var new_data = [];

var labelV = [];
var lineChart = null;

var speedCanvas = document.getElementById("speedChart");

Chart.defaults.global.defaultFontFamily = "Lato";
Chart.defaults.global.defaultFontSize = 15;

function drawPlot(new_data,left,right){

    var speedData = {
    labels:labelV,
    datasets: [
    {
        label: '',
        backgroundColor:'rgb(0,0,0)',
        data: new_data,
        }
    ]
    };

    var chartOptions = {
    legend: {
        legendText:'Plot',
        display: true,
        position: 'top',
        labels: {
            boxWidth: 80,
            fontColor: 'black'
        }
    },
        title:{
            display:true,
            text:'Plot'

            },

        scales:{
            xAxes:[{
                ticks:{
                    min:left,
                    max:right,
                    stepSize:1,
                },

            }],
            yAxes:[{
                gridLines:{
                    offsetGridLines:true
                }
            }]
        }
    }
    lineChart = new Chart(speedCanvas, {
        type: 'line',
        data: speedData,
        options: chartOptions
    });
    removedata(lineChart);
    addData(lineChart,new_data);

}

function send_data(){
  var data = document.getElementById("equation").value;
  //console.log(data);
  var left = document.getElementById("diapasonLeft").value;
  var right = document.getElementById("diapasonRight").value;
  var step = document.getElementById("step").value;
  $.ajax({
    type:"GET",
    url:"calc/",
    data:{
      'equation':data,
      'left':left,
      'right':right,
      'step':step,
    },
    dataType:"text",
    success: function (response) {
      var json = JSON.parse(response);
      new_data = json.values;
      if(json.status!=""){
        alert(json.status);
      } else{
        if(left!='' && right!='' && step != ''){
            labelFormat(left,right,step);
        }else{
            labelFormat();
        }
        console.log(labelV);
        if(lineChart!=null){
            lineChart.destroy()
        }
        drawPlot(new_data,left,right);
        step = 0;
      }

    }

  })
}
function labelFormat(left = 0,right = 5,step = 0.1){
     step = parseFloat(step)
     step = parseFloat(parseFloat(step).toFixed(1));
     left = parseFloat(left);
     right = parseFloat(right);
     while(left<=right+1){
        //console.log(left);
        labelV.push(left.toFixed(1));
        left+=step;
      }
}
function removedata(lineChart){
  lineChart.data.datasets = []
  lineChart.update();
  }
  function addData(lineChart,data){
  lineChart.data.datasets.push({
  'data': data
  });
  lineChart.update();
  labelV.length = 0;
  }
 drawPlot();