module GeoConcerns
  module Extractors
    module Iso19139Helper
      NS = {
        'xmlns:gmd' => 'http://www.isotc211.org/2005/gmd',
        'xmlns:gco' => 'http://www.isotc211.org/2005/gco'
      }.freeze

      # TODO: Migrate this code into an XSLT?
      # TODO: Need to support multivalued fields
      def extract_iso19139_metadata(doc)
        h = {}
        doc.at_xpath('//gmd:identificationInfo/gmd:MD_DataIdentification/gmd:citation/gmd:CI_Citation/gmd:title/gco:CharacterString', NS).tap do |node|
          h[:title] = [node.text.strip]
        end

        doc.at_xpath('//gmd:identificationInfo/gmd:MD_DataIdentification/gmd:extent/gmd:EX_Extent/gmd:geographicElement/gmd:EX_GeographicBoundingBox', NS).tap do |node|
          w = node.at_xpath('gmd:westBoundLongitude/gco:Decimal', NS).text.to_f
          e = node.at_xpath('gmd:eastBoundLongitude/gco:Decimal', NS).text.to_f
          n = node.at_xpath('gmd:northBoundLatitude/gco:Decimal', NS).text.to_f
          s = node.at_xpath('gmd:southBoundLatitude/gco:Decimal', NS).text.to_f
          h[:coverage] = GeoConcerns::Coverage.new(n, e, s, w).to_s
        end

        doc.at_xpath('//gmd:identificationInfo/gmd:MD_DataIdentification/gmd:abstract/gco:CharacterString', NS).tap do |node|
          h[:description] = [node.text.strip]
        end

        doc.xpath('//gmd:identificationInfo/gmd:MD_DataIdentification/gmd:citation/gmd:CI_Citation/gmd:citedResponsibleParty/gmd:CI_ResponsibleParty/gmd:role/gmd:CI_RoleCode[@codeListValue=\'originator\']', NS).each do |node|
          h[:creator] = begin
                          [node.at_xpath('ancestor-or-self::*/gmd:individualName', NS).text.strip]
                        rescue
                          [node.at_xpath('ancestor-or-self::*/gmd:organisationName', NS).text.strip]
                        end
        end

        # TODO: Not sure if custodian is the same as source
        doc.xpath('//gmd:identificationInfo/gmd:MD_DataIdentification/gmd:citation/gmd:CI_Citation/gmd:citedResponsibleParty/gmd:CI_ResponsibleParty/gmd:role/gmd:CI_RoleCode[@codeListValue=\'custodian\']', NS).each do |node|
          h[:source] = begin
                         [node.at_xpath('ancestor-or-self::*/gmd:individualName', NS).text.strip]
                       rescue
                         [node.at_xpath('ancestor-or-self::*/gmd:organisationName', NS).text.strip]
                       end
        end

        h
      end
    end
  end
end