daniatitienei

class CardNumberVisualTransformation : VisualTransformation {
    override fun filter(text: AnnotatedString): TransformedText {
        val trimmed = if (text.length >= 16) text.text.substring(0..15) else text.text
        var out = ""

        for (i in trimmed.indices) {
            out += trimmed[i]
            if (i % 4 == 3 && i != 15) out += " "
        }