# frozen_string_literal: true

module Cocina
  module Models
    module Mapping
      module Normalizers
        # Normalizes a Fedora MODS document, accounting for differences between Fedora MODS and MODS generated from Cocina.
        # these adjustments have been approved by our metadata authority, Arcadia.
        class ModsNormalizer # rubocop:disable Metrics/ClassLength
          include Cocina::Models::Mapping::Normalizers::Base

          MODS_NS = Cocina::Models::Mapping::FromMods::Description::DESC_METADATA_NS
          XLINK_NS = Cocina::Models::Mapping::FromMods::Description::XLINK_NS

          # @param [Nokogiri::Document] mods_ng_xml MODS to be normalized
          # @param [String] druid
          # @param [String] label
          # @return [Nokogiri::Document] normalized MODS
          def self.normalize(mods_ng_xml:, druid:, label:)
            new(mods_ng_xml: mods_ng_xml, druid: druid, label: label).normalize
          end

          # @param [Nokogiri::Document] mods_ng_xml MODS to be normalized
          # @param [String] druid
          # @return [Nokogiri::Document] normalized MODS
          def self.normalize_purl(mods_ng_xml:, druid:)
            new(mods_ng_xml: mods_ng_xml, druid: druid).normalize_purl
          end

          # @param [Nokogiri::Document] mods_ng_xml MODS to be normalized
          # @param [String] druid
          # @param [String] label
          # @return [Nokogiri::Document] normalized MODS
          def self.normalize_purl_and_missing_title(mods_ng_xml:, druid:, label:)
            new(mods_ng_xml: mods_ng_xml, druid: druid, label: label).normalize_purl_and_missing_title
          end

          # @param [Nokogiri::Document] mods_ng_xml MODS to be normalized
          # @return [Nokogiri::Document] normalized MODS
          def self.normalize_identifier_type(mods_ng_xml:)
            new(mods_ng_xml: mods_ng_xml, druid: nil).normalize_identifier_type
          end

          def initialize(mods_ng_xml:, druid:, label: nil)
            @ng_xml = mods_ng_xml.root ? mods_ng_xml.dup : blank_ng_xml
            @ng_xml.encoding = 'UTF-8'
            @druid = druid
            @label = label
          end

          def normalize
            normalize_default_namespace
            normalize_xsi
            normalize_version
            normalize_empty_attributes
            normalize_authority_uris # must be called before OriginInfoNormalizer
            @ng_xml = Cocina::Models::Mapping::Normalizers::Mods::OriginInfoNormalizer.normalize(mods_ng_xml: ng_xml)
            @ng_xml = Cocina::Models::Mapping::Normalizers::Mods::SubjectNormalizer.normalize(mods_ng_xml: ng_xml)
            @ng_xml = Cocina::Models::Mapping::Normalizers::Mods::NameNormalizer.normalize(mods_ng_xml: ng_xml)
            normalize_related_item_other_type
            normalize_unmatched_altrepgroup
            normalize_unmatched_nametitlegroup
            normalize_xml_space
            normalize_language_term_type
            normalize_access_condition
            normalize_identifier_type_attr
            normalize_location_physical_location
            normalize_purl_location
            normalize_empty_notes
            @ng_xml = Cocina::Models::Mapping::Normalizers::Mods::TitleNormalizer.normalize(mods_ng_xml: ng_xml, label: label)
            @ng_xml = Cocina::Models::Mapping::Normalizers::Mods::GeoExtensionNormalizer.normalize(mods_ng_xml: ng_xml, druid: druid)
            normalize_empty_type_of_resource # Must be after normalize_empty_attributes
            normalize_notes
            normalize_abstracts
            normalize_usage_primary
            normalize_related_item_attributes
            # This should be last-ish.
            normalize_empty_related_items
            remove_empty_elements(ng_xml.root) # this must be last
            ng_xml
          end

          def normalize_purl
            normalize_purl_location
            ng_xml
          end

          def normalize_purl_and_missing_title
            normalize_purl_location
            @ng_xml = Cocina::Models::Mapping::Normalizers::Mods::TitleNormalizer.normalize_missing_title(mods_ng_xml: ng_xml, label: label)
            ng_xml
          end

          def normalize_identifier_type
            normalize_identifier_type_attr
            ng_xml
          end

          private

          attr_reader :ng_xml, :druid, :label

          # remove all empty elements that have no attributes and no children, recursively
          def remove_empty_elements(start_node)
            return unless start_node

