import { onLoad } from "@dcloudio/uni-app";
const useTransferPage = () => {
  const funcMap = {
    redirect: uni.redirectTo,
    reLaunch: uni.reLaunch,
    switchTab: uni.switchTab
  };
  let prevData = ref<Record<string, any>>({});
  let transferResolver: ((value: unknown) => void) | null = null;
  let eventChannel: UniApp.EventChannel | null = null;
  // onMounted(() => {
  // 使用instance获取getOpenerEventChannel在非页面级组件中会报错
  // const instance = getCurrentInstance().proxy
  // if (instance) {
  //   eventChannel = instance.getOpenerEventChannel();
  // }
  // });
  type Callback = (() => void) | null;
  type TransferOptions = {
    data?: Record<string, any> | null,
    type?: string,
    bigData?: Record<string, any> | null,
    callback?: Callback
  }

  onLoad((opt) => {
    const pages = getCurrentPages();
    const page = pages[pages.length - 1];
    eventChannel = (page as any).getOpenerEventChannel();
    emit('onPageOpen');
    for (const key in opt) {
      if (opt.hasOwnProperty(key) && !['data', 'storageKey'].includes(key)) {
        prevData.value[key] = decodeURIComponent(opt[key]);
      }
    }
    if (!opt) return;
    let originData = opt.data;
    if (opt.data) {
      if (opt.data.startsWith('%257B')) {
        originData = decodeURIComponent(opt.data);
      }
      const data = JSON.parse(decodeURIComponent(originData || '{}'));
      Object.assign(prevData.value, data);
    }
    const storageKey = opt.storageKey;
    if (storageKey) {
      const storageData = uni.getStorageSync(storageKey);
      Object.assign(prevData.value, storageData);
    }
  });

  function getTransferUrl(url: string, data: any, bigData: any) {
    const urlParams = {
      data: data ? encodeURIComponent(JSON.stringify(data)) : null,
      storageKey: bigData ? 'transferBigData' : null
    };

    // 处理URL中已存在的参数
    const [baseUrl, existingQuery] = url.split('?');
    const existingParams = {};

    // 解析现有参数
    if (existingQuery) {
      existingQuery.split('&').forEach(param => {
        const [key, value] = param.split('=');
        if (key) {
          // 为 existingParams 显式声明类型为 Record<string, string>
          (existingParams as Record<string, string>)[key] = value;
        }
      });
    }

    // 合并新参数
    Object.entries(urlParams)
      .filter(([_, value]) => value)
      .forEach(([key, value]) => {
        (existingParams as Record<string, string>)[key] = value as string;
      });

    // 构建查询字符串
    const queryString = Object.entries(existingParams)
      .map(([key, value]) => `${key}=${value}`)
      .join('&');

    return queryString ? `${baseUrl}?${queryString}` : baseUrl;
  }

  function transferTo(url: string, { data = null, type = 'navigate', bigData = null, callback = null }: TransferOptions = {}) {
    return new Promise((resolve, reject) => {
      transferResolver = resolve;
      if (bigData) {
        uni.setStorageSync('transferBigData', bigData);
      } else {
        // clear big data by force
        uni.removeStorageSync('transferBigData');
      }
      const nextUrl = getTransferUrl(url, data, bigData);
      if (type === 'navigate') {
        uni.navigateTo({
          url: nextUrl,
          events: {
            transferEnd: (data: any) => {
              transferResolver?.(data);
            },
            onPageOpen: () => {
              if (callback) {
                callback?.();
              }
            }
          },
          fail: (err) => { 
            console.log('transferTo fail', err);
          }
        });
      } else {
        const routeFunc = funcMap[type as keyof typeof funcMap];
        routeFunc({
          url: nextUrl,
          fail: (err) => {
            console.log('transferTo fail', err);
            reject(err);
          }
        });
      }


    });
  }
  function transferBack(data:any = null, delta = 1) {
    emit('transferEnd', data);
    // force clear big data
    uni.removeStorageSync('transferBigData');
    const pages = getCurrentPages();
    if (pages.length === 1) {
      switchTab('/pages/splash/splash');
    } else {
      uni.navigateBack({
        delta: delta,
        success: () => { },
        fail: (err) => {
          switchTab('/pages/splash/splash');
        }
      });
    }
  }
  function switchTab(url: string) {
    uni.switchTab({
      url: url,
      fail: (err) => {
        console.log(err);
      }
    });
  }

  function emit(event: string, data = null) {
    if (eventChannel?.emit) {
      eventChannel.emit(event, data);
    } else {
      console.warn('上级页面丢失，无法触发transferEnd');
    }
  }

  return {
    prevData,
    transferTo,
    transferBack,
  }
};

export default useTransferPage;