from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
import httpx
import logging
import sys
import traceback
import os

logging.basicConfig(level=logging.INFO, format="%(asctime)s [%(levelname)s] %(message)s", handlers=[logging.StreamHandler(sys.stdout)])
logger = logging.getLogger(__name__)

app = FastAPI()
app.add_middleware(CORSMiddleware, allow_origins=["*"], allow_credentials=True, allow_methods=["*"], allow_headers=["*"])

class MessageRequest(BaseModel):
    message: str

LANGGRAPH_URL = os.getenv("LANGGRAPH_URL", "http://langgraph-service:8090")

@app.post("/chat")
async def chat(request: MessageRequest):
    """
    Routes all queries through LangGraph Supervisor.
    No hardcoded keywords - LangGraph intelligently routes to:
    - Librarian: For knowledge base queries (RAG)
    - Opencode: For coding tasks
    - Brain: For general LLM queries
    """
    logger.info(f"Gateway: Routing query to LangGraph: {request.message}")
    
    try:
        async with httpx.AsyncClient(timeout=httpx.Timeout(60.0, connect=10.0)) as client:
            response = await client.post(
                f"{LANGGRAPH_URL}/query",
                json={"query": request.message}
            )
            
            if response.status_code == 200:
                result = response.json()
                agent_used = result.get("agent_used", "unknown")
                logger.info(f"Gateway: Response from {agent_used} agent")
                return {"response": result["response"]}
            else:
                logger.error(f"Gateway: LangGraph error {response.status_code}")
                return {"response": "Error: Orchestration service unavailable"}
                
    except Exception as e:
        logger.error(f"Gateway: Error routing through LangGraph: {traceback.format_exc()}")
        return {"response": "Error: Unable to process your request at this time."}

@app.get("/health")
async def health():
    return {"status": "healthy", "service": "chat-gateway"}

@app.get("/agents")
async def list_agents():
    """List available agents from LangGraph."""
    try:
        async with httpx.AsyncClient(timeout=httpx.Timeout(10.0)) as client:
            response = await client.get(f"{LANGGRAPH_URL}/agents")
            if response.status_code == 200:
                return response.json()
    except Exception as e:
        logger.error(f"Error fetching agents: {e}")
    
    return {"agents": [], "error": "Could not retrieve agent list"}