@use 'sass:meta';
@use 'sass:string';
@use 'sass:list';
@use 'sass:math';
@use '../../functions/equals-false' as *;
@use '../../functions/is-alias' as *;
@use '../../functions/is-color' as *;
@use '../../functions/is-falsey' as *;
@use '../../functions/is-global-value' as *;
@use '../../functions/is-list' as *;
@use '../../functions/is-number' as *;
@use '../../functions/is-string' as *;
@use '../../functions/list-to-string' as *;

/// Animates text by making it appear to be glitching in and out.
///
/// @param {Number} $duration [0.5s] - The duration of the animation (`s` or `ms`).
/// @param {Number} $delay [null] - The optional delay time for the animation.
/// @param {Number | String} $iterations [null] - The number of iterations
/// to complete. Sets the value for the `animation-iteration-count` property.
/// Can be `infinite`, any unitless number, or any CSS global value.
/// @param {String} $anim-dir [null] - Sets the value for the
/// `animation-direction` property. Can be `normal`, `reverse`, `alternate`, or
/// `alternate-reverse`. Can also be any CSS global value. Default of `null`
/// assumes the CSS property default of `normal`.
/// @param {Timing-Function} $timing-func [null] - The timing function for the
/// animation. A null timing function will cause the CSS default timing-function
/// of `ease`.
/// @param {Bool} $has-shifts [true] - If true, the animation will have
/// side-to-side position shifts.
/// @param {Bool} $use-margin [false] If true, the animation keyframes will use
/// the `margin-left` property instead of the `left` property to create the
/// glitch animation sideways shifts, If $no-shifts is true, $use-margin has
/// no effect.
/// @param {Number | String} $anim-num [null] - If the mixin is used more than
/// once with different values in a stylesheet, you can pass a number or string
/// to the mixin here that gets appeneded to end of the animation name so that
/// the animations do not overwrite each other.
///
/// @group Animations
/// @require {function} equals-false
/// @require {function} is-alias
/// @require {function} is-color
/// @require {function} is-falsey
/// @require {function} is-global-value
/// @require {function} is-list
/// @require {function} is-number
/// @require {function} is-string
/// @require {function} list-to-string
///
/// @throw Invalid $duration value error.
/// @throw Invalid $delay value error.
/// @throw Invalid $anim-dir value error.
@mixin text-glitch(
  $duration: 0.5s,
  $delay: null,
  $iterations: null,
  $anim-dir: null,
  $timing-func: null,
  $has-shifts: true,
  $use-margin: false,
  $anim-num: null
) {
  $red: hsl(323.72 81.13% 41.57%);
  $blue: hsl(200 100% 50%);
  $yellow: hsl(56 100% 50%);
  $green: hsl(150.12 100% 50%);
  $colors: ($red $blue $yellow $green);

  @if $delay and is-string($delay) {
    $delay: string.to-lower-case($delay);
  }

  @if $anim-dir {
    @if is-list($anim-dir) {
      $anim-dir: list-to-string($anim-dir);
    }

    @if is-string($anim-dir) {
      $anim-dir: string.to-lower-case($anim-dir);
    }
  }

  @if $timing-func and is-string($timing-func) {
    $timing-func: string.to-lower-case($timing-func);
  }

  @if not is-number($duration) {
    @error 'Invalid $duration value of `#{meta.inspect($duration)}` for the ' +
        '[ text-glitch() ] mixin. The duration property must be a number.';
  } @else if math.is-unitless($duration) {
    // If no there is no unit for $duration, unless $duration > 60, assume seconds
    $duration: if($duration > 60, $duration * 1ms, $duration * 1s);
  } @else if not list.index('s' 'ms', math.unit($duration)) {
    @error 'Invalid $duration value of `#{meta.inspect($duration)}` for the ' +
        '[ text-glitch() ] mixin. The duration property must be in either '
        's (second) or ms (millisecond) units.';
  } @else if $duration % 10 == 0ms {
    // If time in ms would be shorter as seconds, convert it
    $duration: math.div($duration, 1000ms) * 1s;

    // Get rid of possible leading zero in front of decimal place
    @if string.slice($duration + '', 1, 2) == '0.' {
      $duration: #{string.slice($duration + '', 2)};
    }
  }

  @if is-falsey($delay) or
      is-alias('none', $delay) or
      $delay == 0s or $delay == 0ms
  {
    $delay: null;
  }

  @if $delay {
    @if not is-number($delay) {
      @error 'Invalid delay value of `#{meta.inspect($delay)}` for the ' +
          '[ text-glitch() ] mixin. The delay property must be a number.';
    } @else if math.is-unitless($delay) {
      // If no there is no unit for $delay, unless $delay > 60, assume seconds
      $delay: if($delay > 60, $delay * 1ms, $delay * 1s);
    } @else if not list.index('s' 'ms', math.unit($delay)) {
      @error 'Invalid delay value of `#{meta.inspect($delay)}` for the ' +
          '[ text-glitch() ] mixin. The delay property must be in either '
          's (second) or ms (millisecond) units.';
    } @else if $delay % 10 == 0ms {
      $delay: math.div($delay, 1000ms) * 1s;

      @if string.slice($delay + '', 1, 2) == '0.' {
        $delay: #{string.slice($delay + '', 2)};
      }
    }
  }

  @if $iterations {
    @if is-string($iterations) {
      $iterations: string.to-lower-case($iterations);
    }

    @if is-alias('infinite', $iterations) {
      $iterations: infinite;
    } @else if not (is-number($iterations) and math.is-unitless($iterations)) and
      not is-global-value($iterations)
    {
      @error 'Invalid $iterations value of `#{meta.inspect($iterations)}` ' +
          'for the [ text-glitch() ] mixin.';
    }
  } @else {
    $iterations: null;
  }

  @if is-falsey($anim-dir) or
      is-alias('none', $anim-dir) or
      is-alias('normal', $anim-dir)
  {
    $anim-dir: null;
  } @else if is-alias('reverse', $anim-dir) {
    $anim-dir: reverse;
  } @else if is-alias('alternate', $anim-dir) {
    $anim-dir: alternate;
  } @else if is-alias('alternate-reverse', $anim-dir) {
    $anim-dir: alternate-reverse;
  } @else if not is-global-value($anim-dir) {
    @error 'Invalid animation-direction value of `#{$anim-dir}` ' +
        'for the [ text-glitch() ] mixin.';
  }

  @if not
    $timing-func or
    is-alias('none', $timing-func) or
    is-alias('normal', $timing-func)
  {
    // Take all potential values the user might pass to keep the default setting
    // and ensure that the timing function remains at that default
    $timing-func: null;
  }

  @if equals-false($anim-num) or $anim-num == '' {
    $anim-num: null;
  } @else {
    $anim-num: '--#{$anim-num}';
  }

  @if $use-margin {
    $use-margin: 'margin-'
  } @else {
    $use-margin: null;
  }

  animation: txt-glitch#{$anim-num} #{$duration} #{$timing-func} #{$delay}
    #{$iterations} #{$anim-dir} both;

  @at-root {
    @keyframes txt-glitch#{$anim-num} {
      @for $i from 0 through 100 {
        $percent: 0% + $i;

        #{$percent} {
          $color: list.nth($colors, math.random(list.length($colors)));

          @if $has-shifts {
            #{#{$use-margin}left}: (math.random(12) * 1px) - 6px;
          }

          text-shadow: ((math.random(70) * 1px) - 35px) 0 0 $color;
        }
      }
    }
  }
}