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;
using Tango.SharedUI;
using System.Reflection;
using Tango.Core.DI;
using System.ComponentModel;
using System.Windows.Data;
using Tango.Logging;

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
    {
        private ConcurrentQueue<PendingNotification<MessageBoxVM, bool>> _pendingMessageBoxes;
        private ConcurrentQueue<PendingNotification<DialogAndView, DialogViewVM>> _pendingDialogs;
        private List<AppButton> _appButtons;

        private bool _notificationsVisible;
        /// <summary>
        /// Gets or sets a value indicating whether to allow notifications visibility.
        /// </summary>
        public bool NotificationsVisible
        {
            get { return _notificationsVisible; }
            set { _notificationsVisible = value; RaisePropertyChangedAuto(); }
        }

        /// <summary>
        /// Gets the collection of notification items.
        /// </summary>
        public ObservableCollection<NotificationItem> NotificationItems { get; private set; }

        /// <summary>
        /// Gets the application bar items.
        /// </summary>
        public ObservableCollection<AppBarItem> AppBarItems { get; private set; }

        /// <summary>
        /// Gets the notification items view.
        /// </summary>
        public ICollectionView NotificationItemsView { get; private set; }

        /// <summary>
        /// Gets the collection of taskbar items.
        /// </summary>
        public ObservableCollection<TaskBarItem> TaskBarItems { get; private set; }

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

            AppBarItems = new ObservableCollection<AppBarItem>();
            CollectionViewSource.GetDefaultView(AppBarItems).SortDescriptions.Add(new SortDescription(nameof(AppBarItem.Priority), ListSortDirection.Ascending));

            TaskBarItems = new ObservableCollection<TaskBarItem>();
            _pendingMessageBoxes = new ConcurrentQueue<PendingNotification<MessageBoxVM, bool>>();
            _pendingDialogs = new ConcurrentQueue<PendingNotification<DialogAndView, DialogViewVM>>();
            _appButtons = new List<AppButton>();

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

            NotificationItems.EnableCrossThreadOperations();

            NotificationItemsView = CollectionViewSource.GetDefaultView(NotificationItems);
            NotificationItemsView.SortDescriptions.Add(new SortDescription(nameof(NotificationItem.Priority), ListSortDirection.Descending));
        }

        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));
                RaisePropertyChanged(nameof(HasDialogOrMessage));
            }
        }

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

        private FrameworkElement _currentDialog;
        /// <summary>
        /// Gets the current dialog if any.
        /// </summary>
        public FrameworkElement CurrentDialog
        {
            get { return _currentDialog; }
            private set
            {
                _currentDialog = value;
                RaisePropertyChangedAuto();
                RaisePropertyChanged(nameof(HasDialog));
                RaisePropertyChanged(nameof(HasDialogOrMessage));
            }
        }

        private AppButton _currentAppButton;
        /// <summary>
        /// Gets the current app button.
        /// </summary>
        public AppButton CurrentAppButton
        {
            get { return _currentAppButton; }
            private set { _currentAppButton = value; RaisePropertyChangedAuto(); }
        }

        /// <summary>
        /// Gets a value indicating whether a dialog is available.
        /// </summary>
        public bool HasDialog
        {
            get
            {
                return CurrentDialog != null;
            }
        }

        public bool HasDialogOrMessage
        {
            get
            {
                return HasDialog || HasMessageBox;
            }
        }

        /// <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 = TouchIconKind.AlertCircleOutline,
                Title = "Error",
                Brush = Application.Current.Resources["TangoMessageBoxErrorBrush"] as Brush,
                HeaderBrush = Application.Current.Resources["TangoMessageBoxHeaderErrorBrush"] 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 = TouchIconKind.AlertCircleOutline,
                Title = "Information",
                Brush = Application.Current.Resources["TangoMessageBoxInfoBrush"] as Brush,
                HeaderBrush = Application.Current.Resources["TangoMessageBoxHeaderInfoBrush"] 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 = TouchIconKind.AlertCircleOutline,
                Title = "Warning",
                Brush = Application.Current.Resources["TangoMessageBoxWarningBrush"] as Brush,
                HeaderBrush = Application.Current.Resources["TangoMessageBoxHeaderWarningBrush"] 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 = TouchIconKind.QuestionCircleRegular,
                Title = "Confirm",
                HasCancel = true,
                Brush = Application.Current.Resources["TangoMessageBoxQuestionBrush"] as Brush,
                HeaderBrush = Application.Current.Resources["TangoMessageBoxHeaderQuestionBrush"] as Brush,
            });
        }

