import logging
import uuid
import json

from fastapi import APIRouter, HTTPException, status
from fastapi.responses import StreamingResponse

from config import QWEN_API_KEY, QWEN_UPSTREAM_URL
from models import ChatRequest
from utils import convert_prompt_to_messages, standard_sse_generator

router = APIRouter()
logger = logging.getLogger("proxy")


@router.post("/qwen/chat")
async def proxy_qwen_chat(request: ChatRequest):

    # 为每个请求生成一个唯一的 ID,方便在日志中追踪
    request_id = f"qwen-{uuid.uuid4()}"

    # 检查 API Key 是否已在 config.py 中配置
    if not QWEN_API_KEY:
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail="Qwen API key is not configured.",
        )

    # 记录从客户端收到的原始请求体
    client_request_body = request.model_dump()
    logger.debug(
        f"[{request_id}] === Qwen New Request ===\n"
        f"[{request_id}] Client Request Body:\n"
        f"{json.dumps(client_request_body, indent=2, ensure_ascii=False)}"
    )

    # 将 prompt 格式转换为 API 所需的 messages 格式
    messages = convert_prompt_to_messages(request.prompt)
    logger.debug(
        f"[{request_id}] Agent Transformed Messages:\n"
        f"{json.dumps(messages, indent=2, ensure_ascii=False)}"
    )

    # 构建发送到上游  API 的 payload
    payload = {
        "model": "qwen-plus",  # 指定使用的模型
        "messages": messages,
        "stream": True,
        "temperature": request.temperature,
        "top_p": request.top_p,
        "max_tokens": request.max_tokens,
    }

    # 如果客户端请求 web_search=True，则为 Qwen 启用网页搜索
    if request.web_search is True:
        payload["enable_search"] = True
        logger.info(f"[{request_id}] Enabled web search for Qwen.")

    logger.debug(
        f"[{request_id}] Upstream Payload:\n"
        f"{json.dumps(payload, indent=2, ensure_ascii=False)}"
    )

    # 请求头,包含认证信息
    headers = {"Authorization": f"Bearer {QWEN_API_KEY}"}

    # 返回一个流式响应对象
    # standard_sse_generator 会处理与上游的通信和流式数据的转发
    return StreamingResponse(
        standard_sse_generator(
            QWEN_UPSTREAM_URL, payload, headers, "Qwen", request_id
        ),
        media_type="text/event-stream",  # 指定 SSE 的 MIME 类型
    )