import os
import sys
from unittest.mock import AsyncMock, Mock, patch

import aiohttp
import pytest

sys.path.insert(
    0, os.path.abspath("../../../..")
)  # Adds the parent directory to the system path

from litellm.llms.custom_httpx.aiohttp_handler import BaseLLMAIOHTTPHandler
from litellm.llms.custom_httpx.aiohttp_transport import LiteLLMAiohttpTransport


class TestBaseLLMAIOHTTPHandler:
    """Test cases for BaseLLMAIOHTTPHandler dependency injection functionality"""

    def test_init_with_no_client_session(self):
        """Test handler initialization with no client session"""
        handler = BaseLLMAIOHTTPHandler()

        assert handler.client_session is None
        assert handler._owns_session is True

    def test_init_with_provided_client_session(self):
        """Test handler initialization with provided client session"""
        # Create a mock client session
        mock_session = Mock()

        handler = BaseLLMAIOHTTPHandler(client_session=mock_session)

        assert handler.client_session is mock_session
        assert handler._owns_session is False

    def test_get_async_client_session_with_dynamic_session(self):
        """Test _get_async_client_session with dynamic session parameter"""
        handler = BaseLLMAIOHTTPHandler()

        dynamic_session = Mock()

        result = handler._get_async_client_session(
            dynamic_client_session=dynamic_session
        )

        assert result is dynamic_session

    def test_get_async_client_session_with_instance_session(self):
        """Test _get_async_client_session with instance session"""
        instance_session = Mock()
        handler = BaseLLMAIOHTTPHandler(client_session=instance_session)

        result = handler._get_async_client_session()

        assert result is instance_session

    @patch("aiohttp.ClientSession")
    def test_get_async_client_session_create_new(self, mock_client_session):
        """Test _get_async_client_session creates new session when none provided"""
        handler = BaseLLMAIOHTTPHandler()
        mock_session_instance = Mock()
        mock_client_session.return_value = mock_session_instance

        result = handler._get_async_client_session()

        # Verify new session was created
        mock_client_session.assert_called_once()
        assert handler.client_session is mock_session_instance
        assert handler._owns_session is True
        assert result is mock_session_instance

    @pytest.mark.asyncio
    async def test_close_with_owned_session(self):
        """Test close() method with owned session"""
        # Create a mock session that we own
        mock_session = Mock()
        mock_session.closed = False
        mock_session.close = AsyncMock()

        # Create handler that owns the session
        handler = BaseLLMAIOHTTPHandler()
        handler.client_session = mock_session
        handler._owns_session = True

        await handler.close()

        # Verify close was called
        mock_session.close.assert_called_once()

    @pytest.mark.asyncio
    async def test_close_with_non_owned_session(self):
        """Test close() method with non-owned session (should not close)"""
        # Create a mock session that we don't own
        mock_session = Mock()
        mock_session.closed = False
        mock_session.close = AsyncMock()

        handler = BaseLLMAIOHTTPHandler(client_session=mock_session)

        await handler.close()

        # Verify close was NOT called since we don't own this session
        mock_session.close.assert_not_called()

    @pytest.mark.asyncio
    async def test_close_with_already_closed_session(self):
        """Test close() method with already closed session"""
        mock_session = Mock()
        mock_session.closed = True
        mock_session.close = AsyncMock()

        handler = BaseLLMAIOHTTPHandler()
        handler.client_session = mock_session
        handler._owns_session = True

        await handler.close()

        # Verify close was NOT called since session is already closed
        mock_session.close.assert_not_called()

    @pytest.mark.asyncio
    async def test_close_with_no_session(self):
        """Test close() method with no session"""
        handler = BaseLLMAIOHTTPHandler()

        # Should not raise any exceptions
        await handler.close()

    def test_session_priority_dynamic_over_instance(self):
        """Test that dynamic session takes priority over instance session"""
        instance_session = Mock()
        dynamic_session = Mock()

        handler = BaseLLMAIOHTTPHandler(client_session=instance_session)

        result = handler._get_async_client_session(
            dynamic_client_session=dynamic_session
        )

        assert result is dynamic_session
        assert result is not instance_session

    def test_session_ownership_tracking(self):
        """Test proper session ownership tracking in various scenarios"""
        # Scenario 1: Provided session - not owned
        provided_session = Mock()
        handler1 = BaseLLMAIOHTTPHandler(client_session=provided_session)
        assert not handler1._owns_session

