Refactor more of item outfit preview into the Outfit class

This is a cute thing that I think sets us up for other stuff down the
line: move more of the outfit appearance logic into the `Outfit` class!
Now, we set up the item page with a temporary instance of `Outfit`,
then ask for its `visible_layers`.

Still missing restricted-zones logic and such, that's next!

app/assets/stylesheets/items/_show.sass

@@ -38,7 +38,7 @@ body.items-show
     height: 16px
     width: 16px
 
-  outfit-viewer
+  .outfit-viewer
     position: relative
     display: block
     width: 300px
@@ -49,7 +49,7 @@ body.items-show
 
     margin: 0 auto .75em
 
-    outfit-layer
+    .outfit-layer
       display: block
       position: absolute
       inset: 0

app/controllers/items_controller.rb

@@ -84,14 +84,10 @@ class ItemsController < ApplicationController
         end
 
         @selected_preview_pet_type = load_selected_preview_pet_type
-        @preview_pet_type = load_preview_pet_type
-
-        @item_layers = @item.appearance_for(
-          @preview_pet_type, swf_asset_includes: [:zone]
-        ).swf_assets
-        @pet_layers = @preview_pet_type.canonical_pet_state.swf_assets.
-          includes(:zone)
-
+        @preview_outfit = Outfit.new(
+          pet_state: load_preview_pet_type.canonical_pet_state,
+          worn_items: [@item],
+        )
         @preview_error = validate_preview
       end
 
@@ -227,7 +223,7 @@ class ItemsController < ApplicationController
   def validate_preview
     if @selected_preview_pet_type.new_record?
       :pet_type_does_not_exist
-    elsif @item_layers.empty?
+    elsif @preview_outfit.item_appearances.values.any?(&:empty?)
       :no_item_data
     end
   end

app/helpers/items_helper.rb

@@ -250,7 +250,7 @@ module ItemsHelper
   end
 
   def outfit_viewer_layer(swf_asset)
-    content_tag "outfit-layer", style: "z-index: #{swf_asset.zone.depth}" do
+    content_tag :div, class: "outfit-layer" do
       image_tag swf_asset.image_url, alt: ""
     end
   end

app/models/item.rb

@@ -557,6 +557,7 @@ class Item < ApplicationRecord
   # bit more suited to it!
   Appearance = Struct.new(:body, :swf_assets) do
     include ActiveModel::Serializers::JSON
+    delegate :present?, :empty?, to: :swf_assets
     def attributes
       {body: body, swf_assets: swf_assets}
     end

app/models/outfit.rb

@@ -25,7 +25,12 @@ class Outfit < ApplicationRecord
   before_validation :ensure_unique_name, if: :user_id?
 
   attr_reader :biology
-  delegate :color, to: :pet_state
+  delegate :pose, to: :pet_state
+  delegate :pet_type, to: :pet_state
+  delegate :color, to: :pet_type
+  delegate :color_id, to: :pet_type
+  delegate :species, to: :pet_type
+  delegate :species_id, to: :pet_type
 
   scope :wardrobe_order, -> { order('starred DESC', :name) }
   
@@ -107,18 +112,6 @@ class Outfit < ApplicationRecord
     )
   end
 
-  def color_id
-    pet_state.pet_type.color_id
-  end
-
-  def species_id
-    pet_state.pet_type.species_id
-  end
-
-  def pose
-    pet_state.pose
-  end
-
   def biology=(biology)
     @biology = biology.slice(:species_id, :color_id, :pose, :pet_state_id)
 
@@ -166,6 +159,18 @@ class Outfit < ApplicationRecord
     self.item_outfit_relationships = new_relationships
   end
 
+  def item_appearances(...)
+    Item.appearances_for(worn_item_ids, pet_type, ...)
+  end
+
+  def visible_layers
+    pet_layers = pet_state.swf_assets.includes(:zone)
+    item_layers = item_appearances(swf_asset_includes: [:zone]).values.
+      map(&:swf_assets).flatten
+
+    (pet_layers + item_layers).sort_by(&:depth)
+  end
+
   def ensure_unique_name
     # If no name was provided, start with "Untitled outfit".
     self.name = "Untitled outfit" if name.blank?

app/views/items/show.html.haml

@@ -14,11 +14,8 @@
     sorry!
 
 = turbo_frame_tag "item-preview" do
-  %outfit-viewer
-    %outfit-pet-appearance
-      = outfit_viewer_layers @pet_layers
-    %outfit-item-appearance
-      = outfit_viewer_layers @item_layers
+  .outfit-viewer
+    = outfit_viewer_layers @preview_outfit.visible_layers
 
   = form_for item_path(@item), method: :get, class: "species-color-picker",
     data: {"is-valid": @preview_error.nil?} do |f|