from fastapi import APIRouter, HTTPException
from fastapi.responses import StreamingResponse
from api.models import ChatRequest, ChatResponse
from api.services import ChatService, StreamService
from api.config import settings
from uuid import uuid4

router = APIRouter(prefix="/chat", tags=["Chat"])


@router.post("", response_model=ChatResponse)
async def chat_simple(request: ChatRequest):
    """
    Simple non-streaming chat endpoint.
    Best for handling interrupts - returns complete response.
    """
    if not settings.system_initialized or not settings.chat_manager:
        raise HTTPException(status_code=503, detail="System initializing...")
    
    try:
        return await ChatService.process_message(
            message=request.message,
            session_id=request.session_id
        )
    except Exception as e:
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/stream")
async def chat_stream(request: ChatRequest):
    """
    Streaming chat endpoint using Server-Sent Events (SSE).
    Streams tokens in real-time and handles interrupts.
    """
    if not settings.system_initialized or not settings.chat_manager:
        raise HTTPException(status_code=503, detail="System initializing...")
    
    session_id = request.session_id or f"api_{uuid4()}"
    
    return StreamingResponse(
        StreamService.stream_chat_response(request.message, session_id),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "Connection": "keep-alive",
            "X-Accel-Buffering": "no"
        }
    )