module Hyrax
  module Workflow
    # Finds a list of works that we can perform a workflow action on
    class StatusListService
      # @param context [#current_user, #logger]
      # @param filter_condition [String] a solr filter
      def initialize(context, filter_condition)
        @context = context
        @filter_condition = filter_condition
      end

      attr_reader :context

      # TODO: We will want to paginate this
      # @return [Array<StatusRow>] a list of results that the given user can take action on.
      def each
        return enum_for(:each) unless block_given?
        solr_documents.each do |doc|
          yield doc
        end
      end

      # TODO: Make this private for version 1.0
      def user
        context.current_user
      end

      private

        delegate :logger, to: :context

        # @return [Hash<String,SolrDocument>] a hash of id to solr document
        def solr_documents
          search_solr.map { |result| ::SolrDocument.new(result) }
        end

        def search_solr
          actionable_roles = roles_for_user
          logger.debug("Actionable roles for #{user.user_key} are #{actionable_roles}")
          return [] if actionable_roles.empty?
          WorkRelation.new.search_with_conditions(query(actionable_roles), rows: 1000, method: :post)
        end

        def query(actionable_roles)
          ["{!terms f=actionable_workflow_roles_ssim}#{actionable_roles.join(',')}",
           @filter_condition]
        end

        # @return [Array<String>] the list of workflow-role combinations this user has
        def roles_for_user
          Sipity::Workflow.all.flat_map do |wf|
            workflow_roles_for_user_and_workflow(wf).map do |wf_role|
              "#{wf.permission_template.admin_set_id}-#{wf.name}-#{wf_role.role.name}"
            end
          end
        end

        # @param workflow [Sipity::Workflow]
        # @return [ActiveRecord::Relation<Sipity::WorkflowRole>]
        def workflow_roles_for_user_and_workflow(workflow)
          Hyrax::Workflow::PermissionQuery.scope_processing_workflow_roles_for_user_and_workflow(user: user, workflow: workflow)
        end
    end
  end
end