//
// System.Web.Security.MembershipProvider
//
// Authors:
//	Ben Maurer (bmaurer@users.sourceforge.net)
//	Lluis Sanchez Gual (lluis@novell.com)
//
// (C) 2003 Ben Maurer
// Copyright (C) 2005 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

#if NET_2_0
using System.Configuration.Provider;
using System.Web.Configuration;
using System.Security.Cryptography;
using System.Text;

namespace System.Web.Security
{
	public abstract class MembershipProvider : ProviderBase
	{
		protected MembershipProvider ()
		{
		}
		
		public abstract bool ChangePassword (string name, string oldPwd, string newPwd);
		public abstract bool ChangePasswordQuestionAndAnswer (string name, string password, string newPwdQuestion, string newPwdAnswer);
		public abstract MembershipUser CreateUser (string username, string password, string email, string pwdQuestion, string pwdAnswer, bool isApproved, object providerUserKey, out MembershipCreateStatus status);
		public abstract bool DeleteUser (string name, bool deleteAllRelatedData);
		public abstract MembershipUserCollection FindUsersByEmail (string emailToMatch, int pageIndex, int pageSize, out int totalRecords);
		public abstract MembershipUserCollection FindUsersByName (string nameToMatch, int pageIndex, int pageSize, out int totalRecords);
		public abstract MembershipUserCollection GetAllUsers (int pageIndex, int pageSize, out int totalRecords);
		public abstract int GetNumberOfUsersOnline ();
		public abstract string GetPassword (string name, string answer);
		public abstract MembershipUser GetUser (string name, bool userIsOnline);
		public abstract MembershipUser GetUser (object providerUserKey, bool userIsOnline);
		public abstract string GetUserNameByEmail (string email);
		public abstract string ResetPassword (string name, string answer);
		public abstract void UpdateUser (MembershipUser user);
		public abstract bool ValidateUser (string name, string password);
		public abstract bool UnlockUser (string userName);
		
		public abstract string ApplicationName { get; set; }
		public abstract bool EnablePasswordReset { get; }
		public abstract bool EnablePasswordRetrieval { get; }
		public abstract bool RequiresQuestionAndAnswer { get; }
		public abstract int MaxInvalidPasswordAttempts { get; }
		public abstract int MinRequiredNonAlphanumericCharacters { get; }
		public abstract int MinRequiredPasswordLength { get; }
		public abstract int PasswordAttemptWindow { get; }
		public abstract MembershipPasswordFormat PasswordFormat { get; }
		public abstract string PasswordStrengthRegularExpression { get; }
		public abstract bool RequiresUniqueEmail { get; }
		
		protected virtual void OnValidatingPassword (ValidatePasswordEventArgs args)
		{
			if (ValidatingPassword != null)
				ValidatingPassword (this, args);
		}

		SymmetricAlgorithm GetAlg (out byte [] decryptionKey)
		{
			MachineKeySection section = (MachineKeySection) WebConfigurationManager.GetSection ("system.web/machineKey");

			if (section.DecryptionKey.StartsWith ("AutoGenerate"))
				throw new ProviderException ("You must explicitly specify a decryption key in the <machineKey> section when using encrypted passwords.");

			string alg_type = section.Decryption;
			if (alg_type == "Auto")
				alg_type = "AES";

			SymmetricAlgorithm alg = null;
			if (alg_type == "AES")
				alg = Rijndael.Create ();
			else if (alg_type == "3DES")
				alg = TripleDES.Create ();
			else
				throw new ProviderException (String.Format ("Unsupported decryption attribute '{0}' in <machineKey> configuration section", alg_type));

			decryptionKey = MachineKeySectionUtils.DecryptionKey192Bits (section);
			return alg;
		}

		internal const int SALT_BYTES = 16;
		protected virtual byte [] DecryptPassword (byte [] encodedPassword)
		{
			byte [] decryptionKey;

			using (SymmetricAlgorithm alg = GetAlg (out decryptionKey)) {
				alg.Key = decryptionKey;

				using (ICryptoTransform decryptor = alg.CreateDecryptor ()) {

					byte [] buf = decryptor.TransformFinalBlock (encodedPassword, 0, encodedPassword.Length);
					byte [] rv = new byte [buf.Length - SALT_BYTES];

					Array.Copy (buf, 16, rv, 0, buf.Length - 16);
					return rv;
				}
			}
		}

		protected virtual byte[] EncryptPassword (byte[] password)
		{
			byte [] decryptionKey;
			byte [] iv = new byte [SALT_BYTES];

			Array.Copy (password, 0, iv, 0, Math.Min(password.Length, SALT_BYTES));

			using (SymmetricAlgorithm alg = GetAlg (out decryptionKey)) {
				using (ICryptoTransform encryptor = alg.CreateEncryptor (decryptionKey, iv)) {
					return encryptor.TransformFinalBlock (password, 0, password.Length);
				}
			}
		}

		public event MembershipValidatePasswordEventHandler ValidatingPassword;
	}
}
#endif