// Game Resource Browser
//
// Copyright (C) 2014-2017 by morkt
//
// 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.IO;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Diagnostics;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Input;
using System.Windows.Interop;
using System.Windows.Threading;
using Microsoft.VisualBasic.FileIO;
using GARbro.GUI.Properties;
using GARbro.GUI.Strings;
using GameRes;
using Rnd.Windows;
using Microsoft.Win32;
using NAudio.Wave;

namespace GARbro.GUI
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        private App m_app;

        public App App { get { return m_app; } }

        const StringComparison StringIgnoreCase = StringComparison.CurrentCultureIgnoreCase;

        public MainWindow()
        {
            m_app = Application.Current as App;
            InitializeComponent();
            if (this.Top < 0) this.Top = 0;
            if (this.Left < 0) this.Left = 0;
            InitDirectoryChangesWatcher();
            InitPreviewPane();
            InitUpdatesChecker();

            if (null == Settings.Default.appRecentFiles)
                Settings.Default.appRecentFiles = new StringCollection();
            m_recent_files = new LinkedList<string> (Settings.Default.appRecentFiles.Cast<string>().Take (MaxRecentFiles));
            RecentFilesMenu.ItemsSource = RecentFiles;

            FormatCatalog.Instance.ParametersRequest += (s, e) => Dispatcher.Invoke (() => OnParametersRequest (s, e));

            CurrentDirectory.SizeChanged += (s, e) => {
                if (e.WidthChanged)
                {
                    pathLine.MinWidth = e.NewSize.Width-79;
                    this.MinWidth = e.NewSize.Width+79;
                }
            };
            pathLine.EnterKeyDown += acb_OnKeyDown;
        }

        void WindowLoaded (object sender, RoutedEventArgs e)
        {
            lv_SetSortMode (Settings.Default.lvSortColumn, Settings.Default.lvSortDirection);
            Dispatcher.InvokeAsync (WindowRendered, DispatcherPriority.ContextIdle);
            ImageData.SetDefaultDpi (Desktop.DpiX, Desktop.DpiY);
        }

        void WindowRendered ()
        {
            DirectoryViewModel vm = null;
            try
            {
                vm = GetNewViewModel (m_app.InitPath);
            }
            catch (Exception X)
            {
                PopupError (X.Message, guiStrings.MsgErrorOpening);
            }
            if (null == vm)
            {
                vm = CreateViewModel (Directory.GetCurrentDirectory(), true);
            }
            ViewModel = vm;
            lv_SelectItem (0);
            if (!vm.IsArchive)
                SetStatusText (guiStrings.MsgReady);
        }

        void WindowKeyDown (object sender, KeyEventArgs e)
        {
            if (MainMenuBar.Visibility != Visibility.Visible && Key.System == e.Key)
            {
                MainMenuBar.Visibility = Visibility.Visible;
                MainMenuBar.IsKeyboardFocusWithinChanged += HideMenuBar;
            }
        }

        void HideMenuBar (object sender, DependencyPropertyChangedEventArgs e)
        {
            if (!MainMenuBar.IsKeyboardFocusWithin)
            {
                MainMenuBar.IsKeyboardFocusWithinChanged -= HideMenuBar;
                MainMenuBar.Visibility = Visibility.Collapsed;
            }
        }

        /// <summary>
        /// Save settings when main window is about to close
        /// </summary>
        protected override void OnClosing (CancelEventArgs e)
        {
            try
            {
                SaveSettings();
                AudioDevice = null;
                CurrentAudio = null;
            }
            catch (Exception X)
            {
                Trace.WriteLine (X.Message, "[OnClosing]");
                Trace.WriteLine (X.StackTrace, "Stack trace");
            }
            base.OnClosing (e);
        }

        /// <summary>
        /// Manually save settings that are not automatically saved by bindings.
        /// </summary>
        private void SaveSettings()
        {
            if (null != m_lvSortByColumn)
            {
                Settings.Default.lvSortColumn = SortMode;
                Settings.Default.lvSortDirection = m_lvSortDirection;
            }
            else
                Settings.Default.lvSortColumn = "";

            Settings.Default.appRecentFiles.Clear();
            foreach (var file in m_recent_files)
                Settings.Default.appRecentFiles.Add (file);

            string cwd = CurrentPath;
            if (!string.IsNullOrEmpty (cwd))
            {
                if (ViewModel.IsArchive)
                    cwd = Path.GetDirectoryName (cwd);
            }
            else
                cwd = Directory.GetCurrentDirectory();
            Settings.Default.appLastDirectory = cwd;
        }

        /// <summary>
        /// Set status line text. Could be called from any thread.
        /// </summary>
        public void SetStatusText (string text)
        {
            Dispatcher.Invoke (() => { appStatusText.Text = text; });
        }

        public void SetResourceText (string text)
        {
            Dispatcher.Invoke (() => { appResourceText.Text = text; });
        }

