@use 'sass:list';
@use 'sass:string';
@use 'sass:selector';
@use 'sass:meta';
@use '../configuration' as *;
@use '../functions' as *;

$namespace: $sar-namespace !default;
$block-separator: $sar-block-separator !default;
$element-separator: $sar-element-separator !default;
$modifier-separator: $sar-modifier-separator !default;

$current-block: '';

@function get-selector-last($selector) {
  $str: $selector + '';
  $list: str-split($str, ',');
  $result: ();
  @each $item in $list {
    $sub-list: str-split($item, ' ');
    $last: list.nth($sub-list, list.length($sub-list));
    $result: list.append($result, $last, $separator: comma);
  }
  @return $result;
}

@function is-block($selector) {
  @return $selector + '' == $current-block;
}

@function get-modifier-selector($modifiers, $parent) {
  $sep-modifier: ();

  @each $item in $modifiers {
    $sep-modifier: list.append(
      $sep-modifier,
      $modifier-separator + $item,
      $separator: comma
    );
  }

  @return selector.append($parent, $sep-modifier);
}

@function get-intersectant-selector($modifiers, $parent) {
  $multi-element: ();

  @each $p in $parent {
    $one-element: '';

    @each $m in $modifiers {
      $one-element: $one-element + $p + $modifier-separator + $m;
    }

    $multi-element: list.append(
      $multi-element,
      $one-element,
      $separator: comma
    );
  }

  @return $multi-element;
}

@function get-element-selector($elements) {
  $sep-elements: ();

  @each $item in $elements {
    $sep-elements: list.append(
      $sep-elements,
      $element-separator + $item,
      $separator: comma
    );
  }

  @return selector.append($current-block, $sep-elements);
}

@mixin bem($block) {
  $selector: '.' + $namespace + $block-separator + $block;
  $current-block: $selector !global;

  #{$selector} {
    @content;
  }
}

@mixin b() {
  & {
    @content;
  }
}

@mixin e($elements...) {
  $selector: get-element-selector($elements);
  $parent: &;

  @if (is-block($parent)) {
    @at-root {
      #{$selector} {
        @content;
      }
    }
  } @else {
    @at-root {
      #{$parent} {
        #{$selector} {
          @content;
        }
      }
    }
  }
}

@mixin m($modifiers...) {
  $selector: get-modifier-selector($modifiers, &);

  @at-root {
    #{$selector} {
      @content;
    }
  }
}

@mixin m-not($modifiers...) {
  $selector-list: ();

  @each $element in & {
    $selector: get-modifier-selector($modifiers, $element);
    $last: get-selector-last($selector);
    $not-selector: selector.replace(':not(selector)', 'selector', $last);
    $selector: selector.append(&, $not-selector);
    $selector-list: list.append($selector-list, $selector, $separator: comma);
  }

  @at-root {
    #{$selector-list} {
      @content;
    }
  }
}

@mixin m-intersect($modifiers...) {
  $selector: get-intersectant-selector($modifiers, &);

  @at-root {
    #{$selector} {
      @content;
    }
  }
}

@mixin m-root($modifiers...) {
  $selector: get-modifier-selector($modifiers, $current-block);
  $parent: &;

  @at-root {
    #{$selector} {
      #{$parent} {
        @content;
      }
    }
  }
}

// experiment
@mixin e-root($elements...) {
  $selector: get-element-selector($elements);

  @at-root {
    #{$selector} {
      @content;
    }
  }
}

@mixin e-last-root($elements...) {
  $selector: get-element-selector($elements);
  $parent: &;

  @at-root {
    #{$selector} {
      &:last-child {
        #{$parent} {
          @content;
        }
      }
    }
  }
}

@mixin m-root-intersect($modifiers...) {
  $selector: get-intersectant-selector($modifiers, $current-block);
  $parent: &;

  @at-root {
    #{$selector} {
      #{$parent} {
        @content;
      }
    }
  }
}

@mixin em($element, $modifiers...) {
  @include e($element) {
    @include m($modifiers) {
      @content;
    }
  }
}

@mixin em-root($element, $modifiers...) {
  $selector: get-element-selector($element);
  $parent: &;

  @at-root {
    #{$selector} {
      @include m($modifiers) {
        #{$parent} {
          @content;
        }
      }
    }
  }
}