import { Component, OnInit, Input, Output,EventEmitter } from '@angular/core';
import { List } from '../service/list';

/*interface LoadOption {
  remote?:Function,
  perPage?:number
}*/

import { BaseLog as Log } from "base-log";
const log = new Log('ListLoadComponent');

@Component({
  selector: 'list-load',
  template: `
  <ion-infinite-scroll
    [enabled]="canBeLoaded"
    (ionInfinite)="loadMoreData($event)">
    <ion-infinite-scroll-content></ion-infinite-scroll-content>
  </ion-infinite-scroll>
`
})
export class ListLoadComponent implements OnInit {
  _listData
  @Input() option
  @Output() listDataChange = new EventEmitter()
  @Input()
  get listData(){
    return this._listData;
  }
  set listData(val){
    this._listData = val
    this.listDataChange.emit(val);
  }

  canBeLoaded = true;

  current
  max
  timer
  remote
  infiniteScroll
  data
  constructor(public list:List) {

  }


  ngOnInit() {

  }

  ngAfterViewInit(){
    const { perPage, remote } = Object.assign({},this.option);
    this.remote = remote;
    this.data = this.list.set(this._listData, perPage);
    this.initLoad();
  }


  // 初始化load
  initLoad = () => {
    const listData = this.data.all();
    this.max = this.getMax(this.data);
    this.current = this.getCurrent(listData, this.data); // 当前页码
    this.canBeLoaded = true;
  }

  // 加载更多
  loadMoreData = (infiniteScroll) => {
    log.info('infiniteScroll',!!infiniteScroll);
    this.infiniteScroll = infiniteScroll;
    if(this.current == this.max){
      if(this.remote){ // 远程更新，添加数据
        return this.remote(this.data,this.option).then((res) => {
          res = res || [];
          if(res.length == 0) return this.finishUpdate();
          this.data.add(res); // 将新数据添加到data中
          this.max = this.getMax(this.data); // 重新计算max
          if(this.max > this.current){
            return this.update();
          }else{
            return this.finishUpdate();
          }
        });
      }else{
        return this.finishUpdate();
      }
    }else{ // 本地更新
      return new Promise((resolve) => {
        this.timer = setTimeout(()=>{
          const current = this.update();
          resolve(current);
        },360);
      })
    }
  }

  // 获取最大页码
  getMax = (data) => {
    return data.count() / data.perPage;
  }

  // 获取当前页码
  getCurrent = (listData,data) => {
    return listData.length / data.perPage;
  }

  // 更新数据
  update = () => {
    const listData = this.data.getPageDataAll(this.current + 1);
    this.infiniteScroll.complete(); // 关闭loading
    this.current = this.getCurrent(listData, this.data);
    this._listData = listData;
    this.listDataChange.emit(listData);
    return listData;
  }

  // 结束更新
  finishUpdate = () => {
    this.canBeLoaded = false;
    clearTimeout(this.timer);
  }
}