"""
Integration Test Suite for Credit Middleware

Tests the complete middleware flow including:
- Request interception
- Credit reservation  
- Response inspection
- Automatic confirmation/refund
"""
import pytest
import json
from unittest.mock import AsyncMock, MagicMock, patch
from fastapi import Request, Response, status
from fastapi.responses import JSONResponse

from services.credit_service.middleware import CreditMiddleware
from services.credit_service.config import CreditServiceConfig
from core.models import User


# =============================================================================
# Fixtures
# =============================================================================

@pytest.fixture
def mock_user():
    """Create a mock user with credits."""
    user = MagicMock(spec=User)
    user.id = 1
    user.user_id = "test_user_123"
    user.credits = 100
    return user


@pytest.fixture
def mock_request(mock_user):
    """Create a mock FastAPI request."""
    request = MagicMock(spec=Request)
    request.method = "POST"
    request.url.path = "/gemini/analyze-image"
    request.state.user = mock_user
    request.state.credit_transaction_id = None
    request.client.host = "127.0.0.1"
    request.headers = {"user-agent": "test"}
    return request


@pytest.fixture
def credit_middleware():
    """Create credit middleware instance."""
    # Register test configuration
    CreditServiceConfig.register(
        route_configs={
            "/gemini/analyze-image": {"cost": 1, "type": "sync"},
            "/gemini/generate-video": {"cost": 10, "type": "async"},
            "/gemini/job/{job_id}": {"cost": 0, "type": "async"},
            "/free-endpoint": {"cost": 0, "type": "free"}
        }
    )
    return CreditMiddleware(MagicMock())


# =============================================================================
# Free Endpoint Tests
# =============================================================================

@pytest.mark.asyncio
async def test_free_endpoint_no_credit_check(credit_middleware, mock_request):
    """Test that free endpoints bypass credit middleware."""
    mock_request.url.path = "/free-endpoint"
    
    async def mock_call_next(request):
        return Response(content="OK", status_code=200)
    
    response = await credit_middleware.dispatch(mock_request, mock_call_next)
    
    assert response.status_code == 200
    assert not hasattr(mock_request.state, 'credit_transaction_id')


@pytest.mark.asyncio
async def test_options_request_bypass(credit_middleware, mock_request):
    """Test that OPTIONS requests bypass middleware."""
    mock_request.method = "OPTIONS"
    
    async def mock_call_next(request):
        return Response(status_code=204)
    
    response = await credit_middleware.dispatch(mock_request, mock_call_next)
    
    assert response.status_code == 204


# =============================================================================
# Unauthenticated Request Tests
# =============================================================================

@pytest.mark.asyncio
async def test_unauthenticated_request(credit_middleware, mock_request):
    """Test that unauthenticated requests are rejected."""
    mock_request.state.user = None
    
    async def mock_call_next(request):
        return Response(status_code=200)
    
    with patch('services.credit_service.middleware.async_session_maker'):
        response = await credit_middleware.dispatch(mock_request, mock_call_next)
        
        assert response.status_code == status.HTTP_401_UNAUTHORIZED


# =============================================================================
# Credit Reservation Tests
# =============================================================================

@pytest.mark.asyncio
async def test_successful_credit_reservation(credit_middleware, mock_request):
    """Test successful credit reservation on request."""
    # Mock database session and transaction manager
    with patch('services.credit_service.middleware.async_session_maker') as mock_session:
        mock_db = AsyncMock()
        mock_session.return_value.__aenter__.return_value = mock_db
        
        # Mock transaction manager
        with patch('services.credit_service.middleware.CreditTransactionManager') as mock_tm:
            mock_transaction = MagicMock()
            mock_transaction.transaction_id = "ctx_test123"
            mock_tm.reserve_credits = AsyncMock(return_value=mock_transaction)
            
            # Mock call_next to return success response
            async def mock_call_next(request):
                # Simulate response iterator
                async def body_iterator():
                    yield b'{"result": "success"}'
                
                response = Response(content=b'{"result": "success"}', status_code=200)
                response.body_iterator = body_iterator()
                return response
            
            response = await credit_middleware.dispatch(mock_request, mock_call_next)
            
