// Mixin :: __tree
// type: private
// description: Used to create the selector structure for family mixins

@mixin __tree($class: false, $offset: 0) {
  // Parent requires class to be passed in.
  // Use default Sass & if $class is not defined
  @if not $class or type-of($class) != "string" {
    & {
      @content;
    }
  }

  // Looping through all the selectors in the & list
  @each $selector in & {
    $len: length($selector);
    // Start the tree with 1st level selector
    $tree: nth($selector, 1);
    // Current selector
    $current: nth($selector, $len);
    // Adjust the offset
    $offset: $len - $offset;

    // Top level selector
    @if ($offset <= 1) {
      // Rebuild tree, starting with the custom class
      $tree: append((), $class);
      $tree: append($tree, $current);
    }
    @else {
      // Iterate through selectors until the parent
      @for $i from 2 to $offset {
        $tree: append($tree, nth($selector, $i));
      }
      // Add the new parent class
      $tree: append($tree, unquote($class));
      // Add the current class
      $tree: append($tree, nth($selector, $len));
    }

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