import dataPreferences from '@ohos.data.preferences';

let preference: dataPreferences.Preferences;
const SYSTEM_DB: string = 'system.db'
let context = getContext(this);

class PreferenceUtils {
  async writeData(value: dataPreferences.ValueType, key: string) {
    // if (value === null) {
    //   return;
    // }
    if (!preference) {
      await this.getPreferencesFromStorage(SYSTEM_DB);
    }
    try {
      await preference.put(key, value);
    } catch (err) {
      console.info(`Failed to put value, Cause: ${err}`);
    }
    await preference.flush();
  }

  // 获取其他缓存数据
  async getData<T extends dataPreferences.ValueType>(key: string) {
    let value: dataPreferences.ValueType = 1;
    if (!preference) {
      await this.getPreferencesFromStorage(SYSTEM_DB);
    }

    try {
      value = (await preference.get(key, ''));
    } catch (err) {
      console.info(`Failed to get value, Cause: ${err}`);
    }
    if (value === '') {
      return;
    }
    return value as T;
  }

  // 创建登录数据preference
  async getPreferencesFromStorage(name: string) {
    try {
      preference = await dataPreferences.getPreferences(context, name);
    } catch (err) {
      console.info(`Failed to get preferences, Cause: ${err}`);
    }
  }
}

export default new PreferenceUtils();