module RailsWorkflow
  module Processes
    #= DefaultRunner
    #
    # This module contains logic of process start, stop, cancel etc.
    #
    module DefaultRunner
      def can_start?
        !operations.empty?
      end

      def start
        if can_start?
          update_attribute(:status, self.class::IN_PROGRESS)
          operations.where(status: RailsWorkflow::Operation::NOT_STARTED).map(&:start)
        end
      end

      def operation_exception
        self.status = self.class::ERROR
      end

      # Process can be completed if all sync operations is complete.

      def can_complete?
        if incomplete_statuses.include? status
          incompleted_operations.size.zero? &&
            workflow_errors.unresolved.size.zero?
        else
          false
        end
      end

      # Returns set or operation that not yet completed.
      # Operation complete in DONE, SKIPPED, CANCELED, etc many other statuses
      def incompleted_operations
        operations.reject(&:completed?)
      end

      # If operation is completed process is responsible for building new operations.
      # We need to calculate operations, depends on completed one and detect ones we
      # can build.
      def operation_complete(operation)
        build_dependencies operation
      end

      def set_done_status
        self.status = self.class::DONE
        save
      end

      def complete_parent_operation
        parent_operation.complete if parent_operation.present?
      end

      def complete
        if can_complete?
          set_done_status
          complete_parent_operation
        end
     end
    end
  end
end