"""对话 API

POST /api/chat/stream - SSE 流式对话
"""

import json
import logging

from fastapi import APIRouter
from fastapi.responses import StreamingResponse
from pydantic import BaseModel

from app.llm.chat_agent import chat_stream

logger = logging.getLogger(__name__)
router = APIRouter(prefix="/api/chat", tags=["chat"])


class ChatMessage(BaseModel):
    role: str
    content: str


class ChatRequest(BaseModel):
    messages: list[ChatMessage]


@router.post("/stream")
async def chat_stream_endpoint(req: ChatRequest):
    """流式对话接口（SSE）"""
    messages = [{"role": m.role, "content": m.content} for m in req.messages]

    async def event_generator():
        try:
            async for msg in chat_stream(messages):
                data = json.dumps(msg, ensure_ascii=False)
                yield f"data: {data}\n\n"
            yield "data: [DONE]\n\n"
        except Exception as e:
            logger.error(f"Chat stream error: {e}")
            error_data = json.dumps(
                {"type": "content", "content": f"出错了: {e}"},
                ensure_ascii=False,
            )
            yield f"data: {error_data}\n\n"
            yield "data: [DONE]\n\n"

    return StreamingResponse(
        event_generator(),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "Connection": "keep-alive",
            "X-Accel-Buffering": "no",
        },
    )