using System;

namespace SteamWare
{
  /// <summary>
  /// gestione licenze applicativi
  /// </summary>
  public class licenseMan
  {
    /// <summary>
    /// numero di licenze attive per cliente/applicativo
    /// </summary>
    /// <param name="cliente"></param>
    /// <param name="applicativo"></param>
    /// <returns></returns>
    public static int getLicenseNum(string cliente, string applicativo)
    {
      // !!!FARE!!! chiamata a webservice 1/mese
      int answ = 1;
      // molto hard-coded e discutibile... licenze "perenni"
      switch (cliente)
      {
        case "SteamWare":
          answ = 50;
          break;
        case "ETS":
          if (applicativo == "GPW")
          {
            answ = 35;
          }
          break;
        case "SPS":
          if (applicativo == "GPW")
          {
            answ = 11;
          }
          break;
        default:
          answ = 1;
          break;
      }

      return answ;
    }
    /// <summary>
    /// Fornisce chiave MD5 x un cliente/applicativo/expiryDate
    /// </summary>
    /// <param name="cliente"></param>
    /// <param name="applicativo"></param>
    /// <param name="licenze"></param>
    /// <param name="expiryDate"></param>
    /// <returns></returns>
    public static string getAuthKey(string cliente, string applicativo, int licenze, DateTime expiryDate)
    {
      string answ = "";
      // algoritmo MD5 formato cliente#applicativo#expDate, via SQLdiventa
      // SELECT CONVERT(VARCHAR(32), HashBytes('MD5', 'ETS#GPW#2013/12/31'), 2)
      string plainAuthKey = string.Format("{0}#{1}-{2}%{3}%", cliente, applicativo.PadLeft(20, '-'), expiryDate.ToString("yyyy/MM/dd"), licenze);
      string passPhrase = string.Format("{0}|{1}", cliente.PadLeft(50, ':'), applicativo);
      answ = SteamCrypto.EncryptString(plainAuthKey, passPhrase); // uso combinazione cliente+applicativo come passphrase!
      return answ;
    }
    /// <summary>
    /// restituisce data decodificata da authKey + applicazione + cliente...
    /// </summary>
    /// <param name="cliente">The cliente.</param>
    /// <param name="applicativo">The applicativo.</param>
    /// <param name="licenze">The licenze.</param>
    /// <param name="authKey">The authentication key.</param>
    /// <returns></returns>
    public static DateTime expiryDateByAuthKey(string cliente, string applicativo, int licenze, string authKey)
    {
      DateTime answ = DateTime.Today.AddYears(-10);

      string plainAuthKey = "";
      try
      {
        string passPhrase = string.Format("{0}|{1}", cliente.PadLeft(50, ':'), applicativo);
        plainAuthKey = SteamCrypto.DecryptString(authKey, passPhrase); // uso combinazione cliente+applicativo come passphrase!
        answ = Convert.ToDateTime(plainAuthKey.Replace(string.Format("{0}#{1}-", cliente, applicativo.PadLeft(20, '-')), "").Replace(string.Format("%{0}%", licenze), ""));
      }
      catch (Exception exc)
      {
        logger.lg.scriviLog(string.Format("Errore decodifica auth key:{0}AuthKey: {1}{0}cliente:{2}{0}applicativo:{3}{0}errore:{4}", Environment.NewLine, authKey, cliente, applicativo, exc), tipoLog.EXCEPTION);
      }
      return answ;
    }
  }
}