from __future__ import annotations

import logging
import time

import httpx
import markdown2

from app.config import settings
from app.schemas import PublishResponse, WechatPublishRequest

logger = logging.getLogger(__name__)


def _detail_for_token_error(data: dict | None) -> str:
    """把微信返回的 errcode 转成可操作的说明。"""
    if not data:
        return "获取微信 access_token 失败（无返回内容）"
    code = data.get("errcode")
    msg = (data.get("errmsg") or "").strip()
    if code == 40164:
        return (
            "微信 errcode=40164：当前请求使用的出口 IP 未在公众号「IP 白名单」中。"
            "请到 微信公众平台 → 设置与开发 → 基本配置 → IP 白名单，添加本服务对外的公网 IP"
            "（日志里 invalid ip 后面的地址）。若在本地/Docker 调试，出口 IP 常会变，需填当前出口或改用固定出口的服务器。"
            f" 微信原文：{msg}"
        )
    if code == 40013:
        return f"微信 errcode=40013：AppSecret 无效或已重置，请检查 WECHAT_SECRET。{msg}"
    if code == 40125:
        return f"微信 errcode=40125：AppSecret 配置错误。{msg}"
    return f"获取微信 access_token 失败：errcode={code} errmsg={msg}"


class WechatPublisher:
    def __init__(self) -> None:
        self._access_token = None
        self._expires_at = 0

    async def publish_draft(self, req: WechatPublishRequest, request_id: str = "") -> PublishResponse:
        rid = request_id or "-"
        if not settings.wechat_appid or not settings.wechat_secret:
            logger.warning("wechat skipped rid=%s reason=missing_appid_or_secret", rid)
            return PublishResponse(ok=False, detail="缺少 WECHAT_APPID / WECHAT_SECRET 配置")

        token, token_from_cache, token_err_body = await self._get_access_token()
        if not token:
            detail = _detail_for_token_error(token_err_body)
            logger.error("wechat access_token_unavailable rid=%s detail=%s", rid, detail[:200])
            return PublishResponse(ok=False, detail=detail, data=token_err_body)

        logger.info(
            "wechat_token rid=%s cache_hit=%s",
            rid,
            token_from_cache,
        )

        html = markdown2.markdown(req.body_markdown)
        logger.info(
            "wechat_draft_build rid=%s title_chars=%d digest_chars=%d html_chars=%d",
            rid,
            len(req.title or ""),
            len(req.summary or ""),
            len(html or ""),
        )
        payload = {
            "articles": [
                {
                    "title": req.title,
                    "author": req.author or settings.wechat_author,
                    "digest": req.summary,
                    "content": html,
                    "content_source_url": "",
                    "need_open_comment": 0,
                    "only_fans_can_comment": 0,
                }
            ]
        }

        async with httpx.AsyncClient(timeout=25) as client:
            url = f"https://api.weixin.qq.com/cgi-bin/draft/add?access_token={token}"
            logger.info(
                "wechat_http_post rid=%s endpoint=cgi-bin/draft/add http_timeout_s=25",
                rid,
            )
            r = await client.post(url, json=payload)
            data = r.json()

        if data.get("errcode", 0) != 0:
            logger.warning(
                "wechat_draft_failed rid=%s errcode=%s errmsg=%s raw=%s",
                rid,
                data.get("errcode"),
                data.get("errmsg"),
                data,
            )
            return PublishResponse(ok=False, detail=f"微信发布失败: {data}", data=data)

        logger.info(
            "wechat_draft_ok rid=%s media_id=%s",
            rid,
            data.get("media_id", data),
        )
        return PublishResponse(ok=True, detail="已发布到公众号草稿箱", data=data)

    async def _get_access_token(self) -> tuple[str | None, bool, dict | None]:
        """成功时第三项为 None；失败时为微信返回的 JSON（含 errcode/errmsg）。"""
        now = int(time.time())
        if self._access_token and now < self._expires_at - 60:
            return self._access_token, True, None

        logger.info("wechat_http_get endpoint=cgi-bin/token reason=refresh_access_token")
        async with httpx.AsyncClient(timeout=20) as client:
            r = await client.get(
                "https://api.weixin.qq.com/cgi-bin/token",
                params={
                    "grant_type": "client_credential",
                    "appid": settings.wechat_appid,
                    "secret": settings.wechat_secret,
                },
            )
            data = r.json() if r.content else {}

        token = data.get("access_token")
        if not token:
            logger.warning(
                "wechat_token_refresh_failed http_status=%s body=%s",
                r.status_code,
                data,
            )
            return None, False, data if isinstance(data, dict) else None

        self._access_token = token
        self._expires_at = now + int(data.get("expires_in", 7200))
        return token, False, None