module Net
  module NTLM

    # base class of data structure
    class FieldSet
      class << FieldSet

        # @macro string_security_buffer
        #   @method $1
        #   @method $1=
        #   @return [String]
        def string(name, opts)
          add_field(name, Net::NTLM::String, opts)
        end

        # @macro int16le_security_buffer
        #   @method $1
        #   @method $1=
        #   @return [Int16LE]
        def int16LE(name, opts)
          add_field(name, Net::NTLM::Int16LE, opts)
        end

        # @macro int32le_security_buffer
        #   @method $1
        #   @method $1=
        #   @return [Int32LE]
        def int32LE(name, opts)
          add_field(name, Net::NTLM::Int32LE, opts)
        end

        # @macro int64le_security_buffer
        #   @method $1
        #   @method $1=
        #   @return [Int64]
        def int64LE(name, opts)
          add_field(name, Net::NTLM::Int64LE, opts)
        end

        # @macro security_buffer
        #   @method $1
        #   @method $1=
        #   @return [SecurityBuffer]
        def security_buffer(name, opts)
          add_field(name, Net::NTLM::SecurityBuffer, opts)
        end

        def prototypes
          @proto
        end

        def names
          return [] if @proto.nil?
          @proto.map{|n, t, o| n}
        end

        def types
          return [] if @proto.nil?
          @proto.map{|n, t, o| t}
        end

        def opts
          return [] if @proto.nil?
          @proto.map{|n, t, o| o}
        end

        private

        def add_field(name, type, opts)
          (@proto ||= []).push [name, type, opts]
          define_accessor name
        end

        def define_accessor(name)
          module_eval(<<-End, __FILE__, __LINE__ + 1)
          def #{name}
            self['#{name}'].value
          end

          def #{name}=(val)
            self['#{name}'].value = val
          end
          End
        end
      end

      def initialize
        @alist = self.class.prototypes.map{ |n, t, o| [n, t.new(o)] }
      end

      def serialize
        @alist.map{|n, f| f.serialize }.join
      end

      def parse(str, offset=0)
        @alist.inject(offset){|cur, a|  cur += a[1].parse(str, cur)}
      end

      def size
        @alist.inject(0){|sum, a| sum += a[1].size}
      end

      def [](name)
        a = @alist.assoc(name.to_s.intern)
        raise ArgumentError, "no such field: #{name}" unless a
        a[1]
      end

      def []=(name, val)
        a = @alist.assoc(name.to_s.intern)
        raise ArgumentError, "no such field: #{name}" unless a
        a[1] = val
      end

      def enable(name)
        self[name].active = true
      end

      def disable(name)
        self[name].active = false
      end
    end

  end
end