from __future__ import annotations

import hashlib
import hmac
import base64
import logging
import time
from urllib.parse import quote_plus

import httpx
from urllib.parse import urlparse

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

logger = logging.getLogger(__name__)


class IMPublisher:
    async def publish(self, req: IMPublishRequest, request_id: str = "") -> PublishResponse:
        rid = request_id or "-"
        if not settings.im_webhook_url:
            logger.warning("im_skipped rid=%s reason=empty_webhook_url", rid)
            return PublishResponse(ok=False, detail="缺少 IM_WEBHOOK_URL 配置")

        parsed = urlparse(settings.im_webhook_url)
        host = parsed.netloc or "(invalid_url)"
        logger.info(
            "im_publish_start rid=%s webhook_host=%s sign_enabled=%s title_chars=%d body_truncated_to=3800",
            rid,
            host,
            bool(settings.im_secret),
            len(req.title or ""),
        )

        webhook = self._with_signature(settings.im_webhook_url, settings.im_secret)
        payload = {
            "msg_type": "post",
            "content": {
                "post": {
                    "zh_cn": {
                        "title": req.title,
                        "content": [[{"tag": "text", "text": req.body_markdown[:3800]}]],
                    }
                }
            },
        }

        async with httpx.AsyncClient(timeout=20) as client:
            logger.info("im_http_post rid=%s method=POST timeout_s=20", rid)
            r = await client.post(webhook, json=payload)
            try:
                data = r.json()
            except Exception:
                data = {"status_code": r.status_code, "text": r.text}

        logger.info(
            "im_http_response rid=%s status=%s body_preview=%s",
            rid,
            r.status_code,
            str(data)[:500],
        )

        if r.status_code >= 400:
            logger.warning("im_push_failed rid=%s http_status=%s", rid, r.status_code)
            return PublishResponse(ok=False, detail=f"IM 推送失败: {data}", data=data)

        logger.info("im_push_ok rid=%s", rid)
        return PublishResponse(ok=True, detail="IM 推送成功", data=data)

    def _with_signature(self, webhook: str, secret: str | None) -> str:
        # 兼容飞书 webhook 签名参数：timestamp/sign
        if not secret:
            return webhook

        ts = str(int(time.time()))
        string_to_sign = f"{ts}\n{secret}".encode("utf-8")
        sign = base64.b64encode(hmac.new(string_to_sign, b"", hashlib.sha256).digest()).decode("utf-8")
        connector = "&" if "?" in webhook else "?"
        return f"{webhook}{connector}timestamp={ts}&sign={quote_plus(sign)}"