/*************************************************************************
 * ModernUO                                                              *
 * Copyright (C) 2019-2020 - ModernUO Development Team                   *
 * Email: hi@modernuo.com                                                *
 * File: AccountSecurity.cs                                              *
 * Created: 2020/05/01 - Updated: 2020/05/02                             *
 *                                                                       *
 * This program is free software: you can redistribute it and/or modify  *
 * it under the terms of the GNU General Public License as published by  *
 * the Free Software Foundation, either version 3 of the License, or     *
 * (at your option) any later version.                                   *
 *                                                                       *
 * This program is distributed in the hope that it will be useful,       *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 * GNU General Public License for more details.                          *
 *                                                                       *
 * You should have received a copy of the GNU General Public License     *
 * along with this program.  If not, see <http://www.gnu.org/licenses/>. *
 *************************************************************************/

using System;

namespace Server.Accounting.Security
{
  public enum PasswordProtectionAlgorithm
  {
    // Obsolete algorithms from RunUO. These are not secure!
    // They are included for password upgrades only.
    None,
    MD5,
    SHA1,

    // Supported algorithms
    SHA2, // ServUO compatibility
    PBKDF2,
    Argon2 // Recommended algorithm for real security.
  }

  public static class AccountSecurity
  {
    // TODO: Put it in a configuration
    public const PasswordProtectionAlgorithm AlgorithmName = PasswordProtectionAlgorithm.Argon2;

    public static readonly IPasswordProtection CurrentPasswordProtection = GetPasswordProtection(AlgorithmName);

    public static void Configure()
    {
      if (AlgorithmName < PasswordProtectionAlgorithm.SHA2)
        throw new Exception($"Security: {AlgorithmName} is obselete and not secure. Do not use it.");
    }

    public static IPasswordProtection GetPasswordProtection(PasswordProtectionAlgorithm algorithm)
    {
      var passwordProtection = algorithm switch
      {
        PasswordProtectionAlgorithm.MD5 => MD5PasswordProtection.Instance,
        PasswordProtectionAlgorithm.SHA1 => SHA1PasswordProtection.Instance,
        PasswordProtectionAlgorithm.SHA2 => SHA2PasswordProtection.Instance,
        PasswordProtectionAlgorithm.PBKDF2 => PBKDF2PasswordProtection.Instance,
        PasswordProtectionAlgorithm.Argon2 => Argon2PasswordProtection.Instance,
        _ => null
      };

      return passwordProtection;
    }
  }
}