//
// A partial implementation of the Ruby fonts functions from Compass:
// https://github.com/Compass/compass/blob/stable/core/lib/compass/core/sass_extensions/functions/font_files.rb
//
// and several functions from the file:
// https://github.com/Compass/compass/blob/stable/core/lib/compass/core/sass_extensions/functions/urls.rb
// -----------------------------------------------------------------------------
// Helper functions font-files and font-url for font-face mixins.
// -----------------------------------------------------------------------------
// use mixin this way:
//
// $font-path: "/public/fonts/roboto";
// @include font-face(
//   'Roboto',
//   font_files("roboto.ttf", "truetype", "roboto.woff", "roboto.woff2"),     // or
//   font_files("roboto.ttf", "roboto.woff", "roboto.woff2"),
//   "roboto.eot",    // [$eot]
//   normal,          // [$weight]
//   normal           // [$style]
// );
// -----------------------------------------------------------------------------


@function font-url($path) {
  $font-path: 'fonts' !default;
  @return url("#{$font-path}/#{$path}");
}


// -----------------------------------------------------------------------------
// helper function to create a list of font files for the src attribute in @font-face.
// In the global variable $font-path, you can specify the path to the folder
// with fonts relative to style files, by default the path to the fonts is "fonts".
//
// Usage: font-files ('file-name-w-ext'[, 'format'][,'file-name-w-ext'[, 'format']]...).
// If the font format is not specified, the function will add the format corresponding to the file extension.
//
// for best results use this order: woff, opentype / truetype, svg.
// -----------------------------------------------------------------------------
// function ported from Ruby.
// -----------------------------------------------------------------------------
@function font-files($font-files...) {
  $font-path: 'fonts' !default;
  // types of font formats from module Compass::Core::SassExtensions::Functions::FontFiles.
  $font-types: (
    'woff': "woff",
    'woff2': "woff2",
    'opentype': "otf",
    // 'opentype': "opentype",
    'truetype': "ttf",
    // 'truetype': "truetype",
    'svg': "svg",
    'embedded-opentype': "eot"
  );

  $full: '';
  // if the font format is specified after the font file name, skip the next iteration.
  $skip-next: false;
  // number of font files including font format.
  $font-file-length: length($font-files);

  @for $i from 1 through $font-file-length {
    @if(not $skip-next) {
      $font-file: nth($font-files, $i);
      $font-file-next: if($i < $font-file-length, nth($font-files, $i + 1), false);

      // add font url.
      $full: $full + 'url("#{$font-path}/#{$font-file}")';

      // add the font format if it is specified after the font file name.
      @if $font-file-next and map-has-key($font-types, $font-file-next) {
        $full: $full + ' format("#{$font-file-next}")';
        $skip-next: true;
      } @else {
        // add a font format based on the font file name extension.
        @each $type, $extension in $font-types {
          $pos: str-index($font-file, '.' + $extension);

          @if($font-file-next == $extension) {
            $full: $full + ' format("#{$type}")';
            $skip-next: true;
          } @else if ($pos and (to-lower-case(str-slice($font-file, $pos + 1)) == $extension)) {
            $full: $full + ' format("#{$type}")';
          }
        }
      }
    } @else {
      $skip-next: false;
    }

    @if (not $skip-next and $i != $font-file-length) { $full: $full + ', ';}
  }

  @return unquote($full);
}