            # Verify reserve_credits was called
            mock_tm.reserve_credits.assert_called_once()
            call_args = mock_tm.reserve_credits.call_args
            assert call_args.kwargs['amount'] == 1  # 1 credit for analyze-image


# =============================================================================
# Insufficient Credits Tests
# =============================================================================

@pytest.mark.asyncio
async def test_insufficient_credits(credit_middleware, mock_request):
    """Test request rejection when user has insufficient credits."""
    from services.credit_service.transaction_manager import InsufficientCreditsError
    
    with patch('services.credit_service.middleware.async_session_maker') as mock_session:
        mock_db = AsyncMock()
        mock_session.return_value.__aenter__.return_value = mock_db
        
        with patch('services.credit_service.middleware.CreditTransactionManager') as mock_tm:
            # Simulate insufficient credits
            mock_tm.reserve_credits = AsyncMock(side_effect=InsufficientCreditsError("Not enough credits"))
            
            async def mock_call_next(request):
                return Response(status_code=200)
            
            response = await credit_middleware.dispatch(mock_request, mock_call_next)
            
            assert response.status_code == status.HTTP_402_PAYMENT_REQUIRED
            content = json.loads(response.body.decode())
            assert "Insufficient credits" in content["detail"]


# =============================================================================
# Response Inspection Tests - Sync Endpoints
# =============================================================================

@pytest.mark.asyncio
async def test_sync_success_confirms_credits(credit_middleware, mock_request):
    """Test that successful sync response confirms credits."""
    with patch('services.credit_service.middleware.async_session_maker') as mock_session:
        mock_db = AsyncMock()
        mock_session.return_value.__aenter__.return_value = mock_db
        
        with patch('services.credit_service.middleware.CreditTransactionManager') as mock_tm:
            mock_transaction = MagicMock()
            mock_transaction.transaction_id = "ctx_test123"
            mock_tm.reserve_credits = AsyncMock(return_value=mock_transaction)
            mock_tm.confirm_credits = AsyncMock()
            
            # Mock successful response
            async def mock_call_next(request):
                async def body_iterator():
                    yield b'{"result": "image analyzed"}'
                
                response = Response(content=b'{"result": "image analyzed"}', status_code=200)
                response.body_iterator = body_iterator()
                return response
            
            await credit_middleware.dispatch(mock_request, mock_call_next)
            
            # Verify confirm was called
            mock_tm.confirm_credits.assert_called_once()


@pytest.mark.asyncio
async def test_sync_failure_refunds_credits(credit_middleware, mock_request):
    """Test that failed sync response refunds credits."""
    with patch('services.credit_service.middleware.async_session_maker') as mock_session:
        mock_db = AsyncMock()
        mock_session.return_value.__aenter__.return_value = mock_db
        
        with patch('services.credit_service.middleware.CreditTransactionManager') as mock_tm:
            mock_transaction = MagicMock()
            mock_transaction.transaction_id = "ctx_test123"
            mock_tm.reserve_credits = AsyncMock(return_value=mock_transaction)
            mock_tm.refund_credits = AsyncMock()
            
            # Mock failed response
            async def mock_call_next(request):
                async def body_iterator():
                    yield b'{"detail": "Invalid image"}'
                
                response = Response(content=b'{"detail": "Invalid image"}', status_code=400)
                response.body_iterator = body_iterator()
                return response
            
            await credit_middleware.dispatch(mock_request, mock_call_next)
            
            # Verify refund was called
            mock_tm.refund_credits.assert_called_once()


# =============================================================================
# Response Inspection Tests - Async Endpoints
# =============================================================================

@pytest.mark.asyncio
async def test_async_job_creation_keeps_reserved(credit_middleware, mock_request):
    """Test that async job creation keeps credits reserved."""
    mock_request.url.path = "/gemini/generate-video"
    
    with patch('services.credit_service.middleware.async_session_maker') as mock_session:
        mock_db = AsyncMock()
        mock_session.return_value.__aenter__.return_value = mock_db
        
        with patch('services.credit_service.middleware.CreditTransactionManager') as mock_tm:
            mock_transaction = MagicMock()
            mock_transaction.transaction_id = "ctx_test123"
            mock_tm.reserve_credits = AsyncMock(return_value=mock_transaction)
            mock_tm.confirm_credits = AsyncMock()
            mock_tm.refund_credits = AsyncMock()
            
