class DarwinCore
  class Generator
    # Creates EML file with meta information about archive
    class EmlXml
      SCHEMA_DATA = {
        :"xml:lang" =>           "en",
        :"xmlns:eml" =>          "eml://ecoinformatics.org/eml-2.1.1",
        :"xmlns:md" =>           "eml://ecoinformatics.org/methods-2.1.1",
        :"xmlns:proj" =>         "eml://ecoinformatics.org/project-2.1.1",
        :"xmlns:d" =>            "eml://ecoinformatics.org/dataset-2.1.1",
        :"xmlns:res" =>          "eml://ecoinformatics.org/resource-2.1.1",
        :"xmlns:dc" =>           "http://purl.org/dc/terms/",
        :"xmlns:xsi" =>          "http://www.w3.org/2001/XMLSchema-instance",
        :"xsi:schemaLocation" => "eml://ecoinformatics.org/eml-2.1.1 "\
          "http://rs.gbif.org/schema/eml-gbif-profile/1.0.1/eml.xsd"
      }

      def initialize(data, path)
        @data = data
        @path = path
        @write = "w:utf-8"
      end

      def create
        schema_data = {
          packageId: "#{@data[:id]}/#{timestamp}",
          system: @data[:system] || "http://globalnames.org"
        }.merge(SCHEMA_DATA)
        builder = Nokogiri::XML::Builder.new do |xml|
          xml.eml(schema_data) do
            build_body(xml)
          end
        end
        save_eml(builder)
      end

      private

      def build_body(xml)
        build_dataset(xml)
        build_additional_metadata(xml)
        xml.parent.namespace = xml.parent.namespace_definitions.first
      end

      def save_eml(builder)
        data = builder.to_xml
        f = open(File.join(@path, "eml.xml"), @write)
        f.write(data)
        f.close
      end

      def build_dataset(xml)
        xml.dataset(id: @data[:id]) do
          xml.title(@data[:title])
          xml.license(@data[:license])
          contacts = []
          build_authors(xml, contacts)
          build_metadata_providers(xml)
          xml.pubDate(Time.now.to_s)
          build_abstract(xml)
          build_contacts(xml, contacts)
        end
      end

      def build_abstract(xml)
        xml.abstract { xml.para(@data[:abstract]) }
      end

      def build_contacts(xml, contacts)
        contacts.each { |contact| xml.contact { xml.references(contact) } }
      end

      def build_metadata_providers(xml)
        @data[:metadata_providers].each do |a|
          xml.metadataProvider { build_person(xml, a) }
        end if @data[:metadata_providers]
      end

      def build_authors(xml, contacts)
        @data[:authors].each_with_index do |a, i|
          creator_id = i + 1
          contacts << creator_id
          xml.creator(id: creator_id, scope: "document") do
            build_person(xml, a)
          end
        end
      end

      def build_additional_metadata(xml)
        xml.additionalMetadata do
          xml.metadata do
            xml.citation(@data[:citation])
            xml.resourceLogoUrl(@data[:logo_url]) if @data[:logo_url]
          end
        end
      end

      def build_person(xml, data)
        a = data
        xml.individualName do
          xml.givenName(a[:first_name])
          xml.surName(a[:last_name])
        end
        xml.organizationName(a[:organization]) if a[:organization]
        xml.positionName(a[:position]) if a[:position]
        xml.onlineUrl(a[:url]) if a[:url]
        xml.electronicMailAddress(a[:email])
      end

      def timestamp
        t = Time.now.getutc.to_a[0..5].reverse
        t[0..2] * ("-") + "::" + t[-3..-1] * (":")
      end
    end
  end
end