"""Personal WeChat (微信) channel using HTTP long-poll API.

Uses the ilinkai.weixin.qq.com API for personal WeChat messaging.
No WebSocket, no local WeChat client needed — just HTTP requests with a
bot token obtained via QR code login.

Protocol reverse-engineered from ``@tencent-weixin/openclaw-weixin`` v1.0.3.
"""

from __future__ import annotations

import asyncio
import base64
import hashlib
import json
import os
import random
import re
import time
import uuid
from collections import OrderedDict
from contextlib import suppress
from pathlib import Path
from typing import Any
from urllib.parse import quote

import httpx
from loguru import logger
from pydantic import Field

from nanobot.bus.events import OutboundMessage
from nanobot.bus.queue import MessageBus
from nanobot.channels.base import BaseChannel
from nanobot.config.paths import get_media_dir, get_runtime_subdir
from nanobot.config.schema import Base
from nanobot.utils.helpers import split_message

# ---------------------------------------------------------------------------
# Protocol constants (from openclaw-weixin types.ts)
# ---------------------------------------------------------------------------

# MessageItemType
ITEM_TEXT = 1
ITEM_IMAGE = 2
ITEM_VOICE = 3
ITEM_FILE = 4
ITEM_VIDEO = 5

# MessageType  (1 = inbound from user, 2 = outbound from bot)
MESSAGE_TYPE_BOT = 2

# MessageState
MESSAGE_STATE_FINISH = 2

WEIXIN_MAX_MESSAGE_LEN = 4000
WEIXIN_CHANNEL_VERSION = "2.1.1"
ILINK_APP_ID = "bot"


def _build_client_version(version: str) -> int:
    """Encode semantic version as 0x00MMNNPP (major/minor/patch in one uint32)."""
    parts = version.split(".")

    def _as_int(idx: int) -> int:
        try:
            return int(parts[idx])
        except Exception:
            return 0

    major = _as_int(0)
    minor = _as_int(1)
    patch = _as_int(2)
    return ((major & 0xFF) << 16) | ((minor & 0xFF) << 8) | (patch & 0xFF)

ILINK_APP_CLIENT_VERSION = _build_client_version(WEIXIN_CHANNEL_VERSION)
BASE_INFO: dict[str, str] = {"channel_version": WEIXIN_CHANNEL_VERSION}

# Session-expired error code
ERRCODE_SESSION_EXPIRED = -14
SESSION_PAUSE_DURATION_S = 60 * 60

# Retry constants (matching the reference plugin's monitor.ts)
MAX_CONSECUTIVE_FAILURES = 3
BACKOFF_DELAY_S = 30
RETRY_DELAY_S = 2
MAX_QR_REFRESH_COUNT = 3
TYPING_STATUS_TYPING = 1
TYPING_STATUS_CANCEL = 2
TYPING_TICKET_TTL_S = 24 * 60 * 60
TYPING_KEEPALIVE_INTERVAL_S = 5
CONFIG_CACHE_INITIAL_RETRY_S = 2
CONFIG_CACHE_MAX_RETRY_S = 60 * 60

# Default long-poll timeout; overridden by server via longpolling_timeout_ms.
DEFAULT_LONG_POLL_TIMEOUT_S = 35

# Media-type codes for getuploadurl  (1=image, 2=video, 3=file, 4=voice)
UPLOAD_MEDIA_IMAGE = 1
UPLOAD_MEDIA_VIDEO = 2
UPLOAD_MEDIA_FILE = 3
UPLOAD_MEDIA_VOICE = 4

# File extensions considered as images / videos for outbound media
_IMAGE_EXTS = {".jpg", ".jpeg", ".png", ".gif", ".bmp", ".webp", ".tiff", ".ico", ".svg"}
_VIDEO_EXTS = {".mp4", ".avi", ".mov", ".mkv", ".webm", ".flv"}
_VOICE_EXTS = {".mp3", ".wav", ".amr", ".silk", ".ogg", ".m4a", ".aac", ".flac"}


def _has_downloadable_media_locator(media: dict[str, Any] | None) -> bool:
    if not isinstance(media, dict):
        return False
    return bool(str(media.get("encrypt_query_param", "") or "") or str(media.get("full_url", "") or "").strip())


class WeixinConfig(Base):
    """Personal WeChat channel configuration."""

    enabled: bool = False
    allow_from: list[str] = Field(default_factory=list)
    base_url: str = "https://ilinkai.weixin.qq.com"
    cdn_base_url: str = "https://novac2c.cdn.weixin.qq.com/c2c"
    route_tag: str | int | None = None
    token: str = ""  # Manually set token, or obtained via QR login
    state_dir: str = ""  # Default: ~/.nanobot/weixin/
    poll_timeout: int = DEFAULT_LONG_POLL_TIMEOUT_S  # seconds for long-poll


class WeixinChannel(BaseChannel):
    """
    Personal WeChat channel using HTTP long-poll.

    Connects to ilinkai.weixin.qq.com API to receive and send personal
    WeChat messages. Authentication is via QR code login which produces
    a bot token.
    """

    name = "weixin"
    display_name = "WeChat"

    @classmethod
    def default_config(cls) -> dict[str, Any]:
        return WeixinConfig().model_dump(by_alias=True)

    def __init__(self, config: Any, bus: MessageBus):
        if isinstance(config, dict):
            config = WeixinConfig.model_validate(config)
        super().__init__(config, bus)
        self.config: WeixinConfig = config

        # State
        self._client: httpx.AsyncClient | None = None
        self._get_updates_buf: str = ""
        self._context_tokens: dict[str, str] = {}  # from_user_id -> context_token
        self._processed_ids: OrderedDict[str, None] = OrderedDict()
        self._state_dir: Path | None = None
        self._token: str = ""
        self._poll_task: asyncio.Task | None = None
        self._next_poll_timeout_s: int = DEFAULT_LONG_POLL_TIMEOUT_S
        self._session_pause_until: float = 0.0
        self._typing_tasks: dict[str, asyncio.Task] = {}
        self._typing_tickets: dict[str, dict[str, Any]] = {}