        /// <summary>
        /// Popup error message box. Could be called from any thread.
        /// </summary>
        public void PopupError (string message, string title)
        {
            Dispatcher.Invoke (() => MessageBox.Show (this, message, title, MessageBoxButton.OK, MessageBoxImage.Error));
        }

        internal FileErrorDialogResult ShowErrorDialog (string error_title, string error_text, IntPtr parent_hwnd)
        {
            var dialog = new FileErrorDialog (error_title, error_text);
            SetModalWindowParent (dialog, parent_hwnd);
            return dialog.ShowDialog();
        }

        internal FileExistsDialogResult ShowFileExistsDialog (string title, string text, IntPtr parent_hwnd)
        {
            var dialog = new FileExistsDialog (title, text);
            SetModalWindowParent (dialog, parent_hwnd);
            return dialog.ShowDialog();
        }

        private void SetModalWindowParent (Window dialog, IntPtr parent_hwnd)
        {
            if (parent_hwnd != IntPtr.Zero)
            {
                var native_dialog = new WindowInteropHelper (dialog);
                native_dialog.Owner = parent_hwnd;
                NativeMethods.EnableWindow (parent_hwnd, false);
                EventHandler on_closed = null;
                on_closed = (s, e) => {
                    NativeMethods.EnableWindow (parent_hwnd, true);
                    dialog.Closed -= on_closed;
                };
                dialog.Closed += on_closed;
            }
            else
            {
                dialog.Owner = this;
            }
        }

        const int MaxRecentFiles = 9;
        LinkedList<string> m_recent_files;

        // Item1 = file name, Item2 = menu item string
        public IEnumerable<Tuple<string,string>> RecentFiles
        {
            get
            {
                int i = 1;
                return m_recent_files.Select (f => Tuple.Create (f, string.Format ("_{0} {1}", i++, f)));
            }
        }

        void PushRecentFile (string file)
        {
            var node = m_recent_files.Find (file);
            if (node != null && node == m_recent_files.First)
                return;
            if (null == node)
            {
                while (MaxRecentFiles <= m_recent_files.Count)
                    m_recent_files.RemoveLast();
                m_recent_files.AddFirst (file);
            }
            else
            {
                m_recent_files.Remove (node);
                m_recent_files.AddFirst (node);
            }
            RecentFilesMenu.ItemsSource = RecentFiles;
        }

        /// <summary>
        /// Set data context of the ListView.
        /// </summary>

        public DirectoryViewModel ViewModel
        {
            get
            {
                var source = CurrentDirectory.ItemsSource as CollectionView;
                if (null == source)
                    return null;
                return source.SourceCollection as DirectoryViewModel;
            }
            private set
            {
                StopWatchDirectoryChanges();
                var cvs = this.Resources["ListViewSource"] as CollectionViewSource;
                cvs.Source = value;

                // update path textbox
                var path_component = value.Path.Last();
                if (string.IsNullOrEmpty (path_component) && value.Path.Count > 1)
                    path_component = value.Path[value.Path.Count-2];
                pathLine.Text = path_component;

                if (value.IsArchive && value.Path.Count <= 2)
                    PushRecentFile (value.Path.First());

                lv_Sort (SortMode, m_lvSortDirection);
                if (!value.IsArchive && !string.IsNullOrEmpty (value.Path.First()))
                {
                    WatchDirectoryChanges (value.Path.First());
                }
                CurrentDirectory.UpdateLayout();
            }
        }

        /// <summary>
        /// Save current position and update view model.
        /// </summary>
        void PushViewModel (DirectoryViewModel vm)
        {
            SaveCurrentPosition();
            ViewModel = vm;
        }

        DirectoryViewModel GetNewViewModel (string path)
        {
            if (!string.IsNullOrEmpty (path))
            {
                if (!VFS.IsVirtual)
                    path = Path.GetFullPath (path);
                var entry = VFS.FindFile (path);
                if (!(entry is SubDirEntry))
                    SetBusyState();
                VFS.ChDir (entry);
            }
            return new DirectoryViewModel (VFS.FullPath, VFS.GetFiles(), VFS.IsVirtual);
        }

        private bool m_busy_state = false;

        public void SetBusyState()
        {
            m_busy_state = true;
            Mouse.OverrideCursor = Cursors.Wait;
            Dispatcher.InvokeAsync (() => {
                m_busy_state = false;
                Mouse.OverrideCursor = null;
            }, DispatcherPriority.ApplicationIdle);
        }

        /// <summary>
        /// Create view model corresponding to <paramref name="path">. Returns null on error.
        /// </summary>
        DirectoryViewModel TryCreateViewModel (string path)
        {
            try
            {
                return GetNewViewModel (path);
            }
            catch (Exception X)
            {
                SetStatusText (string.Format ("{0}: {1}", Path.GetFileName (path), X.Message));
                return null;
            }
        }

        /// <summary>
        /// Create view model corresponding to <paramref name="path"> or empty view model if there was
        /// an error accessing path.
        /// </summary>
        DirectoryViewModel CreateViewModel (string path, bool suppress_warning = false)
        {
            try
            {
                return GetNewViewModel (path);
            }
            catch (Exception X)
            {
                if (!suppress_warning)
                    PopupError (X.Message, guiStrings.MsgErrorOpening);
                return new DirectoryViewModel (new string[] { "" }, new Entry[0], false);
            }
        }

