less.less

// Less RFS mixin
//
// Automated responsive values for font sizes, paddings, margins and much more
//
// See https://github.com/twbs/rfs

// Configuration

// Base value
@rfs-base-value: 1.25rem;
@rfs-unit: rem;

// Breakpoint at where value stops increasing
@rfs-breakpoint: 1200px;
@rfs-breakpoint-unit: px;

// Resize value based on screen height and width
@rfs-two-dimensional: false;

// Factor of decrease
@rfs-factor: 10;

// Mode. Possibilities: "min-media-query", "max-media-query"
@rfs-mode: "min-media-query";

// Generate enable or disable classes. Possibilities: false, "enable" or "disable"
@rfs-class: false;

// 1 rem = @rfs-rem-value px
@rfs-rem-value: 16;

// Safari iframe resize bug: https://github.com/twbs/rfs/issues/14
@rfs-safari-iframe-resize-bug-fix: false;

// Disable RFS by setting @enable-rfs to false
@enable-rfs: true;

// RFS mixin
.rfs(@values, @property: font-size) {
  ._rfs-calculate(1, ~"", ~"");
}

// Recursive calculate mixin
._rfs-calculate(@index, @valueResult, @fluidValueResult) {

  & when (@index <= length(@values)) {
    @currentValue: if(extract(@values, @index) = important, ~"!important" , extract(@values, @index));
    @space: if(@index = length(@values), ~"", ~" ");

    & when (not(isunit(@currentValue, px)) and not(isunit(@currentValue, rem))) {
      ._rfs-calculate((@index + 1), ~"@{valueResult}@{currentValue}@{space}", ~"@{fluidValueResult}@{currentValue}@{space}");
    }

    & when ((isunit(@currentValue, px)) or (isunit(@currentValue, rem))) {
      @val: if(isunit(@currentValue, rem), unit(@currentValue * @rfs-rem-value), unit(@currentValue));

      // Remove unit if zero
      @value-unit: if(@val = 0, ~"", @rfs-unit);

      @renderedValue: unit(if(@rfs-unit = px, @val, @val / @rfs-rem-value), @value-unit);

      @rfs-min: if(isunit(@rfs-base-value, rem), unit(@rfs-base-value * @rfs-rem-value), unit(@rfs-base-value));

      & when (not((abs(@val) > @rfs-min) and (@rfs-factor > 1) and (@enable-rfs = true))) {
        ._rfs-calculate((@index + 1), ~"@{valueResult}@{renderedValue}@{space}", ~"@{fluidValueResult}@{renderedValue}@{space}");
      }

      & when ((abs(@val) > @rfs-min) and (@rfs-factor > 1) and (@enable-rfs = true)) {

        @breakpoint: if(isunit(@rfs-breakpoint, em) or isunit(@rfs-breakpoint, rem), unit(@rfs-breakpoint * @rfs-rem-value), unit(@rfs-breakpoint));
        @max-width: unit(if(@rfs-breakpoint-unit = px, @breakpoint, @breakpoint / @rfs-rem-value), @rfs-breakpoint-unit);

        // Calculate minimum value
        @value-min: @rfs-min + (abs(@val) - @rfs-min) / @rfs-factor;

        // Calculate difference between @val and the minimum value
        // Rounding needed to prevent rounding errors
        @value-variable-width: unit(round((abs(@val) - @value-min) / (@breakpoint / 100), 15), if(@rfs-two-dimensional, vmin, vw));

        & when (@val > 0) {
          @renderedFluidValue: calc(unit(if(@rfs-unit = px, @value-min, @value-min / @rfs-rem-value), @rfs-unit) ~"+" @value-variable-width);
          ._rfs-calculate((@index + 1), ~"@{valueResult}@{renderedValue}@{space}", ~"@{fluidValueResult}@{renderedFluidValue}@{space}");
        }