    # ------------------------------------------------------------------
    # State persistence
    # ------------------------------------------------------------------

    def _get_state_dir(self) -> Path:
        if self._state_dir:
            return self._state_dir
        if self.config.state_dir:
            d = Path(self.config.state_dir).expanduser()
        else:
            d = get_runtime_subdir("weixin")
        d.mkdir(parents=True, exist_ok=True)
        self._state_dir = d
        return d

    def _load_state(self) -> bool:
        """Load saved account state. Returns True if a valid token was found."""
        state_file = self._get_state_dir() / "account.json"
        if not state_file.exists():
            return False
        try:
            data = json.loads(state_file.read_text())
            self._token = data.get("token", "")
            self._get_updates_buf = data.get("get_updates_buf", "")
            context_tokens = data.get("context_tokens", {})
            if isinstance(context_tokens, dict):
                self._context_tokens = {
                    str(user_id): str(token)
                    for user_id, token in context_tokens.items()
                    if str(user_id).strip() and str(token).strip()
                }
            else:
                self._context_tokens = {}
            typing_tickets = data.get("typing_tickets", {})
            if isinstance(typing_tickets, dict):
                self._typing_tickets = {
                    str(user_id): ticket
                    for user_id, ticket in typing_tickets.items()
                    if str(user_id).strip() and isinstance(ticket, dict)
                }
            else:
                self._typing_tickets = {}
            base_url = data.get("base_url", "")
            if base_url:
                self.config.base_url = base_url
            return bool(self._token)
        except Exception:
            self.logger.error("Failed to load Weixin account state", exc_info=True)
            return False

    def _save_state(self) -> None:
        state_file = self._get_state_dir() / "account.json"
        with suppress(Exception):
            data = {
                "token": self._token,
                "get_updates_buf": self._get_updates_buf,
                "context_tokens": self._context_tokens,
                "typing_tickets": self._typing_tickets,
                "base_url": self.config.base_url,
            }
            state_file.write_text(json.dumps(data, ensure_ascii=False))

    # ------------------------------------------------------------------
    # HTTP helpers  (matches api.ts buildHeaders / apiFetch)
    # ------------------------------------------------------------------

    @staticmethod
    def _random_wechat_uin() -> str:
        """X-WECHAT-UIN: random uint32 → decimal string → base64.

        Matches the reference plugin's ``randomWechatUin()`` in api.ts.
        Generated fresh for **every** request (same as reference).
        """
        uint32 = int.from_bytes(os.urandom(4), "big")
        return base64.b64encode(str(uint32).encode()).decode()

    def _make_headers(self, *, auth: bool = True) -> dict[str, str]:
        """Build per-request headers (new UIN each call, matching reference)."""
        headers: dict[str, str] = {
            "X-WECHAT-UIN": self._random_wechat_uin(),
            "Content-Type": "application/json",
            "AuthorizationType": "ilink_bot_token",
            "iLink-App-Id": ILINK_APP_ID,
            "iLink-App-ClientVersion": str(ILINK_APP_CLIENT_VERSION),
        }
        if auth and self._token:
            headers["Authorization"] = f"Bearer {self._token}"
        if self.config.route_tag is not None and str(self.config.route_tag).strip():
            headers["SKRouteTag"] = str(self.config.route_tag).strip()
        return headers

    @staticmethod
    def _is_retryable_media_download_error(err: Exception) -> bool:
        if isinstance(err, httpx.TimeoutException | httpx.TransportError):
            return True
        if isinstance(err, httpx.HTTPStatusError):
            status_code = err.response.status_code if err.response is not None else 0
            return status_code >= 500
        return False

    async def _api_get(
        self,
        endpoint: str,
        params: dict | None = None,
        *,
        auth: bool = True,
        extra_headers: dict[str, str] | None = None,
    ) -> dict:
        assert self._client is not None
        url = f"{self.config.base_url}/{endpoint}"
        hdrs = self._make_headers(auth=auth)
        if extra_headers:
            hdrs.update(extra_headers)
        resp = await self._client.get(url, params=params, headers=hdrs)
        resp.raise_for_status()
        return resp.json()

    async def _api_get_with_base(
        self,
        *,
        base_url: str,
        endpoint: str,
        params: dict | None = None,
        auth: bool = True,
        extra_headers: dict[str, str] | None = None,
    ) -> dict:
        """GET helper that allows overriding base_url for QR redirect polling."""
        assert self._client is not None
        url = f"{base_url.rstrip('/')}/{endpoint}"
        hdrs = self._make_headers(auth=auth)
        if extra_headers:
            hdrs.update(extra_headers)
        resp = await self._client.get(url, params=params, headers=hdrs)
        resp.raise_for_status()
        return resp.json()

    async def _api_post(
        self,
        endpoint: str,
        body: dict | None = None,
        *,
        auth: bool = True,
    ) -> dict:
        assert self._client is not None
        url = f"{self.config.base_url}/{endpoint}"
        payload = body or {}
        if "base_info" not in payload:
            payload["base_info"] = BASE_INFO
        resp = await self._client.post(url, json=payload, headers=self._make_headers(auth=auth))
        resp.raise_for_status()
        return resp.json()

    # ------------------------------------------------------------------
    # QR Code Login  (matches login-qr.ts)
    # ------------------------------------------------------------------

    async def _fetch_qr_code(self) -> tuple[str, str]:
        """Fetch a fresh QR code. Returns (qrcode_id, scan_url)."""
        data = await self._api_get(
            "ilink/bot/get_bot_qrcode",
            params={"bot_type": "3"},
            auth=False,
        )
        qrcode_img_content = data.get("qrcode_img_content", "")
        qrcode_id = data.get("qrcode", "")
        if not qrcode_id:
            raise RuntimeError(f"Failed to get QR code from WeChat API: {data}")
        return qrcode_id, (qrcode_img_content or qrcode_id)

    async def _qr_login(self) -> bool:
        """Perform QR code login flow. Returns True on success."""
        try:
            refresh_count = 0
            qrcode_id, scan_url = await self._fetch_qr_code()
            self._print_qr_code(scan_url)
            current_poll_base_url = self.config.base_url

