Controls: Add Discovery Engine representation

This adds `Control#to_discovery_engine_control` (as well as
`#to_discovery_engine_control_action` for `BoostAction` and
`FilterAction`) to convert a local record into a hash for use by the
Discovery Engine API client.

See https://cloud.google.com/ruby/docs/reference/google-cloud-discovery_engine-v1/latest/Google-Cloud-DiscoveryEngine-V1-ControlService-Client

app/models/control.rb

@@ -14,4 +14,31 @@ class Control < ApplicationRecord
   accepts_nested_attributes_for :action
 
   validates :display_name, presence: true
+
+  # Returns a representation of this Control as a Discovery Engine control resource
+  def to_discovery_engine_control
+    {
+      name:,
+      display_name:,
+      **action.to_discovery_engine_control_action,
+      solution_type: Google::Cloud::DiscoveryEngine::V1::SolutionType::SOLUTION_TYPE_SEARCH,
+      # Trip hazard: despite the plural name, this expects _one_ use case in an array
+      use_cases: [Google::Cloud::DiscoveryEngine::V1::SearchUseCase::SEARCH_USE_CASE_SEARCH],
+    }
+  end
+
+  # The fully qualified name of the control on Discovery Engine (like a path)
+  def name
+    [parent, "controls", discovery_engine_id].join("/")
+  end
+
+  # The parent of the control on Discovery Engine (always the engine)
+  def parent
+    Rails.configuration.discovery_engine_engine
+  end
+
+  # The ID of the resource on Discovery Engine
+  def discovery_engine_id
+    "search-admin-#{id}"
+  end
 end

app/models/control/boost_action.rb

@@ -16,4 +16,15 @@ class Control::BoostAction < ApplicationRecord
 
   validates :filter_expression, presence: true
   validates :boost_factor, numericality: { in: BOOST_FACTOR_RANGE, other_than: 0 }
+
+  # Returns a representation of this boost as part of a Discovery Engine control resource
+  def to_discovery_engine_control_action
+    {
+      boost_action: {
+        filter: filter_expression,
+        boost: boost_factor,
+        data_store: Rails.configuration.discovery_engine_datastore,
+      },
+    }
+  end
 end

app/models/control/filter_action.rb

@@ -10,4 +10,14 @@ class Control::FilterAction < ApplicationRecord
   include Control::Actionable
 
   validates :filter_expression, presence: true
+
+  # Returns a representation of this filter as part of a Discovery Engine control resource
+  def to_discovery_engine_control_action
+    {
+      filter_action: {
+        filter: filter_expression,
+        data_store: Rails.configuration.discovery_engine_datastore,
+      },
+    }
+  end
 end

spec/models/control/boost_action_spec.rb

@@ -48,4 +48,20 @@
       end
     end
   end
+
+  describe "#to_discovery_engine_control_action" do
+    subject(:boost) do
+      build_stubbed(:control_boost_action, filter_expression: "foo = 1", boost_factor: 0.13)
+    end
+
+    it "returns a representation of the action for Discovery Engine" do
+      expect(boost.to_discovery_engine_control_action).to eq({
+        boost_action: {
+          filter: "foo = 1",
+          boost: 0.13,
+          data_store: "[datastore]",
+        },
+      })
+    end
+  end
 end

spec/models/control/filter_action_spec.rb

@@ -15,4 +15,17 @@
       end
     end
   end
+
+  describe "#to_discovery_engine_control_action" do
+    subject(:filter) { build_stubbed(:control_filter_action, filter_expression: "foo = 1") }
+
+    it "returns a representation of the action for Discovery Engine" do
+      expect(filter.to_discovery_engine_control_action).to eq({
+        filter_action: {
+          filter: "foo = 1",
+          data_store: "[datastore]",
+        },
+      })
+    end
+  end
 end

spec/models/control_spec.rb

@@ -26,4 +26,42 @@
       end
     end
   end
+
+  describe "Discovery Engine representation" do
+    subject(:control) { build_stubbed(:control, id: 42, display_name: "My boost control", action:) }
+
+    let(:action) { build(:control_boost_action) }
+
+    describe "#discovery_engine_id" do
+      it "builds an ID from the control's database ID" do
+        expect(control.discovery_engine_id).to eq("search-admin-42")
+      end
+    end
+
+    describe "#parent" do
+      it "is the configured engine" do
+        expect(control.parent).to eq("[engine]")
+      end
+    end
+
+    describe "#name" do
+      it "returns the fully qualified name of the control" do
+        expect(control.name).to eq("[engine]/controls/search-admin-42")
+      end
+    end
+
+    describe "#to_discovery_engine_control" do
+      it "returns a representation of the control for Discovery Engine" do
+        expect(control.to_discovery_engine_control).to include(
+          name: "[engine]/controls/search-admin-42",
+          display_name: "My boost control",
+          # We don't care what's in the action (that's tested elsewhere), but we do care that the
+          # key is present
+          boost_action: hash_including,
+          solution_type: Google::Cloud::DiscoveryEngine::V1::SolutionType::SOLUTION_TYPE_SEARCH,
+          use_cases: [Google::Cloud::DiscoveryEngine::V1::SearchUseCase::SEARCH_USE_CASE_SEARCH],
+        )
+      end
+    end
+  end
 end