Option Explicit

Private iCurCol   As Integer
Private iCurLin   As Integer
Private iCurIndex As Integer

Private sLastVal As String

Sub LoadInterface()
      Dim snLeft!, snTop!
      Dim iAddH%, iAddY%
      Dim iLin%, i%

  For i = 1 To 80
    If (i Mod 9) = 0 Then
      iLin = iLin + 1
    End If
    
    Call Load(txtNum(i))
    
    With txtNum(i)
      If (i Mod 3) = 0 Then
        iAddH = (10 * (i Mod 9))
      End If
      
      If (iLin Mod 3) = 0 Then
        iAddY = (10 * (iLin Mod 9))
      End If
      
      snLeft = (.Width * (i Mod 9)) + iAddH
      snTop = iLin * .Height + iAddY
      
      Call .Move(snLeft, snTop)
      
      .Visible = True
    End With
  Next
  
  Width = txtNum(0).Width * 9 + iAddH
  Height = Width
End Sub

Function RightVal(ByVal Col As Integer, ByVal Lin As Integer, ByVal Index As Integer, ByVal Value As Integer) As Boolean
          Dim iIndex%, i%
          Dim iSelIndex%
          Dim iVal%

  iIndex = Index
  
  If (iIndex Mod 9) > 0 Then
    Do While ((iIndex Mod 9) <> 0)
      iIndex = iIndex - 1
    Loop
  End If
  
  For i = iIndex To iIndex + 8
    If txtNum(i) <> vbNullString Then
      If (Val(txtNum(i)) = Value) And (i <> Index) Then
        Exit Function
      End If
    End If
  Next
  
  For i = 0 To 8
    iSelIndex = (i * 9) + Col
    
    If txtNum(iSelIndex) <> vbNullString Then
      If Val(txtNum(iSelIndex)) = Value And (iSelIndex <> Index) Then
        Exit Function
      End If
    End If
  Next
  
  RightVal = True
End Function

Sub HighlightLin(ByVal Col As Integer, ByVal Lin As Integer, ByVal Index As Integer)
          Dim iIndex%, i%
          Dim iSelIndex%
          Dim iVal%

  iIndex = Index
  
  If (iIndex Mod 9) > 0 Then
    Do While ((iIndex Mod 9) <> 0)
      iIndex = iIndex - 1
    Loop
  End If
  
  For i = 0 To 80
    txtNum(i).BackColor = vbWindowBackground
  Next
  
  For i = iIndex To iIndex + 8
    txtNum(i).BackColor = vbCyan
  Next
  
  For i = 0 To 8
    iSelIndex = (i * 9) + Col
    txtNum(iSelIndex).BackColor = vbCyan
  Next
End Sub

Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
  If KeyCode = vbKeyEscape Then End
End Sub

Private Sub Form_Load()
  txtNum(0) = vbNullString
  Call txtNum(0).Move(0, 0, 360, 360)
  BackColor = 0
  
  Call LoadInterface
End Sub

Private Sub txtNum_GotFocus(Index As Integer)
  txtNum(Index).SelStart = 0
  txtNum(Index).SelLength = Len(txtNum(Index))
  
  iCurIndex = Index
  iCurCol = (iCurIndex Mod 9)
  iCurLin = (iCurIndex \ 9)
  
  Call HighlightLin(iCurCol, iCurLin, iCurIndex)
  
  sLastVal = txtNum(Index)
End Sub

Private Sub txtNum_KeyDown(Index As Integer, KeyCode As Integer, Shift As Integer)
  On Error Resume Next
  
  Select Case KeyCode
    Case vbKeyUp:     Call txtNum(Index - 9).SetFocus
    Case vbKeyDown:   Call txtNum(Index + 9).SetFocus
    Case vbKeyLeft:   Call txtNum(Index - 1).SetFocus
    Case vbKeyRight:  Call txtNum(Index + 1).SetFocus
  End Select
End Sub

Private Sub txtNum_LostFocus(Index As Integer)
        Dim i%
        
  If txtNum(Index) = vbNullString Then Exit Sub
  
  iCurCol = (iCurIndex Mod 9)
  iCurLin = (iCurIndex \ 9)
  
  If Not RightVal(iCurCol, iCurLin, iCurIndex, Val(txtNum(Index))) Then
    Call MsgBox("El número ingresado no es correcto", vbExclamation)
    
    txtNum(Index) = sLastVal
  Else
    For i = 0 To 80
      If txtNum(i) = vbNullString Then Exit Sub
    Next
    
    Call MsgBox("Felicitaciones, ganaste!!", vbExclamation)
    Call Clipboard.SetData(Image, vbCFBitmap)
  End If
End Sub