import { getToken } from '@/utils/auth';
import { ElNotification } from 'element-plus';
import { useNoticeStore } from '@/store/modules/notice';
import { useEventSource } from '@vueuse/core';
import { watch } from 'vue';

// 全局单例保存SSE实例，防止多次创建
let eventSourceInstance: ReturnType<typeof useEventSource> | null = null;
let stopWatchError: (() => void) | null = null;
let stopWatchData: (() => void) | null = null;

// 关闭SSE、清理监听
export const closeSSE = () => {
  if (eventSourceInstance) {
    eventSourceInstance.close();
    eventSourceInstance = null;
  }
  // 销毁watch
  stopWatchError?.();
  stopWatchData?.();
  stopWatchError = null;
  stopWatchData = null;
};

// 初始化SSE
export const initSSE = (url: string) => {
  if (import.meta.env.VITE_APP_SSE === 'false') {
    return;
  }
  // 关键：新建之前先关闭旧连接！
  closeSSE();

  const token = getToken();
  const clientId = import.meta.env.VITE_APP_CLIENT_ID;
  const sseUrl = url + '?Authorization=Bearer ' + token + '&clientid=' + clientId;

  eventSourceInstance = useEventSource(sseUrl, [], {
    autoReconnect: {
      retries: 5,
      delay: 5000,
      onFailed() {
        console.log('Failed to connect after 5 retries');
      }
    }
  });

  const { data, error } = eventSourceInstance;

  stopWatchError = watch(error, () => {
    console.log('SSE connection error:', error.value);
    // error.value = null; // 不要手动覆盖，会干扰useEventSource内部状态
  });

  stopWatchData = watch(data, () => {
    if (!data.value) return;
    const notice = tryParseJson(data.value as string);
    if (typeof notice === 'string') {
      useNoticeStore().addNotice({
        message: notice,
        read: false,
        time: new Date().toLocaleString()
      });
      ElNotification({
        title: '消息',
        message: notice,
        type: 'success',
        duration: 3000
      });
      data.value = null;
      return;
    } else {
      const title = typeof notice.title === 'string' ? notice.title : '消息';
      const message = typeof notice.message === 'string' ? notice.message : '';
      const type = typeof notice.type === 'string' ? notice.type : 'info';
      useNoticeStore().addNotice({
        message,
        read: false,
        time: new Date().toLocaleString()
      });
      ElNotification({
        title,
        message,
        type: type as 'success' | 'warning' | 'info' | 'error',
        duration: 3000
      });
      data.value = null;
    }
  });
};

/**
 * 尝试解析后端返回的字符串
 * 如果是合法JSON对象 → 返回 Record<string, unknown>
 * 否则（数组/null/基础值/非JSON字符串） → 返回原字符串
 * @param str 后端传过来的字符串
 */
function tryParseJson(str: string): string | Record<string, unknown> {
  if (typeof str !== 'string' || str === '') return str;

  const trimStr = str.trim();
  if (trimStr === '') return str;
  try {
    const parsed = JSON.parse(trimStr);
    // 只有纯对象才返回对象，数组/null/基础值等统一当作字符串处理
    if (parsed !== null && typeof parsed === 'object' && !Array.isArray(parsed)) {
      return parsed as Record<string, unknown>;
    }
    return str;
  } catch {
    return str;
  }
}