Deprecate PowerConverter-based to_sipity_action_name

Allow `WorkflowAction` to handle casting to an action name, using `.name_for(object_to_cast)`.

app/conversions/power_converters/sipity_action_name.rb

@@ -1,4 +1,5 @@
 PowerConverter.define_conversion_for(:sipity_action_name) do |input|
+    Deprecation.warn('PowerConverter is deprecated. Use `Sipity::WorkflowAction.name_for(input)` instead')
   case input
   when String, Symbol
     input.to_s.sub(/[\?\!]\Z/, '')

app/models/sipity/workflow_action.rb

@@ -23,5 +23,22 @@ class WorkflowAction < ActiveRecord::Base
              dependent: :destroy,
              as: :scope_for_notification,
              class_name: 'Sipity::NotifiableContext'
+
+    ##
+    # @param [Object] input
+    # @return [String]
+    def self.name_for(input)
+      result = case input
+               when String, Symbol
+                 input.to_s.sub(/[\?\!]\Z/, '')
+               when Sipity::WorkflowAction
+                 input.name
+               end
+      result ||= input.try(:to_sipity_action_name)
+      return result unless result.nil?
+      return yield if block_given?
+
+      raise ConversionError.new(input)
+    end
   end
 end

app/services/hyrax/workflow/permission_query.rb

@@ -147,7 +147,7 @@ def scope_roles_associated_with_the_given_entity(entity:)
       # @param action an object that can be converted into a Sipity::WorkflowAction#name
       # @return [Boolean]
       def authorized_for_processing?(user:, entity:, action:)
-        action_name = PowerConverter.convert_to_sipity_action_name(action)
+        action_name = Sipity::WorkflowAction.name_for(action)
         scope_permitted_workflow_actions_available_for_current_state(user: user, entity: entity)
           .find_by(Sipity::WorkflowAction.arel_table[:name].eq(action_name)).present?
       end

spec/models/sipity/workflow_action_spec.rb

@@ -1,3 +1,7 @@
+# frozen_string_literal: true
+
+require "spec_helper"
+
 module Sipity
   RSpec.describe WorkflowAction, type: :model do
     context 'database configuration' do
@@ -7,5 +11,34 @@ module Sipity
       its(:column_names) { is_expected.to include('resulting_workflow_state_id') }
       its(:column_names) { is_expected.to include('name') }
     end
+
+    describe '.name' do
+      [
+        [:show, 'show'],
+        [:show?, 'show'],
+        [:new?, 'new'],
+        [:new, 'new'],
+        [:edit?, 'edit'],
+        [:edit, 'edit'],
+        [:submit, 'submit'],
+        [:submit?, 'submit'],
+        [:attach, 'attach'],
+        [Sipity::WorkflowAction.new(name: 'hello'), 'hello']
+      ].each_with_index do |(original, expected), index|
+        it "will convert #{original.inspect} to #{expected.inspect} (scenario ##{index})" do
+          expect(described_class.name_for(original)).to eq(expected)
+        end
+      end
+    end
+
+    it 'will raise an exception if it is not processible' do
+      object = double('Bad Wolf')
+      expect { described_class.name_for(object) }.to raise_error(Sipity::ConversionError)
+    end
+
+    it 'will leverage a short-circuit #to_processing_action_name' do
+      object = double(to_sipity_action_name: 'bob')
+      expect(described_class.name_for(object)).to eq('bob')
+    end
   end
 end