import pytest
from fastapi.testclient import TestClient
from unittest.mock import MagicMock, patch, AsyncMock
from ea_chatbot.api.main import app
from ea_chatbot.api.dependencies import get_current_user
from ea_chatbot.history.models import User
from ea_chatbot.api.utils import create_access_token

client = TestClient(app)

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

@pytest.fixture
def auth_header(mock_user):
    app.dependency_overrides[get_current_user] = lambda: mock_user
    token = create_access_token(data={"sub": mock_user.username, "user_id": mock_user.id})
    yield {"Authorization": f"Bearer {token}"}
    app.dependency_overrides.clear()

def test_stream_agent_unauthorized():
    """Test that streaming requires authentication."""
    response = client.post("/chat/stream", json={"message": "hello"})
    assert response.status_code == 401

@pytest.mark.asyncio
async def test_stream_agent_success(auth_header, mock_user):
    """Test successful agent streaming with SSE."""
    # We need to mock the LangGraph app.astream_events
    mock_events = [
        {"event": "on_chat_model_start", "name": "gpt-5", "data": {"input": "..."}},
        {"event": "on_chat_model_stream", "name": "gpt-5", "data": {"chunk": "Hello"}},
        {"event": "on_chain_end", "name": "agent", "data": {"output": "..."}}
    ]
    
    async def mock_astream_events(*args, **kwargs):
        for event in mock_events:
            yield event

    with patch("ea_chatbot.api.routers.agent.app.astream_events", side_effect=mock_astream_events), \
         patch("ea_chatbot.api.routers.agent.get_checkpointer") as mock_cp, \
         patch("ea_chatbot.api.routers.agent.history_manager") as mock_hm:
        
        mock_cp.return_value.__aenter__.return_value = AsyncMock()
        
        # Mock session and DB objects
        mock_session = MagicMock()
        mock_hm.get_session.return_value.__enter__.return_value = mock_session
        from ea_chatbot.history.models import Conversation
        mock_conv = Conversation(id="t1", user_id=mock_user.id)
        mock_session.get.return_value = mock_conv
        
        # Using TestClient with a stream context
        with client.stream("POST", "/chat/stream", 
                          json={"message": "hello", "thread_id": "t1"}, 
                          headers=auth_header) as response:
            assert response.status_code == 200
            assert "text/event-stream" in response.headers["content-type"]
            
            lines = list(response.iter_lines())
            # Each event should start with 'data: ' and be valid JSON
            data_lines = [line for line in lines if line.startswith("data: ")]
            assert len(data_lines) >= len(mock_events)