        #region Refresh view on filesystem changes

        private FileSystemWatcher m_watcher = new FileSystemWatcher();

        void InitDirectoryChangesWatcher ()
        {
            m_watcher.NotifyFilter = NotifyFilters.Size | NotifyFilters.FileName | NotifyFilters.DirectoryName;
            m_watcher.Changed += InvokeRefreshView;
            m_watcher.Created += InvokeRefreshView;
            m_watcher.Deleted += InvokeRefreshView;
            m_watcher.Renamed += InvokeRefreshView;
        }

        void WatchDirectoryChanges (string path)
        {
            m_watcher.Path = path;
            m_watcher.EnableRaisingEvents = true;
        }

        public void StopWatchDirectoryChanges()
        {
            m_watcher.EnableRaisingEvents = false;
        }

        public void ResumeWatchDirectoryChanges ()
        {
            m_watcher.EnableRaisingEvents = !ViewModel.IsArchive;
        }

        private void InvokeRefreshView (object source, FileSystemEventArgs e)
        {
            var watcher = source as FileSystemWatcher;
            var vm = ViewModel;
            if (!vm.IsArchive && vm.Path.First() == watcher.Path)
            {
                watcher.EnableRaisingEvents = false;
                Dispatcher.Invoke (RefreshView);
            }
        }
        #endregion

        /// <summary>
        /// Select specified item within CurrentDirectory and bring it into a view.
        /// </summary>

        void lv_SelectItem (EntryViewModel item)
        {
            if (item != null)
            {
                CurrentDirectory.SelectedItem = item;
                CurrentDirectory.ScrollIntoView (item);
                var lvi = (ListViewItem)CurrentDirectory.ItemContainerGenerator.ContainerFromItem (item);
                if (lvi != null)
                    lvi.Focus();
            }
        }

        void lv_SelectItem (int index)
        {
            CurrentDirectory.SelectedIndex = index;
            CurrentDirectory.ScrollIntoView (CurrentDirectory.SelectedItem);
            var lvi = (ListViewItem)CurrentDirectory.ItemContainerGenerator.ContainerFromIndex (index);
            if (lvi != null)
                lvi.Focus();
        }

        void lv_SelectItem (string name)
        {
            if (!string.IsNullOrEmpty (name))
                lv_SelectItem (ViewModel.Find (name));
        }

        private void lv_Focus ()
        {
            if (CurrentDirectory.SelectedIndex != -1)
            {
                var item = CurrentDirectory.SelectedItem;
                var lvi = CurrentDirectory.ItemContainerGenerator.ContainerFromItem (item) as ListViewItem;
                if (lvi != null)
                {
                    lvi.Focus();
                    return;
                }
            }
            CurrentDirectory.Focus();
        }

        void lvi_Selected (object sender, RoutedEventArgs args)
        {
            var lvi = sender as ListViewItem;
            if (lvi == null)
                return;
            var entry = lvi.Content as EntryViewModel;
            if (entry == null)
                return;
            PreviewEntry (entry.Source);
        }

        EntryViewModel m_last_selected = null;

        void lv_SelectionChanged (object sender, SelectionChangedEventArgs args)
        {
            var lv = sender as ListView;
            if (null == lv)
                return;
            var item = lv.SelectedItem as EntryViewModel;
            if (item != null && m_last_selected != item)
            {
                m_last_selected = item;
                PreviewEntry (item.Source);
            }
        }

        void lvi_DoubleClick (object sender, MouseButtonEventArgs args)
        {
            var lvi = sender as ListViewItem;
            if (Commands.OpenItem.CanExecute (null, lvi))
            {
                Commands.OpenItem.Execute (null, lvi);
                args.Handled = true;
            }
        }

        /// <summary>
        /// Get currently selected item from ListView widget.
        /// </summary>
        private ListViewItem lv_GetCurrentContainer ()
        {
            int current = CurrentDirectory.SelectedIndex;
            if (-1 == current)
                 return null;

            return CurrentDirectory.ItemContainerGenerator.ContainerFromIndex (current) as ListViewItem;
        }

        GridViewColumnHeader    m_lvSortByColumn = null;
        ListSortDirection       m_lvSortDirection = ListSortDirection.Ascending;

        public string SortMode
        {
            get { return GetValue (SortModeProperty) as string; }
            private set { SetValue (SortModeProperty, value); }
        }

        public static readonly DependencyProperty SortModeProperty = 
            DependencyProperty.RegisterAttached ("SortMode", typeof(string), typeof(MainWindow), new UIPropertyMetadata());

