Add ability to render sub facets as metadata

Sub-facets are introduced as part of Nested Facet work on Specialist Publisher. The new structure introduced allows users to define one level of nesting for facet values. These also need to be surfaced as part of metadata.

app/presenters/specialist_document_presenter.rb

@@ -28,6 +28,7 @@ def important_metadata
     super.tap do |m|
       facets_with_friendly_values.each do |facet|
         m.merge!(facet["name"] => value_or_array_of_values(facet["values"]))
+        m.merge!(facet["sub_facet_name"] => value_or_array_of_values(facet["sub_facet_values"])) if facet["sub_facet_values"].present?
       end
     end
   end
@@ -120,18 +121,13 @@ def facet_values
 
   def facets_with_friendly_values
     facets_with_values.map do |facet|
-      facet_key = facet["key"]
-      # Cast all values into an array
-      values = [facet_values[facet_key]].flatten
-
-      facet["values"] = case facet["type"]
-                        when "date"
-                          friendly_facet_date(values)
-                        when "text"
-                          friendly_facet_text(facet, values)
-                        else
-                          values
-                        end
+      values = [facet_values[facet["key"]]].compact.flatten
+      facet["values"] = friendly_facet_values(facet, values)
+
+      if facet["nested_facet"]
+        sub_facet_values = [facet_values[facet["sub_facet_key"]]].compact.flatten
+        facet["sub_facet_values"] = friendly_sub_facet_text(facet, sub_facet_values)
+      end
 
       facet
     end
@@ -146,42 +142,63 @@ def facets_with_values
       .reject { |f| f["key"] == internal_notes_facet_key }
   end
 
+  def friendly_facet_values(facet, values)
+    return friendly_facet_date(values) if facet["type"] == "date"
+    return friendly_facet_text(facet, values) if facet["type"] == "text"
+
+    values
+  end
+
   def friendly_facet_date(dates)
     dates.map { |date| display_date(date) }
   end
 
   def friendly_facet_text(facet, values)
-    if facet["allowed_values"] && facet["allowed_values"].any?
-      facet_blocks(facet, values)
-    else
-      values
-    end
+    return values unless facet["allowed_values"].present?
+
+    facet_blocks(facet["name"],
+                 facet["key"],
+                 facet["allowed_values"],
+                 values,
+                 facet["filterable"])
+  end
+
+  def friendly_sub_facet_text(facet, sub_facet_values)
+    return sub_facet_values unless facet["allowed_values"].present?
+
+    sub_facet_allowed_values = facet["allowed_values"].pluck("sub_facets").compact.flatten
+
+    facet_blocks(facet["sub_facet_name"],
+                 facet["sub_facet_key"],
+                 sub_facet_allowed_values,
+                 sub_facet_values,
+                 facet["filterable"])
   end
 
   # The facet value is hyphenated, map this to the
   # friendly readable version provided in `allowed_values`
-  def facet_blocks(facet, values)
+  def facet_blocks(facet_name, facet_key, allowed_values, values, filterable)
     values.map do |value|
-      allowed_value = facet["allowed_values"].detect { |av| av["value"] == value }
+      allowed_value = allowed_values.detect { |av| av["value"] == value }
 
       if allowed_value
-        facet_block(facet, allowed_value)
+        facet_block(allowed_value, facet_key, filterable)
       else
         GovukError.notify(
           "Facet value not in list of allowed values",
-          extra: { error_message: "Facet value '#{value}' not an allowed value for facet '#{facet['name']}' on #{base_path} content item" },
+          extra: { error_message: "Facet value '#{value}' not an allowed value for facet '#{facet_name}' on #{base_path} content item" },
         )
         value
       end
     end
   end
 
-  def facet_block(facet, allowed_value)
+  def facet_block(allowed_value, facet_key, filterable)
     friendly_value = allowed_value["label"]
 
-    return friendly_value unless facet["filterable"]
+    return friendly_value unless filterable
 
-    facet_link(friendly_value, allowed_value["value"], facet["key"])
+    facet_link(friendly_value, allowed_value["value"], facet_key)
   end
 
   def facet_link(label, value, key)

test/presenters/specialist_document_presenter_test.rb

@@ -329,5 +329,32 @@ def example_facet(overrides = {})
       presented = present_example(example)
       assert Time.zone.parse(presented.published) == Time.zone.parse("2010-01-01")
     end
+
+    test "includes nested facets as text in metadata" do
+      values = { "facet-key" => "main-facet-1-value", "sub-facet-key" => "sub-facet-1-value" }
+      facet = example_facet({
+                              "sub_facet_name" => "Sub Facet name",
+                              "sub_facet_key" => "sub-facet-key",
+                              "nested_facet" => true,
+                              "allowed_values" => [
+                                {
+                                  "label" => "Main Facet Value",
+                                  "value" => "main-facet-1-value",
+                                  "sub_facets" => [
+                                    {
+                                      "label" => "Sub Facet Value",
+                                      "value" => "sub-facet-1-value"
+                                    }
+                                  ]
+                                },
+                              ],
+                            })
+      example = example_with_finder_facets([facet], values)
+
+      presented = present_example(example)
+
+      assert_equal "Main Facet Value", presented.important_metadata["Facet name"]
+      assert_equal "Sub Facet Value", presented.important_metadata["Sub Facet name"]
+    end
   end
 end