        # Scenario 2: No session initially - becomes owned when created
        handler2 = BaseLLMAIOHTTPHandler()
        assert handler2._owns_session

        with patch("aiohttp.ClientSession") as mock_client_session:
            mock_session_instance = Mock()
            mock_client_session.return_value = mock_session_instance

            handler2._get_async_client_session()
            assert handler2._owns_session

    @pytest.mark.asyncio
    async def test_context_manager_pattern_compatibility(self):
        """Test that the handler works well with context manager pattern"""
        mock_session = Mock()
        mock_session.closed = False
        mock_session.close = AsyncMock()

        # Test as context manager style usage
        handler = BaseLLMAIOHTTPHandler()
        handler.client_session = mock_session
        handler._owns_session = True

        try:
            # Simulate some work
            session = handler._get_async_client_session()
            assert session is mock_session
        finally:
            await handler.close()

        # Verify cleanup happened
        mock_session.close.assert_called_once()

    @patch("litellm.llms.custom_httpx.aiohttp_handler.aiohttp.ClientSession")
    def test_lazy_session_creation(self, mock_client_session):
        """Test that session is created lazily only when needed"""
        handler = BaseLLMAIOHTTPHandler()

        # Session should not be created on init
        mock_client_session.assert_not_called()
        assert handler.client_session is None

        # Session should be created when requested
        mock_session_instance = Mock()
        mock_client_session.return_value = mock_session_instance

        session = handler._get_async_client_session()

        mock_client_session.assert_called_once()
        assert session is mock_session_instance
        assert handler.client_session is mock_session_instance

    def test_session_reuse(self):
        """Test that the same session is reused across multiple calls"""
        instance_session = Mock()
        handler = BaseLLMAIOHTTPHandler(client_session=instance_session)

        # Multiple calls should return the same session
        session1 = handler._get_async_client_session()
        session2 = handler._get_async_client_session()
        session3 = handler._get_async_client_session()

        assert session1 is session2 is session3 is instance_session

    # ===============================
    # TRANSPORT INJECTION TESTS
    # ===============================

    def test_init_with_transport(self):
        """Test handler initialization with provided transport"""
        mock_transport = Mock(spec=LiteLLMAiohttpTransport)

        handler = BaseLLMAIOHTTPHandler(transport=mock_transport)

        assert handler.transport is mock_transport
        assert handler._owns_transport is False

    def test_init_with_connector(self):
        """Test handler initialization with provided connector"""
        mock_connector = Mock(spec=aiohttp.BaseConnector)

        handler = BaseLLMAIOHTTPHandler(connector=mock_connector)

        assert handler.connector is mock_connector
        assert handler._owns_connector is False

    def test_init_with_transport_and_session(self):
        """Test handler initialization with both transport and session"""
        mock_transport = Mock(spec=LiteLLMAiohttpTransport)
        mock_session = Mock()

        handler = BaseLLMAIOHTTPHandler(
            client_session=mock_session, transport=mock_transport
        )

        assert handler.transport is mock_transport
        assert handler._owns_transport is False
        assert handler.client_session is mock_session
        assert handler._owns_session is False

    def test_get_connector_from_provided_connector(self):
        """Test _get_connector returns provided connector"""
        mock_connector = Mock(spec=aiohttp.BaseConnector)
        handler = BaseLLMAIOHTTPHandler(connector=mock_connector)

        result = handler._get_connector()

        assert result is mock_connector

    def test_get_connector_from_transport(self):
        """Test _get_connector extracts connector from transport"""
        mock_connector = Mock(spec=aiohttp.BaseConnector)

        # Use a simple object instead of Mock to avoid callable issues
        class MockSession:
            def __init__(self):
                self.connector = mock_connector

        mock_session = MockSession()

        mock_transport = Mock(spec=LiteLLMAiohttpTransport)
        mock_transport.client = mock_session

        handler = BaseLLMAIOHTTPHandler(transport=mock_transport)

        result = handler._get_connector()

        assert result is mock_connector

    def test_get_connector_from_transport_with_callable_client(self):
        """Test _get_connector with transport that has callable client"""
        mock_transport = Mock(spec=LiteLLMAiohttpTransport)
        mock_transport.client = lambda: Mock()  # Callable client

        handler = BaseLLMAIOHTTPHandler(transport=mock_transport)

        result = handler._get_connector()

        assert result is None

    @patch("aiohttp.ClientSession")
    def test_create_client_session_with_transport(self, mock_client_session):
        """Test session creation using transport"""
        mock_session_from_transport = Mock()

        mock_transport = Mock(spec=LiteLLMAiohttpTransport)
        mock_transport._get_valid_client_session = Mock(
            return_value=mock_session_from_transport
        )

        handler = BaseLLMAIOHTTPHandler(transport=mock_transport)

        result = handler._create_client_session_with_transport()

