from __future__ import annotations

import base64
import hashlib
import json
import random
import threading
import time
from collections.abc import Callable
from typing import Any
from urllib.parse import quote
from uuid import uuid4

import httpx
import qrcode
import qrcode.image.svg

from external_connector.providers.fake import _session_view
from external_connector.state import ConnectorSessionState, SidecarStateStore


BridgePoster = Callable[[str, dict[str, Any], dict[str, str]], None]


class WeixinIlinkProvider:
    provider_id = "weixin_ilink"
    fixed_base_url = "https://ilinkai.weixin.qq.com"
    app_client_version = str((2 << 16) | (4 << 8) | 3)

    def __init__(
        self,
        *,
        store: SidecarStateStore,
        http_client: Any | None = None,
        bridge_base_url: str,
        bridge_token: str,
        bridge_post: BridgePoster | None = None,
        start_receivers: bool = True,
    ) -> None:
        self.store = store
        self.http = http_client or httpx.Client(timeout=40)
        self.bridge_base_url = bridge_base_url.rstrip("/")
        self.bridge_token = bridge_token
        self.bridge_post = bridge_post or self._default_bridge_post
        self.start_receivers = start_receivers
        self._receiver_stops: dict[str, threading.Event] = {}
        self._receiver_lock = threading.Lock()
        self._start_existing_connected_receivers()

    def connectors(self) -> list[dict[str, Any]]:
        return [
            {
                "kind": "weixin",
                "displayName": "Weixin",
                "authType": "qr",
                "providerId": self.provider_id,
                "capabilities": ["receive_text", "send_text", "direct_messages"],
            }
        ]

    def health(self) -> dict[str, Any]:
        return {"ok": True, "providerId": self.provider_id}

    def start_session(self, payload: dict[str, Any]) -> dict[str, Any]:
        kind = str(payload["kind"])
        if kind != "weixin":
            raise KeyError(f"Unsupported connector kind: {kind}")
        session = self.store.create_session(
            kind=kind,
            connection_id=str(payload["connectionId"]),
            channel_id=str(payload["channelId"]),
            display_name=str(payload["displayName"]),
            options=dict(payload.get("options") or {}),
        )
        response = self._post_json(
            self.fixed_base_url,
            "ilink/bot/get_bot_qrcode?bot_type=3",
            {"local_token_list": []},
            token=None,
            timeout=20,
        )
        qr_code = str(response.get("qrcode") or "")
        qr_url = str(response.get("qrcode_img_content") or "")
        session = self.store.update_session(
            session.session_id,
            status="qr_ready",
            qr_code=qr_url,
            qr_image=_qr_svg_data_uri(qr_url),
            metadata={
                "qrcode": qr_code,
                "qrBaseUrl": self.fixed_base_url,
                "bridgeBaseUrl": str(payload.get("callbackBaseUrl") or self.bridge_base_url),
                "getUpdatesBuf": "",
            },
        )
        return _session_view(session)

    def get_session(self, session_id: str) -> dict[str, Any]:
        session = self.store.get_session(session_id)
        if session.kind != "weixin":
            raise KeyError(session_id)
        if session.kind == "weixin" and session.status not in {"expired", "error", "cancelled"} and _has_connection_material(session):
            if session.status != "connected":
                session = self.store.update_session(session.session_id, status="connected")
            self._ensure_receiver(session)
            return _session_view(session)
        if session.status in {"connected", "expired", "error", "cancelled"}:
            if session.status == "connected":
                self._ensure_receiver(session)
            return _session_view(session)
        qrcode = str(session.metadata.get("qrcode") or "")
        if not qrcode:
            return _session_view(session)
        endpoint = f"ilink/bot/get_qrcode_status?qrcode={quote(qrcode)}"
        response = self._get_json(self.fixed_base_url, endpoint, timeout=40)
        status = str(response.get("status") or "wait")
        session = self._apply_login_status(session, response, status)
        if session.status == "connected":
            self._ensure_receiver(session)
        return _session_view(session)

    def cancel_session(self, session_id: str) -> None:
        session = self.store.get_session(session_id)
        if session.kind != "weixin":
            raise KeyError(session_id)
        session = self.store.update_session(session_id, status="cancelled")
        self._stop_receiver(session.connection_id)