            # remove node if there are no element children, there is no text value and there are no attributes
            if start_node.elements.empty? &&
               start_node.text.blank? &&
               start_node.attributes.empty? &&
               start_node.name != 'etal'
              parent = start_node.parent
              start_node.remove
              remove_empty_elements(parent) # need to call again after child has been deleted
            else
              start_node.element_children.each { |e| remove_empty_elements(e) }
            end
          end

          def normalize_default_namespace
            xml = ng_xml.to_s

            unless xml.include?('xmlns="http://www.loc.gov/mods/v3"')
              xml.sub!('mods:mods', 'mods:mods xmlns="http://www.loc.gov/mods/v3"')
              xml.gsub!('mods:', '')
            end

            regenerate_ng_xml(xml)
          end

          def normalize_xsi
            return if ng_xml.namespaces.include?('xmlns:xsi')

            xml = ng_xml.to_s
            xml.sub!('<mods ', '<mods xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" ')

            regenerate_ng_xml(xml)
          end

          def normalize_version
            # Only normalize version when version isn't mapped.
            match = /MODS version (\d\.\d)/.match(ng_xml.at('//mods:recordInfo/mods:recordOrigin', mods: MODS_NS)&.content)

            if !match
              ng_xml.root['version'] = '3.7'
              ng_xml.root['xsi:schemaLocation'] = 'http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-7.xsd'
            elsif match && match[1] != ng_xml.root['version']
              ng_xml.root['version'] = match[1]
              ng_xml.root['xsi:schemaLocation'] = "http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-#{match[1].sub('.', '-')}.xsd"
            end
          end

          def normalize_authority_uris
            Cocina::Models::Mapping::FromMods::Authority::NORMALIZE_AUTHORITY_URIS.each do |authority_uri|
              ng_xml.xpath("//mods:*[@authorityURI='#{authority_uri}']", mods: MODS_NS).each do |node|
                node[:authorityURI] = "#{authority_uri}/"
              end
            end
          end

          def normalize_purl_location
            normalize_purl_for(ng_xml.root, purl: Cocina::Models::Mapping::Purl.for(druid: druid))
            ng_xml.xpath('/mods:mods/mods:relatedItem', mods: MODS_NS).each { |related_item_node| normalize_purl_for(related_item_node) }
          end

          def normalize_purl_for(base_node, purl: nil)
            purl_nodes(base_node).each do |purl_node|
              purl_node.content = Cocina::Models::Mapping::FromMods::Purl.purl_value(purl_node)
            end

            # If there is a purl, add a url node if there is not already one.
            if purl && purl_nodes(base_node).to_a.none? { |purl_node| purl_node.content == purl }
              new_location = Nokogiri::XML::Node.new('location', Nokogiri::XML(nil))
              new_url = Nokogiri::XML::Node.new('url', Nokogiri::XML(nil))
              new_url.content = purl
              new_location << new_url
              base_node << new_location
            end

            purl_nodes(base_node).each do |purl_node|
              next if purl_node == Cocina::Models::Mapping::FromMods::Purl.primary_purl_node(base_node, purl)

              # Move into own relatedItem
              new_related_item = Nokogiri::XML::Node.new('relatedItem', Nokogiri::XML(nil))
              location_node = purl_node.parent
              location_node.remove
              new_related_item << location_node
              base_node << new_related_item
              purl_node[:usage] = 'primary display'
            end

            primary_url_node = primary_url_node_for(base_node, purl)
            base_node.xpath('mods:location/mods:url', mods: MODS_NS).each do |url_node|
              if url_node == primary_url_node
                url_node[:usage] = 'primary display'
              elsif url_node[:usage] == 'primary display'
                url_node.delete('usage')
              end
            end
          end

          def purl_nodes(base_node)
            base_node.xpath('mods:location/mods:url', mods: MODS_NS).select { |url_node| ::Cocina::Models::Mapping::Purl.purl?(url_node.text) }
          end

