using System;
using System.ComponentModel;
using System.Windows;
using System.Windows.Input;
using System.Windows.Media.Animation;
using Wox.Helper;
using Wox.Infrastructure.UserSettings;
using Wox.ViewModel;

using Screen = System.Windows.Forms.Screen;
using KeyEventArgs = System.Windows.Input.KeyEventArgs;
using System.Windows.Controls;
using System.Threading.Tasks;
using System.Diagnostics;
using System.Timers;
using Microsoft.PowerLauncher.Telemetry;
using Microsoft.PowerToys.Telemetry;


namespace PowerLauncher
{
    public partial class MainWindow : IDisposable
    {

        #region Private Fields
        private Settings _settings;
        private MainViewModel _viewModel;
        private bool _isTextSetProgrammatically;
        bool _deletePressed = false;
        Timer _firstDeleteTimer = new Timer();

        #endregion

        public MainWindow(Settings settings, MainViewModel mainVM) : this()
        {
            DataContext = mainVM;
            _viewModel = mainVM;
            _settings = settings;

            InitializeComponent();

            _firstDeleteTimer.Elapsed += CheckForFirstDelete;
            _firstDeleteTimer.Interval = 1000;

        }

        private void CheckForFirstDelete(object sender, ElapsedEventArgs e)
        {
            _firstDeleteTimer.Stop();
            if (_deletePressed)
            {
                PowerToysTelemetry.Log.WriteEvent(new LauncherFirstDeleteEvent());
            }

        }
        public MainWindow()
        {
            InitializeComponent();
        }

        private void OnClosing(object sender, CancelEventArgs e)
        {
            _viewModel.Save();
        }

        private void BringProcessToForeground()
        {
            // Use SendInput hack to allow Activate to work - required to resolve focus issue https://github.com/microsoft/PowerToys/issues/4270
            WindowsInteropHelper.INPUT input = new WindowsInteropHelper.INPUT { type = WindowsInteropHelper.INPUTTYPE.INPUT_MOUSE, data = { } };
            WindowsInteropHelper.INPUT[] inputs = new WindowsInteropHelper.INPUT[] { input };

            // Send empty mouse event. This makes this thread the last to send input, and hence allows it to pass foreground permission checks
            _ = WindowsInteropHelper.SendInput(1, inputs, WindowsInteropHelper.INPUT.Size);
            Activate();
        }

        private void OnLoaded(object sender, RoutedEventArgs _)
        {
            WindowsInteropHelper.DisableControlBox(this);
            InitializePosition();

            SearchBox.QueryTextBox.DataContext = _viewModel;
            SearchBox.QueryTextBox.PreviewKeyDown += _launcher_KeyDown;
            SearchBox.QueryTextBox.TextChanged += QueryTextBox_TextChanged;
            SearchBox.QueryTextBox.Focus();

            ListBox.DataContext = _viewModel;
            ListBox.SuggestionsList.SelectionChanged += SuggestionsList_SelectionChanged;
            ListBox.SuggestionsList.PreviewMouseLeftButtonUp += SuggestionsList_PreviewMouseLeftButtonUp;
            _viewModel.PropertyChanged += ViewModel_PropertyChanged;

            BringProcessToForeground();
        }

        private void SuggestionsList_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
        {
            var result = ((FrameworkElement)e.OriginalSource).DataContext;
            if (result != null)
            {
                var resultVM = result as ResultViewModel;

                //This may be null if the tapped item was one of the context buttons (run as admin etc).
                if (resultVM != null)
                {
                    _viewModel.Results.SelectedItem = resultVM;
                    _viewModel.OpenResultCommand.Execute(null);
                }
            }
        }

        private void ViewModel_PropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            if(e.PropertyName == nameof(MainViewModel.MainWindowVisibility)) 
            {
                if (Visibility == System.Windows.Visibility.Visible)
                {
                    // Not called on first launch
                    // Additionally called when deactivated by clicking on screen  
                    UpdatePosition();
                    BringProcessToForeground();

