module Hyrax
  module Workflow
    # Imports a single action for a workflow, including all of the adjacent states,
    # permissions and notifications
    class StateMachineGenerator
      def self.generate_from_schema(workflow:, name:, **keywords)
        new(
          workflow: workflow, action_name: name, config: keywords,
          email_generator_method_name: :schema_based_email_generator_method
        ).call
      end

      def initialize(workflow:, action_name:, config:, email_generator_method_name: :schema_based_email_generator_method)
        self.workflow = workflow
        self.action_name = action_name
        self.config = config
        self.email_generator_method_name = email_generator_method_name
      end

      private

        attr_accessor :workflow, :action_name, :config, :email_generator_method_name

        def create_workflow_action!
          @action = Sipity::WorkflowAction.find_or_create_by!(workflow: workflow, name: action_name.to_s)
        end

      public

      attr_reader :action

      def call
        create_workflow_action!
        build_workflow_attributes
        build_strategy_state_entries
        build_transition_to_state
        build_email_generator
        build_action_methods
      end

      private

        def build_workflow_attributes
          return unless config.key?(:attributes)
          action_attributes = config.fetch(:attributes).stringify_keys
          action_attributes.delete('presentation_sequence') # TODO: remove this line when we want to support presentation_sequence
          existing_action_attributes = action.attributes.slice(*action_attributes.keys)
          return if action_attributes == existing_action_attributes
          action.update_attributes!(action_attributes)
        end

        def build_transition_to_state
          return unless config.key?(:transition_to)
          name = config.fetch(:transition_to).to_s
          transition_to_state = Sipity::WorkflowState.find_or_create_by!(workflow: workflow, name: name)
          return if action.resulting_workflow_state == transition_to_state
          action.resulting_workflow_state = transition_to_state
          action.save!
        end

        def build_strategy_state_entries
          config.fetch(:from_states, []).each do |entry|
            build_from_state(entry.fetch(:names), entry.fetch(:roles))
          end
        end

        # @param [Array] state_names
        # @param [Array] state_roles
        def build_from_state(state_names, state_roles)
          Array.wrap(state_names).each do |state_name|
            workflow_state = Sipity::WorkflowState.find_or_create_by!(workflow: workflow, name: state_name.to_s)
            PermissionGenerator.call(
              actors: [],
              roles: state_roles,
              workflow_state: workflow_state,
              action_names: action_name,
              workflow: workflow
            )
          end
        end

        def build_action_methods
          return unless config.key?(:methods)
          method_list = Array.wrap(config.fetch(:methods))
          MethodGenerator.call(action: action, list: method_list)
        end

        def build_email_generator
          send(email_generator_method_name, workflow: workflow, config: config)
        end

        def schema_based_email_generator_method(workflow:, config:)
          Array.wrap(config.fetch(:notifications, [])).each do |configuration|
            notification_configuration = NotificationConfigurationParameter.build_from_workflow_action_configuration(
              workflow_action: action_name, config: configuration
            )
            NotificationGenerator.call(workflow: workflow, notification_configuration: notification_configuration)
          end
        end
    end
  end
end