=fake_websocket_service,
        anime_service=fake_anime_service,
        series_app=fake_series_app
    )
    
    # Create a test task
    task = SeriesLoadingTask(
        key="test-anime",
        folder="Test Anime",
        name="Test Anime",
        year=2023,
        status=LoadingStatus.PENDING,
        progress={"episodes": False, "nfo": False, "logo": False, "images": False},
        started_at=datetime.now(timezone.utc),
    )
    
    # Mock the database session
    mock_db = AsyncMock()
    mock_series_db = MagicMock()
    
    with patch('src.server.database.connection.get_db_session') as mock_get_db:
        with patch('src.server.database.service.AnimeSeriesService') as mock_service:
            # Configure the async context manager
            mock_get_db.return_value.__aenter__ = AsyncMock(return_value=mock_db)
            mock_get_db.return_value.__aexit__ = AsyncMock(return_value=None)
            
            # Configure service methods
            mock_service.get_by_key = AsyncMock(return_value=mock_series_db)
            mock_db.commit = AsyncMock()
            
            # Mock helper methods - NFO and images are missing
            service.check_missing_data = AsyncMock(return_value={
                "episodes": False,
                "nfo": True,  # NFO is missing
                "logo": True,  # Logo is missing
                "images": True  # Images are missing
            })
            service._load_nfo_and_images = AsyncMock()
            service._broadcast_status = AsyncMock()
            
            # Execute
            await service._load_series_data(task)
            
            # Verify _load_nfo_and_images was called
            service._load_nfo_and_images.assert_called_once_with(task, mock_db)
            
            # Verify task completed
            assert task.status == LoadingStatus.COMPLETED


@pytest.mark.asyncio
async def test_async_context_manager_usage():
    """Direct test that verifies async context manager is used correctly.
    
    This test ensures the code uses 'async with' pattern, not 'async for'.
    """
    from contextlib import asynccontextmanager
    from typing import AsyncGenerator
    
    # Create a test async context manager
    call_log = []
    
    @asynccontextmanager
    async def test_context_manager() -> AsyncGenerator:
        call_log.append("enter")
        yield "test_value"
        call_log.append("exit")
    
    # Test that async with works
    async with test_context_manager() as value:
        assert value == "test_value"
        assert "enter" in call_log
    
    assert "exit" in call_log
    
    # Verify that async for would fail with this pattern
    call_log.clear()
    try:
        async for item in test_context_manager():
            pass
        assert False, "Should have raised TypeError"
    except TypeError as e:
        assert "__aiter__" in str(e) or "async for" in str(e)