#region
/* -----------------------------------------------------------------------
 * <copyright file="ShellViewModel.cs" company="GRNet">
 * 
 * Copyright 2011-2012 GRNET S.A. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 *   1. Redistributions of source code must retain the above
 *      copyright notice, this list of conditions and the following
 *      disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above
 *      copyright notice, this list of conditions and the following
 *      disclaimer in the documentation and/or other materials
 *      provided with the distribution.
 *
 *
 * THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and
 * documentation are those of the authors and should not be
 * interpreted as representing official policies, either expressed
 * or implied, of GRNET S.A.
 * </copyright>
 * -----------------------------------------------------------------------
 */
#endregion
using System.Collections.Concurrent;
using System.Diagnostics;
using System.Diagnostics.Contracts;
using System.IO;
using System.Net;
using System.Reflection;
using System.Runtime.InteropServices;
using System.ServiceModel;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls.Primitives;
using AppLimit.NetSparkle;
using Caliburn.Micro;
using Hardcodet.Wpf.TaskbarNotification;
using Pithos.Client.WPF.Configuration;
using Pithos.Client.WPF.FileProperties;
using Pithos.Client.WPF.Preferences;
using Pithos.Client.WPF.SelectiveSynch;
using Pithos.Client.WPF.Services;
using Pithos.Client.WPF.Shell;
using Pithos.Core;
using Pithos.Core.Agents;
using Pithos.Interfaces;
using System;
using System.Collections.Generic;
using System.Linq;
using Pithos.Network;
using StatusService = Pithos.Client.WPF.Services.StatusService;

namespace Pithos.Client.WPF {
	using System.ComponentModel.Composition;

	
	///<summary>
	/// The "shell" of the Pithos application displays the taskbar  icon, menu and notifications.
	/// The shell also hosts the status service called by shell extensions to retrieve file info
	///</summary>
	///<remarks>
	/// It is a strange "shell" as its main visible element is an icon instead of a window
	/// The shell subscribes to the following events:
	/// * Notification:  Raised by components that want to notify the user. Usually displayed in a balloon
	/// * SelectiveSynchChanges: Notifies that the user made changes to the selective synch folders for an account. Raised by the Selective Synch dialog. Located here because the monitors are here
	/// * ShowFilePropertiesEvent: Raised when a shell command requests the display of the file/container properties dialog
	///</remarks>		
	//TODO: CODE SMELL Why does the shell handle the SelectiveSynchChanges?
	[Export(typeof(IShell))]
	public class ShellViewModel : Screen, IStatusNotification, IShell,
		IHandle<Notification>, IHandle<SelectiveSynchChanges>, IHandle<ShowFilePropertiesEvent>
	{

		//The Status Checker provides the current synch state
		//TODO: Could we remove the status checker and use events in its place?
		private readonly IStatusChecker _statusChecker;
		private readonly IEventAggregator _events;

		public PithosSettings Settings { get; private set; }


		private readonly ConcurrentDictionary<string, PithosMonitor> _monitors = new ConcurrentDictionary<string, PithosMonitor>();
		///<summary>
		/// Dictionary of account monitors, keyed by account
		///</summary>
		///<remarks>
		/// One monitor class is created for each account. The Shell needs access to the monitors to execute start/stop/pause commands,
		/// retrieve account and boject info		
		///</remarks>
		// TODO: Does the Shell REALLY need access to the monitors? Could we achieve the same results with a better design?
		// TODO: The monitors should be internal to Pithos.Core, even though exposing them makes coding of the Object and Container windows easier
		public ConcurrentDictionary<string, PithosMonitor> Monitors
		{
			get { return _monitors; }
		}


		///<summary>
		/// The status service is used by Shell extensions to retrieve file status information
		///</summary>
		//TODO: CODE SMELL! This is the shell! While hosting in the shell makes executing start/stop commands easier, it is still a smell
		private ServiceHost _statusService;

		//Logging in the Pithos client is provided by log4net
        private static readonly log4net.ILog Log = log4net.LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

		//Lazily initialized File Version info. This is done once and lazily to avoid blocking the UI
		private readonly Lazy<FileVersionInfo> _fileVersion;

	    private readonly PollAgent _pollAgent;

