graphql: convert assignment override type to object api

Change-Id: I53c051893133485771eabb9ce7a2745940131ae7
Reviewed-on: https://gerrit.instructure.com/162263
Tested-by: Jenkins
Reviewed-by: Jonathan Featherstone <jfeatherstone@instructure.com>
Product-Review: Cameron Matheson <cameron@instructure.com>
QA-Review: Cameron Matheson <cameron@instructure.com>

app/graphql/types/assignment_override_type.rb

@@ -17,42 +17,6 @@
 #
 
 module Types
-  AssignmentOverrideType = GraphQL::ObjectType.define do
-    name "AssignmentOverride"
-
-    interfaces [Interfaces::TimestampInterface]
-
-    field :_id, !types.ID, "legacy canvas id", property: :id
-
-    field :assignment, AssignmentType, resolve: ->(override, _, _) {
-      Loaders::AssociationLoader.for(AssignmentOverride, :assignment)
-        .load(override)
-        .then { override.assignment }
-    }
-
-    field :title, types.String
-
-    field :set, AssignmentOverrideSetUnion do
-      description "This object specifies what students this override applies to"
-
-      resolve ->(override, _, _) {
-        if override.set_type == "ADHOC"
-          # AdhocStudentsType will load the actual students
-          override
-        else
-          Loaders::AssociationLoader.for(AssignmentOverride, :set)
-            .load(override)
-            .then { override.set }
-        end
-      }
-    end
-
-    field :dueAt, DateTimeType, property: :due_at
-    field :lockAt, DateTimeType, property: :lock_at
-    field :unlockAt, DateTimeType, property: :unlock_at
-    field :allDay, types.Boolean, property: :all_day
-  end
-
   AssignmentOverrideSetUnion = GraphQL::UnionType.define do
     name "AssignmentOverrideSet"
 
@@ -82,4 +46,37 @@ module Types
     }
 
   end
+  class AssignmentOverrideType < ApplicationObjectType
+    graphql_name "AssignmentOverride"
+
+    implements GraphQL::Relay::Node.interface
+    implements Interfaces::TimestampInterface
+
+    alias :override :object
+
+    field :_id, ID, "legacy canvas id", method: :id, null: false
+
+    field :assignment, AssignmentType, null: true
+    def assignment
+      load_association(:assignment)
+    end
+
+    field :title, String, null: true
+
+    field :set, AssignmentOverrideSetUnion,
+      "This object specifies what students this override applies to",
+      null: true
+    def set
+      if override.set_type == "ADHOC"
+        override
+      else
+        load_association(:set)
+      end
+    end
+
+    field :due_at, DateTimeType, null: true
+    field :lock_at, DateTimeType, null: true
+    field :unlock_at, DateTimeType, null: true
+    field :all_day, Boolean, null: true
+  end
 end

schema.graphql

@@ -165,13 +165,16 @@ input AssignmentInput {
   name: String!
 }
 
-type AssignmentOverride implements Timestamped {
+type AssignmentOverride implements Node & Timestamped {
   # legacy canvas id
   _id: ID!
   allDay: Boolean
   assignment: Assignment
   createdAt: DateTime
   dueAt: DateTime
+
+  # ID of the object.
+  id: ID!
   lockAt: DateTime
 
   # This object specifies what students this override applies to