/*
 * Copyright (C) 2024 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.
 */
import {ImageKnife, ImageKnifeRequest} from '@ohos/libraryimageknife'
import { IDataSourcePrefetching } from '@kit.ArkUI';
import { HashMap } from '@kit.ArkTS';

const IMADE_UNAVAILABLE = $r('app.media.failed')
export interface InfoItem {
  albumUrl: string | Resource
}
export default class DataSourcePrefetchingImageKnife implements IDataSourcePrefetching {
  private dataArray: Array<InfoItem>
  private readonly  requestList: HashMap<number,ImageKnifeRequest> = new HashMap()
  private listeners: DataChangeListener[] = [];

  constructor(dataArray: Array<InfoItem>) {
    this.dataArray = dataArray;
  }
  public getData(index: number) {
    return this.dataArray[index]
  }

  public totalCount(): number {
    return this.dataArray.length
  }

  public addData(index: number, data: InfoItem[]): void {
    this.dataArray = this.dataArray.concat(data)
    this.notifyDataAdd(index)
  }

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

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

  notifyDataAdd(index: number): void {
    this.listeners.forEach((listener: DataChangeListener) => {
      listener.onDataAdd(index)
    })
  }
  async prefetch(index: number): Promise<void> {
    let item = this.dataArray[index]
    if (typeof item.albumUrl === 'string') {
      return new Promise((resolve,reject)=>{
        // 图片预加载
        let request = ImageKnife.getInstance().preload({
          loadSrc:item.albumUrl,
          onLoadListener:{
            onLoadSuccess:()=>{
              // 预加载成功，删除成功请求
              this.requestList.remove(index)
              resolve()
            },
            onLoadFailed:()=>{
              // 移除失败请求
              this.requestList.remove(index)
              resolve()
            }
          }
        })
        this.requestList.set(index,request)
      })
    }
  }
  // 取消请求处理
  cancel(index: number) {
    if(this.requestList.hasKey(index)) {
      // 返回MAP对象指定元素
      const request = this.requestList.get(index)
      // 取消请求
      ImageKnife.getInstance().cancel(request)
      // 移除被取消的请求对象
      this.requestList.remove(index)
    }
  }
}