<template>
  <div>
    <div id="chart">
      <apexchart
        type="line"
        height="350"
        ref="chart"
        :options="chartOptions"
        :series="series"
      ></apexchart>
    </div>

    <div class="explanation">
      Real-time streaming with <code>chart.streaming.enabled</code>: each tick
      appends one point with <code>appendData()</code>. The window slides left
      at constant velocity (no easing pulse, no in-place warp), and the series
      array is trimmed automatically to the visible
      <code>xaxis.range</code> window, so memory stays flat no matter how long
      the stream runs. The same scroll works when a fixed-length rolling window
      is passed to <code>updateSeries()</code>.
    </div>
  </div>
</template>

<script>
import VueApexCharts from 'vue-apexcharts'

var TICKINTERVAL = 1000
var XAXISRANGE = 29 * TICKINTERVAL
var lastX = new Date().getTime() - XAXISRANGE
var lastY = 50
var data = []

function nextValue() {
  lastY = Math.max(5, Math.min(95, lastY + (Math.random() - 0.5) * 20))
  return Math.round(lastY)
}

while (data.length < 30) {
  data.push({ x: lastX, y: nextValue() })
  lastX += TICKINTERVAL
}

export default {
components: {
apexchart: VueApexCharts,
},
data: function () {
return {
series: [{
  name: 'Signal',
  data: data.slice()
}],
chartOptions: {
chart: {
  id: 'realtime-streaming',
  height: 350,
  type: 'line',
  streaming: {
    enabled: true
  },
  animations: {
    dynamicAnimation: {
      speed: 1000
    }
  },
  toolbar: {
    show: false
  },
  zoom: {
    enabled: false
  }
},
dataLabels: {
  enabled: false
},
stroke: {
  curve: 'smooth'
},
title: {
  text: 'Streaming (bounded memory + linear scroll)',
  align: 'left'
},
markers: {
  size: 0
},
xaxis: {
  type: 'datetime',
  range: XAXISRANGE
},
yaxis: {
  min: 0,
  max: 100
},
legend: {
  show: false
}
},
}
},
mounted: function () {
  var me = this
  window.setInterval(function () {
    lastX += TICKINTERVAL
    me.$refs.chart.appendData([{
      data: [{ x: lastX, y: nextValue() }]
    }])
  }, TICKINTERVAL)
},,
}
</script>

<style>
#chart {
  max-width: 650px;
  margin: 35px auto;
}
.explanation {
  max-width: 620px;
  margin: 0 auto 12px;
  font-size: 13px;
  color: #777;
}
</style>