          def primary_url_node_for(base_node, purl)
            primary_purl_nodes, primary_url_nodes = base_node.xpath('mods:location/mods:url[@usage="primary display"]', mods: MODS_NS)
                                                             .partition { |url_node| ::Cocina::Models::Mapping::Purl.purl?(url_node.text) }
            all_purl_nodes = base_node.xpath('mods:location/mods:url', mods: MODS_NS)
                                      .select { |url_node| ::Cocina::Models::Mapping::Purl.purl?(url_node.text) }

            this_purl_node = purl ? all_purl_nodes.find { |purl_node| purl_node.content == purl } : nil

            primary_purl_nodes.first || primary_url_nodes.first || this_purl_node || all_purl_nodes.first
          end

          def normalize_related_item_other_type
            ng_xml.xpath('//mods:relatedItem[@type and @otherType]', mods: MODS_NS).each do |related_node|
              related_node.delete('otherType')
              related_node.delete('otherTypeURI')
              related_node.delete('otherTypeAuth')
            end
          end

          def normalize_empty_notes
            ng_xml.xpath('//mods:note[not(text()) and not(@xlink:href)]', mods: MODS_NS, xlink: XLINK_NS).each(&:remove)
          end

          def normalize_empty_type_of_resource
            ng_xml.xpath('//mods:typeOfResource[not(text())][not(@*)]', mods: MODS_NS).each(&:remove)
          end

          def normalize_unmatched_altrepgroup
            normalize_unmatched_altrepgroup_for(ng_xml.root)
            ng_xml.xpath('//mods:relatedItem', mods: MODS_NS).each { |related_item_node| normalize_unmatched_altrepgroup_for(related_item_node) }
          end

          def normalize_unmatched_altrepgroup_for(base_node)
            ids = {}
            base_node.xpath('mods:*[@altRepGroup]', mods: MODS_NS).each do |node|
              id = [node['altRepGroup'], node.name]
              ids[id] ||= []
              ids[id] << node
            end

            ids.each_value do |nodes|
              next unless nodes.size == 1

              nodes.first.delete('altRepGroup')
            end
          end

          def normalize_unmatched_nametitlegroup
            normalize_unmatched_nametitlegroup_for(ng_xml.root)
            ng_xml.xpath('//mods:relatedItem', mods: MODS_NS).each { |related_item_node| normalize_unmatched_nametitlegroup_for(related_item_node) }
          end

          def normalize_unmatched_nametitlegroup_for(base_node)
            ids = {}
            base_node.xpath('mods:name[@nameTitleGroup] | mods:titleInfo[@nameTitleGroup]', mods: MODS_NS).each do |node|
              id = node['nameTitleGroup']
              ids[id] ||= []
              ids[id] << node
            end

            ids.each_value do |nodes|
              next unless nodes.size == 1

              nodes.first.delete('nameTitleGroup')
            end
          end

          def normalize_empty_attributes
            ng_xml.xpath('//mods:*[@*=""]', mods: MODS_NS).each do |node|
              node.each { |attr_name, attr_value| node.delete(attr_name) if attr_value.blank? }
            end
          end

          def normalize_xml_space
            ng_xml.xpath('//mods:*[@xml:space]', mods: MODS_NS).each do |node|
              node.delete('space')
            end
          end

          def normalize_language_term_type
            ng_xml.xpath('//mods:languageTerm[not(@type)]', mods: MODS_NS).each do |node|
              node['type'] = 'code'
            end
          end

          def normalize_access_condition
            ng_xml.xpath('//mods:accessCondition[@type="restrictionOnAccess"]', mods: MODS_NS).each do |node|
              node['type'] = 'restriction on access'
            end
            ng_xml.xpath('//mods:accessCondition[@type="restrictionsOnAccess"]', mods: MODS_NS).each do |node|
              node['type'] = 'restriction on access'
            end
            ng_xml.xpath('//mods:accessCondition[@type="useAndReproduction"]', mods: MODS_NS).each do |node|
              node['type'] = 'use and reproduction'
            end
          end

          def normalize_identifier_type_attr
            ng_xml.xpath('//mods:identifier[@type]', mods: MODS_NS).each do |node|
              node['type'] = normalized_identifier_type_for(node['type'])
            end
            ng_xml.xpath('//mods:nameIdentifier[@type]', mods: MODS_NS).each do |node|
              node['type'] = normalized_identifier_type_for(node['type'])
            end
            ng_xml.xpath('//mods:recordIdentifier[@source]', mods: MODS_NS).each do |node|
              node['source'] = normalized_identifier_type_for(node['source'])
            end
          end