            # Mock job creation response
            async def mock_call_next(request):
                async def body_iterator():
                    yield b'{"job_id": "job_abc", "status": "queued"}'
                
                response = Response(
                    content=b'{"job_id": "job_abc", "status": "queued"}',
                    status_code=200
                )
                response.body_iterator = body_iterator()
                return response
            
            await credit_middleware.dispatch(mock_request, mock_call_next)
            
            # Verify neither confirm nor refund was called
            mock_tm.confirm_credits.assert_not_called()
            mock_tm.refund_credits.assert_not_called()


@pytest.mark.asyncio
async def test_async_job_completed_confirms_credits(credit_middleware, mock_request):
    """Test that completed async job confirms credits."""
    mock_request.url.path = "/gemini/job/job_abc"
    
    with patch('services.credit_service.middleware.async_session_maker') as mock_session:
        mock_db = AsyncMock()
        mock_session.return_value.__aenter__.return_value = mock_db
        
        with patch('services.credit_service.middleware.CreditTransactionManager') as mock_tm:
            # No reservation for status check (cost=0)
            mock_transaction = MagicMock()
            mock_transaction.transaction_id = "ctx_test123"
            mock_tm.confirm_credits = AsyncMock()
            
            # Mock completed job response
            async def mock_call_next(request):
                async def body_iterator():
                    yield b'{"job_id": "job_abc", "status": "completed", "video_url": "..."}'
                
                response = Response(
                    content=b'{"job_id": "job_abc", "status": "completed", "video_url": "..."}',
                    status_code=200
                )
                response.body_iterator = body_iterator()
                return response
            
            # Since cost=0, no reservation happens
            # But this test shows the logic for when a reservation exists
            response = await credit_middleware.dispatch(mock_request, mock_call_next)
            
            assert response.status_code == 200


# =============================================================================
# Error Handling Tests
# =============================================================================

@pytest.mark.asyncio
async def test_database_error_during_reservation(credit_middleware, mock_request):
    """Test handling of database errors during reservation."""
    with patch('services.credit_service.middleware.async_session_maker') as mock_session:
        mock_db = AsyncMock()
        mock_session.return_value.__aenter__.return_value = mock_db
        
        with patch('services.credit_service.middleware.CreditTransactionManager') as mock_tm:
            # Simulate database error
            mock_tm.reserve_credits = AsyncMock(side_effect=Exception("DB connection failed"))
            
            async def mock_call_next(request):
                return Response(status_code=200)
            
            response = await credit_middleware.dispatch(mock_request, mock_call_next)
            
            assert response.status_code == status.HTTP_500_INTERNAL_SERVER_ERROR


@pytest.mark.asyncio
async def test_response_phase_error_doesnt_fail_request(credit_middleware, mock_request):
    """Test that errors in response phase don't break the actual response."""
    with patch('services.credit_service.middleware.async_session_maker') as mock_session:
        mock_db = AsyncMock()
        mock_session.return_value.__aenter__.return_value = mock_db
        
        with patch('services.credit_service.middleware.CreditTransactionManager') as mock_tm:
            mock_transaction = MagicMock()
            mock_transaction.transaction_id = "ctx_test123"
            mock_tm.reserve_credits = AsyncMock(return_value=mock_transaction)
            
            # Confirm will fail, but response should still be returned
            mock_tm.confirm_credits = AsyncMock(side_effect=Exception("Confirm failed"))
            
            async def mock_call_next(request):
                async def body_iterator():
                    yield b'{"result": "success"}'
                
                response = Response(content=b'{"result": "success"}', status_code=200)
                response.body_iterator = body_iterator()
                return response
            
            response = await credit_middleware.dispatch(mock_request, mock_call_next)
            
            # Response should still be 200 even though confirm failed
            assert response.status_code == 200