@use 'sass:list';
@use 'sass:meta';
@use 'sass:math';
@use 'sass:string';
@use 'is-falsey' as *;
@use 'is-number' as *;
@use 'str-to-num' as *;

/// Converts a decimal number into a ratio expressed as a space-separated list.
///
/// @param {Number} $number - The number to convert into a media ratio.
/// @param {Bool} $common-ratio [false] - If value is anything except for `null`
/// and `false`, this flag will direct the function to return the closest common
/// media ratio.
/// @param {Number} $accuracy [50000] - The search limit for the denominator.
/// @param {Number} $tolerance [0.01] - How close the provied $number can get to
/// return a common media ratio when the $common-ratio flag is truthy.
///
/// @return {List} - The number converted into a ratio.
///
/// @access public
/// @group Utilities
/// @require {function} is-falsey
/// @require {function} is-number
/// @require {function} str-to-num
@function num-to-ratio($number, $common-ratio: false, $accuracy: 50000, $tolerance: 0.0175) {
  $common-ratios: (
    '0.56': (9 16), // Vertical video on social media, rotated 16:9
    '0.8': (4 5), // Vertical images - especially on social media
    '1': (1 1), // Popular for images/video on Instagram and other social media
    '1.25': (5 4), // Old computer monitors, medium format cameras
    '1.33': (4 3), // SD television and computer monitors, Academy ratio
    '1.37': (137 100), // Classic 35mm film
    '1.43': (143 100), // IMAX film format
    '1.5': (3 2), // Photography, 35mm film, digital cameras, 1620x1080 monitors
    '1.56': (14 9), // Compromise format between 4:3 and 16:9
    '1.6': (16 10), // Tablets, 1728x1080 monitors
    '1.66': (5 3), // European widescreen theater standard
    '1.78': (16 9), // HDTV, Full HD, 4K UHD, YouTube videos, 1920x1080 monitors
    '1.85': (37 20), // American cinema, between Academy and widescreen ratios
    '1.89': (17 9), // Used in some digital cinema and 4k content
    '2': (18 9), // Smartphones, FullHD+, Univisium, some films and TV productions
    '2.16': (19.5 9), // Modern smartphones
    '2.2': (11 5), // 70mm film format
    '2.33': (21 9), // Ultra-wide HD monitors, cinema, gaming
    '2.35': (47 20), // CinemaScope "65 and wide", movies in theaters, Blu-ray
    '2.39': (239 100), // Alternate CinemaScope, movies in theaters, Blu-ray
    '2.4': (12 5), // Cinema ratio, ultra-widescreen and cinematic content
    '2.55': (51 20), // Original CinemaScope
    '2.76': (69 25), // Ultra Panavision 70, MGM Camera 65
    '3.56': (32 9), // Super ultra-wide monitors
    '4': (4 1) // Ultra-wide panoramic, Polyvision
  );
  $closest-numerator: 1;
  $closest-denominator: 1;
  $min-difference: math.abs($number - math.div($closest-numerator, $closest-denominator));

  @if not is-number($number) {
    @error 'Invalid $number passed to [ num-to-ratio() ] function. Value must ' +
        'be a valid number.';
  }

  @if not is-falsey($common-ratio) {
    @each $decimal, $ratio in $common-ratios {
      @if math.abs($number - str-to-num($decimal)) < $tolerance {
        @return $ratio;
      }
    }
  }

  @for $denominator from 1 through $accuracy + 1 {
    $numerator: math.round($number * $denominator);
    $difference: math.abs($number - math.div($numerator, $denominator));

    @if $difference < $min-difference {
      $min-difference: $difference;
      $closest-numerator: $numerator;
      $closest-denominator: $denominator;

      @if $min-difference == 0 or $difference > $min-difference{
        @return ($closest-numerator $closest-denominator);
      }
    }
  }

  @return ($closest-numerator $closest-denominator);
}

/// Converts a decimal number into a ratio expressed as a space-separated list.
///
/// @param {Number} $number - The number to convert into a media ratio.
/// @param {Bool} $common-ratio [false] - If value is anything except for `null`
/// and `false`, this flag will direct the function to return the closest common
/// media ratio.
/// @param {Number} $accuracy [50000] - The search limit for the denominator.
/// @param {Number} $tolerance [0.01] - How close the provied $number can get to
/// return a common media ratio when the $common-ratio flag is truthy.
///
/// @return {List} - The number converted into a ratio.
///
/// @access public
/// @group Utilities
/// @require {function} num-to-ratio
/// @alias num-to-ratio
@function decimal-to-ratio($number, $common-ratio: false, $accuracy: 50000, $tolerance: 0.0175) {
  @return num-to-ratio($number, $common-ratio, $accuracy, $tolerance);
}