@use 'sass:list';
@use 'sass:math';
@use 'sass:meta';
@use 'sass:string';
@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 popping forward out from a shadow.
///
/// @param {String} $direction ['bottom-left'] - The direction the shadow will be
/// facing. Recommended to use this mixin with the animation-stage mixin or just
/// the perspective property on the parent element.
/// @param {Number} $duration [0.6s] - 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. Default value of null will be the default CSS timing-function
/// propertiy's value of ease.
/// @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 $direction value error.
/// @throw Invalid $duration value error.
/// @throw Invalid $delay value error.
/// @throw Invalid $anim-dir value error.
@mixin text-pop-shadow(
  $direction: 'bottom-left',
  $duration: 0.7s,
  $shadow-color: #555,
  $delay: null,
  $iterations: null,
  $anim-dir: null,
  $timing-func: null,
  $anim-num: null
) {
  @if not $shadow-color {
    $shadow-color: #555;
  }

  // Default value for the 'top' direction
  $trans-val-1: translateY(0);
  $shadow-val:
    0 -1px $shadow-color,
    0 -2px $shadow-color,
    0 -3px $shadow-color,
    0 -4px $shadow-color,
    0 -5px $shadow-color,
    0 -6px $shadow-color,
    0 -7px $shadow-color,
    0 -8px $shadow-color;
  $trans-val-2: translateY(8px);
  $anim-suffix: '-top';

  @if $shadow-color and not is-color($shadow-color) {
    @error 'Invalid $shadow-color value of [ #{meta.inspect($shadow-color)} ] ' +
        'for the [ text-pop-shadow ] mixin.';
  }

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

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

  @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 is-alias('top right', $direction) {
    $trans-val-1: translateX(0) translateY(0);
    $trans-val-2: translateX(-8px) translateY(8px);
    $shadow-val:
      1px -1px $shadow-color,
      2px -2px $shadow-color,
      3px -3px $shadow-color,
      4px -4px $shadow-color,
      5px -5px $shadow-color,
      6px -6px $shadow-color,
      7px -7px $shadow-color,
      8px -8px $shadow-color;
    $anim-suffix: '-top-right';
  } @else if is-alias('right', $direction) {
    $trans-val-1: translateX(0);
    $trans-val-2: translateX(-8px);
    $shadow-val:
      1px 0 $shadow-color,
      2px 0 $shadow-color,
      3px 0 $shadow-color,
      4px 0 $shadow-color,
      5px 0 $shadow-color,
      6px 0 $shadow-color,
      7px 0 $shadow-color,
      8px 0 $shadow-color;
    $anim-suffix: '-right';
  } @else if is-alias('bottom right', $direction) {
    $trans-val-1: translateX(0) translateY(0);
    $trans-val-2: translateX(-8px) translateY(-8px);
    $shadow-val:
      1px 1px $shadow-color,
      2px 2px $shadow-color,
      3px 3px $shadow-color,
      4px 4px $shadow-color,
      5px 5px $shadow-color,
      6px 6px $shadow-color,
      7px 7px $shadow-color,
      8px 8px $shadow-color;
    $anim-suffix: '-bottom-right';
  } @else if is-alias('bottom', $direction) {
    $trans-val-2: translateY(-8px);
    $shadow-val:
      0 1px $shadow-color,
      0 2px $shadow-color,
      0 3px $shadow-color,
      0 4px $shadow-color,
      0 5px $shadow-color,
      0 6px $shadow-color,
      0 7px $shadow-color,
      0 8px $shadow-color;
    $anim-suffix: '-bottom';
  } @else if is-alias('bottom left', $direction) {
    $trans-val-1: translateX(0) translateY(0);
    $trans-val-2: translateX(8px) translateY(-8px);
    $shadow-val:
      -1px 1px $shadow-color,
      -2px 2px $shadow-color,
      -3px 3px $shadow-color,
      -4px 4px $shadow-color,
      -5px 5px $shadow-color,
      -6px 6px $shadow-color,
      -7px 7px $shadow-color,
      -8px 8px $shadow-color;
    $anim-suffix: '-bottom-left';
  } @else if is-alias('left', $direction) {
    $trans-val-1: translateX(0);
    $trans-val-2: translateX(8px);
    $shadow-val:
      -1px 0 $shadow-color,
      -2px 0 $shadow-color,
      -3px 0 $shadow-color,
      -4px 0 $shadow-color,
      -5px 0 $shadow-color,
      -6px 0 $shadow-color,
      -7px 0 $shadow-color,
      -8px 0 $shadow-color;
    $anim-suffix: '-left';
  } @else if is-alias('top left', $direction) {
    $trans-val-1: translateX(0) translateY(0);
    $trans-val-2: translateX(8px) translateY(8px);
    $shadow-val:
      -1px -1px $shadow-color,
      -2px -2px $shadow-color,
      -3px -3px $shadow-color,
      -4px -4px $shadow-color,
      -5px -5px $shadow-color,
      -6px -6px $shadow-color,
      -7px -7px $shadow-color,
      -8px -8px $shadow-color;
    $anim-suffix: '-top-left';
  } @else if not is-alias('top', $direction) {
    @error 'Invalid direction value of `#{meta.inspect($direction)}` for the ' +
        '[ text-pop-shadow() ] mixin.';
  }

  @if not is-number($duration) {
    @error 'Invalid $duration value of `#{meta.inspect($duration)}` for the ' +
        '[ text-pop-shadow() ] 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-pop-shadow() ] mixin. The duration property must be in ' +
        'either s or ms 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($delay)}` for the ' +
          '[ text-pop-shadow() ] mixin. The delay property must be a number.';
    } @else if math.is-unitless($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-pop-shadow() ] mixin. The delay property must be in ' +
          'either s or ms 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) {
      $iterations: infinite;
    } @else if (is-number($iterations) and math.is-unitless($iterations)) or
      is-global-value($iterations)
    {
      $iterations: $iterations;
    } @else {
      @error 'Invalid $iterations value of `#{meta.inspect($iterations)}` ' +
          'for the [ text-pop-shadow() ] 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-pop-shadow() ] mixin.';
  }

  @if not $timing-func or
    $timing-func == 'ease' 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-suffix: string.insert(
      $anim-suffix,
      '--#{$anim-num}',
      string.length($anim-suffix) + 1
    );
  }

  animation: txt-pop-shadow#{$anim-suffix} #{$duration} #{$timing-func} #{$delay}
    #{$iterations} #{$anim-dir} both;

  @at-root {
    @keyframes txt-pop-shadow#{$anim-suffix} {
      0% {
        text-shadow:
          0 0 $shadow-color,
          0 0 $shadow-color,
          0 0 $shadow-color,
          0 0 $shadow-color,
          0 0 $shadow-color,
          0 0 $shadow-color,
          0 0 $shadow-color,
          0 0 $shadow-color;
        transform: #{$trans-val-1};
      }

      100% {
        text-shadow: #{$shadow-val};
        transform: #{$trans-val-2};
      }
    }
  }
}