Add data migration to associate modern language child subjects

app/services/publish_teacher_training/subject/import.rb

@@ -3,8 +3,9 @@ module Subject
     class Import
       include ServicePattern
 
-      PRIMARY_IDS = %w[PrimarySubject].freeze
-      SECONDARY_IDS = %w[SecondarySubject ModernLanguagesSubject].freeze
+      PRIMARY_ID = "PrimarySubject".freeze
+      SECONDARY_ID = "SecondarySubject".freeze
+      MODERN_LANGUAGES_ID = "ModernLanguagesSubject".freeze
 
       def call
         fetch_subject
@@ -15,9 +16,12 @@ def call
       def fetch_subject
         api_response = PublishTeacherTraining::Subject::Api.call
         data = api_response.fetch("data")
-        # Find Primary Subjects IDs
-        primary_subject_ids = fetch_subject_ids(subject_area_ids: PRIMARY_IDS, data:)
-        secondary_subject_ids = fetch_subject_ids(subject_area_ids: SECONDARY_IDS, data:)
+        # Find Primary Subject IDs
+        primary_subject_ids = fetch_subject_ids(subject_area_id: PRIMARY_ID, data:)
+        # Find Secondary Subject IDs
+        secondary_subject_ids = fetch_subject_ids(subject_area_id: SECONDARY_ID, data:)
+        # Find Modern Language Subject IDs
+        modern_language_subject_ids = fetch_subject_ids(subject_area_id: MODERN_LANGUAGES_ID, data:)
 
         subjects_data = api_response.fetch("included")
         # Sync Primary Subjects
@@ -33,36 +37,52 @@ def fetch_subject
           subject_ids: secondary_subject_ids,
           subjects_data:,
         )
+
+        # Sync Modern Language Subjects
+        sync_subjects(
+          subject_area: :secondary,
+          subject_ids: modern_language_subject_ids,
+          subjects_data:,
+          parent_subject: ::Subject.find_by(name: "Modern Languages"),
+        )
       end
 
-      def sync_subjects(subject_area:, subject_ids:, subjects_data:)
+      def sync_subjects(subject_area:, subject_ids:, subjects_data:, parent_subject: nil)
+        return if subject_ids.blank?
+
         subject_area_subjects_data = subjects_data.select do |subject|
           subject_ids.include?(subject["id"])
         end
         subject_area_subjects_data.each do |subject_data|
           subject_attributes = subject_data.fetch("attributes")
           begin
-            ::Subject.find_or_create_by!(
+            subject = ::Subject.find_or_create_by!(
               subject_area:,
               name: subject_attributes.fetch("name"),
               code: subject_attributes.fetch("code"),
             )
+            # Parent subject assigned separately, in case the subject already
+            # exists without the parent subject associated.
+            next if parent_subject.blank?
+
+            subject.update!(parent_subject:)
           rescue ActiveRecord::RecordInvalid => e
             Sentry.capture_exception(e)
           end
         end
       end
 
-      def fetch_subject_ids(subject_area_ids:, data:)
+      def fetch_subject_ids(subject_area_id:, data:)
         subject_ids = []
 
-        subject_areas = data.select do |subject_area_data|
-          subject_area_ids.include?(subject_area_data.fetch("id"))
+        subject_area = data.find do |subject_area_data|
+          subject_area_data["id"] == subject_area_id
         end
-        subject_areas.each do |subject_area|
-          subject_area.dig("relationships", "subjects", "data").each do |subject_data|
-            subject_ids << subject_data["id"]
-          end
+
+        return if subject_area.blank?
+
+        subject_area.dig("relationships", "subjects", "data").each do |subject_data|
+          subject_ids << subject_data["id"]
         end
 
         subject_ids

db/data/20240522123948_update_modern_language_child_subjects.rb

@@ -0,0 +1,55 @@
+class UpdateModernLanguageChildSubjects < ActiveRecord::Migration[7.1]
+  def up
+    api_response = PublishTeacherTraining::Subject::Api.call
+    child_subject_ids = modern_language_child_subject_ids(api_response.fetch("data"))
+
+    subjects_data = api_response.fetch("included")
+
+    assign_parent_subject(parent_subject: modern_languages, child_subject_ids:, subjects_data:)
+  end
+
+  def down
+    return if modern_languages.blank?
+
+    Subject.where(parent_subject: modern_languages).update_all(parent_subject_id: nil)
+  end
+
+  private
+
+  def modern_languages
+    @modern_languages ||= Subject.find_by(name: "Modern Languages")
+  end
+
+  def modern_language_child_subject_ids(data)
+    subject_ids = []
+
+    modern_language_subject_area = data.find do |subject_area|
+      subject_area["id"] == "ModernLanguagesSubject"
+    end
+
+    modern_language_subject_area.dig("relationships", "subjects", "data").each do |subject_data|
+      subject_ids << subject_data["id"]
+    end
+
+    subject_ids
+  end
+
+  def assign_parent_subject(parent_subject:, child_subject_ids:, subjects_data:)
+    return if parent_subject.blank?
+
+    child_subjects_data = subjects_data.select do |subject|
+      child_subject_ids.include?(subject["id"])
+    end
+
+    child_subjects_data.each do |child_subject_data|
+      subject_attributes = child_subject_data["attributes"]
+      child_subject = Subject.find_by(
+        name: subject_attributes["name"],
+        code: subject_attributes["code"],
+      )
+      next if child_subject.blank?
+
+      child_subject.update!(parent_subject:)
+    end
+  end
+end

db/data_schema.rb

@@ -0,0 +1 @@
+DataMigrate::Data.define(version: 20240522123948)

spec/services/publish_teacher_training/subject/import_spec.rb

@@ -16,15 +16,20 @@
           described_class.call
         }.to change(Subject.primary, :count).by(2).and change(
           Subject.secondary, :count
-        ).by(3)
+        ).by(4)
 
         expect(Subject.primary.pluck(:name)).to match_array([
           "Primary", "Primary with English"
         ])
 
         expect(Subject.secondary.pluck(:name)).to match_array([
-          "Art and design", "Science", "French"
+          "Art and design", "Science", "French", "Modern Languages"
         ])
+
+        modern_languages = Subject.find_by(name: "Modern Languages")
+        expect(modern_languages.child_subjects.pluck(:name)).to match_array(
+          %w[French],
+        )
       end
 
       context "when a subject already exists" do
@@ -33,7 +38,7 @@
 
           expect {
             described_class.call
-          }.to change(Subject, :count).by(4)
+          }.to change(Subject, :count).by(5)
         end
       end
     end
@@ -147,6 +152,10 @@ def response_body
                   "type" => "subjects",
                   "id" => "4",
                 },
+                {
+                  "type" => "subjects",
+                  "id" => "7",
+                },
               ],
             },
           },
@@ -209,6 +218,14 @@ def response_body
             "code" => "F0",
           },
         },
+        {
+          "id" => "7",
+          "type" => "subjects",
+          "attributes" => {
+            "name" => "Modern Languages",
+            "code" => nil,
+          },
+        },
         {
           "id" => "5",
           "attributes" => {