module Win32
  class Registry
    module Constants
      HKEY_CLASSES_ROOT = 0x80000000
      HKEY_CURRENT_USER = 0x80000001
      HKEY_LOCAL_MACHINE = 0x80000002
      HKEY_USERS = 0x80000003
      HKEY_PERFORMANCE_DATA = 0x80000004
      HKEY_PERFORMANCE_TEXT = 0x80000050
      HKEY_PERFORMANCE_NLSTEXT = 0x80000060
      HKEY_CURRENT_CONFIG = 0x80000005
      HKEY_DYN_DATA = 0x80000006

      REG_NONE = 0
      REG_SZ = 1
      REG_EXPAND_SZ = 2
      REG_BINARY = 3
      REG_DWORD = 4
      REG_DWORD_LITTLE_ENDIAN = 4
      REG_DWORD_BIG_ENDIAN = 5
      REG_LINK = 6
      REG_MULTI_SZ = 7
      REG_RESOURCE_LIST = 8
      REG_FULL_RESOURCE_DESCRIPTOR = 9
      REG_RESOURCE_REQUIREMENTS_LIST = 10
      REG_QWORD = 11
      REG_QWORD_LITTLE_ENDIAN = 11

      STANDARD_RIGHTS_READ = 0x00020000
      STANDARD_RIGHTS_WRITE = 0x00020000
      KEY_QUERY_VALUE = 0x0001
      KEY_SET_VALUE = 0x0002
      KEY_CREATE_SUB_KEY = 0x0004
      KEY_ENUMERATE_SUB_KEYS = 0x0008
      KEY_NOTIFY = 0x0010
      KEY_CREATE_LINK = 0x0020
      KEY_READ = STANDARD_RIGHTS_READ |
        KEY_QUERY_VALUE | KEY_ENUMERATE_SUB_KEYS | KEY_NOTIFY
      KEY_WRITE = STANDARD_RIGHTS_WRITE |
        KEY_SET_VALUE | KEY_CREATE_SUB_KEY
      KEY_EXECUTE = KEY_READ
      KEY_ALL_ACCESS = KEY_READ | KEY_WRITE | KEY_CREATE_LINK

      REG_OPTION_RESERVED = 0x0000
      REG_OPTION_NON_VOLATILE = 0x0000
      REG_OPTION_VOLATILE = 0x0001
      REG_OPTION_CREATE_LINK = 0x0002
      REG_OPTION_BACKUP_RESTORE = 0x0004
      REG_OPTION_OPEN_LINK = 0x0008
      REG_LEGAL_OPTION = REG_OPTION_RESERVED |
        REG_OPTION_NON_VOLATILE | REG_OPTION_CREATE_LINK |
        REG_OPTION_BACKUP_RESTORE | REG_OPTION_OPEN_LINK

      REG_CREATED_NEW_KEY = 1
      REG_OPENED_EXISTING_KEY = 2

      REG_WHOLE_HIVE_VOLATILE = 0x0001
      REG_REFRESH_HIVE = 0x0002
      REG_NO_LAZY_FLUSH = 0x0004
      REG_FORCE_RESTORE = 0x0008

      MAX_KEY_LENGTH = 514
      MAX_VALUE_LENGTH = 32768
    end
    include Constants
    include Enumerable

    class Error < ::StandardError
      attr_reader :code
    end

    class PredefinedKey < Registry
      def initialize(hkey, keyname)
        @hkey = hkey
        @parent = nil
        @keyname = keyname
        @disposition = REG_OPENED_EXISTING_KEY
      end

      # Predefined keys cannot be closed
      def close
        raise Error.new(5) ## ERROR_ACCESS_DENIED
      end

      # Fake #class method for Registry#open, Registry#create
      def class
        Registry
      end

      # Make all
      Constants.constants.grep(/^HKEY_/) do |c|
        Registry.const_set c, new(Constants.const_get(c), c.to_s)
      end
    end

    def open(*args)
      raise Win32::Registry::Error
    end

    def create(*args)
      Stub.new
    end

    class Stub
      def write_i(*arg)
        # No OP
      end
    end
  end
end