        void lv_SetSortMode (string sortBy, ListSortDirection direction)
        {
            m_lvSortByColumn = null;
            GridView view = CurrentDirectory.View as GridView;
            foreach (var column in view.Columns)
            {
                var header = column.Header as GridViewColumnHeader;
                if (null != header && !string.IsNullOrEmpty (sortBy) && sortBy.Equals (header.Tag))
                {
                    if (ListSortDirection.Ascending == direction)
                        column.HeaderTemplate = Resources["SortArrowUp"] as DataTemplate;
                    else
                        column.HeaderTemplate = Resources["SortArrowDown"] as DataTemplate;
                    m_lvSortByColumn = header;
                    m_lvSortDirection = direction;
                }
                else
                {
                    column.HeaderTemplate = Resources["SortArrowNone"] as DataTemplate;
                }
            }
            SortMode = sortBy;
        }

        private void lv_Sort (string sortBy, ListSortDirection direction)
        {
            var dataView = CollectionViewSource.GetDefaultView (CurrentDirectory.ItemsSource) as ListCollectionView;
            dataView.CustomSort = new FileSystemComparer (sortBy, direction);
        }

        /// <summary>
        /// Sort Listview by columns
        /// </summary>
        void lv_ColumnHeaderClicked (object sender, RoutedEventArgs e)
        {
            var headerClicked = e.OriginalSource as GridViewColumnHeader;

            if (null == headerClicked)
                return;
            if (headerClicked.Role == GridViewColumnHeaderRole.Padding)
                return;

            ListSortDirection direction;
            if (headerClicked != m_lvSortByColumn)
                direction = ListSortDirection.Ascending;
            else if (m_lvSortDirection == ListSortDirection.Ascending)
                direction = ListSortDirection.Descending;
            else
                direction = ListSortDirection.Ascending;

            string sortBy = headerClicked.Tag.ToString();
            lv_Sort (sortBy, direction);
            SortMode = sortBy;

            // Remove arrow from previously sorted header 
            if (m_lvSortByColumn != null && m_lvSortByColumn != headerClicked)
            {
                m_lvSortByColumn.Column.HeaderTemplate = Resources["SortArrowNone"] as DataTemplate;
            }

            if (ListSortDirection.Ascending == direction)
            {
                headerClicked.Column.HeaderTemplate = Resources["SortArrowUp"] as DataTemplate;
            }
            else
            {
                headerClicked.Column.HeaderTemplate = Resources["SortArrowDown"] as DataTemplate;
            }
            m_lvSortByColumn = headerClicked;
            m_lvSortDirection = direction;
        }

        /// <summary>
        /// Handle "Sort By" commands.
        /// </summary>

        private void SortByExec (object sender, ExecutedRoutedEventArgs e)
        {
            string sort_by = e.Parameter as string;
            lv_Sort (sort_by, ListSortDirection.Ascending);
            lv_SetSortMode (sort_by, ListSortDirection.Ascending);
        }

        /// <summary>
        /// Handle "Set file type" commands.
        /// </summary>
        private void SetFileTypeExec (object sender, ExecutedRoutedEventArgs e)
        {
            var selected = CurrentDirectory.SelectedItems.Cast<EntryViewModel>().Where (x => !x.IsDirectory);
            if (!selected.Any())
                return;
            string type = e.Parameter as string;
            foreach (var entry in selected)
            {
                entry.Type = type;
            }
        }

        /// <summary>
        /// Event handler for keys pressed in the directory view pane
        /// </summary>

        private void lv_TextInput (object sender, TextCompositionEventArgs e)
        {
            LookupItem (e.Text, e.Timestamp);
            e.Handled = true;
        }

        private void lv_KeyDown (object sender, KeyEventArgs e)
        {
            if (e.IsDown && LookupActive)
            {
                switch (e.Key)
                {
                case Key.Space:
                    LookupItem (" ", e.Timestamp);
                    e.Handled = true;
                    break;
                case Key.Down:
                case Key.Up:
                case Key.Left:
                case Key.Right:
                case Key.Next:
                case Key.Prior:
                case Key.Home:
                case Key.End:
                case Key.Enter:
                    m_current_input.Reset();
                    break;
                }
            }
        }

        class InputData
        {
            public int              LastTime = 0;
            public StringBuilder    Phrase = new StringBuilder();
            public bool             Mismatch = false;

            public bool LookupActive
            {
                get { return Phrase.Length > 0 && Environment.TickCount - LastTime < TextLookupTimeout; }
            }

            public void Reset ()
            {
                Phrase.Clear ();
                Mismatch = false;
            }

            public void Update (int timestamp)
            {
                if (timestamp - LastTime >= TextLookupTimeout)
                {
                    Reset();
                }
                LastTime = timestamp;
            }
        }

        const int TextLookupTimeout = 1000; // milliseconds

        InputData m_current_input = new InputData();

        public bool LookupActive { get { return m_current_input.LookupActive; } }

        /// <summary>
        /// Lookup item in listview pane by first letters of name.
        /// </summary>

        private void LookupItem (string key, int timestamp)
        {
            if (string.IsNullOrEmpty (key))
                return;
            if ("\x1B" == key) // escape key
            {
                m_current_input.Reset();
                return;
            }
            var source = CurrentDirectory.ItemsSource as CollectionView;
            if (source == null)
                return;

            m_current_input.Update (timestamp);
            if (m_current_input.Mismatch)
                return;