		///<summary>
		/// The Shell depends on MEF to provide implementations for windowManager, events, the status checker service and the settings
		///</summary>
		///<remarks>
		/// The PithosSettings class encapsulates the app's settings to abstract their storage mechanism (App settings, a database or registry)
		///</remarks>
		[ImportingConstructor]		
		public ShellViewModel(IWindowManager windowManager, IEventAggregator events, IStatusChecker statusChecker, PithosSettings settings,PollAgent pollAgent)
		{
			try
			{

				_windowManager = windowManager;
				//CHECK: Caliburn doesn't need explicit command construction
				//OpenPithosFolderCommand = new PithosCommand(OpenPithosFolder);
				_statusChecker = statusChecker;
				//The event subst
				_events = events;
				_events.Subscribe(this);

			    _pollAgent = pollAgent;
				Settings = settings;

				Proxy.SetFromSettings(settings);

				StatusMessage = "In Synch";

				_fileVersion=  new Lazy<FileVersionInfo>(() =>
				{
					Assembly assembly = Assembly.GetExecutingAssembly();
					var fileVersion = FileVersionInfo.GetVersionInfo(assembly.Location);
					return fileVersion;
				});
				_accounts.CollectionChanged += (sender, e) =>
												   {
													   NotifyOfPropertyChange(() => OpenFolderCaption);
													   NotifyOfPropertyChange(() => HasAccounts);
												   };

			}
			catch (Exception exc)
			{
				Log.Error("Error while starting the ShellViewModel",exc);
				throw;
			}

		}


		protected override void OnActivate()
		{
			base.OnActivate();

            _sparkle = new Sparkle(Settings.UpdateUrl);
            _sparkle.updateDetected += OnUpgradeDetected;
            _sparkle.ShowDiagnosticWindow = Settings.UpdateDiagnostics;

            //Must delay opening the upgrade window
            //to avoid Windows Messages sent by the TaskbarIcon
            TaskEx.Delay(5000).ContinueWith(_=>
                Execute.OnUIThread(()=> _sparkle.StartLoop(true,true,Settings.UpdateCheckInterval)));


			StartMonitoring();                    
		}

	    private void OnUpgradeDetected(object sender, UpdateDetectedEventArgs e)
	    {
	        Log.InfoFormat("Update detected {0}",e.LatestVersion);
	    }

        public void CheckForUpgrade()
        {
            _sparkle.StopLoop();
            _sparkle.Dispose();
            _sparkle=new Sparkle(Settings.UpdateUrl);
            _sparkle.StartLoop(true,true,Settings.UpdateCheckInterval);
        }

	    private async void StartMonitoring()
		{
			try
			{
				var accounts = Settings.Accounts.Select(MonitorAccount);
				await TaskEx.WhenAll(accounts);
				_statusService = StatusService.Start();

/*
				foreach (var account in Settings.Accounts)
				{
					await MonitorAccount(account);
				}
*/
				
			}
			catch (AggregateException exc)
			{
				exc.Handle(e =>
				{
					Log.Error("Error while starting monitoring", e);
					return true;
				});
				throw;
			}
		}

		protected override void OnDeactivate(bool close)
		{
			base.OnDeactivate(close);
			if (close)
			{
				StatusService.Stop(_statusService);
				_statusService = null;
			}
		}

		public Task MonitorAccount(AccountSettings account)
		{
			return Task.Factory.StartNew(() =>
			{                                                
				PithosMonitor monitor;
				var accountName = account.AccountName;

				if (_monitors.TryGetValue(accountName, out monitor))
				{
					//If the account is active
                    if (account.IsActive)
                    {
                        //The Api Key may have changed throuth the Preferences dialog
                        monitor.ApiKey = account.ApiKey;
						Debug.Assert(monitor.StatusNotification == this,"An existing monitor should already have a StatusNotification service object");
                        monitor.RootPath = account.RootPath;
                        //Start the monitor. It's OK to start an already started monitor,
                        //it will just ignore the call                        
                        StartMonitor(monitor).Wait();
                    }
                    else
                    {
                        //If the account is inactive
                        //Stop and remove the monitor
                        RemoveMonitor(accountName);
                    }
					return;
				}

