using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Text;
using System.Security.Cryptography;

/// <summary>
/// Helper class to handle the payment integration with PayGate
/// </summary>
/// 

public enum ProcessNowOptions { Yes, No };

public class PayGateSubscriptions
{
  public string PayGate_ID
  { get; set; }

  public string PayGate_Key
  { get; set; }

  public string Reference
  { get; set; }

  public float Amount
  { get; set; }

  public string Currency
  { get; set; }

  public string Return_URL
  { get; set; }

  public string UserEmail
  { get; set; }

  public ProcessNowOptions ProcessNow
  { get; set; }

  public float ProcessNowAmount
  { get; set; }

  public DateTime SubsStartDate
  { get; set; }

  public DateTime SubsEndDate
  { get; set; }

  //private static string PayGate_Server = "https://www.paygate.co.za/paywebv2/process.trans";
  private static string PayGate_Server = "SendRequestSubs.aspx";
  private static string PayGate_Version = "21";

  /****************************************************************************************************/
  /// <summary>
  /// Initializes a new instance of the <see cref="PayGate"/> class.
  /// </summary>
  public PayGateSubscriptions()
	{
    PayGate_ID = System.Configuration.ConfigurationManager.AppSettings.Get("PayGate_ID");
    PayGate_Key = System.Configuration.ConfigurationManager.AppSettings.Get("PayGate_Key");
    Currency = System.Configuration.ConfigurationManager.AppSettings.Get("PayGate_Currency");
    Return_URL = System.Configuration.ConfigurationManager.AppSettings.Get("PayGate_ReturnURL");
	}

  /****************************************************************************************************/
  /// <summary>
  /// Initializes a new instance of the <see cref="PayGate"/> class.
  /// </summary>
  /// <param name="PayGate_ID">The pay gate ID.</param>
  /// <param name="PayGate_Key">The pay gate encryption key.</param>
  /// <param name="PayGate_Currency">The pay gate currency.</param>
  /// <param name="PayGate_ReturnURL">The pay gate return URL.</param>
  public PayGateSubscriptions(string PayGate_ID, string PayGate_Key, string PayGate_Currency, string PayGate_ReturnURL)
  {
    this.PayGate_ID = PayGate_ID;
    this.PayGate_Key = PayGate_Key;
    this.Currency = PayGate_Currency;
    this.Return_URL = PayGate_ReturnURL;
  }

  /****************************************************************************************************/
  /// <summary>
  /// Generates the PayGate MD5 checksum.
  /// </summary>
  /// <param name="Data">The data.</param>
  /// <returns></returns>
  private string GenerateChecksum(string Data)
  {
    ASCIIEncoding AE = new ASCIIEncoding();
    byte[] ByteSource = AE.GetBytes(Data);
    MD5CryptoServiceProvider MD5 = new MD5CryptoServiceProvider();
    byte[] Hash = MD5.ComputeHash(ByteSource);
    string Checksum = "";
    for (int i = 0; i < Hash.Length; i++)
    {
      Checksum += Hash[i].ToString("x2").ToUpper();
    }

    return Checksum;
  }

  /****************************************************************************************************/
  /// <summary>
  /// Starts the payment process.
  /// </summary>
  public string StartPayment()
  {
    string TransDate = DateTime.Now.ToString("yyyy-MM-dd HH:mm");
    string TransAmnt = (Amount * 100).ToString("G0");
    string NowAmnt = (ProcessNowAmount * 100).ToString("G0");
    string Frequency = "201"; //Subs Frequency - set to 1st day of the month. See below.
    string ChecksumSource = PayGate_Version + "|" + PayGate_ID + "|";
    ChecksumSource += Reference + "|";
    ChecksumSource += TransAmnt + "|";
    ChecksumSource += Currency + "|";
    ChecksumSource += Return_URL + "|";
    ChecksumSource += TransDate + "|";
    if (!string.IsNullOrEmpty(UserEmail))
      ChecksumSource += UserEmail + "|";
    ChecksumSource += SubsStartDate.ToString("yyyy-MM-dd") + "|";
    ChecksumSource += SubsEndDate.ToString("yyyy-MM-dd") + "|";

    ChecksumSource += Frequency + "|"; 

    if (ProcessNow == ProcessNowOptions.Yes)
    {
      ChecksumSource += "YES|" + NowAmnt + "|";
    }
    else
    {
      ChecksumSource += "NO||";
    }
    ChecksumSource += PayGate_Key;

    string Checksum = GenerateChecksum(ChecksumSource);

    string PostUrl = PayGate_Server + "?";
    PostUrl += "VERSION=" + PayGate_Version;
    PostUrl += "&PAYGATE_ID=" + PayGate_ID;
    PostUrl += "&REFERENCE=" + Reference;
    PostUrl += "&AMOUNT=" + TransAmnt;
    PostUrl += "&CURRENCY=" + Currency;
    PostUrl += "&TRANSACTION_DATE=" + TransDate;
    PostUrl += "&SUBS_START_DATE=" + SubsStartDate.ToString("yyyy-MM-dd");
    
