Option Explicit

Sub ConvertThaiArabicNumbers()

    Dim userChoice As String
    Dim sourceDigits As String
    Dim targetDigits As String
    Dim thaiDigits As String
    Dim story As Range
    Dim currentRange As Range
    Dim i As Long
    Dim conversionType As String

    ' Create Thai Unicode digits
    For i = &HE50 To &HE59
        thaiDigits = thaiDigits & ChrW$(i)
    Next i

    ' English selection dialog
    userChoice = InputBox( _
        "Select conversion type:" & vbCrLf & vbCrLf & _
        "1 = Arabic to Thai" & vbCrLf & _
        "2 = Thai to Arabic" & vbCrLf & vbCrLf & _
        "Enter your choice (1 or 2):", _
        "Thai / Arabic Number Converter", "1")

    If userChoice = "" Then Exit Sub

    Select Case userChoice

        Case "1"
            sourceDigits = "0123456789"
            targetDigits = thaiDigits
            conversionType = "Arabic to Thai"

        Case "2"
            sourceDigits = thaiDigits
            targetDigits = "0123456789"
            conversionType = "Thai to Arabic"

        Case Else
            MsgBox "Please enter 1 or 2.", _
                   vbExclamation, "Invalid Selection"
            Exit Sub

    End Select

    ' Confirmation
    If MsgBox( _
        "Conversion: " & conversionType & _
        vbCrLf & vbCrLf & _
        "Convert numbers in this document?" & _
        vbCrLf & _
        "Please save a backup first.", _
        vbYesNo + vbQuestion, _
        "Confirm Conversion") <> vbYes Then Exit Sub

    On Error GoTo ErrorHandler

    Application.ScreenUpdating = False

    ' Process document story ranges
    For Each story In ActiveDocument.StoryRanges

        Set currentRange = story

        Do While Not currentRange Is Nothing

            For i = 1 To 10

                With currentRange.Find

                    .ClearFormatting
                    .Replacement.ClearFormatting

                    .Text = Mid$(sourceDigits, i, 1)
                    .Replacement.Text = _
                        Mid$(targetDigits, i, 1)

                    .Forward = True
                    .Wrap = wdFindStop
                    .Format = False
                    .MatchCase = False
                    .MatchWholeWord = False
                    .MatchWildcards = False

                    .Execute Replace:=wdReplaceAll

                End With

            Next i

            Set currentRange = _
                currentRange.NextStoryRange

        Loop

    Next story

    Application.ScreenUpdating = True

    MsgBox _
        "Number conversion completed successfully!" & _
        vbCrLf & _
        "Conversion: " & conversionType, _
        vbInformation, _
        "Conversion Completed"

    Exit Sub

ErrorHandler:

    Application.ScreenUpdating = True

    MsgBox "Error: " & Err.Description, _
           vbCritical, "Conversion Error"

End Sub