    def logout(self, connection_id: str) -> None:
        self._stop_receiver(connection_id)
        try:
            session = self.store.find_session_by_connection_id(connection_id)
        except KeyError:
            return None
        self.store.update_session(session.session_id, status="cancelled")
        return None

    def send(self, payload: dict[str, Any]) -> dict[str, Any]:
        begin = self.store.begin_send(connection_id=str(payload["connectionId"]), request_id=str(payload["requestId"]))
        if not begin.should_send:
            if begin.http_status == 409:
                return {"ok": False, "status": begin.status, "retryAfterSeconds": begin.retry_after_seconds, "httpStatus": 409}
            return {"ok": True, "providerMessageId": begin.provider_message_id}
        session = self.store.find_session_by_connection_id(str(payload["connectionId"]))
        token = str(session.metadata.get("token") or "")
        base_url = str(session.metadata.get("baseUrl") or "")
        if not token or not base_url:
            return {"ok": False, "error": "Weixin connection is not connected"}
        target = dict(payload.get("target") or {})
        metadata = dict(payload.get("metadata") or {})
        peer_id = str(target.get("peerId") or "")
        request_id = str(payload["requestId"])
        client_id = _client_id(request_id)
        message_body = {
            "from_user_id": "",
            "to_user_id": peer_id,
            "client_id": client_id,
            "message_type": 2,
            "message_state": 2,
            "item_list": [{"type": 1, "text_item": {"text": str(payload.get("content") or "")}}],
        }
        context_token = _optional_text(metadata.get("contextToken") or metadata.get("context_token"))
        if not context_token:
            context_token = _cached_context_token(session, peer_id)
        if context_token:
            message_body["context_token"] = context_token
        print(
            json.dumps(
                {
                    "event": "weixin_send_attempt",
                    "connectionId": payload["connectionId"],
                    "peerId": peer_id,
                    "requestId": request_id,
                    "clientId": client_id,
                    "hasContextToken": bool(context_token),
                    "textLength": len(str(payload.get("content") or "")),
                },
                ensure_ascii=False,
            ),
            flush=True,
        )
        try:
            response = self._post_json(
                base_url,
                "ilink/bot/sendmessage",
                {"msg": message_body},
                token=token,
                timeout=20,
            )
        except Exception as exc:
            error = str(exc)
            self.store.fail_send(begin.dedupe_key, error=error)
            return {"ok": False, "error": error, "httpStatus": 502}
        error = _business_error(response)
        if error:
            self.store.fail_send(begin.dedupe_key, error=error)
            return {"ok": False, "error": error, "httpStatus": 502}
        print(
            json.dumps(
                {
                    "event": "weixin_send_result",
                    "connectionId": payload["connectionId"],
                    "requestId": request_id,
                    "responseKeys": sorted(str(key) for key in response.keys()),
                    "businessError": None,
                },
                ensure_ascii=False,
            ),
            flush=True,
        )
        provider_message_id = f"weixin_{payload['requestId']}"
        self.store.complete_send(begin.dedupe_key, provider_message_id=provider_message_id)
        return {"ok": True, "providerMessageId": provider_message_id}

    def poll_once(self, connection_id: str) -> None:
        session = self.store.find_session_by_connection_id(connection_id)
        token = str(session.metadata.get("token") or "")
        base_url = str(session.metadata.get("baseUrl") or "")
        if not token or not base_url:
            return None
        metadata = dict(session.metadata)
        response = self._post_json(
            base_url,
            "ilink/bot/getupdates",
            {"get_updates_buf": str(metadata.get("getUpdatesBuf") or "")},
            token=token,
            timeout=40,
        )
        metadata["getUpdatesBuf"] = str(response.get("get_updates_buf") or metadata.get("getUpdatesBuf") or "")
        for message in response.get("msgs") or []:
            if isinstance(message, dict):
                _remember_context_token(metadata, message)
                event = _bridge_event_from_weixin_message(session, message)
                print(
                    json.dumps(
                        {
                            "event": "weixin_inbound_message",
                            "connectionId": session.connection_id,
                            "messageId": event["messageId"],
                            "peerId": event["peerId"],
                            "hasContextToken": bool(event["metadata"].get("contextToken")),
                            "textLength": len(event["content"]),
                        },
                        ensure_ascii=False,
                    ),
                    flush=True,
                )
                self.bridge_post(
                    f"{_bridge_base_url(session, self.bridge_base_url)}/api/channel-connector-bridge/events",
                    event,
                    {"Authorization": f"Bearer {self.bridge_token}"},
                )
        self.store.update_session(session.session_id, metadata=metadata)
        return None