            if (!(1 == m_current_input.Phrase.Length && m_current_input.Phrase[0] == key[0]))
            {
                m_current_input.Phrase.Append (key);
            }
            int start_index = CurrentDirectory.SelectedIndex;
            if (1 == m_current_input.Phrase.Length)
            {
                // lookup starting from the next item
                if (start_index != -1 && start_index+1 < source.Count)
                    ++start_index;
            }
            var items = source.Cast<EntryViewModel>();
            if (start_index > 0)
            {
                items = items.Skip (start_index).Concat (items.Take (start_index));
            }
            string input = m_current_input.Phrase.ToString();
            var matched = items.FirstOrDefault (e => e.Name.StartsWith (input, StringIgnoreCase));
            if (null != matched)
                lv_SelectItem (matched);
            else
                m_current_input.Mismatch = true;
        }

        static readonly Regex FullpathRe = new Regex (@"^(?:[a-z]:|[\\/])", RegexOptions.IgnoreCase);

        private void acb_OnKeyDown (object sender, KeyEventArgs e)
        {
            if (e.Key != Key.Return)
                return;
            string path = (sender as AutoCompleteBox).Text;
            if (string.IsNullOrEmpty (path))
                return;
            if (FullpathRe.IsMatch (path))
            {
                OpenFile (path);
                return;
            }
            try
            {
                PushViewModel (GetNewViewModel (path));
                lv_Focus();
            }
            catch (Exception X)
            {
                PopupError (X.Message, guiStrings.MsgErrorOpening);
            }
        }

        #region Navigation history implementation

        internal string CurrentPath { get { return ViewModel.Path.First(); } }

        HistoryStack<DirectoryPosition> m_history = new HistoryStack<DirectoryPosition>();

        public DirectoryPosition GetCurrentPosition ()
        {
            var evm = CurrentDirectory.SelectedItem as EntryViewModel;
            return new DirectoryPosition (ViewModel, evm);
        }

        public bool SetCurrentPosition (DirectoryPosition pos)
        {
            try
            {
                VFS.FullPath = pos.Path;
                var vm = TryCreateViewModel (pos.Path.Last());
                if (null == vm)
                    return false;
                ViewModel = vm;
                if (null != pos.Item)
                    lv_SelectItem (pos.Item);
                return true;
            }
            catch (Exception X)
            {
                // if VFS.FullPath throws an exception, ViewModel becomes inconsistent at this point
                // and should be rebuilt
                ViewModel = CreateViewModel (VFS.Top.CurrentDirectory, true);
                SetStatusText (X.Message);
                return false;
            }
        }

        public void SaveCurrentPosition ()
        {
            m_history.Push (GetCurrentPosition());
        }

        public void ChangePosition (DirectoryPosition new_pos)
        {
            var current = GetCurrentPosition();
            if (!current.Path.SequenceEqual (new_pos.Path))
                SaveCurrentPosition();
            SetCurrentPosition (new_pos);
        }

        private void GoBackExec (object sender, ExecutedRoutedEventArgs e)
        {
            DirectoryPosition current = m_history.Undo (GetCurrentPosition());
            if (current != null)
                SetCurrentPosition (current);
        }

        private void GoForwardExec (object sender, ExecutedRoutedEventArgs e)
        {
            DirectoryPosition current = m_history.Redo (GetCurrentPosition());
            if (current != null)
                SetCurrentPosition (current);
        }

        private void CanExecuteGoBack (object sender, CanExecuteRoutedEventArgs e)
        {
            e.CanExecute = m_history.CanUndo();
        }

        private void CanExecuteGoForward (object sender, CanExecuteRoutedEventArgs e)
        {
            e.CanExecute = m_history.CanRedo();
        }
        #endregion

        private void OpenFileExec (object control, ExecutedRoutedEventArgs e)
        {
            var dlg = new OpenFileDialog {
                CheckFileExists = true,
                CheckPathExists = true,
                Multiselect = false,
                Title = guiStrings.TextChooseArchive,
            };
            if (!dlg.ShowDialog (this).Value)
                return;
            OpenFile (dlg.FileName);
        }

        private void OpenFile (string filename)
        {
            try
            {
                OpenFileOrDir (filename);
            }
            catch (OperationCanceledException X)
            {
                SetStatusText (X.Message);
            }
            catch (Exception X)
            {
                PopupError (string.Format("{0}\n{1}", filename, X.Message), guiStrings.MsgErrorOpening);
            }
        }

        private void OpenFileOrDir (string filename)
        {
            if (filename == CurrentPath || string.IsNullOrEmpty (filename))
                return;
            if (File.Exists (filename))
                VFS.FullPath = new string[] { filename, "" };
            else
                VFS.FullPath = new string[] { filename };
            var vm = new DirectoryViewModel (VFS.FullPath, VFS.GetFiles(), VFS.IsVirtual);
            PushViewModel (vm);
            if (null != VFS.CurrentArchive)
                SetStatusText (VFS.CurrentArchive.Description);
            lv_SelectItem (0);
        }

        private void OpenRecentExec (object control, ExecutedRoutedEventArgs e)
        {
            string filename = e.Parameter as string;
            if (string.IsNullOrEmpty (filename))
                return;
            OpenFile (filename);
        }

