@use '../internal/function';
@use '../tokens' as api;
@use '../vars';
@use 'contrast';
@use 'css-vars' as cv;
@use 'sass:map';
@use 'sass:meta';

// Var-Contrast
// ------------
/// An extension of the `contrast()` function,
/// designed to output CSS variables
/// rather than simple color values.
///
/// @group color-contrast
/// @since 2.1.0 -
/// - NEW: Provides access to contrast colors as CSS-variables, when defined
/// @example scss - max contrast / no variable names
///   tools.$colors: (
///     'background': blue,
///     'light': #eee,
///     'dark': #111,
///   );
///   html {
///     color: tools.var-contrast(
///       'background',
///       'light', 'dark', black, white
///     );
///   }
/// @example scss - min contrast / variable names
///   tools.$colors: (
///     'background': blue,
///     'light': #eee,
///     'dark': #111,
///   );
///   html {
///     color: tools.var-contrast(
///       'background',
///       'light', 'dark', black, white,
///       'AAA'
///     );
///   }
///
/// @param {string | list} $color -
///   The name or value of a color.
/// @param {colors | min-contrast} $options... -
///   List of colors to contrast against.
///   This function will choose the best contrast
///   of all the options provided,
///   or the `contrast-light` and `contrast-dark` defaults
///   defined in your color palette or the factory settings.
///
///   - Any  `{'AA' | 'AA-large' | 'AAA' | 0-21 }` values
///     will be treated as a minimum color-contrast ratio –
///     and will return the minimum accessible option,
///     rather than the maximum contrast.
/// @return {color | var()} -
///   CSS Variable for the color-option
///   that has the highest contrast-ratio to `$color`,
///   or the color if no variable exists.
@function var-contrast($color, $options...) {
  $contrast: contrast.best-contrast($color, $options);
  $name: map.get($contrast, 'name');
  $color: map.get($contrast, 'color');

  @if ($name != $color) and not api.is-private-token($name) {
    $name: vars.ident($name, cv.$color-var-prefix);

    @return var($name, $color);
  }

  @return $color;
}

@include function.internal(meta.get-function('var-contrast'), 'var-contrast');

// Var Contrasted
// --------------
/// Apply any background color as a CSS variable,
/// along with the highest-contrast text color from a set of options.
/// This works the same as the `var-contrast()` function,
/// but applies the resulting values to `background-color`
/// and text `color` properties.
///
/// @group color-contrast
/// @since 2.1.0 -
/// - NEW: Applies contrasting colors as CSS-variables, when defined
/// @example scss - max contrast
///   tools.$colors: (
///     'background': blue,
///     'light': #eee,
///     'dark': #111,
///   );
///   html {
///     @include tools.var-contrasted(
///       'background',
///       'light', 'dark', black, white
///     );
///   }
/// @example scss - min contrast
///   tools.$colors: (
///     'background': blue,
///     'light': #eee,
///     'dark': #111,
///   );
///   html {
///     @include tools.var-contrasted(
///       'background',
///       'light', 'dark', black, white,
///       'AAA'
///     );
///   }
///
/// @param {string | list} $background -
///   The name or value of your desired background color.
/// @param {colors | min-contrast} $options... -
///   List of colors to contrast against.
///   This function will choose the best contrast
///   of all the options provided,
///   or the `$contrast-light` and `$contrast-dark` defaults
///   defined in your color palette or the factory settings.
///
///   - Any  `{'AA' | 'AA-large' | 'AAA' | 0-21 }` values
///     will be treated as a minimum color-contrast ratio –
///     and will return the minimum accessible option,
///     rather than the maximum contrast.
/// @output -
///   Sets the `background-color` to `$background`
///   and the foreground `color` to
///   whichever option has better contrast against the given background.
@mixin var-contrasted($background, $options...) {
  background-color: cv.var-color($background);
  color: var-contrast($background, $options...);
}