require 'nokogiri'
require 'digest/sha1'
require 'zlib'

module RightPublish
  class ZyppRepo < YumRepo
    REPO_KEY = :zypp_repo

    private
    def regen_metadata(repo_path)
      super(repo_path)
      do_in_subdir(repo_path) do
        SuseMetadata.new.add
      end
    end

    class Package
      attr_reader :checksum
      attr_reader :name
      attr_reader :arch
      attr_reader :ver
      attr_reader :rel

      def initialize(rpmfile)
        @checksum = Digest::SHA1.hexdigest(File.new(rpmfile).read) 
        rpm = File.basename(rpmfile, ".rpm")
        rpm, _, @arch = rpm.rpartition(".")
        rpm, _,@rel = rpm.rpartition("-")
        @name, _,@ver = rpm.rpartition("-")
      end
    end

    # http://en.opensuse.org/openSUSE:Standards_Rpm_Metadata#SUSE_primary_data_.28susedata.xml.29.2C_extensions_to_primary.xml
    class SuseMetadata
      def initialize
        @packages = Dir["*.rpm"].map { |rpmfile| Package.new(rpmfile) }
      end

      def href 
        "repodata/susedata.xml.gz"
      end

      def suse_data
        @suse_data ||= Nokogiri::XML::Builder.new do |xml|
          xml.susedata("packages" => @packages.length) do |susedata|
            @packages.each do |package|
              susedata.package('pkgid' => package.checksum, 'name' => package.name) do |pkg|
                pkg.version('ver' => package.ver, 'rel' => package.rel, 'arch' => package.arch, 'epoch' => 0)
                pkg.keyword("support_l3")
              end
            end
          end
        end.to_xml
      end

      def create
        susedata_file = File.join("repodata", "susedata.xml.gz")
        Zlib::GzipWriter.open(susedata_file) { |file| file.write(suse_data) }
        @checksum = Digest::SHA256.hexdigest(File.open(susedata_file).read)
        @open_checksum = Digest::SHA256.hexdigest(suse_data)
      end

      def update_repomd
        repomd = File.join("repodata", "repomd.xml")
        doc = Nokogiri::XML(File.open(repomd))
        Nokogiri::XML::Builder.with(doc.at_css("repomd")) do |xml|
          xml.data('type' => 'susedata') do |data|
            data.timestamp(File.ctime(href).to_i)
            data.checksum({ 'type' => 'sha256' },  @checksum)
            data.location('href' => href)
            data.send(:"open-checksum", { 'type' => 'sha256' }, @open_checksum)
          end
        end
        File.open(repomd, "w") { |f| doc.write_xml_to f }
      end

      def add
        create
        update_repomd
      end
    end
  end
  RightPublish::RepoManager.register_repo(ZyppRepo)
end