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

/*
// SPHelper.default.get("key1", "defValue1").then((value1) => {
//   this.message = value1.toString();
// })

// let value2: string = await SPHelper.default.get("key2", "defValue2");
// this.message = result;
*
* 单例模式
 */
export class SPHelper {
  private static context: Context;
  private static spFilename: string = '__SPHelper';

  static init(context: Context) {
    SPHelper.context = context;
  }

  static setSpFilename(spFilename: string) {
    SPHelper.spFilename = spFilename;
  }

  // 静态属性
  static default: SPHelper = new SPHelper();

  // 私有构造函数
  private constructor() {
  }

  private async getVideoPreferences(): Promise<data_preferences.Preferences> {
    let preferences: data_preferences.Preferences = await data_preferences.getPreferences(SPHelper.context, SPHelper.spFilename);
    return preferences;
  }


  async save(key: string, value: data_preferences.ValueType) {
    const preferences: data_preferences.Preferences = await this.getVideoPreferences();
    await preferences.put(key, value)
    await preferences.flush()
  }


  async get(key: string, defValue: data_preferences.ValueType): Promise<data_preferences.ValueType> {
    const preferences: data_preferences.Preferences = await this.getVideoPreferences();
    return await preferences.get(key, defValue);
  }

  async has(key: string): Promise<boolean> {
    const preferences: data_preferences.Preferences = await this.getVideoPreferences();
    return await preferences.has(key);
  }


  async delete(key: string) {
    const preferences: data_preferences.Preferences = await this.getVideoPreferences();
    preferences.delete(key).then(async () => {
      await preferences.flush();
    }).catch((err: Error) => {
      // Logger.error(TAG, 'Failed to delete the key. Cause: ' + err);
    });
  }
}