        /// <summary>
        /// Open file/directory.
        /// </summary>
        private void OpenItemExec (object control, ExecutedRoutedEventArgs e)
        {
            EntryViewModel entry = null;
            var lvi = e.OriginalSource as ListViewItem;
            if (lvi != null)
                entry = lvi.Content as EntryViewModel;
            if (null == entry)
                entry = CurrentDirectory.SelectedItem as EntryViewModel;
            if (null == entry)
                return;
            if ("audio" == entry.Type)
            {
                PlayFile (entry.Source);
                return;
            }
            OpenDirectoryEntry (ViewModel, entry);
        }

        private void OpenDirectoryEntry (DirectoryViewModel vm, EntryViewModel entry)
        {
            string old_dir = null == vm ? "" : vm.Path.Last();
            string new_dir = entry.Source.Name;
            if (".." == new_dir)
            {
                if (null != vm && !vm.IsArchive)
                    new_dir = Path.Combine (old_dir, entry.Name);
                if (vm.Path.Count > 1 && string.IsNullOrEmpty (old_dir))
                    old_dir = vm.Path[vm.Path.Count-2];
            }
            Trace.WriteLine (new_dir, "OpenDirectoryEntry");
            int old_fs_count = VFS.Count;
            vm = TryCreateViewModel (new_dir);
            if (null == vm)
            {
                if (VFS.Count == old_fs_count)
                    return;
                vm = new DirectoryViewModel (VFS.FullPath, new Entry[0], VFS.IsVirtual);
                PushViewModel (vm);
            }
            else
            {
                PushViewModel (vm);
                if (VFS.Count > old_fs_count && null != VFS.CurrentArchive)
                    SetStatusText (string.Format ("{0}: {1}", VFS.CurrentArchive.Description,
                        Localization.Format ("MsgFiles", VFS.CurrentArchive.Dir.Count())));
                else
                    SetStatusText ("");
            }
            if (".." == entry.Name)
                lv_SelectItem (Path.GetFileName (old_dir));
            else
                lv_SelectItem (0);
        }

        WaveOutEvent    m_audio_device;
        WaveOutEvent    AudioDevice
        {
            get { return m_audio_device; }
            set
            {
                var old_value = m_audio_device;
                m_audio_device = value;
                if (old_value != null)
                    old_value.Dispose();
            }
        }

        WaveStream      m_audio_input;
        WaveStream      CurrentAudio
        {
            get { return m_audio_input; }
            set
            {
                var old_value = m_audio_input;
                m_audio_input = value;
                if (old_value != null)
                    old_value.Dispose();
            }
        }

        private void PlayFile (Entry entry)
        {
            SoundInput sound = null;
            try
            {
                SetBusyState();
                var input = VFS.OpenBinaryStream (entry);
                try
                {
                    FormatCatalog.Instance.LastError = null;
                    sound = AudioFormat.Read (input);
                    if (null == sound)
                    {
                        if (null != FormatCatalog.Instance.LastError)
                            throw FormatCatalog.Instance.LastError;
                        return;
                    }

                    if (AudioDevice != null)
                    {
                        AudioDevice.PlaybackStopped -= OnPlaybackStopped;
                        AudioDevice = null;
                    }
                    CurrentAudio = new WaveStreamImpl (sound);
                    AudioDevice = new WaveOutEvent();
                    if ("wav" == sound.SourceFormat)
                        AudioDevice.Init (CurrentAudio.ToSampleProvider());
                    else
                        AudioDevice.Init (CurrentAudio);
                    AudioDevice.PlaybackStopped += OnPlaybackStopped;
                    AudioDevice.Play();
                    input = null;
                    var fmt = CurrentAudio.WaveFormat;
                    SetResourceText (string.Format (guiStrings.MsgPlaying, entry.Name,
                                                    fmt.SampleRate, sound.SourceBitrate / 1000,
                                                    CurrentAudio.TotalTime.ToString ("m':'ss")));
                }
                finally
                {
                    if (input != null)
                        input.Dispose();
                }
            }
            catch (Exception X)
            {
                SetStatusText (X.Message);
                if (null != sound)
                    sound.Dispose();
            }
        }

        private void OnPlaybackStopped (object sender, StoppedEventArgs e)
        {
            try
            {
                SetResourceText ("");
                CurrentAudio = null;
            }
            catch (Exception X)
            {
                Trace.WriteLine (X.Message, "[OnPlaybackStopped]");
            }
        }

        /// <summary>
        /// Launch specified file.
        /// </summary>
        private void SystemOpen (string file)
        {
            try
            {
                Process.Start (file);
            }
            catch (Exception X)
            {
                SetStatusText (X.Message);
            }
        }

        /// <summary>
        /// Refresh current view.
        /// </summary>
        private void RefreshExec (object sender, ExecutedRoutedEventArgs e)
        {
            RefreshView();
        }

        public void RefreshView ()
        {
            VFS.Flush();
            var pos = GetCurrentPosition();
            SetCurrentPosition (pos);
        }