            while self._running:
                try:
                    status_data = await self._api_get_with_base(
                        base_url=current_poll_base_url,
                        endpoint="ilink/bot/get_qrcode_status",
                        params={"qrcode": qrcode_id},
                        auth=False,
                    )
                except Exception as e:
                    if self._is_retryable_qr_poll_error(e):
                        await asyncio.sleep(1)
                        continue
                    raise

                if not isinstance(status_data, dict):
                    await asyncio.sleep(1)
                    continue

                status = status_data.get("status", "")
                if status == "confirmed":
                    token = status_data.get("bot_token", "")
                    bot_id = status_data.get("ilink_bot_id", "")
                    base_url = status_data.get("baseurl", "")
                    user_id = status_data.get("ilink_user_id", "")
                    if token:
                        self._token = token
                        if base_url:
                            self.config.base_url = base_url
                        self._save_state()
                        self.logger.info(
                            "login successful! bot_id={} user_id={}",
                            bot_id,
                            user_id,
                        )
                        return True
                    else:
                        self.logger.error("Login confirmed but no bot_token in response")
                        return False
                elif status == "scaned_but_redirect":
                    redirect_host = str(status_data.get("redirect_host", "") or "").strip()
                    if redirect_host:
                        if redirect_host.startswith("http://") or redirect_host.startswith("https://"):
                            redirected_base = redirect_host
                        else:
                            redirected_base = f"https://{redirect_host}"
                        if redirected_base != current_poll_base_url:
                            current_poll_base_url = redirected_base
                elif status == "expired":
                    refresh_count += 1
                    if refresh_count > MAX_QR_REFRESH_COUNT:
                        self.logger.warning(
                            "QR code expired too many times ({}/{}), giving up.",
                            refresh_count - 1,
                            MAX_QR_REFRESH_COUNT,
                        )
                        return False
                    qrcode_id, scan_url = await self._fetch_qr_code()
                    current_poll_base_url = self.config.base_url
                    self._print_qr_code(scan_url)
                    continue
                # status == "wait" — keep polling

                await asyncio.sleep(1)

        except Exception:
            self.logger.exception("QR login failed")

        return False

    @staticmethod
    def _is_retryable_qr_poll_error(err: Exception) -> bool:
        if isinstance(err, httpx.TimeoutException | httpx.TransportError):
            return True
        if isinstance(err, httpx.HTTPStatusError):
            status_code = err.response.status_code if err.response is not None else 0
            if status_code >= 500:
                return True
        return False

    @staticmethod
    def _print_qr_code(url: str) -> None:
        try:
            import qrcode as qr_lib

            qr = qr_lib.QRCode(border=1)
            qr.add_data(url)
            qr.make(fit=True)
            qr.print_ascii(invert=True)
        except ImportError:
            print(f"\nLogin URL: {url}\n")

    # ------------------------------------------------------------------
    # Channel lifecycle
    # ------------------------------------------------------------------

    async def login(self, force: bool = False) -> bool:
        """Perform QR code login and save token. Returns True on success."""
        if force:
            self._token = ""
            self._get_updates_buf = ""
            state_file = self._get_state_dir() / "account.json"
            if state_file.exists():
                state_file.unlink()
        if self._token or self._load_state():
            return True

        # Initialize HTTP client for the login flow
        self._client = httpx.AsyncClient(
            timeout=httpx.Timeout(60, connect=30),
            follow_redirects=True,
        )
        self._running = True  # Enable polling loop in _qr_login()
        try:
            return await self._qr_login()
        finally:
            self._running = False
            if self._client:
                await self._client.aclose()
                self._client = None

    async def start(self) -> None:
        self._running = True
        self._next_poll_timeout_s = self.config.poll_timeout
        self._client = httpx.AsyncClient(
            timeout=httpx.Timeout(self._next_poll_timeout_s + 10, connect=30),
            follow_redirects=True,
        )

        if self.config.token:
            self._token = self.config.token
        elif not self._load_state():
            if not await self._qr_login():
                self.logger.error("login failed. Run 'nanobot channels login weixin' to authenticate.")
                self._running = False
                return

        self.logger.info("channel starting with long-poll...")

        consecutive_failures = 0
        while self._running:
            try:
                await self._poll_once()
                consecutive_failures = 0
            except httpx.TimeoutException:
                # Normal for long-poll, just retry
                continue
            except Exception:
                if not self._running:
                    break
                consecutive_failures += 1
                if consecutive_failures >= MAX_CONSECUTIVE_FAILURES:
                    consecutive_failures = 0
                    await asyncio.sleep(BACKOFF_DELAY_S)
                else:
                    await asyncio.sleep(RETRY_DELAY_S)

    async def stop(self) -> None:
        self._running = False
        if self._poll_task and not self._poll_task.done():
            self._poll_task.cancel()
        for chat_id in list(self._typing_tasks):
            await self._stop_typing(chat_id, clear_remote=False)
        if self._client:
            await self._client.aclose()
            self._client = None
        self._save_state()
    # ------------------------------------------------------------------
    # Polling  (matches monitor.ts monitorWeixinProvider)
    # ------------------------------------------------------------------

    def _pause_session(self, duration_s: int = SESSION_PAUSE_DURATION_S) -> None:
        self._session_pause_until = time.time() + duration_s

    def _session_pause_remaining_s(self) -> int:
        remaining = int(self._session_pause_until - time.time())
        if remaining <= 0:
            self._session_pause_until = 0.0
            return 0
        return remaining

    def _assert_session_active(self) -> None:
        remaining = self._session_pause_remaining_s()
        if remaining > 0:
            remaining_min = max((remaining + 59) // 60, 1)
            raise RuntimeError(
                f"WeChat session paused, {remaining_min} min remaining (errcode {ERRCODE_SESSION_EXPIRED})"
            )

    async def _poll_once(self) -> None:
        remaining = self._session_pause_remaining_s()
        if remaining > 0:
            await asyncio.sleep(remaining)
            return

        body: dict[str, Any] = {
            "get_updates_buf": self._get_updates_buf,
            "base_info": BASE_INFO,
        }

        # Adjust httpx timeout to match the current poll timeout
        assert self._client is not None
        self._client.timeout = httpx.Timeout(self._next_poll_timeout_s + 10, connect=30)

        data = await self._api_post("ilink/bot/getupdates", body)