          def normalized_identifier_type_for(type)
            cocina_type, _mods_type, identifier_source = Cocina::Models::Mapping::FromMods::IdentifierType.cocina_type_for_mods_type(type)

            return Cocina::Models::Mapping::FromMods::IdentifierType.mods_type_for_cocina_type(cocina_type) if identifier_source

            type
          end

          def normalize_location_physical_location
            ng_xml.xpath('//mods:location', mods: MODS_NS).each do |location_node|
              location_node.xpath('mods:physicalLocation|mods:url|mods:shelfLocator', mods: MODS_NS).each do |node|
                next unless node.content.present? || node['xlink:href']

                new_location = Nokogiri::XML::Node.new('location', ng_xml)
                new_location << node
                location_node.parent << new_location
              end
              location_node.remove
            end
          end

          def normalize_empty_related_items
            ng_xml.xpath('//mods:relatedItem/mods:part[count(mods:*)=1]/mods:detail[count(mods:*)=1]/mods:number[not(text())]',
                         mods: MODS_NS).each do |number_node|
              number_node.parent.parent.remove
            end
            ng_xml.xpath('//mods:relatedItem[not(mods:*) and not(@xlink:href)]', mods: MODS_NS, xlink: XLINK_NS).each(&:remove)
          end

          def normalize_notes
            ng_xml.xpath('//mods:note', mods: MODS_NS).each do |note_node|
              if Cocina::Models::Mapping::ToMods::Note.note_type_to_abstract_type.include?(note_node['type']&.downcase) ||
                 Cocina::Models::Mapping::ToMods::Note.display_label_to_abstract_type.include?(note_node['displayLabel'])
                note_node.delete('type') unless note_node['type']&.downcase == 'summary'
                note_node.name = 'abstract'
              end
              if Cocina::Models::Mapping::ToMods::Note.display_label_to_abstract_type.include? note_node['displayLabel']
                note_node['displayLabel'] =
                  note_node['displayLabel'].capitalize
              end
            end
          end

          def normalize_abstracts
            ng_xml.xpath('/mods:mods/mods:abstract', mods: MODS_NS).each do |abstract_node|
              if Cocina::Models::Mapping::ToMods::Note.note_type_to_abstract_type.include? abstract_node['type']&.downcase
                abstract_node['type'] =
                  abstract_node['type'].downcase
              end
              if Cocina::Models::Mapping::ToMods::Note.display_label_to_abstract_type.include? abstract_node['displayLabel']
                abstract_node['displayLabel'] =
                  abstract_node['displayLabel'].capitalize
              end
              abstract_node.delete('type') if abstract_node['type'] == 'abstract'
            end
          end

          def normalize_usage_primary
            normalize_usage_primary_for(ng_xml.root)
            ng_xml.xpath('/mods:mods/mods:relatedItem', mods: ModsNormalizer::MODS_NS).each do |related_item_node|
              normalize_usage_primary_for(related_item_node)
            end
            ng_xml.xpath('//mods:subject', mods: ModsNormalizer::MODS_NS).each { |subject_node| normalize_usage_primary_for(subject_node) }
          end

          def normalize_usage_primary_for(base_node)
            %w[genre language classification subject titleInfo typeOfResource name].each do |node_name|
              primary_nodes = base_node.xpath("mods:#{node_name}[@usage=\"primary\"]", mods: MODS_NS)
              next if primary_nodes.size < 2

              primary_nodes[1..].each { |primary_node| primary_node.delete('usage') }
            end
          end

          def normalize_related_item_attributes
            ng_xml.xpath('/mods:mods/mods:relatedItem[@lang or @script]', mods: ModsNormalizer::MODS_NS).each do |related_item_node|
              related_item_node.delete('lang')
              related_item_node.delete('script')
            end
          end

          def blank_ng_xml
            Nokogiri::XML(<<~XML
              <mods xmlns="http://www.loc.gov/mods/v3"#{' '}
                xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"#{' '}
                version="3.6"#{' '}
                xsi:schemaLocation="http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-6.xsd" />
            XML
                         )
          end
        end
      end
    end
  end
end