path: root/Software/Visual_Studio/PPC/Tango.PPC.UI/Notifications/DefaultNotificationProvider.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Media;
using Tango.PPC.Common.Notifications;
using Tango.Core;
using System.Collections.Concurrent;
using System.Windows.Media.Imaging;
using Tango.SharedUI.Helpers;
using System.Timers;
using Tango.Core.Commands;
using Tango.Touch.Controls;

namespace Tango.PPC.UI.Notifications
{
    /// <summary>
    /// Represents the default PPC notification provider.
    /// </summary>
    /// <seealso cref="Tango.Core.ExtendedObject" />
    /// <seealso cref="Tango.PPC.Common.Notifications.INotificationProvider" />
    public class DefaultNotificationProvider : ExtendedObject, INotificationProvider
    {
        /// <summary>
        /// Gets the collection of notification items.
        /// </summary>
        public ObservableCollection<NotificationItem> NotificationItems { get; private set; }

        /// <summary>
        /// Represents a pending message box.
        /// </summary>
        private class PendingMessageBox
        {
            /// <summary>
            /// Gets or sets the message view model.
            /// </summary>
            public MessageBoxVM VM { get; set; }

            /// <summary>
            /// Gets or sets the message task completion source.
            /// </summary>
            public TaskCompletionSource<bool> CompletionSource { get; set; }
        }

        private ConcurrentQueue<PendingMessageBox> _pendingMessageBoxes;

        /// <summary>
        /// Initializes a new instance of the <see cref="DefaultNotificationProvider"/> class.
        /// </summary>
        public DefaultNotificationProvider()
        {
            NotificationItems = new ObservableCollection<NotificationItem>();
            _pendingMessageBoxes = new ConcurrentQueue<PendingMessageBox>();

            PopNotificationCommand = new RelayCommand<NotificationItem>((x) => PopNotification(x));
        }

        private MessageBoxVM _currentMessageBox;
        /// <summary>
        /// Gets the current message box if any.
        /// </summary>
        public MessageBoxVM CurrentMessageBox
        {
            get { return _currentMessageBox; }
            private set
            {
                _currentMessageBox = value;
                RaisePropertyChangedAuto();
                RaisePropertyChanged(nameof(HasMessageBox));
            }
        }

        /// <summary>
        /// Gets a value indicating whether a message box is available.
        /// </summary>
        public bool HasMessageBox
        {
            get
            {
                return CurrentMessageBox != null;
            }
        }

        /// <summary>
        /// Shows an error message box.
        /// </summary>
        /// <param name="message">The message.</param>
        /// <returns></returns>
        public Task ShowError(string message)
        {
            return ShowMessageBox(new MessageBoxVM()
            {
                Message = message,
                Icon = ResourceHelper.GetImageFromResources("Images/MessageBox Icons/information.png"),
                Title = "Error",
                Brush = Application.Current.Resources["TangoMessageBoxErrorBrush"] as Brush,
            });
        }

        /// <summary>
        /// Shows an information message box.
        /// </summary>
        /// <param name="message">The message.</param>
        /// <returns></returns>
        public Task ShowInfo(string message)
        {
            return ShowMessageBox(new MessageBoxVM()
            {
                Message = message,
                Icon = ResourceHelper.GetImageFromResources("Images/MessageBox Icons/information.png"),
                Title = "Information",
                Brush = Application.Current.Resources["TangoMessageBoxInfoBrush"] as Brush,
            });
        }

        /// <summary>
        /// Shows warning message box.
        /// </summary>
        /// <param name="message">The message.</param>
        /// <returns></returns>
        public Task ShowWarning(string message)
        {
            return ShowMessageBox(new MessageBoxVM()
            {
                Message = message,
                Icon = ResourceHelper.GetImageFromResources("Images/MessageBox Icons/information.png"),
                Title = "Warning",
                Brush = Application.Current.Resources["TangoMessageBoxWarningBrush"] as Brush,
            });
        }