				
				//Create a new monitor/ Can't use MEF here, it would return a single instance for all monitors
				monitor = new PithosMonitor
							  {
								  UserName = accountName,
								  ApiKey = account.ApiKey,                                  
								  StatusNotification = this,
								  RootPath = account.RootPath
							  };
				//PithosMonitor uses MEF so we need to resolve it
				IoC.BuildUp(monitor);

				monitor.AuthenticationUrl = account.ServerUrl;

				_monitors[accountName] = monitor;

				if (account.IsActive)
				{
					//Don't start a monitor if it doesn't have an account and ApiKey
					if (String.IsNullOrWhiteSpace(monitor.UserName) ||
						String.IsNullOrWhiteSpace(monitor.ApiKey))
						return;
					StartMonitor(monitor);
				}
			});
		}


		protected override void OnViewLoaded(object view)
		{
			UpdateStatus();
			var window = (Window)view;            
			TaskEx.Delay(1000).ContinueWith(t => Execute.OnUIThread(window.Hide));
			base.OnViewLoaded(view);
		}


		#region Status Properties

		private string _statusMessage;
		public string StatusMessage
		{
			get { return _statusMessage; }
			set
			{
				_statusMessage = value;
				NotifyOfPropertyChange(() => StatusMessage);
			}
		}

		private readonly ObservableConcurrentCollection<AccountInfo> _accounts = new ObservableConcurrentCollection<AccountInfo>();
		public ObservableConcurrentCollection<AccountInfo> Accounts
		{
			get { return _accounts; }
		}

		public bool HasAccounts
		{
			get { return _accounts.Count > 0; }
		}


		public string OpenFolderCaption
		{
			get
			{
				return (_accounts.Count == 0)
						? "No Accounts Defined"
						: "Open Pithos Folder";
			}
		}

		private string _pauseSyncCaption="Pause Synching";
		public string PauseSyncCaption
		{
			get { return _pauseSyncCaption; }
			set
			{
				_pauseSyncCaption = value;
				NotifyOfPropertyChange(() => PauseSyncCaption);
			}
		}

		private readonly ObservableConcurrentCollection<FileEntry> _recentFiles = new ObservableConcurrentCollection<FileEntry>();
		public ObservableConcurrentCollection<FileEntry> RecentFiles
		{
			get { return _recentFiles; }
		}


		private string _statusIcon="../Images/Pithos.ico";
		public string StatusIcon
		{
			get { return _statusIcon; }
			set
			{
				//TODO: Ensure all status icons use the Pithos logo
				_statusIcon = value;
				NotifyOfPropertyChange(() => StatusIcon);
			}
		}

		#endregion

		#region Commands

        public void ShowPreferences()
        {
            ShowPreferences(null);
        }

		public void ShowPreferences(string currentTab)
		{
			//Settings.Reload();
		    var preferences = new PreferencesViewModel(_windowManager, _events, this, Settings,currentTab);
		    _windowManager.ShowDialog(preferences);
			
		}

		public void AboutPithos()
		{
			var about = new AboutViewModel();
			_windowManager.ShowWindow(about);
		}

		public void SendFeedback()
		{
			var feedBack =  IoC.Get<FeedbackViewModel>();
			_windowManager.ShowWindow(feedBack);
		}

		//public PithosCommand OpenPithosFolderCommand { get; private set; }

		public void OpenPithosFolder()
		{
			var account = Settings.Accounts.FirstOrDefault(acc => acc.IsActive);
			if (account == null)
				return;
			Process.Start(account.RootPath);
		}

		public void OpenPithosFolder(AccountInfo account)
		{
			Process.Start(account.AccountPath);
		}

		
/*
		public void GoToSite()
		{            
			var site = Properties.Settings.Default.PithosSite;
			Process.Start(site);            
		}
*/

		public void GoToSite(AccountInfo account)
		{
		    var uri = account.SiteUri.Replace("http://","https://");            
		    Process.Start(uri);
		}

