using System;

using System.Linq;

using System.Text.RegularExpressions;

using FluentAssertions;

#nullable enable

public class Program

{

    public static void Main()

    {

    Console.WriteLine("----------------------------TEST PAN--------------------------------------------------------");

​

        TestCC("123456789123", "xxxxxxxx9123");

        TestCC("1234-5678-9123-4567", "xxxx-xxxx-xxxx-4567");

        TestCC("123123123123131For8640", "xxxxxxxxxxx3131For8640");

        TestCC("123123123123131to123123123123177", "xxxxxxxxxxx3131toxxxxxxxxxxx3177");

        TestCC("1234-5678-9123-4567-891", "xxxx-xxxx-xxxx-xxx7-891");

        TestCC("1234 5678 9123 4567", "xxxx xxxx xxxx 4567");

        TestCC("1234567", "1234567");

        TestCC("631000028404","xxxxxxxx8404");

        TestCC("173052593000056901","xxxxxxxxxxxxxx6901");

        TestCC("77768913006","77768913006");

        TestCC("01816000060619511074","01816000060619511074");

        Console.WriteLine("-----------------------------TEST ACCOUNT NUM-------------------------------------------------------");

        TestAccNo("12345678","xxxx5678");

        TestAccNo("123456789","xxxxx6789");

        TestAccNo("1234567","1234567");

        Console.WriteLine("----------------------------TEST BOTH--------------------------------------------------------");

​

        TestCCAndAccNo("1234-5678-1234-1234","xxxx-xxxx-xxxx-1234");

        TestCCAndAccNo("1234 5678 1234 1234","xxxx xxxx xxxx 1234");

        TestCCAndAccNo("no1234567890123abc","noxxxxxxxxx0123abc");

        TestCCAndAccNo("Im paying 2700 dollars with my credit card(123456789012345) to my account(12345678)","Im paying 2700 dollars with my credit card(xxxxxxxxxxx2345) to my account(xxxx5678)");

        TestCC("Im paying 2700 dollars with my credit card(123456789012345) to my account(12345678)","Im paying 2700 dollars with my credit card(xxxxxxxxxxx2345) to my account(12345678)");

        TestCCAndAccNo("from INV 242085229 to SAV 01654876","from INV xxxxx5229 to SAV xxxx4876");

        TestCCAndAccNo("from INV 2420852290 to SAV 0165487","from INV 2420852290 to SAV 0165487");

        TestCCAndAccNo("pan19 digits: 1234567890123456789   o","pan19 digits: xxxxxxxxxxxxxxx6789   o");

        TestCCAndAccNo("11 digits: 12345678901","11 digits: 12345678901");

        TestCCAndAccNo("testing pan 12 digits: 123456789012","testing pan 12 digits: xxxxxxxx9012");

        TestCCAndAccNo("20 digits: 12345678901234567890 end","20 digits: 12345678901234567890 end");

        TestCCAndAccNo("pan 18 digits: 123456789012345678 end","pan 18 digits: xxxxxxxxxxxxxx5678 end");

        TestCCAndAccNo("TFR 02062702 with 12345678901234567890 e","TFR xxxx2702 with 12345678901234567890 e");

        TestCCAndAccNo("TFR 02062702 with 123456789012345678","TFR xxxx2702 with xxxxxxxxxxxxxx5678");

        TestCCAndAccNo("TFR 02062702 with 123456789012 end","TFR xxxx2702 with xxxxxxxx9012 end");

        TestCCAndAccNo("TFR 02062702 with 12345678901 end","TFR xxxx2702 with 12345678901 end");

        TestCCAndAccNo("TFR 02062702 with 1234567890123456789","TFR xxxx2702 with xxxxxxxxxxxxxxx6789");

        TestCCAndAccNo("Transfer to SAV 12016643 to 1 a Ong - 525","Transfer to SAV xxxx6643 to 1 a Ong - 525");

        TestCCAndAccNo("Biller code 3038 - Receipt No 3514616375 221414441406","Biller code 3038 - Receipt No 3514616375 xxxxxxxx1406"); //CCNo should get masked

        TestCCAndAccNo("Biller code 3038 - Receipt No 351461637 221414441406","Biller code 3038 - Receipt No xxxxx1637 xxxxxxxx1406"); //Both AccNo and CCNo should get masked

