Update GraphQL approach for world index

Given we're still in the learning stage with the GraphQL project, we've
decided to minimise the changes needed on frontend apps by retaining the
current heavily nested data structure. This updates Collections to work
with that format (the changes to Publishing API are also in progress).
This means that the code for the world index page in collections will be
less divergent between paths for GraphQL and REST data sources. This
commit undoes some of the divergence we initially introduced

We plan to revisit simplifying the data structure later (into a less
nested form)

app/controllers/world_controller.rb

@@ -1,13 +1,14 @@
 class WorldController < ApplicationController
   def index
-    if Features.graphql_feature_enabled? || params.include?(:graphql)
-      index = WorldIndexGraphql.find!("/world")
-      @presented_index = WorldIndexGraphqlPresenter.new(index)
+    if params.include?(:graphql)
+      world_index = Graphql::WorldIndex.find!(request.path)
+      content_item_data = world_index.content_item
     else
-      index = WorldIndex.find!("/world")
-      @presented_index = WorldIndexPresenter.new(index)
+      world_index = WorldIndex.find!(request.path)
+      content_item_data = world_index.content_item.content_item_data
     end
 
-    setup_content_item_and_navigation_helpers(index)
+    @presented_index = WorldIndexPresenter.new(content_item_data)
+    setup_content_item_and_navigation_helpers(world_index)
   end
 end

app/models/graphql/world_index.rb

@@ -0,0 +1,19 @@
+class Graphql::WorldIndex
+  attr_reader :content_item
+
+  def initialize(content_item)
+    @content_item = content_item
+  end
+
+  def self.find!(base_path)
+    query = Graphql::WorldIndexQuery.new(base_path).query
+
+    # binding.pry
+
+    edition = Services.publishing_api.graphql_query(query)
+      .dig("data", "edition")
+      .deep_transform_keys(&:underscore)
+
+    new(edition)
+  end
+end

app/presenters/world_index_presenter.rb

@@ -4,22 +4,22 @@ class WorldIndexPresenter
   delegate :count, to: :world_locations, prefix: true
   delegate :count, to: :international_delegations, prefix: true
 
-  def initialize(world_index)
-    @world_index = world_index
+  def initialize(content_item_data)
+    @content_item_data = content_item_data
   end
 
   def title
-    @world_index.content_item.title
+    @content_item_data.fetch("title")
   end
 
   def grouped_world_locations
-    world_locations
+    @content_item_data.dig("details", "world_locations")
       .group_by { |location| location_group(location) }
       .sort
   end
 
   def international_delegations
-    details["international_delegations"]
+    @content_item_data.dig("details", "international_delegations")
   end
 
   def world_location_link(world_location)
@@ -45,10 +45,10 @@ def location_group(location)
   end
 
   def details
-    @world_index.content_item.details
+    @content_item_data.fetch("details")
   end
 
   def world_locations
-    details["world_locations"]
+    @content_item_data.dig("details", "world_locations")
   end
 end

app/queries/graphql/world_index_query.rb

@@ -16,12 +16,14 @@ def query
           ... on WorldIndex {
             title
 
-            worldLocations {
-              ...worldLocationInfo
-            }
+            details {
+              worldLocations {
+                ...worldLocationInfo
+              }
 
-            internationalDelegations {
-              ...worldLocationInfo
+              internationalDelegations {
+                ...worldLocationInfo
+              }
             }
           }
         }

spec/presenters/world_index_presenter_spec.rb

@@ -3,7 +3,7 @@
     fixture = GovukSchemas::Example.find("world_index", example_name: "world_index")
     content_item = ContentItem.new(fixture)
     world_index = WorldIndex.new(content_item)
-    @world_index_presenter ||= described_class.new(world_index)
+    @world_index_presenter ||= described_class.new(world_index.content_item.content_item_data)
   end
 
   describe "#title" do