	    /// <summary>
        /// Open an explorer window to the target path's directory
        /// and select the file
        /// </summary>
        /// <param name="entry"></param>
        public void GoToFile(FileEntry entry)
        {
            var fullPath = entry.FullPath;
            if (!File.Exists(fullPath) && !Directory.Exists(fullPath))
                return;
            Process.Start("explorer.exe","/select, " + fullPath);
        }

        public void OpenLogPath()
        {
            var appDataPath = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData);
            var pithosDataPath = Path.Combine(appDataPath, "GRNET");

            Process.Start(pithosDataPath);
        }
        
        public void ShowFileProperties()
		{
			var account = Settings.Accounts.First(acc => acc.IsActive);            
			var dir = new DirectoryInfo(account.RootPath + @"\pithos");
			var files=dir.GetFiles();
			var r=new Random();
			var idx=r.Next(0, files.Length);
			ShowFileProperties(files[idx].FullName);            
		}

		public void ShowFileProperties(string filePath)
		{
			if (String.IsNullOrWhiteSpace(filePath))
				throw new ArgumentNullException("filePath");
			if (!File.Exists(filePath) && !Directory.Exists(filePath))
				throw new ArgumentException(String.Format("Non existent file {0}",filePath),"filePath");
			Contract.EndContractBlock();

			var pair=(from monitor in  Monitors
							   where filePath.StartsWith(monitor.Value.RootPath, StringComparison.InvariantCultureIgnoreCase)
								   select monitor).FirstOrDefault();
			var accountMonitor = pair.Value;

			if (accountMonitor == null)
				return;

			var infoTask=Task.Factory.StartNew(()=>accountMonitor.GetObjectInfo(filePath));

			

			var fileProperties = new FilePropertiesViewModel(this, infoTask,filePath);
			_windowManager.ShowWindow(fileProperties);
		} 
		
		public void ShowContainerProperties()
		{
			var account = Settings.Accounts.First(acc => acc.IsActive);            
			var dir = new DirectoryInfo(account.RootPath);
			var fullName = (from folder in dir.EnumerateDirectories()
							where (folder.Attributes & FileAttributes.Hidden) == 0
							select folder.FullName).First();
			ShowContainerProperties(fullName);            
		}

		public void ShowContainerProperties(string filePath)
		{
			if (String.IsNullOrWhiteSpace(filePath))
				throw new ArgumentNullException("filePath");
			if (!Directory.Exists(filePath))
				throw new ArgumentException(String.Format("Non existent file {0}",filePath),"filePath");
			Contract.EndContractBlock();

			var pair=(from monitor in  Monitors
							   where filePath.StartsWith(monitor.Value.RootPath, StringComparison.InvariantCultureIgnoreCase)
								   select monitor).FirstOrDefault();
			var accountMonitor = pair.Value;            
			var info = accountMonitor.GetContainerInfo(filePath);

			

			var containerProperties = new ContainerPropertiesViewModel(this, info,filePath);
			_windowManager.ShowWindow(containerProperties);
		}

		public void SynchNow()
		{
			_pollAgent.SynchNow();
		}

		public ObjectInfo RefreshObjectInfo(ObjectInfo currentInfo)
		{
			if (currentInfo==null)
				throw new ArgumentNullException("currentInfo");
			Contract.EndContractBlock();

			var monitor = Monitors[currentInfo.Account];
			var newInfo=monitor.CloudClient.GetObjectInfo(currentInfo.Account, currentInfo.Container, currentInfo.Name);
			return newInfo;
		}

		public ContainerInfo RefreshContainerInfo(ContainerInfo container)
		{
			if (container == null)
				throw new ArgumentNullException("container");
			Contract.EndContractBlock();

			var monitor = Monitors[container.Account];
			var newInfo = monitor.CloudClient.GetContainerInfo(container.Account, container.Name);
			return newInfo;
		}


		public void ToggleSynching()
		{
			bool isPaused=false;
			foreach (var pair in Monitors)
			{
				var monitor = pair.Value;
				monitor.Pause = !monitor.Pause;
				isPaused = monitor.Pause;
			}
                        

			PauseSyncCaption = isPaused ? "Resume syncing" : "Pause syncing";
			var iconKey = isPaused? "TraySyncPaused" : "TrayInSynch";
			StatusIcon = String.Format(@"../Images/{0}.ico", iconKey);
		}

		public void ExitPithos()
		{
			foreach (var pair in Monitors)
			{
				var monitor = pair.Value;
				monitor.Stop();
			}

