--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Chronosv2/source/Presentation/ViewModel/WindowViewModel.cs	Tue Feb 21 17:25:44 2012 +0700
@@ -0,0 +1,466 @@
+/*
+The MIT License
+
+Copyright (c) 2009-2010. Carlos Guzmán Álvarez. http://chronoswpf.codeplex.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.
+*/
+
+using System;
+using System.ComponentModel;
+using System.Threading;
+using System.Threading.Tasks;
+using Chronos.Presentation.Core.ViewModel;
+using Chronos.Presentation.Core.Windows;
+using NLog;
+using nRoute.Components;
+
+namespace Chronos.Presentation.ViewModel
+{
+    public abstract class WindowViewModel<TEntity>
+        : NavigationViewModel, IWindowViewModel where TEntity: class, new()
+    {
+        #region · Logger ·
+
+        private static Logger Logger = LogManager.GetCurrentClassLogger();
+
+        #endregion
+
+        #region · Inner Types ·
+
+        [Serializable]
+        protected enum InquiryActionResultType
+        {
+            DataFetched,
+            RequestedNew,
+            DataNotFound
+        }
+
+        protected sealed class InquiryActionResult<TResult>
+            where TResult : class
+        {
+            #region · Properties ·
+
+            public TResult Data
+            {
+                get;
+                set;
+            }
+
+            public InquiryActionResultType Result
+            {
+                get;
+                set;
+            }
+
+            #endregion
+
+            #region · Constructors ·
+
+            public InquiryActionResult()
+            {
+            }
+
+            #endregion
+        }
+
+        #endregion
+
+        #region · PropertyChangedEventArgs Cached Instances ·
+
+        private static readonly PropertyChangedEventArgs ViewModeChangedArgs            = CreateArgs<WindowViewModel<TEntity>>(x => x.ViewMode);
+        private static readonly PropertyChangedEventArgs StatusMessageChangedArgs       = CreateArgs<WindowViewModel<TEntity>>(x => x.StatusMessage);
+        private static readonly PropertyChangedEventArgs NotificationMessageChangedArgs = CreateArgs<WindowViewModel<TEntity>>(x => x.NotificationMessage);
+
+        #endregion
+
+        #region · Events ·
+
+        /// <summary>
+        /// Occurs when view mode is changed.
+        /// </summary>
+        public event EventHandler ViewModeChanged;
+
+        #endregion
+
+        #region · Fields ·
+
+        private TEntity                             originalEntity;
+        private string                              statusMessage;
+        private string                              notificationMessage;
+        private TEntity                             entity;
+        private ViewModeType                        viewMode;
+        private PropertyStateCollection<TEntity>    propertyStates;
+
+        #region · Commands ·
+
+        private ActionCommand inquiryCommand;
+
+        #endregion
+        
+        #endregion
+
+        #region · Properties ·
+
+        /// <summary>
+        /// Gets the property state collection
+        /// </summary>
+        public PropertyStateCollection<TEntity> PropertyStates
+        {
+            get
+            {
+                if (this.propertyStates == null)
+                {
+                    this.propertyStates = new PropertyStateCollection<TEntity>();
+                }
+
+                return this.propertyStates;
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets the state of the smart part.
+        /// </summary>
+        /// <value>The state of the smart part.</value>
+        public ViewModeType ViewMode
+        {
+            get { return this.viewMode; }
+            set
+            {
+                if (this.viewMode != value)
+                {
+                    this.viewMode = value;
+                    try
+                    {
+                        this.OnViewModeChanged();
+                    }
+                    catch
+                    {
+#warning TODO: This is done to prevent DataGrid erroros when discarding changes on new records
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets the inquiry data command
+        /// </summary>
+        public ActionCommand InquiryCommand
+        {
+            get
+            {
+                if (this.inquiryCommand == null)
+                {
+                    this.inquiryCommand = new ActionCommand
+                    (
+                        () => OnInquiryData(),
+                        () => CanInquiryData()
+                    );
+                }
+
+                return this.inquiryCommand;
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets the status message text
+        /// </summary>
+        public string StatusMessage
+        {
+            get { return this.statusMessage; }
+            set
+            {
+                if (this.statusMessage != value)
+                {
+                    this.statusMessage = value;
+                    this.NotifyPropertyChanged(StatusMessageChangedArgs);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets the notification message text
+        /// </summary>
+        public string NotificationMessage
+        {
+            get { return this.notificationMessage; }
+            set
+            {
+                if (this.notificationMessage != value)
+                {
+                    this.notificationMessage = value;
+                    this.NotifyPropertyChanged(NotificationMessageChangedArgs);
+                }
+            }
+        }
+
+        #endregion
+
+        #region · Protected Properties ·
+
+        /// <summary>
+        /// Gets or sets the data model.
