module NewspaperWorks
  module Ingest
    module NDNP
      # Ingester for reel/container, given reel source data
      #   and required publication (NewspaperTitle) asset.
      #   Responsibile for creating/finding container, linking
      #   to (parent) publication and (child) pages.
      class ContainerIngester
        include NewspaperWorks::Ingest::NDNP::NDNPAssetHelper

        attr_accessor :source, :target, :publication, :opts

        # Create ingester in context of source reel data, NewspaperTitle
        # @param source [NewspaperWorks::Ingest::NDNP::ContainerIngest]
        # @param publication [NewspaperTitle] Required publication to link to
        # @param opts [Hash]
        #   ingest options, e.g. administrative metadata
        def initialize(source, publication, opts = {})
          @source = source
          @publication = publication
          @opts = opts
          # initially nil, populate w/ NewspaperContainer object via .ingest
          @target = nil
        end

        def ingest
          find_or_create_container
          link_publication
        end

        # Link a page to target container
        # @param page [NewspaperPage]
        def link(page)
          @target.ordered_members << page
          # save each link attempt (for now no deferring/bundling)
          @target.save!
        end

        def find_or_create_container
          @target = find_container
          create_container if @target.nil?
        end

        private

          def metadata
            @source.metadata
          end

          def find_container
            NewspaperContainer.where(identifier: metadata.reel_number).first
          end

          def create_container
            @target = NewspaperContainer.create
            copy_metadata
            assign_administrative_metadata
            @target.save!
          end

          def copy_metadata
            reel_number = metadata.reel_number
            @target.identifier = [reel_number]
            @target.title = ["Microform reel (#{reel_number})"]
            copy_fields = [
              :held_by,
              :publication_date_start,
              :publication_date_end
            ]
            copy_fields.each do |fieldname|
              value = metadata.send(fieldname.to_s)
              @target.send("#{fieldname}=", value)
            end
          end

          def link_publication
            return unless @target.publication.nil?
            @publication.members << @target
            @publication.save!
          end
      end
    end
  end
end