@use "sass:math"

$fs: 21px
$mplr: 1.667
$lcct: 32

$lgth: $lcct * 1rem
$lmch: $mplr * 1rem
$lsid: calc(($mplr - 1) / 2) * 1rem
$lacs: (2 * $mplr - 1) * 1rem


html, body
  writing-mode: vertical-rl
  font-size: $fs

article
  height: $lgth
  text:
    align: justify
  margin: $lacs


// Style text frame
@mixin text_frame($_lcct, $should_set_fs: false)
  @if $should_set_fs 
    html, body
      font-size: $fs
  article
    height: $_lcct * 1rem

@function corresponding_screen_height($text_frame_height)
  // Should return `px`
  @debug $text_frame_height, $fs, $text_frame_height + (2 * $mplr - 1) * 2 * $fs
  @return $text_frame_height + (2 * $mplr - 1) * 2 * $fs

// Create `max-height` breakpoints
$_last_breakpoint: null
@mixin screen_breakpoints($start_lcct, $decrease, $fs)
  $fs: $fs !global
  @for $i from 0 through $decrease
    @if $i == 0
      @if $_last_breakpoint != null
        @media screen and (max-height: corresponding_screen_height($_last_breakpoint))
          @include text_frame($start_lcct - $i, true)
    @else
      @media screen and (max-height: corresponding_screen_height(($start_lcct - $i + 1) * $fs))
        @include text_frame($start_lcct - $i)
      @if $i == $decrease
        $_last_breakpoint: ($start_lcct - $i) * $fs !global

@mixin lgth_step_down($ideal_lcct, $min_lcct, $sizes...)
  $sizes: append($sizes, 0px)
  @for $i from 1 to length($sizes)
    $greedy_step: math.floor(math.div((nth($sizes, $i) - nth($sizes, $i + 1)) * $ideal_lcct, nth($sizes, $i)))
    $step: min($greedy_step, $ideal_lcct - $min_lcct)
    @include screen_breakpoints($ideal_lcct, $step, nth($sizes, $i))
    

@include lgth_step_down($lcct, 18, 21px, 18px, 16px)