// SCSS variables are information about icon's compiled state, stored under its original file name
//
// .icon-home {
//   width: map-get($icon-home, 'width');
// }
//
// At the bottom of this section, we provide information about the spritesheet itself
$sprite-dash-case: (
  name: 'sprite-dash-case',
  x: 0px,
  y: 0px,
  offset-x: 0px,
  offset-y: 0px,
  width: 10px,
  height: 20px,
  total-width: 80px,
  total-height: 100px,
  image: 'nested/dir/spritesheet.png'
);
$sprite-snake-case: (
  name: 'sprite_snake_case',
  x: 10px,
  y: 20px,
  offset-x: -10px,
  offset-y: -20px,
  width: 20px,
  height: 30px,
  total-width: 80px,
  total-height: 100px,
  image: 'nested/dir/spritesheet.png'
);
$sprite-camel-case: (
  name: 'spriteCamelCase',
  x: 30px,
  y: 50px,
  offset-x: -30px,
  offset-y: -50px,
  width: 50px,
  height: 50px,
  total-width: 80px,
  total-height: 100px,
  image: 'nested/dir/spritesheet.png'
);
$sprite-dash-case-2x: (
  name: 'sprite-dash-case@2x',
  x: 0px,
  y: 0px,
  offset-x: 0px,
  offset-y: 0px,
  width: 20px,
  height: 40px,
  total-width: 160px,
  total-height: 200px,
  image: 'nested/dir/spritesheet@2x.png'
);
$sprite-snake-case-2x: (
  name: 'sprite_snake_case@2x',
  x: 20px,
  y: 40px,
  offset-x: -20px,
  offset-y: -40px,
  width: 40px,
  height: 60px,
  total-width: 160px,
  total-height: 200px,
  image: 'nested/dir/spritesheet@2x.png'
);
$sprite-camel-case-2x: (
  name: 'spriteCamelCase@2x',
  x: 60px,
  y: 100px,
  offset-x: -60px,
  offset-y: -100px,
  width: 100px,
  height: 100px,
  total-width: 160px,
  total-height: 200px,
  image: 'nested/dir/spritesheet@2x.png'
);
$spritesheet: (
  width: 80px,
  height: 100px,
  image: 'nested/dir/spritesheet.png',
  sprites: ($sprite-dash-case, $sprite-snake-case, $sprite-camel-case, )
);
$retina-spritesheet: (
  width: 160px,
  height: 200px,
  image: 'nested/dir/spritesheet@2x.png',
  sprites: ($sprite-dash-case-2x, $sprite-snake-case-2x, $sprite-camel-case-2x, )
);

// These "retina group" variables are mappings for the naming and pairing of normal and retina sprites.
//
// The map variables are intended for the `retina-sprite` mixin. The list variable is for `retina-sprites`.
$sprite-dash-case-group: (
  name: 'sprite-dash-case',
  normal: $sprite-dash-case,
  retina: $sprite-dash-case-2x
);
$sprite-snake-case-group: (
  name: 'sprite_snake_case',
  normal: $sprite-snake-case,
  retina: $sprite-snake-case-2x
);
$sprite-camel-case-group: (
  name: 'spriteCamelCase',
  normal: $sprite-camel-case,
  retina: $sprite-camel-case-2x
);
$retina-groups: ($sprite-dash-case-group, $sprite-snake-case-group, $sprite-camel-case-group, );

// The provided mixins are intended to be used with variables directly
//
// .icon-home {
//   @include sprite-width($icon-home);
// }
//
// .icon-email {
//   @include sprite($icon-email);
// }
//
// Example usage in HTML:
//
// `display: block` sprite:
// <div class="icon-home"></div>
//
// To change `display` (e.g. `display: inline-block;`), we suggest using a common CSS class:
//
// // CSS
// .icon {
//   display: inline-block;
// }
//
// // HTML
// <i class="icon icon-home"></i>
@mixin sprite-width($sprite) {
  width: map-get($sprite, 'width');
}

@mixin sprite-height($sprite) {
  height: map-get($sprite, 'height');
}

@mixin sprite-position($sprite) {
  background-position: map-get($sprite, 'offset-x') map-get($sprite, 'offset-y');
}

@mixin sprite-image($sprite) {
  background-image: url(map-get($sprite, 'image'));
}

@mixin sprite($sprite) {
  @include sprite-image($sprite);
  @include sprite-position($sprite);
  @include sprite-width($sprite);
  @include sprite-height($sprite);
}

// The `retina-sprite` mixin sets up rules and a media query for a sprite/retina sprite.
//   It should be used with a "retina group" variable.
//
// The media query is from CSS Tricks: https://css-tricks.com/snippets/css/retina-display-media-query/
//
// $icon-home-group: (
//   name: 'icon-home',
//   normal: $icon-home,
//   retina: $icon-home-2x
// );
//
// .icon-home {
//   @include retina-sprite($icon-home-group);
// }
@mixin sprite-background-size($sprite) {
  background-size: map-get($sprite, 'total-width') map-get($sprite, 'total-height');
}

@mixin retina-sprite($retina-group) {
  $normal-sprite: map-get($retina-group, 'normal');
  $retina-sprite: map-get($retina-group, 'retina');
  @include sprite($normal-sprite);

  @media (-webkit-min-device-pixel-ratio: 2),
         (min-resolution: 192dpi) {
    @include sprite-image($retina-sprite);
    @include sprite-background-size($normal-sprite);
  }
}

// The `sprites` mixin generates identical output to the CSS template
//   but can be overridden inside of SCSS
//
// @include sprites(map-get($spritesheet, 'sprites'));
@mixin sprites($sprites) {
  @each $sprite in $sprites {
    $sprite-name: map-get($sprite, 'name');
    .#{$sprite-name} {
      @include sprite($sprite);
    }
  }
}

// The `retina-sprites` mixin generates a CSS rule and media query for retina groups
//   This yields the same output as CSS retina template but can be overridden in SCSS
//
// @include retina-sprites($retina-groups);
@mixin retina-sprites($retina-groups) {
  @each $retina-group in $retina-groups {
    $sprite-name: map-get($retina-group, 'name');
    .#{$sprite-name} {
      @include retina-sprite($retina-group);
    }
  }
}