@use "sass:math";

//
// Typography
//

$font-size-root: 16px !default;

$px-to-pt: math.div(3, 4);

@function pass($n) { @return $n; }

@function number-to-em($n) { @return $n * 1em; }
@function em-to-number($n) { @return math.div($n, 1em); }

@function number-to-rem($n) { @return $n * 1rem; }
@function rem-to-number($n) { @return math.div($n, 1rem); }

@function number-to-px($n, $fs: $font-size-root) { @return $n * $fs; }
@function px-to-number($n, $fs: $font-size-root) { @return math.div($n, $fs); }

@function em-to-px($n, $fs: $font-size-root) {
    @return number-to-px(em-to-number($n), $fs);
}

@function px-to-em($n, $fs: $font-size-root) {
    @return number-to-em(px-to-number($n, $fs));
}

@function rem-to-px($n, $fs: $font-size-root) {
    @return number-to-px(rem-to-number($n), $fs);
}

@function px-to-rem($n, $fs: $font-size-root) {
    @return number-to-rem(px-to-number($n, $fs));
}

@function pt-to-px($n) { @return math.div($n, $px-to-pt); }
@function px-to-pt($n) { @return $n * $px-to-pt; }

@function to-em($n) {
    $unit: math.unit($n);
    @if $unit {
        // 'em' 'ex' 'ch' 'rem' 'vw' 'vh' 'vmin' 'vmax'
        @if $unit == 'px' { @return px-to-em($n); }
        @else if $unit == 'em' { @return number-to-em($n); }
        @return pass($n);
    } @else {
        @return number-to-em($n);
    }
}

@function line-height-offset($line-height, $base: 1) {
    @return ($line-height - $base) * 0.5;
}

@function rem($n) {
    @return px-to-rem($n);
}