"""消息发送处理器：JSON 解析、参数校验、QQ API 超时与重试。"""

import asyncio
from pathlib import Path

from aiohttp import web

from ..config import QQ_API_MAX_RETRIES, QQ_API_TIMEOUT, UPLOAD_DIR
from ..response import error, ok

VALID_MSG_TYPES = {"text", "image", "file", "video"}

# 每种消息类型必填的字段
REQUIRED_FIELDS: dict[str, list[str]] = {
    "text": ["msg"],
    "image": ["url"],
    "file": ["url"],
    "video": ["url"],
}


def _validate_payload(data: dict) -> tuple[dict | None, web.Response | None]:
    """校验请求体，返回 (data, None) 或 (None, error_response)。"""
    group_id = data.get("group_id")
    user_id = data.get("user_id")

    if not group_id and not user_id:
        return None, error("need group_id or user_id")

    msg_type = data.get("type", "text")
    if msg_type not in VALID_MSG_TYPES:
        return None, error(f"invalid type: {msg_type}, must be one of {VALID_MSG_TYPES}")

    # 检查必填字段
    missing = [f for f in REQUIRED_FIELDS.get(msg_type, []) if not data.get(f)]
    if missing:
        return None, error(f"missing required fields: {', '.join(missing)}")

    return data, None


async def _call_qq_api(coro_factory, request: web.Request) -> web.Response:
    """带超时和重试的 QQ API 调用。"""
    logger = request.app["logger"]
    rid = request.get("request_id", "-")

    last_exc: Exception | None = None
    for attempt in range(1, QQ_API_MAX_RETRIES + 1):
        try:
            await asyncio.wait_for(coro_factory(), timeout=QQ_API_TIMEOUT)
            return ok()
        except asyncio.TimeoutError:
            last_exc = asyncio.TimeoutError()
            logger.warning(f"[{rid}] QQ API timeout, attempt {attempt}/{QQ_API_MAX_RETRIES}")
        except Exception as exc:
            last_exc = exc
            logger.error(f"[{rid}] QQ API error: {exc}, attempt {attempt}/{QQ_API_MAX_RETRIES}")

    logger.error(f"[{rid}] QQ API failed after {QQ_API_MAX_RETRIES} retries: {last_exc}")
    return error(f"qq api failed: {last_exc}", code=502, status=502)


async def webhook_handler(request: web.Request) -> web.Response:
    """处理消息发送请求。"""
    # 安全解析 JSON（aiohttp 可能抛 JSONDecodeError 或 ContentTypeError）
    try:
        data = await request.json()
    except Exception:
        return error("invalid json")

    if not isinstance(data, dict):
        return error("request body must be a json object")

    data, err = _validate_payload(data)
    if err:
        return err

    msg_type = data.get("type", "text")
    group_id = data.get("group_id")
    user_id = data.get("user_id")
    msg = data.get("msg", "")
    url = data.get("url", "")

    # 如果 url 是本地已上传的文件（相对路径），补全为绝对路径
    file_path = Path(url)
    if not file_path.is_absolute() and (UPLOAD_DIR / url).exists():
        url = str((UPLOAD_DIR / url).resolve())

    # 获取 ncatbot API 实例
    api = request.app["qq_api"]

    if group_id:
        match msg_type:
            case "text":
                return await _call_qq_api(
                    lambda: api.qq.send_group_text(group_id=group_id, text=msg), request
                )
            case "image":
                return await _call_qq_api(
                    lambda: api.qq.send_group_image(group_id=group_id, image=url), request
                )
            case "file":
                return await _call_qq_api(
                    lambda: api.qq.send_group_file(group_id=group_id, file=url, name=url.split("/")[-1]),
                    request,
                )
            case "video":
                return await _call_qq_api(
                    lambda: api.qq.send_group_video(group_id=group_id, video=url), request
                )
    else:
        match msg_type:
            case "text":
                return await _call_qq_api(
                    lambda: api.qq.send_private_text(user_id=user_id, text=msg), request
                )
            case "image":
                return await _call_qq_api(
                    lambda: api.qq.send_private_image(user_id=user_id, image=url), request
                )
            case "file":
                return await _call_qq_api(
                    lambda: api.qq.send_private_file(user_id=user_id, file=url, name=url.split("/")[-1]),
                    request,
                )
            case "video":
                return await _call_qq_api(
                    lambda: api.qq.send_private_video(user_id=user_id, video=url), request
                )

    return error("unreachable", code=500, status=500)