"""
企微 HTTP 路由：回调验签入队 + 本机注入联调。

本文件职责：GET URL 验证、POST 收消息快回、dev 注入。
禁止：在本路由同步调 LLM / 等企微发送完成 / 跑 Graph。
路径：/wecom/callback（与现网对外路径语义对齐，本机测 8910）。
"""

from __future__ import annotations

import logging
import re
import xml.etree.ElementTree as ET

from fastapi import APIRouter, HTTPException, Query, Request, Response
from pydantic import BaseModel, Field

from agent.channel.queue import get_message_store
from agent.channel.wecom.crypto import WeComCrypto, WeComCryptoError
from agent.channel.wecom.parse import inbound_from_inject, parse_plain_xml
from agent.config import get_settings

logger = logging.getLogger(__name__)

router = APIRouter(tags=["wecom"])


def _crypto() -> WeComCrypto:
    s = get_settings()
    return WeComCrypto(
        token=s.wecom_callback_token,
        encoding_aes_key=s.wecom_encoding_aes_key,
        corp_id=s.wecom_corp_id,
    )


@router.get("/wecom/callback")
def wecom_callback_verify(
    msg_signature: str = Query(...),
    timestamp: str = Query(...),
    nonce: str = Query(...),
    echostr: str = Query(...),
) -> Response:
    """
    企微配置回调 URL 时的 GET 验证。

    成功：响应体为解密后的明文 echostr（纯文本，非 JSON）。
    失败：403。不入业务队列。
    """
    try:
        plain = _crypto().verify_url(msg_signature, timestamp, nonce, echostr)
    except WeComCryptoError as exc:
        logger.warning("企微 URL 验证失败: %s", exc)
        raise HTTPException(status_code=403, detail="verify failed") from exc
    return Response(content=plain, media_type="text/plain")


@router.post("/wecom/callback")
async def wecom_callback_receive(
    request: Request,
    msg_signature: str = Query(...),
    timestamp: str = Query(...),
    nonce: str = Query(...),
) -> Response:
    """
    企微消息回调：验签解密 → 归一 → 入 inbox → 立即返回 success。

    为何不在此发回复：企微回调有超时；发送走 outbox 独立线程。
    无 sender_id：不入队，仍返回 success，避免企微狂重试。
    """
    body = (await request.body()).decode("utf-8", errors="replace")
    encrypt = _extract_encrypt(body)
    if not encrypt:
        logger.warning("回调体缺少 Encrypt")
        raise HTTPException(status_code=400, detail="missing encrypt")

    settings = get_settings()
    try:
        crypto = _crypto()
        crypto.verify_signature(msg_signature, timestamp, nonce, encrypt)
        plain = crypto.decrypt(encrypt)
    except WeComCryptoError as exc:
        logger.warning("回调验签/解密失败: %s", exc)
        raise HTTPException(status_code=403, detail="crypto failed") from exc

    inbound = parse_plain_xml(plain, default_agent_id=str(settings.wecom_agent_id))
    if not inbound.has_sender():
        logger.warning("回调无 FromUserName/sender_id，丢弃 msg_id=%s", inbound.message_id)
        return Response(content="success", media_type="text/plain")

    store = get_message_store()
    ok, info = store.enqueue_inbound(inbound)
    logger.info("回调入队 ok=%s info=%s type=%s", ok, info, inbound.msg_type)
    return Response(content="success", media_type="text/plain")


def _extract_encrypt(xml_or_json: str) -> str:
    """从回调体取出 Encrypt 字段（XML 为主）。"""
    text = xml_or_json.strip()
    if not text:
        return ""
    if text.startswith("<"):
        try:
            root = ET.fromstring(text)
            node = root.find("Encrypt")
            return (node.text or "").strip() if node is not None else ""
        except ET.ParseError:
            m = re.search(r"<Encrypt><!\[CDATA\[(.*?)\]\]></Encrypt>", text, re.S)
            return m.group(1).strip() if m else ""
    m = re.search(r'"Encrypt"\s*:\s*"([^"]+)"', text)
    return m.group(1) if m else ""


class InjectTextBody(BaseModel):
    """本机注入私聊文字：模拟企微入站，走同一套 inbox→echo→outbox。"""

    sender_id: str = Field(..., description="企微 userid，必须真实，否则发不出")
    content: str = Field(..., description="模拟用户发送的文字")
    message_id: str = Field(default="", description="可选幂等键；空则自动生成")


@router.post("/internal/dev/inject-text")
def inject_text(body: InjectTextBody) -> dict[str, object]:
    """
    并存期联调入口：不经公网回调，直接入 inbox，并由 outbox 向 sender_id 真发企微消息。

    安全：YTD_ENV=prod 时默认拒绝。
    副作用：入队；发送在后台线程异步完成。
    """
    settings = get_settings()
    if settings.ytd_env == "prod" and not settings.dev_inject_enabled:
        raise HTTPException(status_code=403, detail="prod 禁止注入，除非 DEV_INJECT_ENABLED=true")

    inbound = inbound_from_inject(
        {
            "sender_id": body.sender_id,
            "content": body.content,
            "message_id": body.message_id,
        },
        default_agent_id=str(settings.wecom_agent_id),
    )
    if not inbound.has_sender():
        raise HTTPException(status_code=400, detail="sender_id 必填")

    ok, info = get_message_store().enqueue_inbound(inbound)
    return {
        "accepted": ok,
        "info": info,
        "queue": get_message_store().stats(),
        "hint": "请查企微是否收到 [test] 回复；并存期公网回调仍进现网，真收消息需切流",
    }


@router.get("/internal/dev/queue-stats")
def queue_stats() -> dict[str, object]:
    """查看内存队列积压（联调）。"""
    return get_message_store().stats()