// String Util Functions
// --------------------------------------------------

// String Replace Function
// --------------------------------------------------

@function str-replace($string, $search, $replace: "") {
  $index: str-index($string, $search);

  @if $index {
    @return str-slice($string, 1, $index - 1) + $replace + str-replace(str-slice($string, $index + str-length($search)), $search, $replace);
  }

  @return $string;
}

// String Split Function
// --------------------------------------------------

@function str-split($string, $separator) {
  // empty array/list
  $split-arr: ();
  // first index of separator in string
  $index: str-index($string, $separator);
  // loop through string
  @while $index != null {
    // get the substring from the first character to the separator
    $item: str-slice($string, 1, $index - 1);
    // push item to array
    $split-arr: append($split-arr, $item);
    // remove item and separator from string
    $string: str-slice($string, $index + 1);
    // find new index of separator
    $index: str-index($string, $separator);
  }
  // add the remaining string to list (the last item)
  $split-arr: append($split-arr, $string);

  @return $split-arr;
}


// Str Extract Function
// --------------------------------------------------

@function str-extract($string, $start, $end) {
  $start-index: str-index($string, $start);

  @if $start-index {
    $post: str-slice($string, $start-index + str-length($start));
    $end-index: str-index($post, $end);

    @if $end-index {
      @return str-slice($post, 1, $end-index - 1);
    }
  }

  @return null;
}


// Str Contains Function
// --------------------------------------------------

@function str-contains($string, $needle) {
  @if (type-of($string) == string) {
    @return str-index($string, $needle) != null;
  }

  @return false;
}


// URL Encode Function
// --------------------------------------------------

@function url-encode($val) {
  $spaces: str-replace($val, " ", "%20");
  $encoded: str-replace($spaces, "#", "%23");
  @return $encoded;
}


// Add Selector
// --------------------------------------------------
// Used to cleanly add selectors to :host and :host()

@function add-root-selector($root, $addHostSelector, $shadowDom: false) {
  $selectors: str-split($root, ",");

  $list: ();

  @each $selector in $selectors {
    @if str-contains($selector, ":host(") {
      $updated-host: str-replace($selector, ":host(", ":host(#{$addHostSelector}");
      $list: append($list, $updated-host, comma);

    } @else if str-contains($selector, ":host") {
      $list: append($list, ":host(#{$addHostSelector}) + b", comma);

    } @else if $shadowDom == true {
      $list: append($list, ":host(#{$addHostSelector}) #{$selector}", comma);

    } @else {
      // TODO host-context should be for scoped only
      $list: append($list, ":host-context(#{$addHostSelector}) #{$selector}", comma);
    }
  }

  @return $list;
}