import pytest
from fastapi.testclient import TestClient
from unittest.mock import MagicMock, patch
from ea_chatbot.api.main import app
from ea_chatbot.history.models import User, Conversation, Message
from langchain_core.messages import HumanMessage, AIMessage

@pytest.fixture
def client():
    return TestClient(app)

@pytest.fixture
def mock_user():
    return User(id="user-123", username="test@test.com")

def test_chat_stream_loads_history(client, mock_user):
    """
    Test that the /chat/stream endpoint loads history from the DB
    and passes it to stream_agent_events.
    """
    # 1. Setup mocks
    from ea_chatbot.api.dependencies import get_current_user
    app.dependency_overrides[get_current_user] = lambda: mock_user
    
    try:
        with patch("ea_chatbot.api.routers.agent.history_manager") as mock_hm, \
             patch("ea_chatbot.api.routers.agent.stream_agent_events") as mock_stream:
            
            # Mock conversation exists and belongs to user
            mock_conv = Conversation(id="conv-123", user_id=mock_user.id, summary="Old summary")
            
            mock_session = MagicMock()
            mock_session.get.return_value = mock_conv
            mock_hm.get_session.return_value.__enter__.return_value = mock_session
            
            # Mock history window returns some messages
            mock_db_messages = [
                Message(role="user", content="Question 1"),
                Message(role="assistant", content="Answer 1")
            ]
            mock_hm.get_messages_by_window.return_value = mock_db_messages
            
            # Mock stream_agent_events to return an empty generator
            async def empty_gen(*args, **kwargs):
                yield 'data: {"type": "done"}\n\n'
            
            mock_stream.side_effect = empty_gen
            
            # 2. Execute request
            response = client.post(
                "/api/v1/chat/stream",
                json={"message": "New question", "thread_id": "conv-123"}
            )
            
            # 3. Assertions
            assert response.status_code == 200
            
            # Verify history_manager was called to get history
            mock_hm.get_messages_by_window.assert_called_once_with("conv-123", window_size=10)
            
            # Verify stream_agent_events was called with loaded history and summary
            args, kwargs = mock_stream.call_args
            # args: message, thread_id, user_id, summary, messages
            assert args[0] == "New question"
            assert args[1] == "conv-123"
            assert args[2] == mock_user.id
            assert args[3] == "Old summary"
            
            passed_messages = args[4]
            assert len(passed_messages) == 2
            assert isinstance(passed_messages[0], HumanMessage)
            assert passed_messages[0].content == "Question 1"
            assert isinstance(passed_messages[1], AIMessage)
            assert passed_messages[1].content == "Answer 1"
            
            # Verify current message was saved AFTER loading history (based on code logic)
            mock_hm.add_message.assert_called_with("conv-123", "user", "New question")
    finally:
        app.dependency_overrides.clear()