import React from 'react'
import ReactApexChart from 'react-apexcharts'
import ApexCharts from 'apexcharts'
import './styles.css'

var raceEntities = [
  'United States',
  'China',
  'Germany',
  'Japan',
  'France',
  'United Kingdom',
  'India',
  'Brazil',
  'Canada',
  'Italy',
]

// A fixed color per country. With distributed bars the color is applied by bar
// POSITION, but this is a race where the bars re-sort every tick, so raceFrame()
// re-orders this palette to match the current ranking below. That keeps each
// country's color stable as it rides up and down the ranks.
var raceColors = {
  'United States': '#3B82F6',
  China: '#EF4444',
  Germany: '#F59E0B',
  Japan: '#10B981',
  France: '#8B5CF6',
  'United Kingdom': '#EC4899',
  India: '#14B8A6',
  Brazil: '#F97316',
  Canada: '#6366F1',
  Italy: '#84CC16',
}

// A flag emoji per country, prepended to its axis label by
// yaxis.labels.formatter. SVG axis labels are plain text, so an emoji is the
// simplest way to put an icon in front of a label (real image flags would need
// custom DOM work). Emoji flags render on most platforms; a few Windows
// browsers show the two-letter country code instead.
var raceFlags = {
  'United States': '🇺🇸',
  China: '🇨🇳',
  Germany: '🇩🇪',
  Japan: '🇯🇵',
  France: '🇫🇷',
  'United Kingdom': '🇬🇧',
  India: '🇮🇳',
  Brazil: '🇧🇷',
  Canada: '🇨🇦',
  Italy: '🇮🇹',
}

// Persistent value per entity, nudged a little each tick so ranks swap
// gradually (a smooth race rather than a random shuffle).
var raceValues = {}
raceEntities.forEach(function (name, i) {
  raceValues[name] = 300 + (raceEntities.length - i) * 90
})

function raceFrame() {
  raceEntities.forEach(function (name) {
    raceValues[name] = Math.max(
      50,
      raceValues[name] + (Math.random() - 0.45) * 220,
    )
  })
  var ranked = raceEntities
    .map(function (name) {
      return { name: name, value: Math.round(raceValues[name]) }
    })
    .sort(function (a, b) {
      return b.value - a.value
    })
  return {
    categories: ranked.map(function (r) {
      return r.name
    }),
    data: ranked.map(function (r) {
      return r.value
    }),
    // Colors follow the ranking so each country keeps its own color (see above).
    colors: ranked.map(function (r) {
      return raceColors[r.name]
    }),
  }
}

var raceInitial = raceFrame()

const ApexChart = () => {
  const [state, setState] = React.useState({
    series: [
      {
        name: 'Value',
        data: raceInitial.data,
      },
    ],
    options: {
      chart: {
        id: 'horizontal-bar-race',
        type: 'bar',
        height: 420,
        animations: {
          dynamicAnimation: {
            speed: 800,
          },
        },
        toolbar: {
          show: false,
        },
      },
      plotOptions: {
        bar: {
          borderRadius: 4,
          borderRadiusApplication: 'end',
          horizontal: true,
          // Each bar gets its own color, taken from the `colors` palette by position.
          distributed: true,
        },
      },
      colors: raceInitial.colors,
      dataLabels: {
        enabled: true,
        // Opt-in race polish: the value labels ride to each bar's new rank and
        // count up/down from their previous value on every tick.
        animate: {
          enabled: true,
        },
        countUp: {
          enabled: true,
        },
      },
      title: {
        text: 'Bar Chart Race',
        align: 'left',
      },
      xaxis: {
        categories: raceInitial.categories,
      },
      yaxis: {
        labels: {
          // Prepend each country's flag emoji to its axis label.
          formatter: function (val) {
            return (raceFlags[val] || '') + '  ' + val
          },
        },
      },
      legend: {
        show: false,
      },
    },
  })

  React.useEffect(() => {
    const raceInterval = window.setInterval(() => {
      const frame = raceFrame()
      ApexCharts.exec('horizontal-bar-race', 'updateOptions', {
        series: [{ data: frame.data }],
        xaxis: { categories: frame.categories },
        colors: frame.colors,
      })
    }, 1200)
    return () => window.clearInterval(raceInterval)
  }, [])

  return (
    <div>
      <div id="chart">
        <ReactApexChart
          options={state.options}
          series={state.series}
          type="bar"
          height={420}
        />
      </div>

      <div className="explanation">
        A "bar chart race": each tick re-sorts the entities by value and updates
        the chart. The bars slide to their new ranks and the left-hand category
        labels ride along with them (automatic whenever a reorder update runs
        with
        <code>dynamicAnimation</code> enabled). The value labels also ride each
        bar and count up/down, via the opt-in <code>dataLabels.animate</code>{' '}
        and
        <code>dataLabels.countUp</code> flags: together these complete the race.
      </div>
    </div>
  )
}

export default ApexChart