const ExtractType = {
    平均值:0,
    最大值:1
}
const Options = {};

function DataExtract(options={}){
    this.Key = options.Key;
    this.Options = Object.assign(Options, {
        TaskId:0,
        Period:options.Period  || 500,
        ExtractType:options.ExtractType || ExtractType.最大值,
        SourceRange: Object.assign({},{ min:0,max:16384 },options.SourceRange),
        CurrentRange:Object.assign({},{ min:0,max:16384 },options.CurrentRange),
        clientPixel:options.clientPixel || 350,
        Console:false
    });
}

DataExtract.prototype.SetOptions = function(options = {}){
    this.QueueCache.length = 0;
    if(options.hasOwnProperty("Period"))this.Options.Period = options.Period;
    if(options.hasOwnProperty("ExtractType"))this.Options.ExtractType = options.ExtractType;
    if(options.hasOwnProperty("SourceRange"))this.Options.SourceRange = options.SourceRange;
    if(options.hasOwnProperty("CurrentRange"))this.Options.CurrentRange = options.CurrentRange;
    if(options.hasOwnProperty("clientPixel"))this.Options.clientPixel = options.clientPixel;
}
// 用于展示的点数
var __DisplayPoints = new Array(1).fill(0);
DataExtract.prototype.Execute = function(data,TaskId = 0){
    if(!this.Switch) return;
    if(this.Options.TaskId != 0 ) return;
    this.Options.TaskId = TaskId;
    const {sourceMin,sourceMax,currentMin,currentMax,clientPixel,ExtractType} = this.Options;

    if(_DisplayPoints.length != clientPixel){
        _DisplayPoints = new Array(clientPixel);
    }
    _DisplayPoints.fill(NaN);
    if(data){
        if(currentMin < 0 && currentMax < 0) {
            postMessage({ key: "OnComplate", payload:[] });
            return
        };
        // data = new Uint16Array(data.buffer);//Array.from(,x=>x/256);
        var sourceSpan = sourceMax - sourceMin;
        var displaySpan = currentMax -  currentMin;
        // 源点偏移
        var currentOffset = 0;
        var currentSpan = 0;
        var currentSpanMin = sourceMin;
        var currentSpanMax = sourceMax;

        if( currentMax < currentSpanMax){
            currentSpanMax = currentMax;
        }
        if( currentMin > currentSpanMin){
            currentSpanMin = currentMin;
        }
        currentSpan = currentSpanMax  - currentSpanMin;

        currentOffset = (currentMin - sourceMin);

        var pointScale = sourceSpan / data.length ; // 多少带宽一个点
        var pixelScale = clientPixel / displaySpan;
        // 当前FFT点数
        var currentPointCount = currentSpan / sourceSpan * data.length;
            // currentSpan / pointScale + Math.abs(currentOffset) / pointScale;

        // 轴起始偏移
        let displayOffset = 0;
        let offsetPoint = 0;

        if(currentOffset < 0){
            displayOffset = Math.abs(Math.ceil(currentOffset * pixelScale))
        }else{
            offsetPoint = Math.abs(Math.round(currentOffset / pointScale))
        }
        if(displayOffset > 0){
            _DisplayPoints.fill(NaN,0);
        }
        var i = 0;
        if(currentPointCount > _DisplayPoints.length){
            var start = 0;
            for( i = 0;i<clientPixel - displayOffset;i++){
                if(TASK_ID != this.Options.TaskId) return;
                let end = Math.round(offsetPoint + (i) / pixelScale / pointScale );
                var partial = data.slice(start,end);
                start = end;
                if(partial.length > 0 ){
                    var val = Math.max(...partial);
                    _DisplayPoints[displayOffset + i] = val;
                }else if(start > 0 && end > 0){
                    break;
                }
            }

        }else{
            // 补帧
            for( i = 0;i<clientPixel - displayOffset;i++){

                let dataIndex = Math.round(offsetPoint + (i) / pixelScale / pointScale );
                var val = data[dataIndex];
                if(val == -Infinity || isNaN(val) || val === undefined){
                    break;
                }else{
                    _DisplayPoints[displayOffset + i] = val;
                }
            }
            //补帧
        }
    }

}