/***
 * Mod Query
 *
 * A damn clever way to select elements when the number of children is divisible
 * by a given integer. As opposed to the absolute [Quantity Query](#/utilities/mixins/quantity-query),
 * this selects when `children % n = 0`, or if a remainder is also passed, when
 * `children % n = remainder`.
 *
 * Gleefully stolen from Patrick Clancey's article: http://alistapart.com/article/using-css-mod-queries-with-range-selectors
 *
 * @param $divisibleBy
 * @param $remainder
 * @param $selector - string passed that represents selector for siblings
 *
 * scss:
 *   @include selectRange(5,9) {
 *     // things you want only items 5 - 9 to do
 *   }
 *   @include modQuery(3, 0, '.custom-selector') {
 *     // things you want all .custom-selectors in a given parent to do
 *     // when their total number is divisible by 3
 *   }
 *   @include modFirst(3, 1) {
 *     // things you want the first element to do when the total number of
 *     // children matches n % 3 == 1
 *   }
 */

// range selector mixin
@mixin selectRange($start, $end){
  &:nth-child(n+#{$start}):nth-child(-n+#{$end}){
    @content;
  }
}
// mod query mixin
@mixin modQuery($mod, $remainder: 0, $selector: li){
  &:nth-last-child(#{$mod}n+#{$remainder}):first-child,
  &:nth-last-child(#{$mod}n+#{$remainder}):first-child ~ #{$selector} {
    @content;
  }
}

@mixin modFirst($mod, $remainder: 0) {
  &:nth-last-child(#{$mod}n+#{$remainder}):first-child {
    @content;
  }
}