        /// <summary>
        /// Shows a success message box.
        /// </summary>
        /// <param name="message">The message.</param>
        /// <returns></returns>
        public Task ShowSuccess(string message)
        {
            return ShowMessageBox(new MessageBoxVM()
            {
                Message = message,
                Icon = TouchIconKind.Check,
                Title = "Success",
                Brush = Application.Current.Resources["TangoMessageBoxSuccessBrush"] as Brush,
                HeaderBrush = Application.Current.Resources["TangoMessageBoxHeaderSuccessBrush"] as Brush,
            });
        }

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

            LogManager.Log($"Displaying MessagBox '{vm.Message}'.");

            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 PendingNotification<MessageBoxVM, bool>(vm, source));
            }

            return source.Task;
        }

        /// <summary>
        /// Called when the message box has been closed.
        /// </summary>
        private void OnMessageBoxClosed()
        {
            LogManager.Log("MessageBox closed.");

            CurrentMessageBox = null;

            if (_pendingMessageBoxes.Count > 0)
            {
                PendingNotification<MessageBoxVM, bool> p = null;
                if (_pendingMessageBoxes.TryDequeue(out p))
                {
                    CurrentMessageBox = p.Item;
                }
            }
        }

        /// <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)
        {
            item.Time = DateTime.Now;
            LogManager.Log($"Pushing NotificationItem '{item.GetType().Name}'.");
            item.RemoveAction = () => { PopNotification(item); };
            NotificationItems.Insert(0, item);
            RaisePropertyChanged(nameof(HasNotificationItems));
            RaisePropertyChanged(nameof(NotificationItems));
            return item;
        }

        /// <summary>
        /// Pushes the notification.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public NotificationItem PushNotification<T>() where T : NotificationItem
        {
            return PushNotification(Activator.CreateInstance<T>());
        }

        /// <summary>
        /// Removed the specified notification item.
        /// </summary>
        /// <param name="item">The item.</param>
        public void PopNotification(NotificationItem item)
        {
            LogManager.Log($"Popping out NotificationItem '{item.GetType().Name}'.");
            NotificationItems.Remove(item);
            RaisePropertyChanged(nameof(HasNotificationItems));
            RaisePropertyChanged(nameof(NotificationItems));
        }

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

        /// <summary>
        /// Gets the pop notification command.
        /// </summary>
        public RelayCommand<NotificationItem> PopNotificationCommand { get; private set; }

        /// <summary>
        /// Displays the specified dialog in a modal design.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="datacontext">The data context.</param>
        /// <param name="view">The view.</param>
        /// <returns></returns>
        public async Task<T> ShowDialog<T>(T datacontext, FrameworkElement view) where T : DialogViewVM
        {
            TaskCompletionSource<DialogViewVM> source = new TaskCompletionSource<DialogViewVM>();

            InvokeUI(() =>
            {
                view.DataContext = datacontext;

                TangoIOC.Default.Inject(datacontext);

                view.Loaded += (_, __) =>
                {
                    view.DataContext = datacontext;
                    datacontext.OnShow();
                };

                datacontext.Accepted += () => { OnDialogClosed(); source.SetResult(datacontext); };
                datacontext.Canceled += () => { OnDialogClosed(); source.SetResult(datacontext); };

                if (CurrentDialog == null)
                {
                    CurrentDialog = view;
                }
                else
                {
                    _pendingDialogs.Enqueue(new PendingNotification<DialogAndView, DialogViewVM>(new DialogAndView(datacontext, view), source));
                }

            });

            var result = await source.Task;
            return result as T;
        }

        /// <summary>
        /// Called when [dialog closed].
        /// </summary>
        private void OnDialogClosed()
        {
            CurrentDialog = null;

            if (_pendingDialogs.Count > 0)
            {
                PendingNotification<DialogAndView, DialogViewVM> p = null;
                if (_pendingDialogs.TryDequeue(out p))
                {
                    CurrentDialog = p.Item.View;
                }
            }
        }

        /// <summary>
        /// Displays the specified dialog in a modal design.
        /// The notification provider will try to locate the view automatically using conventions.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="datacontext">The data context.</param>
        /// <returns></returns>
        public Task<T> ShowDialog<T>(T datacontext) where T : DialogViewVM
        {
            TaskCompletionSource<T> source = new TaskCompletionSource<T>();

            InvokeUI(async () =>
            {
                var callingAssembly = datacontext.GetType().Assembly;
                String viewName = datacontext.GetType().FullName.Replace("VM", "");
                var viewType = callingAssembly.GetType(viewName);

                if (viewType == null)
                {
                    throw new NullReferenceException("View type for " + datacontext.GetType().Name + " could not be found!");
                }

                var view = Activator.CreateInstance(viewType) as FrameworkElement;

                if (view == null)
                {
                    throw new NullReferenceException("The view " + viewType.ToString() + " is not of type framework element.");
                }