        # Should use transport's session creation method
        mock_transport._get_valid_client_session.assert_called_once()
        assert result is mock_session_from_transport

        # Should not call aiohttp.ClientSession directly
        mock_client_session.assert_not_called()

    @patch("aiohttp.ClientSession")
    def test_create_client_session_with_connector(self, mock_client_session):
        """Test session creation using connector"""
        mock_connector = Mock(spec=aiohttp.BaseConnector)
        mock_session_instance = Mock()
        mock_client_session.return_value = mock_session_instance

        handler = BaseLLMAIOHTTPHandler(connector=mock_connector)

        result = handler._create_client_session_with_transport()

        # Should create session with connector
        mock_client_session.assert_called_once_with(connector=mock_connector)
        assert result is mock_session_instance

    @patch("aiohttp.ClientSession")
    def test_create_client_session_default(self, mock_client_session):
        """Test default session creation when no transport/connector provided"""
        mock_session_instance = Mock()
        mock_client_session.return_value = mock_session_instance

        handler = BaseLLMAIOHTTPHandler()

        result = handler._create_client_session_with_transport()

        # Should create default session
        mock_client_session.assert_called_once_with()
        assert result is mock_session_instance

    def test_get_or_create_transport(self):
        """Test that _get_or_create_transport creates or returns a transport.
        
        When no transport exists, the method should attempt to create one.
        If creation succeeds, it should be stored on the handler.
        If creation fails (e.g. in test environments), None is returned gracefully.
        """
        handler = BaseLLMAIOHTTPHandler()
        assert handler.transport is None  # no transport initially

        result = handler._get_or_create_transport()

        # The method should either create a transport or gracefully return None
        if result is not None:
            assert handler.transport is result
            assert handler._owns_transport is True
            assert isinstance(result, LiteLLMAiohttpTransport)
        else:
            # Creation can fail in test environments without full aiohttp setup
            # This is the graceful fallback path
            pass

    def test_get_or_create_transport_with_existing(self):
        """Test _get_or_create_transport returns existing transport"""
        mock_transport = Mock(spec=LiteLLMAiohttpTransport)
        handler = BaseLLMAIOHTTPHandler(transport=mock_transport)

        result = handler._get_or_create_transport()

        assert result is mock_transport

    @pytest.mark.asyncio
    async def test_close_with_owned_transport(self):
        """Test close() method with owned transport"""
        mock_transport = Mock(spec=LiteLLMAiohttpTransport)
        mock_transport.aclose = AsyncMock()

        handler = BaseLLMAIOHTTPHandler()
        handler.transport = mock_transport
        handler._owns_transport = True

        await handler.close()

        # Verify transport close was called
        mock_transport.aclose.assert_called_once()

    @pytest.mark.asyncio
    async def test_close_with_non_owned_transport(self):
        """Test close() method with non-owned transport (should not close)"""
        mock_transport = Mock(spec=LiteLLMAiohttpTransport)
        mock_transport.aclose = AsyncMock()

        handler = BaseLLMAIOHTTPHandler(transport=mock_transport)

        await handler.close()

        # Verify transport close was NOT called since we don't own this transport
        mock_transport.aclose.assert_not_called()

    @pytest.mark.asyncio
    async def test_close_transport_without_aclose_method(self):
        """Test close() handles transport without aclose method gracefully"""
        mock_transport = Mock()  # No aclose method

        handler = BaseLLMAIOHTTPHandler()
        handler.transport = mock_transport
        handler._owns_transport = True

        # Should not raise any exceptions
        await handler.close()

    def test_transport_priority_hierarchy(self):
        """Test that session creation follows the right priority: transport > connector > default"""
        # Test with transport having _get_valid_client_session
        mock_transport = Mock(spec=LiteLLMAiohttpTransport)
        mock_session_from_transport = Mock()
        mock_transport._get_valid_client_session = Mock(
            return_value=mock_session_from_transport
        )

        mock_connector = Mock(spec=aiohttp.BaseConnector)

        handler = BaseLLMAIOHTTPHandler(
            transport=mock_transport, connector=mock_connector
        )

        result = handler._create_client_session_with_transport()

        # Should use transport, not connector
        mock_transport._get_valid_client_session.assert_called_once()
        assert result is mock_session_from_transport