        # Check for API-level errors (monitor.ts checks both ret and errcode)
        ret = data.get("ret", 0)
        errcode = data.get("errcode", 0)
        is_error = (ret is not None and ret != 0) or (errcode is not None and errcode != 0)

        if is_error:
            if errcode == ERRCODE_SESSION_EXPIRED or ret == ERRCODE_SESSION_EXPIRED:
                self._pause_session()
                remaining = self._session_pause_remaining_s()
                self.logger.warning(
                    "session expired (errcode {}). Pausing {} min.",
                    errcode,
                    max((remaining + 59) // 60, 1),
                )
                return
            raise RuntimeError(
                f"getUpdates failed: ret={ret} errcode={errcode} errmsg={data.get('errmsg', '')}"
            )

        # Honour server-suggested poll timeout (monitor.ts:102-105)
        server_timeout_ms = data.get("longpolling_timeout_ms")
        if server_timeout_ms and server_timeout_ms > 0:
            self._next_poll_timeout_s = max(server_timeout_ms // 1000, 5)

        # Update cursor
        new_buf = data.get("get_updates_buf", "")
        if new_buf:
            self._get_updates_buf = new_buf
            self._save_state()

        # Process messages (WeixinMessage[] from types.ts)
        msgs: list[dict] = data.get("msgs", []) or []
        for msg in msgs:
            with suppress(Exception):
                await self._process_message(msg)

    # ------------------------------------------------------------------
    # Inbound message processing  (matches inbound.ts + process-message.ts)
    # ------------------------------------------------------------------

    async def _process_message(self, msg: dict) -> None:
        """Process a single WeixinMessage from getUpdates."""
        # Skip bot's own messages (message_type 2 = BOT)
        if msg.get("message_type") == MESSAGE_TYPE_BOT:
            return

        msg_id = str(msg.get("message_id", "") or msg.get("seq", ""))
        if not msg_id:
            msg_id = f"{msg.get('from_user_id', '')}_{msg.get('create_time_ms', '')}"

        from_user_id = msg.get("from_user_id", "") or ""
        if not from_user_id:
            return

        if not self.is_allowed(from_user_id):
            return

        # Deduplication by message_id
        if msg_id in self._processed_ids:
            return
        self._processed_ids[msg_id] = None
        while len(self._processed_ids) > 1000:
            self._processed_ids.popitem(last=False)

        # Cache context_token (required for all replies — inbound.ts:23-27)
        ctx_token = msg.get("context_token", "")
        if ctx_token:
            self._context_tokens[from_user_id] = ctx_token
            self._save_state()

        # Parse item_list (WeixinMessage.item_list — types.ts:161)
        item_list: list[dict] = msg.get("item_list") or []
        content_parts: list[str] = []
        media_paths: list[str] = []
        has_top_level_downloadable_media = False

        for item in item_list:
            item_type = item.get("type", 0)

            if item_type == ITEM_TEXT:
                text = (item.get("text_item") or {}).get("text", "")
                if text:
                    # Handle quoted/ref messages (inbound.ts:86-98)
                    ref = item.get("ref_msg")
                    if ref:
                        ref_item = ref.get("message_item")
                        # If quoted message is media, just pass the text
                        if ref_item and ref_item.get("type", 0) in (
                            ITEM_IMAGE,
                            ITEM_VOICE,
                            ITEM_FILE,
                            ITEM_VIDEO,
                        ):
                            content_parts.append(text)
                        else:
                            parts: list[str] = []
                            if ref.get("title"):
                                parts.append(ref["title"])
                            if ref_item:
                                ref_text = (ref_item.get("text_item") or {}).get("text", "")
                                if ref_text:
                                    parts.append(ref_text)
                            if parts:
                                content_parts.append(f"[引用: {' | '.join(parts)}]\n{text}")
                            else:
                                content_parts.append(text)
                    else:
                        content_parts.append(text)

            elif item_type == ITEM_IMAGE:
                image_item = item.get("image_item") or {}
                if _has_downloadable_media_locator(image_item.get("media")):
                    has_top_level_downloadable_media = True
                file_path = await self._download_media_item(image_item, "image")
                if file_path:
                    content_parts.append(f"[image]\n[Image: source: {file_path}]")
                    media_paths.append(file_path)
                else:
                    content_parts.append("[image]")

            elif item_type == ITEM_VOICE:
                voice_item = item.get("voice_item") or {}
                # Voice-to-text provided by WeChat (inbound.ts:101-103)
                voice_text = voice_item.get("text", "")
                if voice_text:
                    content_parts.append(f"[voice] {voice_text}")
                else:
                    if _has_downloadable_media_locator(voice_item.get("media")):
                        has_top_level_downloadable_media = True
                    file_path = await self._download_media_item(voice_item, "voice")
                    if file_path:
                        transcription = await self.transcribe_audio(file_path)
                        if transcription:
                            content_parts.append(f"[voice] {transcription}")
                        else:
                            content_parts.append(f"[voice]\n[Audio: source: {file_path}]")
                        media_paths.append(file_path)
                    else:
                        content_parts.append("[voice]")

            elif item_type == ITEM_FILE:
                file_item = item.get("file_item") or {}
                if _has_downloadable_media_locator(file_item.get("media")):
                    has_top_level_downloadable_media = True
                file_name = file_item.get("file_name", "unknown")
                file_path = await self._download_media_item(
                    file_item,
                    "file",
                    file_name,
                )
                if file_path:
                    content_parts.append(f"[file: {file_name}]\n[File: source: {file_path}]")
                    media_paths.append(file_path)
                else:
                    content_parts.append(f"[file: {file_name}]")

            elif item_type == ITEM_VIDEO:
                video_item = item.get("video_item") or {}
                if _has_downloadable_media_locator(video_item.get("media")):
                    has_top_level_downloadable_media = True
                file_path = await self._download_media_item(video_item, "video")
                if file_path:
                    content_parts.append(f"[video]\n[Video: source: {file_path}]")
                    media_paths.append(file_path)
                else:
                    content_parts.append("[video]")

