Full font face generator mixin

_font.scss

// Set defaults in parameters...
@mixin generate-font-face($font-name, $sizes:false, $font-folder-name:false, $font-file-prefix: false, $font-file-suffix: "webfont", $font-name-separator:"-", $dir-separator:"/", $formats:(woff2, ttf, svg, eot)) {

  $web-font-folder-name: $font-name;

  @if $font-folder-name != false {
    $web-font-folder-name: $font-folder-name;
  }

  // default font-file prefix
  $web-font-file-name-prefix: $font-name;

  @if $font-file-prefix != false {
    $web-font-file-name-prefix: $font-file-prefix;
  }

  // Default (most commonly used sizes)
  $font-sizes:  (light,   200, normal),
                (regular, 400, normal),
                (bold,    700, normal);

  @if $sizes != false {
    $font-sizes: $sizes;
  }
  
  // Build font file name

  $all-formats: (woff, woff2, ttf, otf, svg);

  $eot-file: false;

  @each $type, $weight, $style in $font-sizes {

    @if NULL == $weight {
      @if light == $type {
        $weight: 200;
      }
      @else if regular == $type {
        $weight: 400;
      }
      @else if bold == $type {
        $weight: 700;
      }
    }

    @if NULL == $style {
      $style: normal;
    }

    $font-full-file-name: $web-font-folder-name + $dir-separator + $type + $dir-separator + $web-font-file-name-prefix + $font-name-separator + $type + $font-name-separator + $font-file-suffix;

    $web-font-files: ();

    $font-1: NULL;
    $font-2: NULL;
    $font-3: NULL;

    @each $format in $all-formats {

      $full-name: $font-full-file-name + ".#{$format}";

      @if index($formats, $format) != false {
        @if woff == $format or woff2 == $format {
          $font-1: $full-name;
        }
        @else if ttf == $format or otf == $format{
          $font-2: $full-name;
        }
        @else if svg == $format {
          $font-3: $full-name;
        }
      }

    }

    @if index($formats, eot) {
      $eot-file: "#{$font-full-file-name}.eot";
    }

    @include font-face(
      $font-name,
      font-files( $font-1, $font-2, $font-3 ),
      $eot-file,
      $weight,
      $style
    );

  }
}

// Example implementations
@include generate-font-face("proxima-nova");