//===================================================================================

// Microsoft patterns & practices

// Composite Application Guidance for Windows Presentation Foundation and Silverlight

//===================================================================================

// Copyright (c) Microsoft Corporation.  All rights reserved.

// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY

// OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT

// LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

// FITNESS FOR A PARTICULAR PURPOSE.

//===================================================================================

// The example companies, organizations, products, domain names,

// e-mail addresses, logos, people, places, and events depicted

// herein are fictitious.  No association with any real company,

// organization, product, domain name, email address, logo, person,

// places, or events is intended or should be inferred.

//===================================================================================

using System;

using System.Collections.ObjectModel;

using System.ComponentModel;

using System.ComponentModel.Composition;

using System.Text;

using System.Threading;

using System.Windows.Data;

using System.Windows.Input;

using Microsoft.Practices.Prism;

using Microsoft.Practices.Prism.Commands;

using Microsoft.Practices.Prism.Regions;

using Microsoft.Practices.Prism.ViewModel;

using ViewSwitchingNavigation.Email.Model;

using ViewSwitchingNavigation.Infrastructure;



namespace ViewSwitchingNavigation.Email.ViewModels

{

    [Export]

    public class InboxViewModel : NotificationObject

    {

        private const string ComposeEmailViewKey = "ComposeEmailView";

        private const string ReplyToKey = "ReplyTo";

        private const string EmailViewKey = "EmailView";

        private const string EmailIdKey = "EmailId";



        private readonly SynchronizationContext synchronizationContext;

        private readonly IEmailService emailService;

        private readonly IRegionManager regionManager;

        private readonly DelegateCommand<object> composeMessageCommand;

        private readonly DelegateCommand<object> replyMessageCommand;

        private readonly DelegateCommand<EmailDocument> openMessageCommand;

        private readonly ObservableCollection<EmailDocument> messagesCollection;



        private static Uri ComposeEmailViewUri = new Uri(ComposeEmailViewKey, UriKind.Relative);



        [ImportingConstructor]

        public InboxViewModel(IEmailService emailService, IRegionManager regionManager)

        {

            this.synchronizationContext = SynchronizationContext.Current ?? new SynchronizationContext();



            this.composeMessageCommand = new DelegateCommand<object>(this.ComposeMessage);

            this.replyMessageCommand = new DelegateCommand<object>(this.ReplyMessage, this.CanReplyMessage);

            this.openMessageCommand = new DelegateCommand<EmailDocument>(this.OpenMessage);



            this.messagesCollection = new ObservableCollection<EmailDocument>();

            this.Messages = new PagedCollectionView(this.messagesCollection);

            this.Messages.CurrentChanged += (s, e) =>

                this.replyMessageCommand.RaiseCanExecuteChanged();



            this.emailService = emailService;

            this.regionManager = regionManager;



            this.emailService.BeginGetEmailDocuments(

                r =>

                {

                    var messages = this.emailService.EndGetEmailDocuments(r);



                    this.synchronizationContext.Post(

                        s =>

                        {

                            foreach (var message in messages)

                            {

                                this.messagesCollection.Add(message);

                            }

                        },

                        null);

                },

                null);

        }



        public ICollectionView Messages { get; private set; }



        public ICommand ComposeMessageCommand

        {

            get { return this.composeMessageCommand; }

        }



        public ICommand ReplyMessageCommand

        {

            get { return this.replyMessageCommand; }

        }



        public ICommand OpenMessageCommand

        {

            get { return this.openMessageCommand; }

        }



        private void ComposeMessage(object ignored)

        {

            // todo: 02 - New Email: Navigating to a view in a region

            // Any region can be navigated by passing in a relative Uri for the email view name.

            // By the default, the navigation service will look for an item already in the region

            // with a type name that matches the Uri.

            //

            // If an item is not found in the region, the navigation services uses the 

            // ServiceLocator to find an item that matches the Uri, in the example below it would

            // be ComposeEmailView.

            this.regionManager.RequestNavigate(RegionNames.MainContentRegion, ComposeEmailViewUri);

        }



        private void ReplyMessage(object ignored)

        {

            // todo: 03 - Reply Email: Navigating to a view in a region with context

            // When navigating, you can also supply context so the target view or

            // viewmodel can orient their data to something appropriate.  In this case,

            // we've chosen to pass the email id in a name/value pair as part of the Uri.

            //

            // The recipient of the context can get access to this information by

            // implementing the INavigationAware or IConfirmNavigationRequest interface, as shown by the 

            // the ComposeEmailViewModel.

            //

            var currentEmail = this.Messages.CurrentItem as EmailDocument;

            var builder = new StringBuilder();

            builder.Append(ComposeEmailViewKey);

            if (currentEmail != null)

            {

                var query = new UriQuery();

                query.Add(ReplyToKey, currentEmail.Id.ToString("N"));

                builder.Append(query);

            }

            this.regionManager.RequestNavigate(RegionNames.MainContentRegion, new Uri(builder.ToString(), UriKind.Relative));

        }



        private bool CanReplyMessage(object ignored)

        {

            return this.Messages.CurrentItem != null;

        }



        private void OpenMessage(EmailDocument document)

        {

            // todo: 04 - Open Email: Navigating to a view in a region with context

            // When navigating, you can also supply context so the target view or

            // viewmodel can orient their data to something appropriate.  In this case,

            // we've chosen to pass the email id in a name/value pair as part of the Uri.

            //

            // The EmailViewModel retrieves this context by implementing the INavigationAware

            // interface.

            //

            var builder = new StringBuilder();

            builder.Append(EmailViewKey);

            var query = new UriQuery();

            query.Add(EmailIdKey, document.Id.ToString("N"));

            builder.Append(query);

            this.regionManager.RequestNavigate(RegionNames.MainContentRegion, new Uri(builder.ToString(), UriKind.Relative));

        }

    }

}