                    if (!_viewModel.LastQuerySelected)
                    {
                        _viewModel.LastQuerySelected = true;
                    }
                }
            }          
            else if (e.PropertyName == nameof(MainViewModel.SystemQueryText))
            {
                this._isTextSetProgrammatically = true;
                if (_viewModel.Results != null)
                {
                    SearchBox.QueryTextBox.Text = MainViewModel.GetSearchText(
                        _viewModel.Results.SelectedIndex,
                        _viewModel.SystemQueryText,
                        _viewModel.QueryText);
                }
            }
        }

        private void OnMouseDown(object sender, MouseButtonEventArgs e)
        {
            if (e.ChangedButton == MouseButton.Left) DragMove();
        }

        private void InitializePosition()
        {
            Top = WindowTop();
            Left = WindowLeft();
            _settings.WindowTop = Top;
            _settings.WindowLeft = Left;
        }

        private void OnActivated(object sender, EventArgs e)
        {
	        if (_settings.ClearInputOnLaunch)
	        {
		        _viewModel.ClearQueryCommand.Execute(null);
	        }
        }

        private void OnDeactivated(object sender, EventArgs e)
        {
	        if (_settings.HideWhenDeactivated)
            {
                //(this.FindResource("OutroStoryboard") as Storyboard).Begin();
                Hide();
            }              
        }

        private void UpdatePosition()
        {
            if (_settings.RememberLastLaunchLocation)
            {
                Left = _settings.WindowLeft;
                Top = _settings.WindowTop;
            }
            else
            {              
                Top = WindowTop();
                Left = WindowLeft();
            }
        }

        private void OnLocationChanged(object sender, EventArgs e)
        {
            if (_settings.RememberLastLaunchLocation)
            {
                _settings.WindowLeft = Left;
                _settings.WindowTop = Top;
            }
        }

        /// <summary>
        /// Calculates X co-ordinate of main window top left corner.
        /// </summary>
        /// <returns>X co-ordinate of main window top left corner</returns>
        private double WindowLeft()
        {
            var screen = Screen.FromPoint(System.Windows.Forms.Cursor.Position);
            var dip1 = WindowsInteropHelper.TransformPixelsToDIP(this, screen.WorkingArea.X, 0);
            var dip2 = WindowsInteropHelper.TransformPixelsToDIP(this, screen.WorkingArea.Width, 0);
            var left = (dip2.X - ActualWidth) / 2 + dip1.X;
            return left;
        }

        private double WindowTop()
        {
            var screen = Screen.FromPoint(System.Windows.Forms.Cursor.Position);
            var dip1 = WindowsInteropHelper.TransformPixelsToDIP(this, 0, screen.WorkingArea.Y);
            var dip2 = WindowsInteropHelper.TransformPixelsToDIP(this, 0, screen.WorkingArea.Height);
            var top = (dip2.Y - this.SearchBox.ActualHeight) / 4 + dip1.Y;
            return top;
        }

        private void _launcher_KeyDown(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Tab && Keyboard.IsKeyDown(Key.LeftShift))
            {
                _viewModel.SelectPrevTabItemCommand.Execute(null);
                UpdateTextBoxToSelectedItem();
                e.Handled = true;
            }
            else if (e.Key == Key.Tab)
            {
                _viewModel.SelectNextTabItemCommand.Execute(null);
                UpdateTextBoxToSelectedItem();
                e.Handled = true;
            }
            else if (e.Key == Key.Down)
            {
                _viewModel.SelectNextItemCommand.Execute(null);
                UpdateTextBoxToSelectedItem();
                e.Handled = true;
            }
            else if (e.Key == Key.Up)
            {
                _viewModel.SelectPrevItemCommand.Execute(null);
                UpdateTextBoxToSelectedItem();
                e.Handled = true;
            }
            else if (e.Key == Key.PageDown)
            {
                _viewModel.SelectNextPageCommand.Execute(null);
                e.Handled = true;
            }
            else if (e.Key == Key.PageUp)
            {
                _viewModel.SelectPrevPageCommand.Execute(null);
                e.Handled = true;
            }
            else if (e.Key == Key.Back)
            {
                _deletePressed = true;
            }
            else
            {
                _viewModel.HandleContextMenu(e.Key, Keyboard.Modifiers);
            }
        }

