require 'windows/api'
require 'windows/msvcrt/string'
include Windows

module Windows
   module Unicode
      include Windows::MSVCRT::String
      
      API.auto_namespace = 'Windows::Unicode'
      API.auto_constant  = true
      API.auto_method    = true
      API.auto_unicode   = false

      CP_ACP         = 0
      CP_OEMCP       = 1
      CP_MACCP       = 2
      CP_THREAD_ACP  = 3
      CP_SYMBOL      = 42
      CP_UTF7        = 65000
      CP_UTF8        = 65001

      MB_PRECOMPOSED       = 0x00000001
      MB_COMPOSITE         = 0x00000002
      MB_USEGLYPHCHARS     = 0x00000004
      MB_ERR_INVALID_CHARS = 0x00000008

      WC_COMPOSITECHECK    = 0x00000200 
      WC_DISCARDNS         = 0x00000010
      WC_SEPCHARS          = 0x00000020
      WC_DEFAULTCHAR       = 0x00000040
      WC_NO_BEST_FIT_CHARS = 0x00000400

      ANSI_CHARSET        = 0
      DEFAULT_CHARSET     = 1
      SYMBOL_CHARSET      = 2
      SHIFTJIS_CHARSET    = 128
      HANGEUL_CHARSET     = 129
      HANGUL_CHARSET      = 129
      GB2312_CHARSET      = 134
      CHINESEBIG5_CHARSET = 136
      OEM_CHARSET         = 255
      JOHAB_CHARSET       = 130
      HEBREW_CHARSET      = 177
      ARABIC_CHARSET      = 178
      GREEK_CHARSET       = 161
      TURKISH_CHARSET     = 162
      VIETNAMESE_CHARSET  = 163
      THAI_CHARSET        = 222
      EASTEUROPE_CHARSET  = 238
      RUSSIAN_CHARSET     = 204

      IS_TEXT_UNICODE_ASCII16            = 0x0001
      IS_TEXT_UNICODE_REVERSE_ASCII16    = 0x0010
      IS_TEXT_UNICODE_STATISTICS         = 0x0002
      IS_TEXT_UNICODE_REVERSE_STATISTICS = 0x0020
      IS_TEXT_UNICODE_CONTROLS           = 0x0004
      IS_TEXT_UNICODE_REVERSE_CONTROLS   = 0x0040
      IS_TEXT_UNICODE_SIGNATURE          = 0x0008
      IS_TEXT_UNICODE_REVERSE_SIGNATURE  = 0x0080
      IS_TEXT_UNICODE_ILLEGAL_CHARS      = 0x0100
      IS_TEXT_UNICODE_ODD_LENGTH         = 0x0200
      IS_TEXT_UNICODE_DBCS_LEADBYTE      = 0x0400
      IS_TEXT_UNICODE_NULL_BYTES         = 0x1000
      IS_TEXT_UNICODE_UNICODE_MASK       = 0x000F
      IS_TEXT_UNICODE_REVERSE_MASK       = 0x00F0
      IS_TEXT_UNICODE_NOT_UNICODE_MASK   = 0x0F00
      IS_TEXT_UNICODE_NOT_ASCII_MASK     = 0xF000

      TCI_SRCCHARSET  = 1
      TCI_SRCCODEPAGE = 2
      TCI_SRCFONTSIG  = 3
      TCI_SRCLOCALE   = 0x100

      API.new('GetTextCharset', 'L', 'I', 'gdi32')
      API.new('GetTextCharsetInfo', 'LPL', 'I', 'gdi32')
      API.new('IsDBCSLeadByte', 'P', 'B')
      API.new('IsDBCSLeadByteEx', 'IP', 'B')
      API.new('IsTextUnicode', 'PIP', 'B', 'advapi32')
      API.new('MultiByteToWideChar', 'ILPIPI', 'I')
      API.new('TranslateCharsetInfo', 'PPL', 'B', 'gdi32')
      API.new('WideCharToMultiByte', 'ILPIPIPP', 'I')

      # Convenient wrapper methods
       
      # Maps a wide character string to a new character string using the
      # specified +encoding+.  If no encoding is specified, then CP_UTF8 
      # iss used if $KCODE is set to UTF8. Otherwise, CP_ACP is used.
      # 
      # If the function fails it simply returns the string as-is.
      # 
      def multi_to_wide(string, encoding=nil)
         unless encoding
            encoding = ($KCODE == 'UTF8') ? CP_UTF8 : CP_ACP
         end
         
         buf = ' ' * strlen(string) * 2
         
         int = MultiByteToWideChar(
            encoding,
            0,
            string,
            strlen(string),
            buf,
            strlen(buf)
         )
         
         if int > 0
            dest = ' ' * int * 2
            wcsncpy(dest, buf, int)
            dest
         else
            string
         end
      end
      
      # Maps a wide character string to a new character string using the
      # specified +encoding+.  If no encoding is specified, then CP_UTF8 
      # iss used if $KCODE is set to UTF8. Otherwise, CP_ACP is used.
      # 
      # If the function fails it simply returns the string as-is.
      # 
      def wide_to_multi(string, encoding=nil)
         unless encoding
            encoding = ($KCODE == 'UTF8') ? CP_UTF8 : CP_ACP
         end
         
         buf = ' ' * wcslen(string)

         int = WideCharToMultiByte(
            encoding,
            0,
            string,
            wcslen(string),
            buf,
            strlen(buf),
            0,
            0
         )

         if int > 0
            dest = ' ' * int
            strncpy(dest, buf, int)
            dest
         else
            string
         end
      end
   end
end