Use a pet face when there's no paint brush, in Item Getting Guide

Now, for colors like Mutant or Magma where there's no paint brush
image to show, we use a sample pet image instead, to help it have equal
visual weight and clarity as the cases with the paint brushes.

We do some cleverness in here to make sure to always show the relevant
species, if possible!

app/controllers/items_controller.rb

@@ -122,13 +122,28 @@ class ItemsController < ApplicationController
       return
     end
 
+    # Group the items by category!
     @nc_mall_items = @items.select(&:currently_in_mall?)
     @other_nc_items = @items.select(&:nc?).reject(&:currently_in_mall?)
     @np_items = @items.select(&:np?)
     @pb_items = @items.select(&:pb?)
+
+    # Also, PB items have some special handling: we group them by color, then
+    # load example pet types for the colors that don't have paint brushes.
     @pb_items_by_color = @pb_items.group_by(&:pb_color).
       sort_by { |color, items| color.name }.to_h
 
+    colors_without_thumbnails =
+      @pb_items_by_color.keys.reject(&:pb_item_thumbnail_url?)
+
+    @pb_color_pet_types = colors_without_thumbnails.map do |color|
+      # Infer the ideal species from the first item we can, then try to find a
+      # matching pet type to use as the thumbnail, if needed.
+      species = @pb_items_by_color[color].map(&:pb_species).select(&:present?)
+        .first
+      [color, color.example_pet_type(preferred_species: species)]
+    end.to_h
+
     render layout: "application"
   end
 

app/helpers/items_helper.rb

@@ -2,23 +2,34 @@ require "addressable/template"
 
 module ItemsHelper
   module PetTypeImage
-    Format = 'https://pets.neopets.com/cp/%s/%i/%i.png'
+    Template = Addressable::Template.new(
+      "https://pets.neopets.com/cp/{hash}/{emotion}/{size}.png"
+    )
 
     Emotions = {
-      :happy => 1,
-      :sad => 2,
-      :angry => 3,
-      :ill => 4
+      happy: 1,
+      sad: 2,
+      angry: 3,
+      ill: 4,
     }
 
     Sizes = {
-      :face => 1,
-      :thumb => 2,
-      :zoom => 3,
-      :full => 4
+      face: 1,
+      thumb: 2,
+      zoom: 3,
+      full: 4,
+      face_2x: 6,
     }
   end
 
+  def pet_type_image_url(pet_type, emotion: :happy, size: :face)
+    PetTypeImage::Template.expand(
+      hash: pet_type.basic_image_hash || pet_type.image_hash,
+      emotion: PetTypeImage::Emotions[emotion],
+      size: PetTypeImage::Sizes[size],
+    ).to_s
+  end
+
   def standard_species_search_links
     build_on_pet_types(Species.alphabetical) do |pet_type|
       image = pet_type_image(pet_type, :happy, :zoom)
@@ -157,9 +168,7 @@ module ItemsHelper
   end
 
   def pet_type_image(pet_type, emotion, size)
-    emotion_id = PetTypeImage::Emotions[emotion]
-    size_id = PetTypeImage::Sizes[size]
-    src = sprintf(PetTypeImage::Format, pet_type.basic_image_hash, emotion_id, size_id)
+    src = pet_type_image_url(pet_type, emotion:, size:)
     human_name = pet_type.species.name.humanize
     image_tag(src, :alt => human_name, :title => human_name)
   end

app/models/color.rb

@@ -21,6 +21,11 @@ class Color < ApplicationRecord
     end
   end
 
+  def example_pet_type(preferred_species: Species.first)
+    pet_types.order([Arel.sql("species_id = ? DESC"), preferred_species.id],
+      "species_id ASC").first
+  end
+
   def unfunny_human_name
     if name
       name.split(' ').map { |word| word.capitalize }.join(' ')

app/models/item.rb

@@ -197,6 +197,14 @@ class Item < ApplicationRecord
       find { |c| normalized_name.include?(c.name.downcase.gsub(/\s/, "")) }
   end
 
+  # If this is a PB item, return the corresponding Species, inferred from the
+  # item name. If it's not a PB item, or we fail to infer, return nil.
+  def pb_species
+    return nil unless pb?
+    normalized_name = name.downcase
+    Species.order(:name).find { |s| normalized_name.include?(s.name.downcase) }
+  end
+
   def pb_item_name
     pb_color&.pb_item_name
   end

app/views/items/sources.html.haml

@@ -67,6 +67,10 @@
 					- if color.pb_item_thumbnail_url?
 						= image_tag color.pb_item_thumbnail_url,
 							alt: "Item thumbnail for #{color.pb_item_name}"
+					- else
+						= image_tag pet_type_image_url(@pb_color_pet_types[color], size: :face),
+							srcset: ["#{pet_type_image_url(@pb_color_pet_types[color], size: :face_2x)} 2x"],
+							alt: @pb_color_pet_types[color].human_name
 				%th
 					#{color.pb_item_name || color.name.humanize}
 					(#{pluralize items.size, "item"})