Properly support multiple content types in details fields

According to ADR-004, it is possible to represent content in an array
format containing multiple types. This can include already parsed
govspeak in HTML format or only govspeak. In the latter case, Publishing
API parses this and converts to HTML before sending the content to
Content Store.

This replicates that behaviour for GraphQL responses, expanding this to
all fields within `details`, not just the body.

It also has the side effect of supporting embeddded content and full
change history in GraphQL responses.

app/graphql/types/edition_type.rb

@@ -153,17 +153,6 @@ class WhipOrganisation < Types::BaseObject
       field :supports_historical_accounts, Boolean
       field :whip_organisation, WhipOrganisation
       field :world_locations, [EditionType], null: false
-
-      def body
-        return object[:body] if object[:body].is_a?(String)
-
-        govspeak = object.fetch(:body, [])
-          .filter { _1[:content_type] == "text/govspeak" }
-          .map { _1[:content] }
-          .first
-
-        Govspeak::Document.new(govspeak).to_html if govspeak.present?
-      end
     end
 
     field :active, Boolean, null: false
@@ -197,6 +186,16 @@ def body
     field :web_url, String
     field :withdrawn_notice, WithdrawnNotice
 
+    def details
+      Presenters::ContentTypeResolver.new("text/html").resolve(
+        Presenters::DetailsPresenter.new(
+          object.to_h[:details],
+          Presenters::ChangeHistoryPresenter.new(object),
+          Presenters::ContentEmbedPresenter.new(object),
+        ).details,
+      )
+    end
+
     def withdrawn_notice
       return nil unless object.unpublishing&.withdrawal?
 

spec/graphql/types/edition_type_spec.rb

@@ -30,4 +30,54 @@
       end
     end
   end
+
+  context "content types in the details" do
+    context "when the body is a string" do
+      it "returns the string" do
+        edition = create(:edition, details: { body: "some text" })
+
+        expect(
+          run_graphql_field(
+            "Edition.details",
+            edition,
+          )[:body],
+        ).to eq("some text")
+      end
+    end
+
+    context "when there are multiple content types and one is html" do
+      it "returns the html" do
+        edition = create(:edition, details: {
+          body: [
+            { content_type: "text/govspeak", content: "some text" },
+            { content_type: "text/html", content: "<p>some other text</p>" },
+          ],
+        })
+
+        expect(
+          run_graphql_field(
+            "Edition.details",
+            edition,
+          )[:body],
+        ).to eq("<p>some other text</p>")
+      end
+    end
+
+    context "when there are multiple content types and none are html" do
+      it "converts the govspeak to html" do
+        edition = create(:edition, details: {
+          body: [
+            { content_type: "text/govspeak", content: "some text" },
+          ],
+        })
+
+        expect(
+          run_graphql_field(
+            "Edition.details",
+            edition,
+          )[:body],
+        ).to eq("<p>some text</p>\n")
+      end
+    end
+  end
 end