#region Disclaimer / License
// Copyright (C) 2008, Kenneth Skovhede
// http://www.hexad.dk, opensource@hexad.dk
// 
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// 
// This library 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
// Lesser General Public License for more details.
// 
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
// 
#endregion
using System;
using System.Collections.Generic;
using System.Text;

namespace Duplicati.Library.Encryption
{
    /// <summary>
    /// Class that wraps a backend and transparently encrypts and decrypts data to and from the backend
    /// </summary>
    public class EncryptedBackendWrapper : Backend.IBackendInterface
    {
        private Backend.IBackendInterface m_realbackend;
        private IEncryption m_encryptionEngine;

        public EncryptedBackendWrapper(string target, Dictionary<string, string> options)
            : this(Backend.BackendLoader.GetBackend(target, options), options)
        {
        }

        public EncryptedBackendWrapper(Backend.IBackendInterface backend, Dictionary<string, string> options)
        {
            if (!options.ContainsKey("passphrase") || string.IsNullOrEmpty(options["passphrase"]))
                throw new Exception("No passphrase set");

            string passphrase = options["passphrase"];

            m_realbackend = backend;
            if (options.ContainsKey("gpg-encryption"))
                m_encryptionEngine = new GPGEncryption(passphrase, options.ContainsKey("sign-key") ? options["sign-key"] : null);
            else
                m_encryptionEngine = new AESEncryption(passphrase);
        }

        #region IBackendInterface Members

        public string DisplayName
        {
            get { return m_realbackend.DisplayName; }
        }

        public string ProtocolKey
        {
            get { return m_realbackend.ProtocolKey; }
        }

        public List<Duplicati.Library.Backend.FileEntry> List()
        {
            return m_realbackend.List();
        }

        public void Put(string remotename, string filename)
        {
            remotename += (m_encryptionEngine is AESEncryption ? ".aes" : ".gpg");
            using (Core.TempFile tf = new Duplicati.Library.Core.TempFile())
            {
                m_encryptionEngine.Encrypt(filename, tf);
                m_realbackend.Put(remotename, tf);
            }
        }

        public void Get(string remotename, string filename)
        {
            using (Core.TempFile tf = new Duplicati.Library.Core.TempFile())
            {
                m_realbackend.Get(remotename, tf); 
                m_encryptionEngine.Decrypt(tf, filename);
            }
        }

        public void Delete(string remotename)
        {
            m_realbackend.Delete(remotename);
        }

        #endregion

        public static Backend.IBackendInterface WrapWithEncryption(Backend.IBackendInterface backend, Dictionary<string, string> options)
        {
            if (options.ContainsKey("no-encryption"))
                return backend;
            else
                return new EncryptedBackendWrapper(backend, options);
        }

    }
}