import { ref } from 'vue';
import * as signalR from '@microsoft/signalr';
import { getAccessToken } from './request';
import request from './request';

// 全局未读数量（layout 徽章 与 消息页共用）
export const unreadCount = ref(0);

let connection = null;
const messageHandlers = [];
const businessChangeHandlers = [];

/** 加载未读数量 */
export async function loadUnreadCount() {
  try {
    const res = await request.get('/notification/unread-count');
    unreadCount.value = res.data.count;
  } catch (e) {}
}

/**
 * 初始化 SignalR 通知连接（幂等，重复调用返回同一连接）
 * @param {Function} onMessage 收到新消息时的回调 (msg) => void
 */
export function initNotification(onMessage) {
  if (connection) {
    if (onMessage) messageHandlers.push(onMessage);
    return connection;
  }

  if (onMessage) messageHandlers.push(onMessage);

  connection = new signalR.HubConnectionBuilder()
    .withUrl('/hubs/notification', {
      accessTokenFactory: () => getAccessToken() || ''
    })
    .withAutomaticReconnect()
    .configureLogging(signalR.LogLevel.Warning)
    .build();

  connection.on('ReceiveNotification', (msg) => {
    unreadCount.value++; // 全局未读 +1
    messageHandlers.forEach((h) => { try { h(msg); } catch (e) {} });
  });

  // 业务状态变更事件（多端同步：某端操作后，其它端刷新已打开的页面）
  connection.on('BusinessChanged', (e) => {
    businessChangeHandlers.forEach((h) => { try { h(e); } catch (err) {} });
  });

  connection.start().catch(() => {});
  return connection;
}

/**
 * 订阅业务状态变更事件（用于多端同步刷新）。
 * @param {Function} handler (e) => void，e 含 businessType / businessId / action
 */
export function onBusinessChanged(handler) {
  if (handler) businessChangeHandlers.push(handler);
  initNotification(); // 确保连接已建立（幂等）
}

/**
 * 打开消息：标记已读 + 跳转到业务页面（消息自带 routePath 时）。
 * @param {Object} msg 消息对象（含 id/readStatus/routePath/category）
 * @param {Object} router vue-router 实例
 * @returns {boolean} 是否发生了页面跳转
 */
export async function openMessage(msg, router) {
  // 待办消息（category=1）点击"去处理"不标记已读，保持未读提醒；
  // 只有真正完成待办后（后端完成待办时会标记已读）才消失
  if (msg.readStatus === 0 && msg.category !== 1) {
    try {
      await request.put(`/notification/messages/${msg.id}/read`);
      msg.readStatus = 1;
      loadUnreadCount();
    } catch (e) {}
  }
  if (msg.routePath) {
    router.push(msg.routePath);
    return true;
  }
  return false;
}

/** 停止连接（登出时调用） */
export function stopNotification() {
  if (connection) {
    connection.stop().catch(() => {});
    connection = null;
  }
  messageHandlers.length = 0;
  unreadCount.value = 0;
}

export function getNotificationConnection() {
  return connection;
}