/**
 * Copyright (c) 2021 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


export default class BasicDataSource implements IDataSource {
  private listeners: DataChangeListener[] = [];

  public totalCount(): number {
    return 0;
  }

  public getData(index: number): any {
    return undefined;
  }

  registerDataChangeListener(listener: DataChangeListener): void {
    if (this.listeners.indexOf(listener) < 0) {
      this.listeners.push(listener);
    }
  }

  unregisterDataChangeListener(listener: DataChangeListener): void {
    const position = this.listeners.indexOf(listener);
    if (position >= 0) {
      this.listeners.splice(position, 1);
    }
  }

  notifyDataReload(): void {
    this.listeners.forEach(listener => {
      listener.onDataReloaded();
    })
  }

  notifyDataAdd(index: number): void {
    this.listeners.forEach(listener => {
      listener.onDataAdded(index);
    })
  }

  notifyDataChange(index: number): void {
    this.listeners.forEach(listener => {
      listener.onDataChanged(index);
    })
  }

  notifyDataDelete(index: number): void {
    this.listeners.forEach(listener => {
      listener.onDataDeleted(index);
    })
  }

  notifyDataMove(from: number, to: number): void {
    this.listeners.forEach(listener => {
      listener.onDataMoved(from, to);
    })
  }
}