/// # Tint & Shade Utilities
/// @group util


// Tint
// ----
/// Mix a color with `white` to get a lighter tint.
///
/// @group util
///
/// @param {String | list} $color -
///   The name of a color in your palette,
///   with optional adjustments in the form of `(<function-name>: <args>)`.
/// @param {Percentage} $percentage -
///   The percentage of white to mix in.
///   Higher percentages will result in a lighter tint.
/// @return {Color} -
///   A calculated css-ready color-value based on your global color palette.
@function tint(
  $color,
  $percentage
) {
  $color: color($color);

  @return mix(#fff, $color, $percentage);
}


// Shade
// -----
/// Mix a color with `black` to get a darker shade.
///
/// @group util
///
/// @param {String | list} $color -
///   The name of a color in your palette,
///   with optional adjustments in the form of `(<function-name>: <args>)`.
/// @param {Percentage} $percentage -
///   The percentage of black to mix in.
///   Higher percentages will result in a darker shade.
/// @return {Color} -
///   A calculated css-ready color-value based on your global color palette.
@function shade(
  $color,
  $percentage
) {
  $color: color($color);

  @return mix(#000, $color, $percentage);
}


// Get Function
// ------------
/// Get a first-class function in Sass 3.5+,
/// or the function name string (unchanged)
/// in older Sass versions.
/// This is safe to use internally,
/// as it allows users to pass in
/// either a string, or a previously-captured function.
///
/// @access private
///
/// @param {String | Function} $function -
///   The name (string) of a function,
///   or the function to be called.
/// @return {String | Function} -
///   Returns a first-class function in Sass 3.5+,
///   or the function name string in older Sass versions.
@function _ac-color-get-function(
  $function
) {
  $type: type-of($function);

  @if ($type == 'function') {
    @return $function;
  }

  @if function-exists('get-function') {
    // sass-lint:disable variable-name-format
    @if index($_LOCAL-COLOR-FUNCTIONS, $function) {
      @return get-function($function);
    }

    @if map-has-key($functions, $function) {
      $function: map-get($functions, $function);
      @return _ac-color-get-function($function);
    }

    @error '[#{$type}] `#{$function}` must be a first-class function';
  }

  @return $function;
}