// @category  utilities/lists

// remove an index from a list
// @function  list-remove
// @param     $list {List} the list to remove from
// @param     $idx {Number} the index to remove
// @param     $separator {String} the separator to use [auto|comma|space]
// @return    $new-list {Boolean} the list with removed index
@function list-remove($list: (), $idx: false, $separator: auto) {
  @return list-replace($list: $list, $idx: $idx, $value: nil, $separator: $separator);
}

// replace an index in a list
// @function  list-replace
// @param     $list {List} the list to replace from
// @param     $value {*} the value to replace (if nil, it's a removal)
// @param     $idx {Number} the index to replace
// @param     $separator {String} the separator to use [auto|comma|space]
// @return    $new-list {List} the list with replaced index
@function list-replace($list: (), $idx: false, $value: nil, $separator: auto) {
  $list: -compass-list($list);
  // if no index was provided, just return the original list
  @if($idx == false) {
    @return $list;
  }
  $new-list: ();
  @for $i from 1 through length($list) {
    @if $i != $idx {
      $new-list: append($new-list, nth($list, $i), $separator);
    }
    @else if($value != nil) {
      $new-list: append($new-list, $value, $separator);
    }
  }
  @return $new-list;
}

// map collection items to conform to a well defined collection
// this is primarily used to convert shorthand notations into symmetrical longhand notations
// @function  get-collection
// @private
// @param     $list {List} input list
// @param     $components {List} list of components
// @param     $min {Number} the minimum length of the collection
// @return    $list {List} formatted collection
// @usage:
// $padding: get-collection(10px, $min: 2) => 10px 10px
// $offset:  get-collection($components: (1 2), $min: 4) => 1 2 1 2
@function get-collection($list: false, $components: false, $min: 1) {
  @if($list == false) {
    $list: $components;
  }
  @while(length($list) < $min) {
    $list: $list $list;
  }
  @return $list;
}