        //TestCCAndAccNo("Biller code 3038 - Receipt No 3514611 221414441406","Biller code 3038 - Receipt No 3514611 xxxxxxxx1406"); //CCNo should get masked

        TestCCAndAccNo("Biller code 3038 - Receipt No 221414441406 3514616375","Biller code 3038 - Receipt No xxxxxxxx1406 3514616375"); //CCNo should get masked

        TestCCAndAccNo("Biller code 3038 - Receipt No 221414441406 351461637","Biller code 3038 - Receipt No xxxxxxxx1406 xxxxx1637"); //Both AccNo and CCNo should get masked

        TestCCAndAccNo("Biller code 3038 - Receipt No 22141444140 351461637","Biller code 3038 - Receipt No 22141444140 xxxxx1637"); //AccNo should get masked

        TestCCAndAccNo("Biller code 3038 - Receipt No 22141444140 3514616375","Biller code 3038 - Receipt No 22141444140 3514616375"); //Both should not get masked

    }

    public static void TestCC(string @value, string expected)

    {

        var result = @value.MaskCCNo();

        result.Should().Be(expected);

        Console.WriteLine($"{@value} => {result}");

    }

    public static void TestAccNo(string @value, string expected)

    {

        var result = @value.MaskAccNo();

        result.Should().Be(expected);

        Console.WriteLine($"{@value} => {result}");

    }

    public static void TestCCAndAccNo(string @value, string expected)

    {

        var result = @value.MaskIfContainCreditCardPanorAcctNumNew();

        result.Should().Be(expected);

        Console.WriteLine($"{@value} => {result}");

    }

}

​

public static class MaskingExtensions

{   

    public static string MaskCCNo(this string value)

  {

      //var a = Regex.Replace(value, @"(?:\G(?!^)|(?<!\d[ -]?)(?=(?:[ -]?\d){12,19}(?![ -]?\d)))\d(?=(?:[ -]?\d){4})([ -]?)", "x$1");

        var a = Regex.Replace(value, @"(?<!\d)\d(?:[\s-]?\d){11,18}(?!\d)", m => Regex.Replace(m.Value, @"\d(?=(?:[\s-]?\d){4})", "x")); 

        //var a = Regex.Replace(value,@"(?:\G(?!^)|\b(?<!-)(?=(?:\d{8,9}|\d{12,19})\b(?!-)))\d(?=\d{4})","x$1");

      return a;

  }

    public static string MaskAccNo(this string value)

  {

        var a = Regex.Replace(value, @"(?<!\d)\d(?:[-]?\d){7,8}(?!\d)", m => Regex.Replace(m.Value, @"\d(?=(?:[-]?\d){4})", "x"));

      //var a = Regex.Replace(value, @"(?:\G(?!^)|(?<!\d[-]?)(?=(?:[-]?\d){8,9}(?![-]?\d)))\d(?=(?:[-]?\d){4})([-]?)", "x$1");

      return a;

  }

    public static string MaskIfContainCreditCardPanorAcctNumNew(this string value)

{

    if (string.IsNullOrEmpty(value))

        return value;

        //return Regex.Replace(value,@"(?:\G(?!^)|(?=(?:\d{8,9}|(?=\d){12,19})))\d(?=(?:[- ]?\d){4})","x");

        //return Regex.Replace(value,@"(?:\G(?!^)|(?<![\d-])(?=(?:\d{8,9}|\d{12,19})(?![\d-])))\d(?=\d{4})","x");

        //return Regex.Replace(value,@"(?:\G(?!^)|\b(?<!-)(?=\d{8}(?:\d|\d{4,11})?\b(?!-)))\d(?=\d{4})","x");

        //return Regex.Replace(value,@"(?:\G(?!^)|\b(?<!-)(?=(?:\d{8,9}|\d{12,19})\b(?!-)))\d(?=\d{4})","x");

        //return Regex.Replace(value,@"(?:\G(?!^)|(?<![\d-])(?=(?:\d{8,9}|\d{12,19})(?![\d-])))\d(?=\d{4})","x");

    var maskedCCNumber = value.MaskCCNo();

​

    return maskedCCNumber.MaskAccNo();

}

}