        /// <summary>
        /// Shows a question message box.
        /// </summary>
        /// <param name="message">The message.</param>
        /// <returns></returns>
        public Task<bool> ShowQuestion(string message)
        {
            return ShowMessageBox(new MessageBoxVM()
            {
                Message = message,
                Icon = ResourceHelper.GetImageFromResources("Images/MessageBox Icons/information.png"),
                Title = "Confirm",
                HasCancel = true,
                Brush = Application.Current.Resources["TangoMessageBoxQuestionBrush"] as Brush,
            });
        }

        /// <summary>
        /// Shows the message box.
        /// </summary>
        /// <param name="vm">The view model.</param>
        /// <returns></returns>
        private Task<bool> ShowMessageBox(MessageBoxVM vm)
        {
            TaskCompletionSource<bool> source = new TaskCompletionSource<bool>();

            vm.Accepted += () => { OnMessageBoxClosed(); source.SetResult(true); };
            vm.Canceled += () => { OnMessageBoxClosed(); source.SetResult(false); };

            if (CurrentMessageBox == null)
            {
                CurrentMessageBox = vm;
            }
            else
            {
                _pendingMessageBoxes.Enqueue(new PendingMessageBox()
                {
                    VM = vm,
                    CompletionSource = source,
                });
            }

            return source.Task;
        }

        /// <summary>
        /// Called when the message box has been closed.
        /// </summary>
        private void OnMessageBoxClosed()
        {
            CurrentMessageBox = null;

            if (_pendingMessageBoxes.Count > 0)
            {
                PendingMessageBox p = null;
                if (_pendingMessageBoxes.TryDequeue(out p))
                {
                    CurrentMessageBox = p.VM;
                }
            }
        }

        /// <summary>
        /// Inserts the notification item to the bottom of the notifications collection.
        /// </summary>
        /// <param name="item">The item.</param>
        /// <returns></returns>
        public NotificationItem PushNotification(NotificationItem item)
        {
            return PushNotification(item, null, false, null);
        }

        /// <summary>
        /// Inserts the notification item to the bottom of the notifications collection.
        /// </summary>
        /// <param name="item">The item.</param>
        /// <param name="condition">A condition which determines if this item is still relevant.</param>
        /// <param name="autoCheck">Determines whether to perform automatic checking of the condition.</param>
        /// <param name="checkInterval">Determines how frequently the condition function will be invoked. (Default 1 second)</param>
        /// <returns></returns>
        public NotificationItem PushNotification(NotificationItem item, Func<bool> condition, bool autoCheck = true, TimeSpan? checkInterval = default(TimeSpan?))
        {
            item.Condition = condition;
            item.AutoCheck = autoCheck;
            item.AutoCheckInterval = checkInterval != null ? checkInterval.Value : TimeSpan.FromSeconds(1);
            item.RemoveAction = () => { PopNotification(item); };
            NotificationItems.Insert(0, item);

            if (autoCheck && condition != null)
            {
                Timer timer = new Timer();
                item.Timer = timer;
                timer.Interval = item.AutoCheckInterval.TotalMilliseconds;
                timer.Elapsed += (x, y) =>
                {
                    if (!item.Condition())
                    {
                        PopNotification(item);
                    }
                };
                timer.Start();
            }

            RaisePropertyChanged(nameof(HasNotificationItems));

            return item;
        }

        /// <summary>
        /// Removed the specified notification item.
        /// </summary>
        /// <param name="item">The item.</param>
        public void PopNotification(NotificationItem item)
        {
            if (item.Timer != null)
            {
                item.Timer.Stop();
            }

            NotificationItems.Remove(item);

            RaisePropertyChanged(nameof(HasNotificationItems));
        }

        /// <summary>
        /// Invokes the notification items conditions.
        /// </summary>
        public void InvokeNotificationItemsConditions()
        {
            var list = NotificationItems.ToList();

            foreach (var item in list.Where(x => x.Condition != null))
            {
                if (!item.Condition())
                {
                    PopNotification(item);
                }
            }
        }

        /// <summary>
        /// Gets a value indicating whether this instance has notification items.
        /// </summary>
        public bool HasNotificationItems
        {
            get
            {
                return NotificationItems.Count > 0;
            }
        }

        public RelayCommand<NotificationItem> PopNotificationCommand { get; private set; }
    }
}