        # Fallback: when no top-level media was downloaded, try quoted/referenced media.
        # This aligns with the reference plugin behavior that checks ref_msg.message_item
        # when main item_list has no downloadable media.
        if not media_paths and not has_top_level_downloadable_media:
            ref_media_item: dict[str, Any] | None = None
            for item in item_list:
                if item.get("type", 0) != ITEM_TEXT:
                    continue
                ref = item.get("ref_msg") or {}
                candidate = ref.get("message_item") or {}
                if candidate.get("type", 0) in (ITEM_IMAGE, ITEM_VOICE, ITEM_FILE, ITEM_VIDEO):
                    ref_media_item = candidate
                    break

            if ref_media_item:
                ref_type = ref_media_item.get("type", 0)
                if ref_type == ITEM_IMAGE:
                    image_item = ref_media_item.get("image_item") or {}
                    file_path = await self._download_media_item(image_item, "image")
                    if file_path:
                        content_parts.append(f"[image]\n[Image: source: {file_path}]")
                        media_paths.append(file_path)
                elif ref_type == ITEM_VOICE:
                    voice_item = ref_media_item.get("voice_item") or {}
                    file_path = await self._download_media_item(voice_item, "voice")
                    if file_path:
                        transcription = await self.transcribe_audio(file_path)
                        if transcription:
                            content_parts.append(f"[voice] {transcription}")
                        else:
                            content_parts.append(f"[voice]\n[Audio: source: {file_path}]")
                        media_paths.append(file_path)
                elif ref_type == ITEM_FILE:
                    file_item = ref_media_item.get("file_item") or {}
                    file_name = file_item.get("file_name", "unknown")
                    file_path = await self._download_media_item(file_item, "file", file_name)
                    if file_path:
                        content_parts.append(f"[file: {file_name}]\n[File: source: {file_path}]")
                        media_paths.append(file_path)
                elif ref_type == ITEM_VIDEO:
                    video_item = ref_media_item.get("video_item") or {}
                    file_path = await self._download_media_item(video_item, "video")
                    if file_path:
                        content_parts.append(f"[video]\n[Video: source: {file_path}]")
                        media_paths.append(file_path)

        content = "\n".join(content_parts)
        if not content:
            return

        self.logger.info(
            "inbound: from={} items={} bodyLen={}",
            from_user_id,
            ",".join(str(i.get("type", 0)) for i in item_list),
            len(content),
        )

        await self._start_typing(from_user_id, ctx_token)

        await self._handle_message(
            sender_id=from_user_id,
            chat_id=from_user_id,
            content=content,
            media=media_paths or None,
            metadata={"message_id": msg_id},
        )

    # ------------------------------------------------------------------
    # Media download  (matches media-download.ts + pic-decrypt.ts)
    # ------------------------------------------------------------------

    async def _download_media_item(
        self,
        typed_item: dict,
        media_type: str,
        filename: str | None = None,
    ) -> str | None:
        """Download + AES-decrypt a media item. Returns local path or None."""
        try:
            media = typed_item.get("media") or {}
            encrypt_query_param = str(media.get("encrypt_query_param", "") or "")
            full_url = str(media.get("full_url", "") or "").strip()

            if not encrypt_query_param and not full_url:
                return None

            # Resolve AES key (media-download.ts:43-45, pic-decrypt.ts:40-52)
            # image_item.aeskey is a raw hex string (16 bytes as 32 hex chars).
            # media.aes_key is always base64-encoded.
            # For images, prefer image_item.aeskey; for others use media.aes_key.
            raw_aeskey_hex = typed_item.get("aeskey", "")
            media_aes_key_b64 = media.get("aes_key", "")

            aes_key_b64: str = ""
            if raw_aeskey_hex:
                # Convert hex → raw bytes → base64 (matches media-download.ts:43-44)
                aes_key_b64 = base64.b64encode(bytes.fromhex(raw_aeskey_hex)).decode()
            elif media_aes_key_b64:
                aes_key_b64 = media_aes_key_b64

            # Reference protocol behavior: VOICE/FILE/VIDEO require aes_key;
            # only IMAGE may be downloaded as plain bytes when key is missing.
            if media_type != "image" and not aes_key_b64:
                return None

            assert self._client is not None
            fallback_url = ""
            if encrypt_query_param:
                fallback_url = (
                    f"{self.config.cdn_base_url}/download"
                    f"?encrypted_query_param={quote(encrypt_query_param)}"
                )

            download_candidates: list[tuple[str, str]] = []
            if full_url:
                download_candidates.append(("full_url", full_url))
            if fallback_url and (not full_url or fallback_url != full_url):
                download_candidates.append(("encrypt_query_param", fallback_url))

            data = b""
            for idx, (download_source, cdn_url) in enumerate(download_candidates):
                try:
                    resp = await self._client.get(cdn_url)
                    resp.raise_for_status()
                    data = resp.content
                    break
                except Exception as e:
                    has_more_candidates = idx + 1 < len(download_candidates)
                    should_fallback = (
                        download_source == "full_url"
                        and has_more_candidates
                        and self._is_retryable_media_download_error(e)
                    )
                    if should_fallback:
                        self.logger.warning(
                            "media download failed via full_url, falling back to encrypt_query_param: type={} err={}",
                            media_type,
                            e,
                        )
                        continue
                    raise

            if aes_key_b64 and data:
                data = _decrypt_aes_ecb(data, aes_key_b64)

            if not data:
                return None

            media_dir = get_media_dir("weixin")
            ext = _ext_for_type(media_type)
            if not filename:
                ts = int(time.time())
                hash_seed = encrypt_query_param or full_url
                h = abs(hash(hash_seed)) % 100000
                filename = f"{media_type}_{ts}_{h}{ext}"
            safe_name = os.path.basename(filename)
            file_path = media_dir / safe_name
            file_path.write_bytes(data)
            return str(file_path)

        except Exception:
            self.logger.exception("Error downloading media")
            return None

