// Gallery Syntax
// ==============

// Gallery
// -------
// Create an isolated gallery
// - $input       : <span>
// - [$selector]  : child | of-type
@mixin gallery(
  $layout,
  $selector: child
) {
  $layout             : parse-span($layout);
  $layout             : map-merge($layout, (location: 1));

  $span               : susy-get(span, $layout);
  $columns            : susy-get(columns, $layout);
  $context            : column-count($columns);
  $flow               : susy-get(flow, $layout);

  $box                : susy-get(box-sizing, $layout);
  $inside             : is-inside($layout);
  $from               : from($flow);
  $line               : floor($context / $span);
  $symmetrical        : is-symmetrical($columns);

  $output: (
    width             : null,
    float             : from,
    margin_before     : null,
    margin_after      : null,
    padding_before    : null,
    padding_after     : null,
    flow              : $flow,
  );

  @if $inside {
    $gutters: get-gutters($layout);
    $output: map-merge($output, (
      padding_before: map-get($gutters, before),
      padding_after: map-get($gutters, after),
    ));
  }

  @if $symmetrical {
    $output: map-merge($output, (width: get-span-width($layout)));
  }

  // Collective Output
  @if $box == border-box or $inside {
    @include susy-box-sizing(border-box);
  } @else if $box == content-box {
    @include susy-box-sizing(content-box);
  }

  @include float-span-output($output...);

  // Individual Loop
  @for $item from 1 through $line {
    $nth: '#{$line}n + #{$item}';
    &:#{format-nth($nth,$selector)} {
      // Individual Prep
      $output: (
        width             : if($symmetrical, null, get-span-width($layout)),
        float             : null,
        margin_before     : get-isolation($layout),
        margin_after      : -100%,
        padding_before    : null,
        padding_after     : null,
        flow              : $flow,
      );

      // Individual Output
      @include float-span-output($output...);

      @if is-first(susy-get(location, $layout)) {
        @include first($layout);
        clear: $from;
      } @else {
        clear: none;
      }

      // Individual Location Increment
      $location: susy-get(location, $layout) + $span;
      $location: if($location > $context, 1, $location);
      $layout: map-merge($layout, (location: $location));
    }
  }
}