from __future__ import annotations

import json
import logging
import time
from typing import Any

from fastapi import APIRouter, Request, Response

from .signature import kwaisign_verify
from .types import InboundKuaishouMessage

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/webhook/kuaishou", tags=["kuaishou"])

# TODO(P1-2): 当快手开放 IM API 后，替换为官方实际事件类型
KUAISHOU_IM_EVENT_TYPE = "im_message_receive"


def parse_inbound_message(raw: dict[str, Any]) -> InboundKuaishouMessage | None:
    try:
        event = raw.get("event", "")
        if event != KUAISHOU_IM_EVENT_TYPE:
            return None

        msg_data = raw.get("message", raw)
        return InboundKuaishouMessage(
            msg_id=str(msg_data.get("msg_id", "")),
            open_id=str(msg_data.get("open_id", "")),
            msg_type=msg_data.get("msg_type", "text"),
            content=msg_data.get("content", ""),
            create_time=msg_data.get("create_time", int(time.time() * 1000)),
            conversation_type=msg_data.get("conversation_type", "1"),
            nickname=msg_data.get("nickname", ""),
            avatar_url=msg_data.get("avatar", ""),
            raw_event=raw,
        )
    except Exception:
        logger.exception("解析快手入站消息失败")
        return None


def create_webhook_handler(app_secret: str):

    @router.post("/callback")
    async def kuaishou_webhook(request: Request):
        body_bytes = await request.body()

        # 快手官方 WebHook 签名通过 kwaisign header 传递，算法：MD5(body + appsecret)
        kwaisign = request.headers.get("kwaisign", "")
        if not kwaisign_verify(body_bytes, app_secret, kwaisign):
            return Response(content='{"status":"signature_invalid"}', status_code=403)

        event_data = json.loads(body_bytes.decode("utf-8"))

        if event_data.get("event") != KUAISHOU_IM_EVENT_TYPE:
            return {"status": "ok"}

        inbound = parse_inbound_message(event_data)
        if inbound is None:
            return {"status": "ok"}

        return {"status": "ok", "msg_id": inbound.msg_id}

    return kuaishou_webhook