			((Window)GetView()).Close();
		}
		#endregion


		private readonly Dictionary<PithosStatus, StatusInfo> _iconNames = new List<StatusInfo>
			{
				new StatusInfo(PithosStatus.InSynch, "All files up to date", "TrayInSynch"),
				new StatusInfo(PithosStatus.PollSyncing, "Polling Files", "TraySynching"),
                new StatusInfo(PithosStatus.LocalSyncing, "Syncing Files", "TraySynching"),
				new StatusInfo(PithosStatus.SyncPaused, "Sync Paused", "TraySyncPaused")
			}.ToDictionary(s => s.Status);

		readonly IWindowManager _windowManager;
		
        //private int _syncCount=0;


        private PithosStatus _pithosStatus = PithosStatus.Disconnected;

        public void SetPithosStatus(PithosStatus status)
        {
            if (_pithosStatus == PithosStatus.LocalSyncing && status == PithosStatus.PollComplete)
                return;
            if (_pithosStatus == PithosStatus.PollSyncing && status == PithosStatus.LocalComplete)
                return;
            if (status == PithosStatus.LocalComplete || status == PithosStatus.PollComplete)
                _pithosStatus = PithosStatus.InSynch;
            else
                _pithosStatus = status;
            UpdateStatus();
        }

        public void SetPithosStatus(PithosStatus status,string message)
        {
            StatusMessage = message;
            SetPithosStatus(status);
        }



		///<summary>
		/// Updates the visual status indicators of the application depending on status changes, e.g. icon, stat		
		///</summary>
		public void UpdateStatus()
		{

			if (_iconNames.ContainsKey(_pithosStatus))
			{
				var info = _iconNames[_pithosStatus];
				StatusIcon = String.Format(@"../Images/{0}.ico", info.IconName);
			}

            if (_pithosStatus == PithosStatus.InSynch)
                StatusMessage = "All files up to date";
		}


	   
		private Task StartMonitor(PithosMonitor monitor,int retries=0)
		{
			return Task.Factory.StartNew(() =>
			{
				using (log4net.ThreadContext.Stacks["Monitor"].Push("Start"))
				{
					try
					{
						Log.InfoFormat("Start Monitoring {0}", monitor.UserName);

						monitor.Start();
					}
					catch (WebException exc)
					{
						if (AbandonRetry(monitor, retries))
							return;

						HttpStatusCode statusCode =HttpStatusCode.OK;
						var response = exc.Response as HttpWebResponse;
						if(response!=null)
							statusCode = response.StatusCode;

						switch (statusCode)
						{
							case HttpStatusCode.Unauthorized:
								var message = String.Format("API Key Expired for {0}. Starting Renewal",
															monitor.UserName);
								Log.Error(message, exc);
						        var account = Settings.Accounts.Find(acc => acc.AccountName == monitor.UserName);                                
						        account.IsExpired = true;
                                Notify(new ExpirationNotification(account));
								//TryAuthorize(monitor.UserName, retries).Wait();
								break;
							case HttpStatusCode.ProxyAuthenticationRequired:
								TryAuthenticateProxy(monitor,retries);
								break;
							default:
								TryLater(monitor, exc, retries);
								break;
						}
					}
					catch (Exception exc)
					{
						if (AbandonRetry(monitor, retries)) 
							return;

						TryLater(monitor,exc,retries);
					}
				}
			});
		}

		private void TryAuthenticateProxy(PithosMonitor monitor,int retries)
		{
			Execute.OnUIThread(() =>
								   {                                       
									   var proxyAccount = IoC.Get<ProxyAccountViewModel>();
										proxyAccount.Settings = Settings;
									   if (true != _windowManager.ShowDialog(proxyAccount)) 
										   return;
									   StartMonitor(monitor, retries);
									   NotifyOfPropertyChange(() => Accounts);
								   });
		}

		private bool AbandonRetry(PithosMonitor monitor, int retries)
		{
			if (retries > 1)
			{
				var message = String.Format("Monitoring of account {0} has failed too many times. Will not retry",
											monitor.UserName);
				_events.Publish(new Notification
									{Title = "Account monitoring failed", Message = message, Level = TraceLevel.Error});
				return true;
			}
			return false;
		}


