Refactor of auth_resolver

Author: Matt Muller

gems/smithy/lib/smithy/views/client/auth_resolver.rb

@@ -18,39 +18,45 @@ def module_name
           @plan.module_name
         end
 
-        # rubocop:disable Metrics/AbcSize
-        # rubocop:disable Metrics/MethodLength
         def auth_rules_code
           lines = []
           lines << 'options = []'
           auth_operations = operations_with_auth_traits
           if auth_operations.empty?
-            service_auth_schemes.each do |auth_scheme|
-              lines << "options << '#{auth_scheme}'"
-            end
+            add_service_auth_schemes_to_code(lines)
           else
-            lines << 'case parameters.operation_name'
-            auth_operations.each do |id, operation|
-              operation_name = Model::Shape.name(id).underscore
-              lines << "when :#{operation_name}"
-              operation_auth_schemes(operation).each do |auth_scheme|
-                lines << "  options << '#{auth_scheme}'"
-              end
-            end
-            lines << 'else'
-            service_auth_schemes.each do |auth_scheme|
-              lines << "  options << '#{auth_scheme}'"
-            end
-            lines << 'end'
+            add_operation_case_to_code(lines, auth_operations)
           end
           lines << 'options'
           lines
         end
-        # rubocop:enable Metrics/MethodLength
-        # rubocop:enable Metrics/AbcSize
 
         private
 
+        def add_service_auth_schemes_to_code(lines)
+          service_auth_schemes.each do |auth_scheme|
+            lines << "options << '#{auth_scheme}'"
+          end
+        end
+
+        def add_operation_case_to_code(lines, auth_operations)
+          lines << 'case parameters.operation_name'
+          auth_operations.each do |id, operation|
+            operation_name = Model::Shape.name(id).underscore
+            lines << "when :#{operation_name}"
+            add_operation_auth_options_to_code(lines, operation)
+          end
+          lines << 'else'
+          add_service_auth_schemes_to_code(lines)
+          lines << 'end'
+        end
+
+        def add_operation_auth_options_to_code(lines, operation)
+          operation_auth_schemes(operation).each do |auth_scheme|
+            lines << "  options << '#{auth_scheme}'"
+          end
+        end
+
         def auth_schemes(welds)
           weld_auth_schemes = welds.map(&:add_auth_schemes).reduce([], :+)
           weld_auth_schemes -= welds.map(&:remove_auth_schemes).reduce([], :+)
@@ -89,20 +95,34 @@ def optional_operation_auth?(operation)
 
         def operation_auth_schemes(operation)
           operation_traits = operation.fetch('traits', {})
+          auth_schemes = build_operation_auth_schemes(operation, operation_traits)
+          auth_schemes << 'smithy.api#noAuth' if auth_schemes.empty? || optional_operation_auth?(operation)
+          auth_schemes
+        end
+
+        def build_operation_auth_schemes(operation, operation_traits)
           auth_schemes = []
           if operation_auth?(operation)
-            operation_auth = operation_traits.fetch('smithy.api#auth', [])
-            add_auth_schemes_from_auth_trait(auth_schemes, operation_auth)
-          elsif optional_operation_auth?(operation)
-            auth_schemes = service_auth_schemes << 'smithy.api#noAuth'
-            auth_schemes.uniq!
-          else
+            add_explicit_operation_auth_schemes(auth_schemes, operation_traits)
+          elsif !service_has_auth_trait? && !optional_operation_auth?(operation)
             add_registered_auth_schemes(auth_schemes, operation_traits)
+          else
+            add_service_auth_schemes_for_operation(auth_schemes)
           end
-          auth_schemes << 'smithy.api#noAuth' if auth_schemes.empty?
           auth_schemes
         end
 
+        def add_explicit_operation_auth_schemes(auth_schemes, operation_traits)
+          operation_auth = operation_traits.fetch('smithy.api#auth', [])
+          add_auth_schemes_from_auth_trait(auth_schemes, operation_auth)
+        end
+
+        def add_service_auth_schemes_for_operation(auth_schemes)
+          service_auth_schemes.each do |auth_scheme|
+            auth_schemes << auth_scheme unless auth_scheme == 'smithy.api#noAuth'
+          end
+        end
+
         def add_auth_schemes_from_auth_trait(auth_schemes, auth_trait)
           auth_trait.each do |auth_scheme|
             auth_schemes << auth_scheme if @auth_schemes.include?(auth_scheme)