    def _apply_login_status(
        self,
        session: ConnectorSessionState,
        response: dict[str, Any],
        status: str,
    ) -> ConnectorSessionState:
        if status == "wait":
            return self.store.update_session(session.session_id, status="qr_ready")
        if status == "scaned":
            return self.store.update_session(session.session_id, status="scanned")
        if status == "expired":
            return self.store.update_session(session.session_id, status="expired", error="QR code expired")
        if status == "confirmed":
            token = str(response.get("bot_token") or "")
            account_id = str(response.get("ilink_bot_id") or "")
            base_url = str(response.get("baseurl") or self.fixed_base_url)
            if not token or not account_id:
                return self.store.update_session(session.session_id, status="confirmed")
            metadata = dict(session.metadata)
            metadata.update(
                {
                    "token": token,
                    "baseUrl": base_url,
                    "userId": str(response.get("ilink_user_id") or ""),
                    "getUpdatesBuf": str(metadata.get("getUpdatesBuf") or ""),
                }
            )
            return self.store.update_session(
                session.session_id,
                status="connected",
                account_id=f"weixin:{account_id}",
                metadata=metadata,
            )
        if status == "need_verifycode":
            return self.store.update_session(
                session.session_id,
                status="waiting_for_user",
                instructions=["Enter the verification code shown in Weixin, then refresh status."],
            )
        return self.store.update_session(session.session_id, status="waiting_for_user")

    def _ensure_receiver(self, session: ConnectorSessionState) -> None:
        if not self.start_receivers:
            return None
        with self._receiver_lock:
            if session.connection_id in self._receiver_stops:
                return None
            stop = threading.Event()
            self._receiver_stops[session.connection_id] = stop
            thread = threading.Thread(target=self._receiver_loop, args=(session.connection_id, stop), daemon=True)
            thread.start()
        print(
            json.dumps(
                {
                    "event": "weixin_receiver_started",
                    "connectionId": session.connection_id,
                    "channelId": session.channel_id,
                },
                ensure_ascii=False,
            ),
            flush=True,
        )
        return None

    def _start_existing_connected_receivers(self) -> None:
        if not self.start_receivers:
            return None
        for session in self.store.list_sessions():
            if session.kind != "weixin" or session.status != "connected":
                continue
            if _has_connection_material(session):
                self._ensure_receiver(session)
        return None

    def _receiver_loop(self, connection_id: str, stop: threading.Event) -> None:
        while not stop.is_set():
            try:
                self.poll_once(connection_id)
            except Exception as exc:
                print(
                    json.dumps(
                        {
                            "event": "weixin_receiver_error",
                            "connectionId": connection_id,
                            "error": str(exc)[:300],
                        },
                        ensure_ascii=False,
                    ),
                    flush=True,
                )
                time.sleep(5)
            stop.wait(1)

    def _stop_receiver(self, connection_id: str) -> None:
        with self._receiver_lock:
            stop = self._receiver_stops.pop(connection_id, None)
        if stop is not None:
            stop.set()

    def _post_json(
        self,
        base_url: str,
        endpoint: str,
        body: dict[str, Any],
        *,
        token: str | None,
        timeout: float,
    ) -> dict[str, Any]:
        response = self.http.post(
            _url(base_url, endpoint),
            json={**body, "base_info": _base_info()},
            headers=_headers(token),
            timeout=timeout,
        )
        response.raise_for_status()
        return dict(response.json())

    def _get_json(self, base_url: str, endpoint: str, *, timeout: float) -> dict[str, Any]:
        response = self.http.get(_url(base_url, endpoint), headers=_common_headers(), timeout=timeout)
        response.raise_for_status()
        return dict(response.json())

    def _default_bridge_post(self, url: str, payload: dict[str, Any], headers: dict[str, str]) -> None:
        response = self.http.post(url, json=payload, headers=headers, timeout=20)
        response.raise_for_status()


