Refactor modeling viewer data handling into a new ViewerData class

app/models/pet.rb

@@ -4,41 +4,15 @@ class Pet < ApplicationRecord
   attr_reader :items, :pet_state, :alt_style
 
   def load!(timeout: nil)
-    viewer_data = Neopets::CustomPets.fetch_viewer_data(name, timeout:)
-    use_viewer_data(viewer_data)
+    viewer_data_hash = Neopets::CustomPets.fetch_viewer_data(name, timeout:)
+    use_viewer_data(ViewerData.new(viewer_data_hash))
   end
 
   def use_viewer_data(viewer_data)
-    pet_data = viewer_data[:custom_pet]
-
-    raise UnexpectedDataFormat unless pet_data[:species_id]
-    raise UnexpectedDataFormat unless pet_data[:color_id]
-    raise UnexpectedDataFormat unless pet_data[:body_id]
-
-    @pet_state = Pet.pet_state_from_pet_data(pet_data)
-    self.pet_type = @pet_state.pet_type
-
-    begin
-      pet_type.consider_pet_image(name)
-    rescue => error
-      Rails.logger.warn "Failed to load pet image: #{error.full_message}"
-    end
-
-    if pet_data[:alt_style]
-      raise UnexpectedDataFormat unless pet_data[:alt_color]
-      raise UnexpectedDataFormat if pet_data[:biology_by_zone].empty?
-
-      @alt_style = AltStyle.find_or_initialize_by(id: pet_data[:alt_style].to_i)
-      @alt_style.assign_attributes(
-        color_id: pet_data[:alt_color].to_i,
-        species_id: pet_data[:species_id].to_i,
-        body_id: pet_data[:body_id].to_i,
-        biology: pet_data[:biology_by_zone],
-      )
-    end
-
-    @items = Item.collection_from_pet_type_and_registries(self.pet_type,
-      viewer_data[:object_info_registry], viewer_data[:object_asset_registry])
+    self.pet_type = viewer_data.pet_type
+    @pet_state = viewer_data.pet_state
+    @alt_style = viewer_data.alt_style
+    @items = viewer_data.items
   end
 
   def wardrobe_query
@@ -84,39 +58,92 @@ class Pet < ApplicationRecord
     pet
   end
 
-  def self.pet_state_from_pet_data(pet_data)
-    # First, set up the pet type.
-    pet_type = PetType.find_or_initialize_by(
-      species_id: pet_data[:species_id],
-      color_id: pet_data[:color_id],
-    )
+  class UnexpectedDataFormat < RuntimeError;end
 
-    # Apply the pet's body ID to the pet type, unless it's wearing an alt
-    # style, in which case ignore it, because it's the *alt style*'s body ID.
-    # (This can theoretically cause a problem saving a new pet type when
-    # there's an alt style too!)
-    pet_type.body_id = pet_data[:body_id] unless pet_data[:alt_style]
-    if pet_type.body_id.nil?
-      raise UnexpectedDataFormat,
-        "can't process alt style on first occurrence of pet type"
+  # A representation of a Neopets::CustomPets viewer data response, translated
+  # to DTI's database models!
+  class ViewerData
+    def initialize(viewer_data_hash)
+      @custom_pet = viewer_data_hash[:custom_pet]
+      @object_info_registry = viewer_data_hash[:object_info_registry]
+      @object_asset_registry = viewer_data_hash[:object_asset_registry]
     end
 
-    # Then, set up the biology assets.
-    pet_state_biology = pet_data[:alt_style].present? ?
-      pet_data[:original_biology] :
-      pet_data[:biology_by_zone]
-    body_id = pet_data[:body_id].to_i
-    swf_assets = pet_state_biology.values.map do |biology_data|
-      SwfAsset.from_biology_data(body_id, biology_data)
-    end
-    swf_asset_ids = swf_assets.map(&:remote_id).sort.join(",")
+    def pet_type
+      @pet_type ||= begin
+        raise UnexpectedDataFormat unless @custom_pet[:species_id]
+        raise UnexpectedDataFormat unless @custom_pet[:color_id]
+        raise UnexpectedDataFormat unless @custom_pet[:body_id]
 
-    # Finally, set up the pet state, and use these biology assets.
-    pet_type.pet_states.find_or_initialize_by(swf_asset_ids:).tap do |pet_state|
-      pet_state.swf_assets = swf_assets
+        @custom_pet => {species_id:, color_id:}
+        PetType.find_or_initialize_by(species_id:, color_id:).tap do |pet_type|
+          # Apply the pet's body ID to the pet type, unless it's wearing an alt
+          # style, in which case ignore it, because it's the *alt style*'s body ID.
+          # (This can theoretically cause a problem saving a new pet type when
+          # there's an alt style too!)
+          pet_type.body_id = @custom_pet[:body_id] unless @custom_pet[:alt_style]
+          if pet_type.body_id.nil?
+            raise UnexpectedDataFormat,
+              "can't process alt style on first occurrence of pet type"
+          end
+
+          # Try using this pet for the pet type's thumbnail, but don't worry
+          # if it fails.
+          begin
+            pet_type.consider_pet_image(@custom_pet[:name])
+          rescue => error
+            Rails.logger.warn "Failed to load pet image: #{error.full_message}"
+          end
+        end
+      end
+    end
+
+    def pet_state
+      @pet_state ||= begin
+        # Choose the right biology, depending on if there's an alt style.
+        pet_state_biology = @custom_pet[:alt_style].present? ?
+          @custom_pet[:original_biology] :
+          @custom_pet[:biology_by_zone]
+        raise UnexpectedDataFormat if pet_state_biology.empty?
+
+        # Then, set up the biology assets.
+        body_id = @custom_pet[:body_id].to_i
+        swf_assets = pet_state_biology.values.map do |biology_data|
+          SwfAsset.from_biology_data(body_id, biology_data)
+        end
+        swf_asset_ids = swf_assets.map(&:remote_id).sort.join(",")
+
+        # Then, set up the pet state, using these biology assets.
+        pet_type.pet_states.find_or_initialize_by(swf_asset_ids:).tap do |pet_state|
+          pet_state.swf_assets = swf_assets
+        end
+      end
+    end
+
+    def alt_style
+      @alt_style ||= begin
+        return nil unless @custom_pet[:alt_style]
+
+        raise UnexpectedDataFormat unless @custom_pet[:alt_color]
+        raise UnexpectedDataFormat if @custom_pet[:biology_by_zone].empty?
+
+        id = @custom_pet[:alt_style].to_i
+        AltStyle.find_or_initialize_by(id:).tap do |alt_style|
+          alt_style.assign_attributes(
+            color_id: @custom_pet[:alt_color].to_i,
+            species_id: @custom_pet[:species_id].to_i,
+            body_id: @custom_pet[:body_id].to_i,
+            biology: @custom_pet[:biology_by_zone],
+          )
+        end
+      end
+    end
+
+    def items
+      @items ||= Item.collection_from_pet_type_and_registries(
+        pet_type, @object_info_registry, @object_asset_registry
+      )
     end
   end
-
-  class UnexpectedDataFormat < RuntimeError;end
 end