    # ------------------------------------------------------------------
    # Outbound  (matches send.ts buildTextMessageReq + sendMessageWeixin)
    # ------------------------------------------------------------------

    async def _get_typing_ticket(self, user_id: str, context_token: str = "") -> str:
        """Get typing ticket with per-user refresh + failure backoff cache."""
        now = time.time()
        entry = self._typing_tickets.get(user_id)
        if entry and now < float(entry.get("next_fetch_at", 0)):
            return str(entry.get("ticket", "") or "")

        body: dict[str, Any] = {
            "ilink_user_id": user_id,
            "context_token": context_token or None,
            "base_info": BASE_INFO,
        }
        data = await self._api_post("ilink/bot/getconfig", body)
        if data.get("ret", 0) == 0:
            ticket = str(data.get("typing_ticket", "") or "")
            self._typing_tickets[user_id] = {
                "ticket": ticket,
                "ever_succeeded": True,
                "next_fetch_at": now + (random.random() * TYPING_TICKET_TTL_S),
                "retry_delay_s": CONFIG_CACHE_INITIAL_RETRY_S,
            }
            return ticket

        prev_delay = float(entry.get("retry_delay_s", CONFIG_CACHE_INITIAL_RETRY_S)) if entry else CONFIG_CACHE_INITIAL_RETRY_S
        next_delay = min(prev_delay * 2, CONFIG_CACHE_MAX_RETRY_S)
        if entry:
            entry["next_fetch_at"] = now + next_delay
            entry["retry_delay_s"] = next_delay
            return str(entry.get("ticket", "") or "")

        self._typing_tickets[user_id] = {
            "ticket": "",
            "ever_succeeded": False,
            "next_fetch_at": now + CONFIG_CACHE_INITIAL_RETRY_S,
            "retry_delay_s": CONFIG_CACHE_INITIAL_RETRY_S,
        }
        return ""

    async def _send_typing(self, user_id: str, typing_ticket: str, status: int) -> None:
        """Best-effort sendtyping wrapper."""
        if not typing_ticket:
            return
        body: dict[str, Any] = {
            "ilink_user_id": user_id,
            "typing_ticket": typing_ticket,
            "status": status,
            "base_info": BASE_INFO,
        }
        await self._api_post("ilink/bot/sendtyping", body)

    async def _typing_keepalive_loop(self, user_id: str, typing_ticket: str, stop_event: asyncio.Event) -> None:
        try:
            while not stop_event.is_set():
                await asyncio.sleep(TYPING_KEEPALIVE_INTERVAL_S)
                if stop_event.is_set():
                    break
                with suppress(Exception):
                    await self._send_typing(user_id, typing_ticket, TYPING_STATUS_TYPING)
        finally:
            pass

    async def send(self, msg: OutboundMessage) -> None:
        if not self._client or not self._token:
            raise RuntimeError("WeChat client not initialized or not authenticated")
        self._assert_session_active()

        is_progress = bool((msg.metadata or {}).get("_progress", False))
        if not is_progress:
            await self._stop_typing(msg.chat_id, clear_remote=True)

        content = msg.content.strip()
        ctx_token = self._context_tokens.get(msg.chat_id, "")
        if not ctx_token:
            raise RuntimeError(
                f"WeChat context_token missing for chat_id={msg.chat_id}, cannot send"
            )

        typing_ticket = ""
        with suppress(Exception):
            typing_ticket = await self._get_typing_ticket(msg.chat_id, ctx_token)

        if typing_ticket:
            with suppress(Exception):
                await self._send_typing(msg.chat_id, typing_ticket, TYPING_STATUS_TYPING)

        typing_keepalive_stop = asyncio.Event()
        typing_keepalive_task: asyncio.Task | None = None
        if typing_ticket:
            typing_keepalive_task = asyncio.create_task(
                self._typing_keepalive_loop(msg.chat_id, typing_ticket, typing_keepalive_stop)
            )

        try:
            # --- Send media files first (following Telegram channel pattern) ---
            for media_path in (msg.media or []):
                try:
                    await self._send_media_file(msg.chat_id, media_path, ctx_token)
                except (httpx.TimeoutException, httpx.TransportError):
                    # Network/transport errors: do NOT fall back to text —
                    # the text send would also likely fail, and the outer
                    # except will re-raise so ChannelManager retries properly.
                    self.logger.opt(exception=True).warning(
                        "Network error sending media {}",
                        media_path,
                    )
                    raise
                except httpx.HTTPStatusError as http_err:
                    status_code = (
                        http_err.response.status_code
                        if http_err.response is not None
                        else 0
                    )
                    if status_code >= 500:
                        # Server-side / retryable HTTP error — same as network.
                        self.logger.exception(
                            "Server error ({} {}) sending media {}",
                            status_code,
                            http_err.response.reason_phrase
                            if http_err.response is not None
                            else "",
                            media_path,
                        )
                        raise
                    # 4xx client errors are NOT retryable — fall back to text.
                    filename = Path(media_path).name
                    self.logger.exception("Failed to send media {}", media_path)
                    await self._send_text(
                        msg.chat_id, f"[Failed to send: {filename}]", ctx_token,
                    )
                except Exception:
                    # Non-network errors (format, file-not-found, etc.):
                    # notify the user via text fallback.
                    filename = Path(media_path).name
                    self.logger.exception("Failed to send media {}", media_path)
                    # Notify user about failure via text
                    await self._send_text(
                        msg.chat_id, f"[Failed to send: {filename}]", ctx_token,
                    )

