<main class="main">
  <button id="random" class="button">Random value</button>
  <h1 class="main__title">Gauge Chart</h1>
  
  <div class="gauge-container">
    <div class="gauge"></div>
    <div class="gauge"></div>
    <div class="gauge"></div>
  </div>
</main>

<footer class="footer">
  <p>A pen by <a href="http://brunocarvalho.me">Bruno Carvalho</a></p>
</footer>

<svg width="0" height="0" version="1.1" class="gradient-mask" xmlns="http://www.w3.org/2000/svg">
  <defs>
      <linearGradient id="gradientGauge">
        <stop class="color-red" offset="0%"/>
        <stop class="color-yellow" offset="17%"/>
        <stop class="color-green" offset="40%"/>
        <stop class="color-yellow" offset="87%"/>
        <stop class="color-red" offset="100%"/>
      </linearGradient>
  </defs>  
</svg>

// Vars
$color--blue-dark: #395467;
$color--gray: #212629;
$color--gray-dark: #26323a;
$color--white: #fff;
$color--green: #25cd6b;
$color--green-light: #a7db29;
$color--yellow: #fbe500;
$color--red: #e23131;
$color--orange: #ed811c;
$unit--spacing: 20px;

* { box-sizing: border-box; }

body {
  background-image: linear-gradient(140deg, $color--gray, $color--blue-dark);
  min-height: 100vh;
  color: $color--white;
  font-family: 'Open Sans', sans-serif;
  position: relative;
  padding-top: $unit--spacing * 4;
}

a {
  color: lighten($color--blue-dark, 20%);
  text-decoration: none;
}

.color-red { stop-color: $color--red; }
.color-yellow { stop-color: $color--yellow;}
.color-green { stop-color: $color--green; }

.footer {
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  background-color: $color--gray-dark;
  padding: $unit--spacing;
  text-align: center;
  font-size: 12px;
  letter-spacing: 3px;
  word-spacing: 4px;
  
  a {
    letter-spacing: 2px;
    word-spacing: 2px;
  }
}

.main {
  max-width: 1200px;
  margin: 0 auto;
  
  &__title {
    text-align: center;
    font-size: 48px;
  }
}

.gradient-mask { visibility: hidden; }

.button {
  position: absolute;
  right: $unit--spacing * 2;
  top: $unit--spacing * 2;
  border: 2px solid $color--white;
  background-color: $color--gray-dark;
  color: $color--white;
  font-weight: bold;
  font-size: 16px;
  padding: $unit--spacing / 2 $unit--spacing;
  border-radius: 4px;
  cursor: pointer;
  transition: .2s;
  
  &:active {
    transform: translateY(3px);
    outline: 0;
  }
  
  &:hover,
  &:focus {
    outline: 0;
    background: linear-gradient(-140deg, $color--gray, $color--blue-dark);
  }
}

.gauge-container {
  padding: $unit--spacing;
  margin-top: $unit--spacing * 4;
  display: flex;
  justify-content: space-around;
}

.gauge {
  height: 220px;
  width: 300px;
  
  .dxg-range.dxg-background-range { fill: url(#gradientGauge); }
  
  .dxg-line {
    transform: scaleX(1.04) scaleY(1.03) translate(-4px, -4px);

    path:first-child,
    path:last-child { display: none; }
    path:nth-child(2),
    path:nth-child(6) { stroke: $color--orange; }
    path:nth-child(3),
    path:nth-child(5) { stroke: $color--green-light; }
    path:nth-child(4) { stroke: $color--green; }
  }
  
  .dxg-elements {
    text:first-child { transform: translate(19px, 13px); }
    text:last-child { transform: translate(-27px, 14px); }
  }
  
  .dxg-value-indicator {
    path {
      transform: scale(1.2) translate(0, -5px);
      transform-origin: center center;
    }
    
    .dxg-title {
      text-transform: uppercase;
      
      text:first-child { transform: translateY(5px); }
    }
    
    .dxg-spindle-border:nth-child(4),
    .dxg-spindle-hole:nth-child(5){ transform: translate(0, -109px); }
    .dxg-spindle-hole { fill: $color--gray-dark; }
  }
}

$(function() {
  
  class GaugeChart {
    constructor(element, params) {
      this._element = element;
      this._initialValue = params.initialValue;
      this._higherValue = params.higherValue;
      this._title = params.title;
      this._subtitle = params.subtitle;
    }
    
    _buildConfig() {
      let element = this._element;
      
      return {
        value: this._initialValue,
        valueIndicator: {
          color: '#fff'
        },
        geometry: {
          startAngle: 180,
          endAngle: 360
        },
        scale: {
          startValue: 0,
          endValue: this._higherValue,
          customTicks: [0, 250, 500, 780, 1050, 1300, 1560],
          tick: { 
            length: 8
          },
          label: {
            font: {
              color: '#87959f',
              size: 9,
              family: '"Open Sans", sans-serif'
            }
          }
        },
        title: {
          verticalAlignment: 'bottom',
          text: this._title,
          font: {
            family: '"Open Sans", sans-serif',
            color: '#fff',
            size: 10
          },
          subtitle: {
            text: this._subtitle,
            font: {
              family: '"Open Sans", sans-serif',
              color: '#fff',
              weight: 700,
              size: 28
            }
          }
        },
        onInitialized: function() {
          let currentGauge = $(element);
          let circle = currentGauge.find('.dxg-spindle-hole').clone();
          let border = currentGauge.find('.dxg-spindle-border').clone();

          currentGauge.find('.dxg-title text').first().attr('y', 48);
          currentGauge.find('.dxg-title text').last().attr('y', 28);
          currentGauge.find('.dxg-value-indicator').append(border, circle);
        }
        
      }
    }
    
    init() {
      $(this._element).dxCircularGauge(this._buildConfig());
    }
  }
 
  $(document).ready(function () {
    
    $('.gauge').each(function(index, item){
      let params = {
        initialValue: 780,
        higherValue: 1560,
        title: `Temperature ${index + 1}`,
        subtitle: '780 ºC'
      };

      let gauge = new GaugeChart(item, params);
      gauge.init();
    });
    
    $('#random').click(function() {

      $('.gauge').each(function(index, item) {
        let gauge = $(item).dxCircularGauge('instance');
        let randomNum = Math.round(Math.random() * 1560);
        let gaugeElement = $(gauge._$element[0]);

        gaugeElement.find('.dxg-title text').last().html(`${randomNum} ºC`);
        gauge.value(randomNum);
      });
    });
  });
  
});