    PostUrl += "&SUBS_END_DATE=" + SubsEndDate.ToString("yyyy-MM-dd");
    PostUrl += "&SUBS_FREQUENCY=" + Frequency;
    if (ProcessNow == ProcessNowOptions.Yes)
    {
      PostUrl += "&PROCESS_NOW=YES";
      PostUrl += "&PROCESS_NOW_AMOUNT=" + NowAmnt;
    }
    else
    {
      PostUrl += "&PROCESS_NOW=NO";
      PostUrl += "&PROCESS_NOW_AMOUNT=";
    }
    PostUrl += "&RETURN_URL=" + Return_URL;
    if (!string.IsNullOrEmpty(UserEmail))
      PostUrl += "&EMAIL=" + UserEmail;
    PostUrl += "&CHECKSUM=" + Checksum;

    return PostUrl;
  }

  /****************************************************************************************************/
  /// <summary>
  /// Confirms the checksum result.
  /// </summary>
  /// <param name="rxAmount">The rx amount.</param>
  /// <param name="Transaction_Status">The transaction_ status.</param>
  /// <param name="Result_Code">The result_ code.</param>
  /// <param name="Result_Desc">The result_ desc.</param>
  /// <param name="Auth_Code">The auth_ code.</param>
  /// <param name="Transaction_Id">The transaction_ id.</param>
  /// <param name="Risk_Indicator">The risk_ indicator.</param>
  /// <param name="Checksum">The checksum.</param>
  /// <returns></returns>
  public bool ConfirmChecksumResult(string rxAmount, string Transaction_Status, string Result_Code, string Result_Desc, string Auth_Code, string Transaction_Id, string Subscription_Id, string Risk_Indicator, string rxChecksum)
  {
    bool result = false;

    string ChecksumSource = PayGate_ID + "|";
    ChecksumSource += Reference + "|";
    ChecksumSource += Transaction_Status + "|";
    ChecksumSource += Result_Code + "|";
    ChecksumSource += Auth_Code + "|";
    ChecksumSource += rxAmount + "|";
    ChecksumSource += Result_Desc + "|";
    ChecksumSource += Transaction_Id + "|";
    ChecksumSource += Subscription_Id + "|";

    if (!string.IsNullOrEmpty(Risk_Indicator))
      ChecksumSource += Risk_Indicator + "|";
    ChecksumSource += PayGate_Key;

    result = rxChecksum.ToUpper().Equals(GenerateChecksum(ChecksumSource));

    return result;
  }

  /****************************************************************************************************/
  public string GetChecksumResult(string rxAmount, string Transaction_Status, string Result_Code, string Result_Desc, string Auth_Code, string Transaction_Id, string Subscription_Id, string Risk_Indicator, string rxChecksum)
  {
    string result = "";

    string ChecksumSource = PayGate_ID + "|";
    ChecksumSource += Reference + "|";
    ChecksumSource += Transaction_Status + "|";
    ChecksumSource += Result_Code + "|";
    ChecksumSource += Auth_Code + "|";
    ChecksumSource += rxAmount + "|";
    ChecksumSource += Result_Desc + "|";
    ChecksumSource += Transaction_Id + "|";
    ChecksumSource += Subscription_Id + "|";

    if (!string.IsNullOrEmpty(Risk_Indicator))
      ChecksumSource += Risk_Indicator + "|";
    ChecksumSource += PayGate_Key;

    result = GenerateChecksum(ChecksumSource);

    return result;
  }

  /****************************************************************************************************/
  /// <summary>
  /// Gets the transaction status.
  /// </summary>
  /// <param name="Status">The status.</param>
  /// <returns></returns>
  public string GetTransactionStatus(int Status)
  {
    string result = "";
    switch (Status)
    {
      case 0:
        result = "Pending";
        break;
      case 1:
        result = "Approved";
        break;
      case 2:
        result = "Declined";
        break;
    }
    return result;
  }

  /****************************************************************************************************/
  /// <summary>
  /// Gets the result code.
  /// </summary>
  /// <param name="Code">The code.</param>
  /// <returns></returns>
  public string GetResultCode(int Code)
  {
    string result = "";
    switch (Code)
    {
      case 0:
        result = "N/A";
        break;
      case 990017:
        result = "Approved Transaction";
        break;
      case 900003:
        result = "Insufficient Funds";
        break;
      case 900007:
        result = "Declined Transaction";
        break;
      case 900004:
        result = "Invalid Card Number";
        break;
      case 990022:
        result = "Unprocessed Transaction";
        break;
    }
    return result;
  }

