#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2010 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab 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.
 *
 * HeuristicLab 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 HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Linq;
using HeuristicLab.Clients.Common;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.PluginInfrastructure;

namespace HeuristicLab.Clients.OKB.Authentication {
  [Item("AuthenticationClient", "OKB authentication client.")]
  public sealed class AuthenticationClient : IContent {
    private static AuthenticationClient instance;
    public static AuthenticationClient Instance {
      get {
        if (instance == null) instance = new AuthenticationClient();
        return instance;
      }
    }

    #region Properties
    private IEnumerable<User> users;
    public IEnumerable<User> Users {
      get { return users; }
    }
    #endregion

    private AuthenticationClient() { }

    #region Refresh
    public void Refresh() {
      OnRefreshing();
      try {
        users = CallAuthenticationService<List<User>>(s => s.GetUsers()).OrderBy(x => x.Name);
      }
      finally {
        OnRefreshed();
      }
    }
    public void RefreshAsync(Action<Exception> exceptionCallback) {
      var call = new Func<Exception>(delegate() {
        try {
          Refresh();
        }
        catch (Exception ex) {
          return ex;
        }
        return null;
      });
      call.BeginInvoke(delegate(IAsyncResult result) {
        Exception ex = call.EndInvoke(result);
        if (ex != null) exceptionCallback(ex);
      }, null);
    }
    #endregion

    #region User Methods
    public static IEnumerable<User> GetUsers() {
      return CallAuthenticationService<List<User>>(s => s.GetUsers()).OrderBy(x => x.Name);
    }
    #endregion

    #region Events
    public event EventHandler Refreshing;
    private void OnRefreshing() {
      EventHandler handler = Refreshing;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    public event EventHandler Refreshed;
    private void OnRefreshed() {
      EventHandler handler = Refreshed;
      if (handler != null) handler(this, EventArgs.Empty);
    }
    #endregion

    #region Helpers
    private static T CallAuthenticationService<T>(Func<IAuthenticationService, T> call) {
      AuthenticationServiceClient client = ClientFactory.CreateClient<AuthenticationServiceClient, IAuthenticationService>();
      try {
        return call(client);
      }
      finally {
        try {
          client.Close();
        }
        catch (Exception) {
          client.Abort();
        }
      }
    }
    #endregion
  }
}