            # --- Send text content ---
            if not content:
                return

            chunks = split_message(content, WEIXIN_MAX_MESSAGE_LEN)
            for chunk in chunks:
                await self._send_text(msg.chat_id, chunk, ctx_token)
        except Exception:
            self.logger.exception("Error sending message")
            raise
        finally:
            if typing_keepalive_task:
                typing_keepalive_stop.set()
                typing_keepalive_task.cancel()
                with suppress(asyncio.CancelledError):
                    await typing_keepalive_task

            if typing_ticket and not is_progress:
                with suppress(Exception):
                    await self._send_typing(msg.chat_id, typing_ticket, TYPING_STATUS_CANCEL)

    async def _start_typing(self, chat_id: str, context_token: str = "") -> None:
        """Start typing indicator immediately when a message is received."""
        if not self._client or not self._token or not chat_id:
            return
        await self._stop_typing(chat_id, clear_remote=False)
        try:
            ticket = await self._get_typing_ticket(chat_id, context_token)
            if not ticket:
                return
            await self._send_typing(chat_id, ticket, TYPING_STATUS_TYPING)
        except Exception as e:
            self.logger.debug("typing indicator start failed for {}: {}", chat_id, e)
            return

        stop_event = asyncio.Event()

        async def keepalive() -> None:
            try:
                while not stop_event.is_set():
                    await asyncio.sleep(TYPING_KEEPALIVE_INTERVAL_S)
                    if stop_event.is_set():
                        break
                    with suppress(Exception):
                        await self._send_typing(chat_id, ticket, TYPING_STATUS_TYPING)
            finally:
                pass

        task = asyncio.create_task(keepalive())
        task._typing_stop_event = stop_event  # type: ignore[attr-defined]
        self._typing_tasks[chat_id] = task

    async def _stop_typing(self, chat_id: str, *, clear_remote: bool) -> None:
        """Stop typing indicator for a chat."""
        task = self._typing_tasks.pop(chat_id, None)
        if task and not task.done():
            stop_event = getattr(task, "_typing_stop_event", None)
            if stop_event:
                stop_event.set()
            task.cancel()
            with suppress(asyncio.CancelledError):
                await task
        if not clear_remote:
            return
        entry = self._typing_tickets.get(chat_id)
        ticket = str(entry.get("ticket", "") or "") if isinstance(entry, dict) else ""
        if not ticket:
            return
        try:
            await self._send_typing(chat_id, ticket, TYPING_STATUS_CANCEL)
        except Exception as e:
            self.logger.debug("typing clear failed for {}: {}", chat_id, e)

    async def _send_text(
        self,
        to_user_id: str,
        text: str,
        context_token: str,
    ) -> None:
        """Send a text message matching the exact protocol from send.ts."""
        client_id = f"nanobot-{uuid.uuid4().hex[:12]}"

        item_list: list[dict] = []
        if text:
            item_list.append({"type": ITEM_TEXT, "text_item": {"text": text}})

        weixin_msg: dict[str, Any] = {
            "from_user_id": "",
            "to_user_id": to_user_id,
            "client_id": client_id,
            "message_type": MESSAGE_TYPE_BOT,
            "message_state": MESSAGE_STATE_FINISH,
        }
        if item_list:
            weixin_msg["item_list"] = item_list
        if context_token:
            weixin_msg["context_token"] = context_token

        body: dict[str, Any] = {
            "msg": weixin_msg,
            "base_info": BASE_INFO,
        }

        data = await self._api_post("ilink/bot/sendmessage", body)
        errcode = data.get("errcode", 0)
        if errcode and errcode != 0:
            raise RuntimeError(
                f"WeChat send text error (code {errcode}): {data.get('errmsg', '')}"
            )

    async def _send_media_file(
        self,
        to_user_id: str,
        media_path: str,
        context_token: str,
    ) -> None:
        """Upload a local file to WeChat CDN and send it as a media message.

        Follows the exact protocol from ``@tencent-weixin/openclaw-weixin`` v1.0.3:
        1. Generate a random 16-byte AES key (client-side).
        2. Call ``getuploadurl`` with file metadata + hex-encoded AES key.
        3. AES-128-ECB encrypt the file and POST to CDN (``{cdnBaseUrl}/upload``).
        4. Read ``x-encrypted-param`` header from CDN response as the download param.
        5. Send a ``sendmessage`` with the appropriate media item referencing the upload.
        """
        p = Path(media_path)
        if not p.is_file():
            raise FileNotFoundError(f"Media file not found: {media_path}")

        raw_data = p.read_bytes()
        raw_size = len(raw_data)
        raw_md5 = hashlib.md5(raw_data).hexdigest()

        # Determine upload media type from extension
        ext = p.suffix.lower()
        if ext in _IMAGE_EXTS:
            upload_type = UPLOAD_MEDIA_IMAGE
            item_type = ITEM_IMAGE
            item_key = "image_item"
        elif ext in _VIDEO_EXTS:
            upload_type = UPLOAD_MEDIA_VIDEO
            item_type = ITEM_VIDEO
            item_key = "video_item"
        elif ext in _VOICE_EXTS:
            upload_type = UPLOAD_MEDIA_VOICE
            item_type = ITEM_VOICE
            item_key = "voice_item"
        else:
            upload_type = UPLOAD_MEDIA_FILE
            item_type = ITEM_FILE
            item_key = "file_item"

        # Generate client-side AES-128 key (16 random bytes)
        aes_key_raw = os.urandom(16)
        aes_key_hex = aes_key_raw.hex()

        # Compute encrypted size: PKCS7 padding to 16-byte boundary
        # Matches aesEcbPaddedSize: Math.ceil((size + 1) / 16) * 16
        padded_size = ((raw_size + 1 + 15) // 16) * 16

        # Step 1: Get upload URL from server (prefer upload_full_url, fallback to upload_param)
        file_key = os.urandom(16).hex()
        upload_body: dict[str, Any] = {
            "filekey": file_key,
            "media_type": upload_type,
            "to_user_id": to_user_id,
            "rawsize": raw_size,
            "rawfilemd5": raw_md5,
            "filesize": padded_size,
            "no_need_thumb": True,
            "aeskey": aes_key_hex,
        }

        assert self._client is not None
        upload_resp = await self._api_post("ilink/bot/getuploadurl", upload_body)

        upload_full_url = str(upload_resp.get("upload_full_url", "") or "").strip()
        upload_param = str(upload_resp.get("upload_param", "") or "")
        if not upload_full_url and not upload_param:
            raise RuntimeError(
                "getuploadurl returned no upload URL "
                f"(need upload_full_url or upload_param): {upload_resp}"
            )