        /// <summary>
        /// Open current file in Explorer.
        /// </summary>

        private void ExploreItemExec (object sender, ExecutedRoutedEventArgs e)
        {
            var entry = CurrentDirectory.SelectedItem as EntryViewModel;
            if (entry != null && !ViewModel.IsArchive)
            {
                try
                {
                    string name = Path.Combine (CurrentPath, entry.Name);
                    Process.Start ("explorer.exe", "/select,"+name);
                }
                catch (Exception X)
                {
                    // ignore
                    Trace.WriteLine (X.Message, "explorer.exe");
                }
            }
        }

        /// <summary>
        /// Delete item from both media library and disk drive.
        /// </summary>
        private void DeleteItemExec (object sender, ExecutedRoutedEventArgs e)
        {
            var items = CurrentDirectory.SelectedItems.Cast<EntryViewModel>().Where (f => !f.IsDirectory);
            if (!items.Any())
                return;

            this.IsEnabled = false;
            try
            {
                VFS.Flush();
                ResetPreviewPane();
                if (!items.Skip (1).Any()) // items.Count() == 1
                {
                    string item_name = Path.Combine (CurrentPath, items.First().Name);
                    Trace.WriteLine (item_name, "DeleteItemExec");
                    FileSystem.DeleteFile (item_name, UIOption.AllDialogs, RecycleOption.SendToRecycleBin);
                    DeleteItem (lv_GetCurrentContainer());
                    SetStatusText (string.Format(guiStrings.MsgDeletedItem, item_name));
                }
                else
                {
                    int count = 0;
                    StopWatchDirectoryChanges ();
                    try
                    {
                        var file_list = items.Select (entry => Path.Combine (CurrentPath, entry.Name));
                        GARbro.Shell.File.Delete (file_list);
                        count = file_list.Count();
                    }
                    catch
                    {
                        ResumeWatchDirectoryChanges();
                        throw;
                    }
                    RefreshView();
                    SetStatusText (Localization.Format ("MsgDeletedItems", count));
                }
            }
            catch (OperationCanceledException)
            {
            }
            catch (Exception X)
            {
                SetStatusText (X.Message);
            }
            finally
            {
                this.IsEnabled = true;
            }
        }

        /// <summary>
        /// Delete item at the specified position within ListView, correctly adjusting current
        /// position.
        /// </summary>
        private void DeleteItem (ListViewItem item)
        {
            int i = CurrentDirectory.SelectedIndex;
            int next = -1;
            if (i+1 < CurrentDirectory.Items.Count)
                next = i + 1;
            else if (i > 0)
                next = i - 1;

            if (next != -1)
                CurrentDirectory.SelectedIndex = next;

            var entry = item.Content as EntryViewModel;
            if (entry != null)
            {
                ViewModel.Remove (entry);
            }
        }

        /// <summary>
        /// Rename selected item.
        /// </summary>
        private void RenameItemExec(object sender, ExecutedRoutedEventArgs e)
        {
            RenameElement (lv_GetCurrentContainer());
        }

        /// <summary>
        /// Rename item contained within specified framework control.
        /// </summary>
        void RenameElement (ListViewItem  item)
        {
            if (item == null)
                return;
/*
            TextBlock block = FindByName (item, "item_Text") as TextBlock;
            TextBox box = FindSibling (block, "item_Input") as TextBox;

            if (block == null || box == null)
                return;

            IsRenameActive = true;

            block.Visibility = Visibility.Collapsed;
            box.Text = block.Text;
            box.Visibility = Visibility.Visible;
            box.Select (0, box.Text.Length);
            box.Focus();
*/
        }

        /// <summary>
        /// Select files matching mask.
        /// </summary>
        void AddSelectionExec (object sender, ExecutedRoutedEventArgs e)
        {
            try
            {
                var ext_list = new SortedSet<string>();
                foreach (var entry in ViewModel)
                {
                    var ext = Path.GetExtension (entry.Name).ToLowerInvariant();
                    if (!string.IsNullOrEmpty (ext))
                        ext_list.Add (ext);
                }
                var selection = new EnterMaskDialog (ext_list.Select (ext => "*"+ext));
                selection.Owner = this;
                var result = selection.ShowDialog();
                if (!result.Value)
                    return;
                if ("*.*" == selection.Mask.Text)
                {
                    CurrentDirectory.SelectAll();
                    return;
                }
                SetBusyState();
                var glob = new FileNameGlob (selection.Mask.Text);
                var matching = ViewModel.Where (entry => glob.IsMatch (entry.Name));
                if (!matching.Any())
                {
                    SetStatusText (string.Format (guiStrings.MsgNoMatching, selection.Mask.Text));
                    return;
                }
                var selected = CurrentDirectory.SelectedItems.Cast<EntryViewModel>();
                matching = matching.Except (selected).ToList();
                int count = matching.Count();
                CurrentDirectory.SetSelectedItems (selected.Concat (matching));
                if (count != 0)
                    SetStatusText (Localization.Format ("MsgSelectedFiles", count));
            }
            catch (Exception X)
            {
                SetStatusText (X.Message);
            }
        }