                T result = await ShowDialog<T>(datacontext, view);
                source.SetResult(result);
            });

            return source.Task;
        }

        /// <summary>
        /// Displays the specified dialog in a modal design.
        /// The data context instance will be automatically created.
        /// The notification provider will try to locate the view automatically using conventions.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public Task<T> ShowDialog<T>() where T : DialogViewVM
        {
            TaskCompletionSource<T> source = new TaskCompletionSource<T>();

            InvokeUI(async () =>
            {
                var result = await ShowDialog<T>(Activator.CreateInstance<T>());
                source.SetResult(result);
            });

            return source.Task;
        }

        /// <summary>
        /// Sets the global busy message.
        /// </summary>
        /// <param name="message">The message.</param>
        public void SetGlobalBusyMessage(string message)
        {
            GlobalBusyMessage = message;
            IsInGlobalBusyState = true;

            RaisePropertyChanged(nameof(IsInGlobalBusyState));
            RaisePropertyChanged(nameof(GlobalBusyMessage));
        }

        /// <summary>
        /// Releases the global busy message.
        /// </summary>
        public void ReleaseGlobalBusyMessage()
        {
            GlobalBusyMessage = null;
            IsInGlobalBusyState = false;

            RaisePropertyChanged(nameof(IsInGlobalBusyState));
            RaisePropertyChanged(nameof(GlobalBusyMessage));
        }

        /// <summary>
        /// Gets the current global busy message.
        /// </summary>
        public string GlobalBusyMessage { get; private set; }

        /// <summary>
        /// Gets a value indicating whether this instance is in global busy state.
        /// </summary>
        public bool IsInGlobalBusyState { get; private set; }

        /// <summary>
        /// Gets a value indicating whether this instance has application bar item.
        /// </summary>
        public bool HasAppBarItems
        {
            get { return AppBarItems.Count > 0; }
        }

        /// <summary>
        /// Pushes the application bar item.
        /// </summary>
        /// <param name="appBarItem">The application bar item.</param>
        /// <returns></returns>
        public AppBarItem PushAppBarItem(AppBarItem appBarItem)
        {
            LogManager.Log($"Pushing AppBarItem '{appBarItem.GetType().Name}'.");
            AppBarItems.Add(appBarItem);
            appBarItem.RemoveAction = () => PopAppBarItem(appBarItem);
            RaisePropertyChanged(nameof(HasAppBarItems));
            return appBarItem;
        }

        /// <summary>
        /// Pushes the application bar item.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public T PushAppBarItem<T>() where T : AppBarItem
        {
            return PushAppBarItem(Activator.CreateInstance<T>()) as T;
        }

        /// <summary>
        /// Pops the application bar item.
        /// </summary>
        /// <param name="appBarItem">The application bar item.</param>
        public void PopAppBarItem(AppBarItem appBarItem)
        {
            InvokeUI(() =>
            {
                LogManager.Log($"Popping out AppBarItem '{appBarItem.GetType().Name}'.");
                AppBarItems.Remove(appBarItem);
                RaisePropertyChanged(nameof(HasAppBarItems));
            });
        }

        /// <summary>
        /// Pushes the task bar item.
        /// </summary>
        /// <param name="taskBarItem">The task bar item.</param>
        /// <returns></returns>
        public TaskBarItem PushTaskBarItem(TaskBarItem taskBarItem)
        {
            TaskBarItems.Add(taskBarItem);
            return taskBarItem;
        }

        /// <summary>
        /// Handles the Push Task Bar Item event.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public TaskBarItem PushTaskBarItem<T>() where T : TaskBarItem
        {
            return PushTaskBarItem(Activator.CreateInstance<T>());
        }

        /// <summary>
        /// Pops the task bar item.
        /// </summary>
        /// <param name="taskBarItem"></param>
        public void PopTaskBarItem(TaskBarItem taskBarItem)
        {
            TaskBarItems.Remove(taskBarItem);
        }

        /// <summary>
        /// Pushes the app button.
        /// </summary>
        /// <param name="appButton">The app button.</param>
        public void PushAppButton(AppButton appButton)
        {
            if (appButton != null)
            {
                LogManager.Log($"Pushing app button '{appButton.GetType().Name}'...");
            }

            _appButtons.Insert(0, appButton);
            CurrentAppButton = appButton;
        }

        /// <summary>
        /// Pops the app button.
        /// </summary>
        /// <param name="appButton">The app button.</param>
        public void PopAppButton(AppButton appButton)
        {
            if (appButton != null)
            {
                LogManager.Log($"Popping app button '{appButton.GetType().Name}'...");
            }
            else
            {
                LogManager.Log("Popping app button 'null' ??", LogCategory.Warning);
            }

            _appButtons.RemoveAll(x => x == appButton);

            CurrentAppButton = _appButtons.FirstOrDefault();
        }
    }
}