  /****************************************************************************************************/
  /// <summary>
  /// Gets the risk indicator.
  /// </summary>
  /// <param name="Status">The status.</param>
  /// <returns></returns>
  public string GetRiskIndicator(string Status)
  {
    string result = "";
    switch (Status.ToUpper())
    {
      case "AX":
        result = "Authenticated";
        break;
      case "NX":
        result = "Not Authenticated";
        break;
      default:
        result = "N/A";
        break;
    }
    return result;
  }

  /****************************************************************************************************/
  /// <summary>
  /// Return the results code as a status code.
  /// </summary>
  /// <param name="Code">The code.</param>
  /// <returns></returns>
  public int ResultCodeAsStatus(int Code)
  {
    int result = 0;
    switch (Code)
    {
      case 0:
        result = (int)PaymentResults.Pending;
        break;
      case 990017:
        result = (int)PaymentResults.Approved;
        break;
      case 900003:
        result = (int)PaymentResults.InsufficientFunds;
        break;
      case 900007:
        result = (int)PaymentResults.Declined;
        break;
      case 900004:
        result = (int)PaymentResults.InvalidCard;
        break;
      case 990022:
        result = (int)PaymentResults.Pending;
        break;
    }
    return result;
  }

  /****************************************************************************************************/
  /* Subscription Frequency Codes */
  /*
    Code    Description
    111     Weekly on Sun
    112     Weekly on Mon
    113     Weekly on Tue
    114     Weekly on Wed
    115     Weekly on Thu
    116     Weekly on Fri
    117     Weekly on Sat
    121     2nd Weekly on Sun
    122     2nd Weekly on Mon
    123     2nd Weekly on Tue
    124     2nd Weekly on Wed
    125     2nd Weekly on Thu
    126     2nd Weekly on Fri
    127     2nd Weekly on Sat
    131     3rd Weekly on Sun
    132     3rd Weekly on Mon
    133     3rd Weekly on Tue
    134     3rd Weekly on Wed
    135     3rd Weekly on Thu
    136     3rd Weekly on Fri
    137     3rd Weekly on Sat
    201     Monthly on 1st
    202     Monthly on 2nd
    203     Monthly on 3rd
    204     Monthly on 4th
    205     Monthly on 5th
    206     – 227 as above
   
    228     Monthly on 28th
    229     Last day of the month

    301     – 328 Every 2nd month on 1st to 28th respectively
    329     Every 2nd month on last day of the month

    401     – 428 Every 3rd month on 1st to 28th respectively
    429     Every 3rd month on last day of the month
  */

  /****************************************************************************************************/
  /*
  Card Brand Card Number Risk Indicator
Approved Transactions. RESULT_CODE = 990017; TRANSACTION_STATUS = 1.
Visa 4000000000000002 Authenticated (AX) *
MasterCard 5200000000000015 Authenticated (AX)
American Express 378282246310005 Not Authenticated (NX)
FNB Cell Pay Point N/A; enter MR PASS
in Account Holder
field.
Authenticated (AX)
Mobux 6397729999003950 Not Applicable (XX)
Ukash Voucher
(with new voucher issued as change)
9999991500000000012 Authenticated (AX)
Ukash Voucher
(with no change voucher issued)
9999991500000000020 Authenticated (AX)
Ukash Card 9826160000000005 Authenticated (AX)
Insufficient Funds Transactions. RESULT_CODE = 900003; TRANSACTION_STATUS = 2.
MasterCard 5200000000000023 Not Authenticated (NX) *
Visa 4000000000000028 Not Authenticated (NX)
American Express 371449635398431 Not Authenticated (NX)
Declined Transactions. RESULT_CODE = 900007; TRANSACTION_STATUS = 2.
Visa 4000000000000036 Authenticated (AX) *
MasterCard 5200000000000049 Authenticated (AX) *
Diners Club 30569309025904 Not Applicable (XX)
FNB Cell Pay Point N/A; enter MR FAIL in
Account Holder field.
Not Applicable (XX)
Mobux 6397729999003550 Not Applicable (XX)
Ukash Voucher 9999991500000000038 Not Applicable (XX)
Ukash Card 9826160000000013 Not Applicable (XX)
Invalid Card Number. RESULT_CODE = 900004; TRANSACTION_STATUS = 2.
All other card numbers Not Applicable (XX)
Unprocessed Transactions. RESUT_CODE = 990022; TRANSACTION_STATUS = 0.
MasterCard 5200000000000064 Not Applicable (XX)
Expiry Date must be in the future; Card Holder & CVV or Ukash PIN can be made up.
* = Using these card numbers will allow you to test the MasterCard SecureCode / Verified-by-Visa
authentication process.
The default test account does not allow any customisation; all options are enabled and there is no logo.
   */ 
}