	    private void TryLater(PithosMonitor monitor, Exception exc,int retries)
		{
			var message = String.Format("An exception occured. Can't start monitoring\nWill retry in 10 seconds");
			Task.Factory.StartNewDelayed(10000, () => StartMonitor(monitor,retries+1));
			_events.Publish(new Notification
								{Title = "Error", Message = message, Level = TraceLevel.Error});
			Log.Error(message, exc);
		}


		public void NotifyChange(string status, TraceLevel level=TraceLevel.Info)
		{
			StatusMessage = status;
			
			_events.Publish(new Notification { Title = "Pithos", Message = status, Level = level });
		}

		public void NotifyChangedFile(string filePath)
		{
            if (RecentFiles.Any(e => e.FullPath == filePath))
                return;
            
			IProducerConsumerCollection<FileEntry> files=RecentFiles;
			FileEntry popped;
			while (files.Count > 5)
				files.TryTake(out popped);
            var entry = new FileEntry { FullPath = filePath };
			files.TryAdd(entry);
		}

		public void NotifyAccount(AccountInfo account)
		{
			if (account== null)
				return;
			//TODO: What happens to an existing account whose Token has changed?
			account.SiteUri= String.Format("{0}/ui/?token={1}&user={2}",
				account.SiteUri, Uri.EscapeDataString(account.Token),
				Uri.EscapeDataString(account.UserName));

			if (Accounts.All(item => item.UserName != account.UserName))
				Accounts.TryAdd(account);

		}

		public void NotifyConflicts(IEnumerable<FileSystemInfo> conflictFiles, string message)
		{
			if (conflictFiles == null)
				return;
		    //Convert to list to avoid multiple iterations
            var files = conflictFiles.ToList();
			if (files.Count==0)
				return;

			UpdateStatus();
			//TODO: Create a more specific message. For now, just show a warning
			NotifyForFiles(files,message,TraceLevel.Warning);

		}

		public void NotifyForFiles(IEnumerable<FileSystemInfo> files, string message,TraceLevel level=TraceLevel.Info)
		{
			if (files == null)
				return;
			if (!files.Any())
				return;

			StatusMessage = message;

			_events.Publish(new Notification { Title = "Pithos", Message = message, Level = level});
		}

		public void Notify(Notification notification)
		{
			_events.Publish(notification);
		}


		public void RemoveMonitor(string accountName)
		{
			if (String.IsNullOrWhiteSpace(accountName))
				return;

			var accountInfo=_accounts.FirstOrDefault(account => account.UserName == accountName);
            if (accountInfo != null)
            {
                _accounts.TryRemove(accountInfo);
                _pollAgent.RemoveAccount(accountInfo);
            }

		    PithosMonitor monitor;
			if (Monitors.TryRemove(accountName, out monitor))
			{
				monitor.Stop();
                //TODO: Also remove any pending actions for this account
                //from the network queue                
			}
		}

		public void RefreshOverlays()
		{
			foreach (var pair in Monitors)
			{
				var monitor = pair.Value;

				var path = monitor.RootPath;

				if (String.IsNullOrWhiteSpace(path))
					continue;

				if (!Directory.Exists(path) && !File.Exists(path))
					continue;

				IntPtr pathPointer = Marshal.StringToCoTaskMemAuto(path);

				try
				{
					NativeMethods.SHChangeNotify(HChangeNotifyEventID.SHCNE_UPDATEITEM,
												 HChangeNotifyFlags.SHCNF_PATHW | HChangeNotifyFlags.SHCNF_FLUSHNOWAIT,
												 pathPointer, IntPtr.Zero);
				}
				finally
				{
					Marshal.FreeHGlobal(pathPointer);
				}
			}
		}

		#region Event Handlers
		
		public void Handle(SelectiveSynchChanges message)
		{
			var accountName = message.Account.AccountName;
			PithosMonitor monitor;
			if (_monitors.TryGetValue(accountName, out monitor))
			{
				monitor.SetSelectivePaths(message.Uris,message.Added,message.Removed);

			}
			
		}


		private bool _pollStarted;
	    private Sparkle _sparkle;