        # Step 2: AES-128-ECB encrypt and POST to CDN
        aes_key_b64 = base64.b64encode(aes_key_raw).decode()
        encrypted_data = _encrypt_aes_ecb(raw_data, aes_key_b64)

        if upload_full_url:
            cdn_upload_url = upload_full_url
        else:
            cdn_upload_url = (
                f"{self.config.cdn_base_url}/upload"
                f"?encrypted_query_param={quote(upload_param)}"
                f"&filekey={quote(file_key)}"
            )

        cdn_resp = await self._client.post(
            cdn_upload_url,
            content=encrypted_data,
            headers={"Content-Type": "application/octet-stream"},
        )
        cdn_resp.raise_for_status()

        # The download encrypted_query_param comes from CDN response header
        download_param = cdn_resp.headers.get("x-encrypted-param", "")
        if not download_param:
            raise RuntimeError(
                "CDN upload response missing x-encrypted-param header; "
                f"status={cdn_resp.status_code} headers={dict(cdn_resp.headers)}"
            )

        # Step 3: Send message with the media item
        # aes_key for CDNMedia is the hex key encoded as base64
        # (matches: Buffer.from(uploaded.aeskey).toString("base64"))
        cdn_aes_key_b64 = base64.b64encode(aes_key_hex.encode()).decode()

        media_item: dict[str, Any] = {
            "media": {
                "encrypt_query_param": download_param,
                "aes_key": cdn_aes_key_b64,
                "encrypt_type": 1,
            },
        }

        if item_type == ITEM_IMAGE:
            media_item["mid_size"] = padded_size
        elif item_type == ITEM_VIDEO:
            media_item["video_size"] = padded_size
        elif item_type == ITEM_FILE:
            media_item["file_name"] = p.name
            media_item["len"] = str(raw_size)

        # Send each media item as its own message (matching reference plugin)
        client_id = f"nanobot-{uuid.uuid4().hex[:12]}"
        item_list: list[dict] = [{"type": item_type, item_key: media_item}]

        weixin_msg: dict[str, Any] = {
            "from_user_id": "",
            "to_user_id": to_user_id,
            "client_id": client_id,
            "message_type": MESSAGE_TYPE_BOT,
            "message_state": MESSAGE_STATE_FINISH,
            "item_list": item_list,
        }
        if context_token:
            weixin_msg["context_token"] = context_token

        body: dict[str, Any] = {
            "msg": weixin_msg,
            "base_info": BASE_INFO,
        }

        data = await self._api_post("ilink/bot/sendmessage", body)
        errcode = data.get("errcode", 0)
        if errcode and errcode != 0:
            raise RuntimeError(
                f"WeChat send media error (code {errcode}): {data.get('errmsg', '')}"
            )


# ---------------------------------------------------------------------------
# AES-128-ECB encryption / decryption  (matches pic-decrypt.ts / aes-ecb.ts)
# ---------------------------------------------------------------------------


def _parse_aes_key(aes_key_b64: str) -> bytes:
    """Parse a base64-encoded AES key, handling both encodings seen in the wild.

    From ``pic-decrypt.ts parseAesKey``:

    * ``base64(raw 16 bytes)``            → images (media.aes_key)
    * ``base64(hex string of 16 bytes)``  → file / voice / video

    In the second case base64-decoding yields 32 ASCII hex chars which must
    then be parsed as hex to recover the actual 16-byte key.
    """
    decoded = base64.b64decode(aes_key_b64)
    if len(decoded) == 16:
        return decoded
    if len(decoded) == 32 and re.fullmatch(rb"[0-9a-fA-F]{32}", decoded):
        # hex-encoded key: base64 → hex string → raw bytes
        return bytes.fromhex(decoded.decode("ascii"))
    raise ValueError(
        f"aes_key must decode to 16 raw bytes or 32-char hex string, got {len(decoded)} bytes"
    )


def _encrypt_aes_ecb(data: bytes, aes_key_b64: str) -> bytes:
    """Encrypt data with AES-128-ECB and PKCS7 padding for CDN upload."""
    try:
        key = _parse_aes_key(aes_key_b64)
    except Exception as e:
        logger.warning("Failed to parse AES key for encryption, sending raw: {}", e)
        return data

    # PKCS7 padding
    pad_len = 16 - len(data) % 16
    padded = data + bytes([pad_len] * pad_len)

    with suppress(ImportError):
        from Crypto.Cipher import AES

        cipher = AES.new(key, AES.MODE_ECB)
        return cipher.encrypt(padded)

    try:
        from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes

        cipher_obj = Cipher(algorithms.AES(key), modes.ECB())
        encryptor = cipher_obj.encryptor()
        return encryptor.update(padded) + encryptor.finalize()
    except ImportError:
        logger.warning("Cannot encrypt media: install 'pycryptodome' or 'cryptography'")
        return data


def _decrypt_aes_ecb(data: bytes, aes_key_b64: str) -> bytes:
    """Decrypt AES-128-ECB media data.

    ``aes_key_b64`` is always base64-encoded (caller converts hex keys first).
    """
    try:
        key = _parse_aes_key(aes_key_b64)
    except Exception as e:
        logger.warning("Failed to parse AES key, returning raw data: {}", e)
        return data

    decrypted: bytes | None = None

    with suppress(ImportError):
        from Crypto.Cipher import AES

        cipher = AES.new(key, AES.MODE_ECB)
        decrypted = cipher.decrypt(data)

    if decrypted is None:
        try:
            from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes

            cipher_obj = Cipher(algorithms.AES(key), modes.ECB())
            decryptor = cipher_obj.decryptor()
            decrypted = decryptor.update(data) + decryptor.finalize()
        except ImportError:
            logger.warning("Cannot decrypt media: install 'pycryptodome' or 'cryptography'")
            return data

    return _pkcs7_unpad_safe(decrypted)


def _pkcs7_unpad_safe(data: bytes, block_size: int = 16) -> bytes:
    """Safely remove PKCS7 padding when valid; otherwise return original bytes."""
    if not data:
        return data
    if len(data) % block_size != 0:
        return data
    pad_len = data[-1]
    if pad_len < 1 or pad_len > block_size:
        return data
    if data[-pad_len:] != bytes([pad_len]) * pad_len:
        return data
    return data[:-pad_len]


def _ext_for_type(media_type: str) -> str:
    return {
        "image": ".jpg",
        "voice": ".silk",
        "video": ".mp4",
        "file": "",
    }.get(media_type, "")