+        /// </summary>
+        /// <value>The data model.</value>
+        protected TEntity Entity
+        {
+            get { return this.entity; }
+            private set
+            {
+                if (!Object.ReferenceEquals(this.entity, value))
+                {
+                    this.entity = value;
+                }
+            }
+        }
+
+        protected TEntity OriginalEntity
+        {
+            get { return this.originalEntity; }
+            set { this.originalEntity = value; }
+        }
+
+        #endregion
+
+        #region · Constructors ·
+
+        protected WindowViewModel()
+            : base()
+        {
+            this.InitializePropertyStates();
+
+            this.Entity     = new TEntity();
+            this.ViewMode   = ViewModeType.ViewOnly;
+        }
+
+        #endregion
+
+        #region · Command Actions ·
+
+        #region · Inquiry ·
+
+        protected virtual bool CanInquiryData()
+        {
+            return (this.ViewMode == ViewModeType.ViewOnly);
+        }
+
+        protected void OnInquiryData()
+        {
+            InquiryActionResult<TEntity> result = new InquiryActionResult<TEntity>
+            {
+                Result = InquiryActionResultType.DataNotFound
+            };
+
+            this.ViewMode       = ViewModeType.Busy;
+            this.StatusMessage  = "Obteniendo datos, espere por favor ...";
+
+            Task task = Task.Factory.StartNew
+            (
+                (o) =>
+                {
+                    Logger.Debug("Obteniendo datos '{0}'", this.Entity.ToString());
+
+                    this.OnInquiryAction(result);
+                }, result
+            );
+
+            task.ContinueWith
+            (
+                (t) =>
+                {
+                    Logger.Debug("Error al obtener datos '{0}'", t.Exception.InnerException.ToString());
+
+                    this.OnInquiryActionFailed();
+
+                    Exception exception     = null;
+                    this.OriginalEntity     = null;
+
+                    if (t.Exception.InnerException != null)
+                    {
+                        exception = t.Exception.InnerException;
+                    }
+                    else
+                    {
+                        exception = t.Exception;
+                    }
+
+                    this.NotificationMessage = exception.Message;
+                }, 
+                CancellationToken.None,
+                TaskContinuationOptions.OnlyOnFaulted | TaskContinuationOptions.AttachedToParent,
+                TaskScheduler.FromCurrentSynchronizationContext()
+            );
+
+            task.ContinueWith
+            (
+                _ =>
+                {
+                    Logger.Debug("Datos obtenidos correctamente '{0}'", this.Entity.ToString());
+
+                    this.StatusMessage = null;
+                    this.OnInquiryActionComplete(result);
+                }, 
+                CancellationToken.None,
+                TaskContinuationOptions.OnlyOnRanToCompletion | TaskContinuationOptions.AttachedToParent,
+                TaskScheduler.FromCurrentSynchronizationContext()
+            );
+        }
+
+        protected abstract void OnInquiryAction(InquiryActionResult<TEntity> result);
+
+        protected virtual void OnInquiryActionComplete(InquiryActionResult<TEntity> result)
+        {
+            switch (result.Result)
+            {
+                case InquiryActionResultType.DataNotFound:
+                    this.OriginalEntity = null;
+
+                    this.ResetDataModel();
+                    
+                    this.ViewMode = ViewModeType.ViewOnly;
+                    break;
+
+                case InquiryActionResultType.RequestedNew:
+                    throw new InvalidOperationException("Requested New is not valid on this type of ViewModel");
+
+                case InquiryActionResultType.DataFetched:
+                    this.ResetDataModel(result.Data);
+
+                    this.OriginalEntity = this.entity;
+                    this.ViewMode       = ViewModeType.ViewOnly;
+                    break;
+            }
+        }
+
+        protected virtual void OnInquiryActionFailed()
+        {
+            this.ViewMode = ViewModeType.ViewOnly;
+        }
+
+        #endregion
+
+        #endregion
+
+        #region · Overriden Methods ·
+
+        /// <summary>
+        /// Called when the related view is being closed.
+        /// </summary>
+        public override void Close()
+        {
+            Logger.Debug("Cerrar ventana '{0}'", this.GetType());
+
+            if (this.originalEntity != null)
+            {
+                this.originalEntity = null;
+            }
+            if (this.entity != null)
+            {
+                this.entity = null;
+            }
+            if (this.propertyStates != null)
+            {
+                this.propertyStates.Clear();
+                this.propertyStates = null;
+            }
+
+            this.inquiryCommand         = null;
+            this.statusMessage          = null;
+            this.notificationMessage    = null;
+
+            base.Close();
+        }
+
+        #endregion
+
+        #region · DataModel Reset Methods ·
+
+        protected void ResetDataModel()
+        {
+            Logger.Debug("Resetar model '{0}'", this.GetType());
+            this.ResetDataModel(new TEntity());
+            Logger.Debug("Model reseteado '{0}'", this.GetType());
+        }
+
+        protected virtual void ResetDataModel(TEntity model)
+        {
+            this.OnResetingDataModel(this.Entity, model);
+
+            this.OriginalEntity = null;
+            this.Entity         = model;
+
+            this.OnResetedDataModel(model);
+        }
+
+        protected virtual void OnResetingDataModel(TEntity oldModel, TEntity newModel)
+        {
+        }
+
+        protected virtual void OnResetedDataModel(TEntity newModel)
+        {
+            this.NotifyAllPropertiesChanged();
+        }
+
+        #endregion        
+
+        #region · Protected Methods ·
+
+        protected virtual void InitializePropertyStates()
+        {
+        }
+
+        protected virtual void OnViewModeChanged()
+        {
+            if (this.ViewModeChanged != null)
+            {
+                this.ViewModeChanged(this, new EventArgs());            
+            }
+
+            this.NotifyPropertyChanged(ViewModeChangedArgs);
+        }
+
+        protected virtual void UpdateAllowedUserActions()
+        {
+            this.Invoke
+            (
+                () =>
+                {
+                    this.InquiryCommand.RequeryCanExecute();
+                }
+            );
+        }
+
+        protected override void NotifyPropertyChanged(PropertyChangedEventArgs args)
+        {
+            if (args != StatusMessageChangedArgs)
+            {
+                this.StatusMessage = null;
+            }
+            if (args != NotificationMessageChangedArgs)
+            {
+                this.NotificationMessage = null;
+            }
+
+            this.UpdateAllowedUserActions();
+            base.NotifyPropertyChanged(args);
+        }
+
+        #endregion
+    }
+}