        & when (@val < 0) {
          @renderedFluidValue: calc(unit(if(@rfs-unit = px, -@value-min, -@value-min / @rfs-rem-value), @rfs-unit) ~"-" @value-variable-width);
          ._rfs-calculate((@index + 1), ~"@{valueResult}@{renderedValue}@{space}", ~"@{fluidValueResult}@{renderedFluidValue}@{space}");
        }
      }
    }
  }

  & when (@index > length(@values)) {
    @fluidValue: @fluidValueResult;

    & when (@valueResult = @fluidValueResult) {
      @{property}: @valueResult;
    }

    & when (not(@valueResult = @fluidValueResult)) {

      & when (@rfs-class = "disable") and (@rfs-mode = "max-media-query") {
        &,
        .disable-rfs &,
        &.disable-rfs {
          @{property}: @valueResult;
        }
      }

      & when (@rfs-class = "enable") and (@rfs-mode = "min-media-query") {
        @{property}: @valueResult;

        .enable-rfs &,
        &.enable-rfs {
          @{property}: @fluidValue;
        }
      }

      & when (not((@rfs-class = "disable") and (@rfs-mode = "max-media-query"))) and not((@rfs-class = "enable") and (@rfs-mode = "min-media-query")) {
        @{property}: if(@rfs-mode = "min-media-query", @fluidValue, @valueResult);
      }

      // Media query
      & when (@rfs-class = "enable") {
        .enable-rfs &,
        &.enable-rfs {
          ._rfs-render-media-query();
        }
      }

      & when (@rfs-class = "disable") and (@rfs-mode = "min-media-query") {
        .disable-rfs &,
        &.disable-rfs {
          @{property}: @valueResult;
        }

        ._rfs-render-media-query();
      }

      & when (not(@rfs-class = "enable")) and not(@rfs-class = "disable") {
        ._rfs-render-media-query();
      }

      & when ((@rfs-safari-iframe-resize-bug-fix)) {
        // stylelint-disable-next-line length-zero-no-unit
        min-width: 0vw;
      }
    }
  }
}

._rfs-render-media-query () {
  & when (@rfs-two-dimensional) {
    & when (@rfs-mode = "min-media-query") {
      @media (min-width: @max-width) and (min-height: @max-width) {
        @{property}: @valueResult;
      }
    }

    & when (@rfs-mode = "max-media-query") {
      @media (max-width: @max-width), (max-height: @max-width) {
        @{property}: @fluidValue;
      }
    }
  }

  & when (not(@rfs-two-dimensional)) {
    & when (@rfs-mode = "min-media-query") {
      @media (min-width: @max-width) {
        @{property}: @valueResult;
      }
    }

    & when (@rfs-mode = "max-media-query") {
      @media (max-width: @max-width) {
        @{property}: @fluidValue;
      }
    }
  }
}

._rfs-render-media-query-content() {

  & when (@rfs-class = "enable") {
    .enable-rfs &,
    &.enable-rfs {
      @{property}: if(@rfs-mode = "min-media-query", @valueResult, @fluidValue);
    }
  }

  & when (not(@rfs-class = "enable")) {
    @{property}: if(@rfs-mode = "min-media-query", @valueResult, @fluidValue);
  }
}

// Sharthand mixins
.font-size(@value) {
  .rfs(@value);
}

.padding(@value, @property: padding) {
  .rfs(@value, @property);
}

.padding-top(@value, @property: padding-top) {
  .rfs(@value, @property);
}

.padding-right(@value, @property: padding-right) {
  .rfs(@value, @property);
}

.padding-bottom(@value, @property: padding-bottom) {
  .rfs(@value, @property);
}

.padding-left(@value, @property: padding-left) {
  .rfs(@value, @property);
}

.margin(@value, @property: margin) {
  .rfs(@value, @property);
}

.margin-top(@value, @property: margin-top) {
  .rfs(@value, @property);
}

.margin-right(@value, @property: margin-right) {
  .rfs(@value, @property);
}

.margin-bottom(@value, @property: margin-bottom) {
  .rfs(@value, @property);
}

.margin-left(@value, @property: margin-left) {
  .rfs(@value, @property);
}