// components/page-scroll/page-scroll.js
Component({
  /**
   * 组件的属性列表
   */
  properties: {
    "className":{
      value:"",
      type:String
    },
    "styleSheet":{
      value:"",
      type:String
    },
    "upper-threshold":{      
      value:5,
      type:Number
    },
    "scrollitem":{          
      value:[],
      type:Array
    },
    "scrollto":{
      value:"",
      type:Number
    }
  },

  /**
   * 组件的初始数据
   */
  data: {
    height:0,
    upper:true,
    index:0
  },
  ready:function(){
  },
  methods: {
    scrollLower:function(e){
      this.triggerEvent("scrolltolower",e.detail);
    },
    scrollUpper:function(e){
      this.triggerEvent("scrolltoupper",e.detail);
    },
    scroll:function(e){
      var scrolltop = e.detail.scrollTop;
      var scrollitem =this.data.scrollitem;
      var index = 0;
      if(this.data.upper){
        if(scrolltop>this.data["upper-threshold"]){
          this.setData({
            upper:false,
            height:0
          })
        }
      }else{
        if(scrolltop<this.data["upper-threshold"]){
          this.setData({
            upper:true
          })
        }
      }
      var l = scrollitem.length;
      if(scrolltop>scrollitem[l-1]){
        index=l;
      }else{
        for(var i=0;i<l;i++){
          if(scrolltop<scrollitem[i]){
            index = i;
            break;
          }
        }
      }
      if(index!=this.data.index){
        this.setData({
          index:index
        });
        this.triggerEvent("swc",index);
      }
      this.triggerEvent("scroll",this.data.upper);
    },
    changeHeight:function(e){
      var _self=this;
      if(this.data.starttop){
        this.setData({
          height:(e.touches[0].pageY-this.data.starttop)/2
        })
        this.triggerEvent("topheight",this.data.height);
      }else{
        this.setData({
          starttop:e.touches[0].pageY
        })
      }
    },
    endChange:function(e){
      var obj = {
        starttop:0
      }
      if(this.data.height){
        obj.height=0;
      }
      this.setData(obj);
      this.triggerEvent("topheight",this.data.height);
    }
  }
})