/// Returns viewport size from $viewport-sizes map for provided key.
/// @group base
/// @author Richard Davis
/// @param {String} $_key - The key to return an associated viewport size for.
/// @example
///   viewport-size("M");
@function viewport-size($_key) {
  @if map-has-key($viewport-sizes, $_key) {
    @return map-get($viewport-sizes, $_key);
  }

  @else {
    @error "Key provided not found in $viewport-sizes map.";
  }
}

/// Returns spacing size from $spacing-sizes map for provided key.
/// @group base
/// @author Richard Davis
/// @param {Number} $_key - The key to return an associated spacing size for.
/// @example
///   spacing-size(4);
@function spacing-size($_key) {
  @if map-has-key($spacing-sizes, $_key) {
    @return map-get($spacing-sizes, $_key);
  }

  @else {
    @error "Key provided not found in $spacing-sizes map.";
  }
}

/// Returns theme color from $theme-colors map for provided key.
/// @group base
/// @author Richard Davis
/// @param {String} $_key - The key to return an associated color for.
/// @example
///   theme-color("primary");
@function theme-color($_key) {
  @if map-has-key($theme-colors, $_key) {
    @return map-get($theme-colors, $_key);
  }

  @else {
    @error "Key provided not found in $theme-colors map.";
  }
}

/// Returns semantic color from $semantic-colors map for provided key.
/// @group base
/// @author Richard Davis
/// @param {String} $_key - The key to return an associated color for.
/// @example
///   semantic-color("safe");
@function semantic-color($_key) {
  @if map-has-key($semantic-colors, $_key) {
    @return map-get($semantic-colors, $_key);
  }

  @else {
    @error "Key provided not found in $semantic-colors map.";
  }
}

/// Returns grayscale color from $grayscale-colors map for provided key.
/// @group base
/// @author Richard Davis
/// @param {Number} $_key - The token to return an associated color for.
/// @example
///   grayscale-color(10);
@function grayscale-color($_key) {
  @if map-has-key($grayscale-colors, $_key) {
    @return map-get($grayscale-colors, $_key);
  }

  @else {
    @error "Key provided not found in $grayscale-colors map.";
  }
}

/// Returns scaled font size
/// @group base
/// @author Richard Davis
/// @param {Number} $_key - The factor by which to scale the font size
/// @example
///   font-scale(2);
@function font-scale($_factor) {
  $_ratio: 1.618;
  $_value: $_ratio * 100%;

  @if ($_factor > 1) {
    @for $_i from 1 through ($_factor) {
      $_value: $_value + ($_i * 33%);
    }
  }

  @return $_value;
}