        private void UpdateTextBoxToSelectedItem()
        {
            var itemText = _viewModel?.Results?.SelectedItem?.ToString() ?? null;
            if (!string.IsNullOrEmpty(itemText))
            {
                _viewModel.ChangeQueryText(itemText);
            }
        }

        private void SuggestionsList_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            ListView listview = (ListView)sender;
            _viewModel.Results.SelectedItem = (ResultViewModel) listview.SelectedItem;
            if (e.AddedItems.Count > 0 && e.AddedItems[0] != null)
            {
                listview.ScrollIntoView(e.AddedItems[0]);
            }

            // To populate the AutoCompleteTextBox as soon as the selection is changed or set.
            // Setting it here instead of when the text is changed as there is a delay in executing the query and populating the result        
            if (_viewModel.Results != null)
            {
                SearchBox.AutoCompleteTextBlock.Text = MainViewModel.GetAutoCompleteText(
                    _viewModel.Results.SelectedIndex,
                    _viewModel.Results.SelectedItem?.ToString(),
                    _viewModel.QueryText);
            }          
        }

        private const int millisecondsToWait = 100;
        private static DateTime s_lastTimeOfTyping;
        private bool disposedValue = false;

        private void QueryTextBox_TextChanged(object sender, TextChangedEventArgs e)
        {          
            if (_isTextSetProgrammatically)
            {
                var textBox = ((TextBox)sender);
                textBox.SelectionStart = textBox.Text.Length;
                _isTextSetProgrammatically = false;
            }
            else
            {
                var text = ((TextBox)sender).Text;
                if (string.IsNullOrEmpty(text))
                {
                    SearchBox.AutoCompleteTextBlock.Text = string.Empty;
                }
                _viewModel.QueryText = text;
                var latestTimeOfTyping = DateTime.Now;

                Task.Run(() => DelayedCheck(latestTimeOfTyping));
                s_lastTimeOfTyping = latestTimeOfTyping;
            }
        }

        private async Task DelayedCheck(DateTime latestTimeOfTyping)
        {
            await Task.Delay(millisecondsToWait).ConfigureAwait(false);
            if (latestTimeOfTyping.Equals(s_lastTimeOfTyping))
            {
                await System.Windows.Application.Current.Dispatcher.BeginInvoke(new Action(() =>
                {
                    _viewModel.Query();
                }));
            }
        }
        
        private void ListBox_PreviewMouseDown(object sender, MouseButtonEventArgs e)
        {
            if (e.ChangedButton == MouseButton.Right)
            {
                e.Handled = true;
            }
        }

        private void OnVisibilityChanged(object sender, DependencyPropertyChangedEventArgs e)
        {
            if (Visibility == Visibility.Visible)
            {
                _deletePressed = false;
                _firstDeleteTimer.Start();
                // (this.FindResource("IntroStoryboard") as Storyboard).Begin();

                SearchBox.QueryTextBox.Focus();
                Keyboard.Focus(SearchBox.QueryTextBox);

                _settings.ActivateTimes++;

                if (!String.IsNullOrEmpty(SearchBox.QueryTextBox.Text))
                {
                    SearchBox.QueryTextBox.SelectAll();
                }
            }
            else
            {
                _firstDeleteTimer.Stop();
            }
        }

        private void OutroStoryboard_Completed(object sender, EventArgs e)
        {
            Hide();
        }

        protected virtual void Dispose(bool disposing)
        {
            if (!disposedValue)
            {
                if (disposing)
                {
                    _firstDeleteTimer.Dispose();
                }

                // TODO: free unmanaged resources (unmanaged objects) and override finalizer
                // TODO: set large fields to null
                disposedValue = true;
            }
        }

        // // TODO: override finalizer only if 'Dispose(bool disposing)' has code to free unmanaged resources
        // ~MainWindow()
        // {
        //     // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
        //     Dispose(disposing: false);
        // }

        public void Dispose()
        {
            // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
            Dispose(disposing: true);
            GC.SuppressFinalize(this);
        }
    }
}