// i guess this serif will do, consistent char dimensions.
@import url(https://fonts.googleapis.com/css?family=Old+Standard+TT);

// clock size
$clock-di: 400px; // change this for gobal size
// timing
$second: 1000ms; // change this to speed it up
$minute: $second * 60;
$hour: $minute * 60;
$transition: $second * 0.2;
// fonts
$font: "Old Standard TT";
$big-font: $clock-di * 0.135;
$small-font: $clock-di * 0.07;
$char-width: $clock-di * 0.0818181;

// background needs to be its own element because of codepen bodies?
.bg {
  background-color: #000;
  $vin-dark: rgba(255,255,255,0);
  $vin-light: transparentize(#f1c8ab,0.8);
  background-image: radial-gradient(center, $vin-light, $vin-dark);
  position: fixed;
  top: 0; right: 0; bottom: 0; left: 0;
}

// the clock face
.clock {
  position: absolute;
  display: block;
  height: $clock-di; width: $clock-di;
  left: 50%; top: 50%;
  transform: translate3d(-50%, -50%, 0);
  border-radius: 50%;
  background-color: #383434;
  color: #f1c8ab;
  font-family: $font; 
  // the perimeter of the clock face
  box-shadow: 
    inset 0px 0px 12px 0px #111111,
    0px 0px 0px $clock-di * 0.022 #404241,
    0px 0px 0px $clock-di * 0.066 #202021,
    0px 0px 0px $clock-di * 0.084 #edc7ae,
    0px 0px 0px $clock-di * 0.092 #b6a091,
    0px 0px 0px $clock-di * 0.111 #edc7ae;

  // inset shadow on opening
  &::before {
    content: "";
    width: $clock-di * 0.175;
    height: $clock-di * 0.2916666667;
    border-radius: 8%;
    box-shadow: inset 0px 0px 8px rgba(0,0,0,0.4);
    position: absolute;
    left: calc(50% - #{$clock-di * 0.175 / 2});
    top: $clock-di * 0.04;
  }
  // subtle gradient overlay
  &::after {
    content: "";
    $grad-offset: 0.23;
    $grad-di: $clock-di * (1 + $grad-offset);
    width: $grad-di; height: $grad-di; 
    border-radius: 50%; 
    background: radial-gradient(ellipse at top center, rgba(0,0,0,0) 0%, rgba(0,0,0,0) 20%, rgba(0,0,0,0.9) 100%);
    position: absolute;
    top: $clock-di * $grad-offset / -2;
    left: $clock-di * $grad-offset / -2;
  }
  // svg img mask
  img {
    display: block; position: absolute;
    height: $clock-di; width: $clock-di;
    z-index: 99;    
    opacity: 0.65;
  }
}

// each set of numbers
figure {
  position: absolute;
  display: block; 
  border-radius: 50%;
  margin: 0;
  text-shadow: 2px 2px 1px rgba(0,0,0,0.2);
  // a plate
/*
  &::before {
    content: "";
    display: block;
    position: absolute;
    background-color: transparentize(#383434,0.3);
    border-radius: 50%;
    box-shadow: 
      0px 0px 0px 2px darken(desaturate(#f1c8ab,30%),20%),  
      0px 0px 8px rgba(0,0,0,0.2);
  }
*/
  // each number
  span {
    display: block; position: absolute;
    width: $char-width; 
    left: calc(50% + #{$char-width / -2});
    transform-origin: 50% 100%;
  }
  // using content attributes for numbers
  span::before {
    content: attr(val);
    position: absolute;
    top: 0; right: 0; bottom: 0; left: 0;
    text-align: center;
    line-height: 1;
  }
}

// must create unique animation per set of numbers
@mixin animation($name) {
  @keyframes #{$name} {
    @content;
  }
}

// mixin for each set of numbers
@mixin rotation($di, $font, $count, $name, $rotation-time, $direction) {
  width: $di; height: $di;
  font-size: $font;
  animation: $name $rotation-time linear infinite;
  // steps() animations do not allow for transitions between steps?
  // math to the rescue!
  $percentage-change: $transition / $rotation-time * 100; 
  @if $direction == "CC" {
    @include animation($name) {    
      0% { transform: rotate(360deg); }
      @for $i from 1 through $count {
        #{ $i / $count * 100 - $percentage-change }% { 
          transform: rotate(360 - ($i - 1) / $count * 360deg); 
        }
        #{ $i / $count * 100 }% { 
          transform: rotate(360 - ($i / $count) * 360deg); 
        }
      }      
    }
  } @else {
    @include animation($name) {    
      0% { transform: rotate(0deg); }
      @for $i from 1 through $count {
        #{ $i / $count * 100 - $percentage-change }% { 
          transform: rotate(($i - 1) / $count * 360deg); 
        }
        #{ $i / $count * 100 }% { 
          transform: rotate(($i / $count) * 360deg); 
        }
      }      
    }
  }
  span { height: $di / 2; }
  // rotate each number parent
  @for $i from 1 through $count {
    @if $direction == "CC" {
      span:nth-child(#{$i}) {
        transform: rotate(360deg * (($i - 1) / $count) );
      }
    } @else {
      span:nth-child(#{$i}) {
        transform: rotate(360deg * (($i) / $count) );
      }
    }
  }
  // a plate
/*
  &::before {
    top: $font; right: $font; bottom: $font; left: $font;
  }
*/
}


// diameters for each group of numbers
$big-loop: $clock-di * 0.85;
$mid-loop: $clock-di * 0.75;
$tiny-loop: $clock-di * 0.55;
// how far down we want the numbers to be
$off-top: 5%;

// shared top values for each increment
.hour-ten, .hour { top: $off-top; }
.min-ten,  .min  { top: calc(#{ $off-top } + #{ $small-font }); }
.sec-ten,  .sec  { top: calc(#{ $off-top } + #{ $small-font + $big-font }); }

// calling the mixin and left positions for each group
.hour-ten {
  @include rotation( $tiny-loop, $small-font, 4, "hour-ten", 4 * ($hour*3), "C" );
  left: calc(50% - #{ $tiny-loop/2 + $char-width/2 }); 
}
.hour {
  @include rotation( $big-loop, $small-font, 12, "hour", 12 * $hour, "CC" );
  left: calc(50% - #{ $big-loop/2 - $char-width/2 }); 
}

.min-ten {
  @include rotation( $tiny-loop, $big-font, 6, "min-ten", 6 * ($minute*10), "C" );
  left: calc(50% - #{ $tiny-loop/2 + $char-width/2 }); 
}
.min {
  @include rotation( $mid-loop, $big-font, 10, "min", 10 * $minute, "CC" );
  left: calc(50% - #{ $mid-loop/2 - $char-width/2 }); 
}

.sec-ten {
  @include rotation( $tiny-loop, $small-font, 6, "sec-ten", 6 * ($second*10), "C" );
  left: calc(50% - #{ $tiny-loop/2 + $char-width/2 }); 
}
.sec {
  @include rotation( $tiny-loop, $small-font, 10, "sec", 10 * $second, "CC" );
  left: calc(50% - #{ $tiny-loop/2 - $char-width/2 }); 
}