def _url(base_url: str, endpoint: str) -> str:
    return f"{base_url.rstrip('/')}/{endpoint.lstrip('/')}"


def _bridge_base_url(session: ConnectorSessionState, fallback: str) -> str:
    return str(session.metadata.get("bridgeBaseUrl") or fallback).rstrip("/")


def _base_info() -> dict[str, str]:
    return {"channel_version": "2.4.3", "bot_agent": "Beaver/1.0"}


def _common_headers() -> dict[str, str]:
    return {"iLink-App-Id": "bot", "iLink-App-ClientVersion": WeixinIlinkProvider.app_client_version}


def _headers(token: str | None) -> dict[str, str]:
    headers = {
        **_common_headers(),
        "Content-Type": "application/json",
        "AuthorizationType": "ilink_bot_token",
        "X-WECHAT-UIN": base64.b64encode(str(random.getrandbits(32)).encode("utf-8")).decode("ascii"),
    }
    if token:
        headers["Authorization"] = f"Bearer {token}"
    return headers


def _qr_svg_data_uri(value: str) -> str:
    image = qrcode.make(value, image_factory=qrcode.image.svg.SvgPathImage)
    raw = image.to_string(encoding="unicode")
    return "data:image/svg+xml;base64," + base64.b64encode(raw.encode("utf-8")).decode("ascii")


def _bridge_event_from_weixin_message(session: ConnectorSessionState, message: dict[str, Any]) -> dict[str, Any]:
    message_id = str(message.get("message_id") or uuid4().hex)
    peer_id = str(message.get("from_user_id") or "")
    text = _extract_text(message)
    return {
        "eventId": f"{session.channel_id}:{message_id}",
        "timestamp": time.strftime("%Y-%m-%dT%H:%M:%SZ", time.gmtime()),
        "deliveryAttempt": 1,
        "connectionId": session.connection_id,
        "channelId": session.channel_id,
        "kind": "weixin",
        "accountId": session.account_id,
        "peerId": peer_id,
        "peerType": "dm",
        "userId": peer_id,
        "threadId": None,
        "messageId": message_id,
        "messageType": "text",
        "content": text,
        "metadata": {"contextToken": message.get("context_token")},
    }


def _remember_context_token(metadata: dict[str, Any], message: dict[str, Any]) -> None:
    peer_id = _optional_text(message.get("from_user_id"))
    context_token = _optional_text(message.get("context_token"))
    if not peer_id or not context_token:
        return None
    context_tokens = metadata.get("contextTokens")
    if not isinstance(context_tokens, dict):
        context_tokens = {}
    context_tokens[peer_id] = context_token
    metadata["contextTokens"] = context_tokens
    return None


def _extract_text(message: dict[str, Any]) -> str:
    for item in message.get("item_list") or []:
        if not isinstance(item, dict):
            continue
        text_item = item.get("text_item")
        if isinstance(text_item, dict) and text_item.get("text") is not None:
            return str(text_item["text"])
    return ""


def _business_error(response: dict[str, Any]) -> str | None:
    for key in ("ret", "code", "errcode"):
        if key not in response:
            continue
        try:
            value = int(response.get(key) or 0)
        except (TypeError, ValueError):
            value = -1
        if value == 0:
            return None
        message = response.get("errmsg") or response.get("msg") or response.get("error") or response
        return str(message)
    return None


def _has_connection_material(session: ConnectorSessionState) -> bool:
    metadata = dict(session.metadata)
    return bool(str(metadata.get("token") or "").strip() and str(metadata.get("baseUrl") or "").strip() and session.account_id)


def _cached_context_token(session: ConnectorSessionState, peer_id: str) -> str | None:
    context_tokens = dict(session.metadata.get("contextTokens") or {})
    return _optional_text(context_tokens.get(peer_id))


def _client_id(request_id: str) -> str:
    text = str(request_id).strip()
    if text and len(text) <= 64 and all(char.isalnum() or char in {"_", "-"} for char in text):
        return text
    digest = hashlib.sha256(text.encode("utf-8")).hexdigest()[:24]
    return f"beaver-weixin-{digest}"


def _optional_text(value: Any) -> str | None:
    if value is None:
        return None
    text = str(value).strip()
    return text or None