	    //SMELL: Doing so much work for notifications in the shell is wrong
		//The notifications should be moved to their own view/viewmodel pair
		//and different templates should be used for different message types
		//This will also allow the addition of extra functionality, eg. actions
		//
		public void Handle(Notification notification)
		{
			UpdateStatus();

			if (!Settings.ShowDesktopNotifications)
				return;

			if (notification is PollNotification)
			{
				_pollStarted = true;
				return;
			}
			if (notification is CloudNotification)
			{
				if (!_pollStarted) 
					return;
				_pollStarted= false;
				notification.Title = "Pithos";
				notification.Message = "Start Synchronisation";
			}

		    var progress = notification as ProgressNotification;
		    if (progress != null)
		    {
		        StatusMessage = String.Format("Pithos {0}\r\n{1} {2:p2} of {3} - {4}",
		                                      _fileVersion.Value.FileVersion, 
                                              progress.Action,
		                                      progress.Block/(double)progress.TotalBlocks,
		                                      progress.FileSize.ToByteSize(),
		                                      progress.FileName);
		        return;
		    }

		    var info = notification as StatusNotification;
            if (info != null)
            {
                StatusMessage = String.Format("Pithos {0}\r\n{1}",
                                              _fileVersion.Value.FileVersion,
                                              info.Title);
                return;
            }
			if (String.IsNullOrWhiteSpace(notification.Message) && String.IsNullOrWhiteSpace(notification.Title))
				return;

			ShowBalloonFor(notification);
		}

	    private void ShowBalloonFor(Notification notification)
	    {
            Contract.Requires(notification!=null);
            
            if (!Settings.ShowDesktopNotifications) 
                return;
            
            BalloonIcon icon;
	        switch (notification.Level)
	        {
	            case TraceLevel.Info:
	            case TraceLevel.Verbose:
	                return;
                case TraceLevel.Error:
                    icon = BalloonIcon.Error;
                    break;
                case TraceLevel.Warning:
	                icon = BalloonIcon.Warning;
	                break;
	            default:
	                return;
	        }

	        var tv = (ShellView) GetView();
	        System.Action clickAction = null;
	        if (notification is ExpirationNotification)
	        {
	            clickAction = () => ShowPreferences("AccountTab");
	        }
	        var balloon = new PithosBalloon
	                          {
	                              Title = notification.Title,
	                              Message = notification.Message,
	                              Icon = icon,
	                              ClickAction = clickAction
	                          };
	        tv.TaskbarView.ShowCustomBalloon(balloon, PopupAnimation.Fade, 4000);
	    }

	    #endregion

		public void Handle(ShowFilePropertiesEvent message)
		{
			if (message == null)
				throw new ArgumentNullException("message");
			if (String.IsNullOrWhiteSpace(message.FileName) )
				throw new ArgumentException("message");
			Contract.EndContractBlock();

			var fileName = message.FileName;
			//TODO: Display file properties for non-container folders
			if (File.Exists(fileName))
				//Retrieve the full name with exact casing. Pithos names are case sensitive				
				ShowFileProperties(FileInfoExtensions.GetProperFilePathCapitalization(fileName));
			else if (Directory.Exists(fileName))
				//Retrieve the full name with exact casing. Pithos names are case sensitive
			{
				var path = FileInfoExtensions.GetProperDirectoryCapitalization(fileName);
				if (IsContainer(path))
					ShowContainerProperties(path);
				else
					ShowFileProperties(path);
			}
		}

		private bool IsContainer(string path)
		{
			var matchingFolders = from account in _accounts
								  from rootFolder in Directory.GetDirectories(account.AccountPath)
								  where rootFolder.Equals(path, StringComparison.InvariantCultureIgnoreCase)
								  select rootFolder;
			return matchingFolders.Any();
		}

		public FileStatus GetFileStatus(string localFileName)
		{
			if (String.IsNullOrWhiteSpace(localFileName))
				throw new ArgumentNullException("localFileName");
			Contract.EndContractBlock();
			
			var statusKeeper = IoC.Get<IStatusKeeper>();
			var status=statusKeeper.GetFileStatus(localFileName);
			return status;
		}
	}
}