Android Code Snippet [B4X] Validate and verify CIF, NIF, DNI and Others

Private Sub Button1_Click
    Log(Cif_Validation("A58818501"))
    Log(Cif_Validation("A12345678"))
    Log(Cif_Validation("K5881850A"))
    Log(Cif_Validation("12345678Z"))
End Sub

Public Sub Cif_Validation(CIF As String) As Boolean
    Dim Result As Boolean = False
    Select True
        Case Regex.IsMatch("(^[XYZ\d]\d{7})([TRWAGMYFPDXBNJZSQVHLCKE]$)", CIF.ToUpperCase)
            Dim Matcher1 As Matcher = Regex.Matcher("(^[XYZ\d]\d{7})([TRWAGMYFPDXBNJZSQVHLCKE]$)", CIF.ToUpperCase)
            Matcher1.Find
            Dim Control = "TRWAGMYFPDXBNJZSQVHLCKE" As String
            Dim Checksum As Int = Matcher1.Group(1).Replace("X",0).Replace("Y",1).Replace("Z",2)
            Dim Digit As String = Control.CharAt(Checksum Mod 23)
            Result = Matcher1.Group(2) = Digit
     
        Case Regex.IsMatch("(^[ABCDEFGHIJKLMUV])(\d{7})(\d$)", CIF.ToUpperCase)
            Dim Matcher1 As Matcher = Regex.Matcher("(^[ABCDEFGHIJKLMUV])(\d{7})(\d$)", CIF.ToUpperCase)
            Matcher1.Find
            Dim Checksum = 0, Pos = 0 As Int
            For Each Val As Int In Regex.Split("", Matcher1.Group(2))
                Dim Sum As Int
                For Each Num As Int In Regex.Split("", (Val*(2-(Pos Mod 2))).As(String))
                    Sum = Sum + Num
                Next
                Checksum = Checksum + Sum
                Pos = Pos + 1
            Next
            Checksum = ((10 - (Checksum Mod 10)) Mod 10)
            Result = Matcher1.Group(3) = Checksum
         
        Case Regex.IsMatch("(^[KLMNPQRSW])(\d{7})([JABCDEFGHI]$)", CIF.ToUpperCase)
            Dim Matcher1 As Matcher = Regex.Matcher("(^[KLMNPQRSW])(\d{7})([JABCDEFGHI]$)", CIF.ToUpperCase)
            Matcher1.Find
            Dim Control = "JABCDEFGHI" As String
            Dim Checksum = 0, Pos = 0 As Int
            For Each Val As Int In Regex.Split("", Matcher1.Group(2))
                Dim Sum As Int
                For Each Num As Int In Regex.Split("", (Val*(2-(Pos Mod 2))).As(String))
                    Sum = Sum + Num
                Next
                Checksum = Checksum + Sum
                Pos = Pos + 1
            Next
            Dim Digit As String = Control.CharAt(((10 - (Checksum Mod 10)) Mod 10))
            Result = Matcher1.Group(3) = Digit
    End Select
    Return Result
End Sub