        void SelectAllExec (object sender, ExecutedRoutedEventArgs e)
        {
            CurrentDirectory.SelectAll();
        }

        void CopyNamesExec (object sender, ExecutedRoutedEventArgs e)
        {
            var names = CurrentDirectory.SelectedItems.Cast<EntryViewModel>().Select (f => f.Name);
            if (names.Any())
            {
                try
                {
                    Clipboard.SetText (string.Join ("\r\n", names));
                }
                catch (Exception X)
                {
                    Trace.WriteLine (X.Message, "Clipboard error");
                }
            }
        }

        void NextItemExec (object sender, ExecutedRoutedEventArgs e)
        {
            if (LookupActive)
                return;

            var index = CurrentDirectory.SelectedIndex + 1;
            if (index < CurrentDirectory.Items.Count)
            {
                CurrentDirectory.SelectedIndex = index;
                CurrentDirectory.ScrollIntoView (CurrentDirectory.SelectedItem);
            }
        }

        /// <summary>
        /// Handle "Exit" command.
        /// </summary>
        void ExitExec (object sender, ExecutedRoutedEventArgs e)
        {
            Application.Current.Shutdown();
        }
 
        private void AboutExec (object sender, ExecutedRoutedEventArgs e)
        {
            var about = new AboutBox();
            about.Owner = this;
            about.ShowDialog();
        }

        private void CanExecuteAlways (object sender, CanExecuteRoutedEventArgs e)
        {
            e.CanExecute = true;
        }

        private void CanExecuteControlCommand (object sender, CanExecuteRoutedEventArgs e)
        {
            Control target = e.Source as Control;
            e.CanExecute = target != null;
        }

        private void CanExecuteOnSelected (object sender, CanExecuteRoutedEventArgs e)
        {
            e.CanExecute = CurrentDirectory.SelectedIndex != -1;
        }

        private void CanExecuteConvertMedia (object sender, CanExecuteRoutedEventArgs e)
        {
            if (CurrentDirectory.SelectedItems.Count >= 1)
            {
                e.CanExecute = !ViewModel.IsArchive;
            }
        }

        private void CanExecuteOnImage (object sender, CanExecuteRoutedEventArgs e)
        {
            var entry = CurrentDirectory.SelectedItem as EntryViewModel;
            e.CanExecute = !ViewModel.IsArchive && entry != null && entry.Type == "image";
        }

        private void CanExecuteInArchive (object sender, CanExecuteRoutedEventArgs e)
        {
            e.CanExecute = ViewModel.IsArchive && CurrentDirectory.SelectedIndex != -1;
        }

        private void CanExecuteCreateArchive (object sender, CanExecuteRoutedEventArgs e)
        {
            e.CanExecute = !ViewModel.IsArchive && CurrentDirectory.SelectedItems.Count > 0;
        }

        private void CanExecuteInDirectory (object sender, CanExecuteRoutedEventArgs e)
        {
            e.CanExecute = !ViewModel.IsArchive;
        }

        private void CanExecuteExtract (object sender, CanExecuteRoutedEventArgs e)
        {
            if (ViewModel.IsArchive)
            {
                e.CanExecute = true;
                return;
            }
            else if (CurrentDirectory.SelectedIndex != -1)
            {
                var entry = CurrentDirectory.SelectedItem as EntryViewModel;
                if (entry != null && !entry.IsDirectory)
                {
                    e.CanExecute = true;
                    return;
                }
            }
            e.CanExecute = false;
        }

        private void CanExecuteOnPhysicalFile (object sender, CanExecuteRoutedEventArgs e)
        {
            if (!ViewModel.IsArchive && CurrentDirectory.SelectedIndex != -1)
            {
                var entry = CurrentDirectory.SelectedItem as EntryViewModel;
                if (entry != null && !entry.IsDirectory)
                {
                    e.CanExecute = true;
                    return;
                }
            }
            e.CanExecute = false;
        }

        private void OnParametersRequest (object sender, ParametersRequestEventArgs e)
        {
            var format = sender as IResource;
            if (null != format)
            {
                var control = format.GetAccessWidget() as UIElement;
                if (null != control)
                {
                    bool busy_state = m_busy_state;
                    var param_dialog = new ArcParametersDialog (control, e.Notice);
                    param_dialog.Owner = this;
                    e.InputResult = param_dialog.ShowDialog() ?? false;
                    if (e.InputResult)
                        e.Options = format.GetOptions (control);
                    if (busy_state)
                        SetBusyState();
                }
            }
        }

        private void CanExecuteFitWindow (object sender, CanExecuteRoutedEventArgs e)
        {
            e.CanExecute = ImageCanvas.Source != null;
        }

        private void HideStatusBarExec (object sender, ExecutedRoutedEventArgs e)
        {
            ToggleVisibility (AppStatusBar);
        }

        private void HideMenuBarExec (object sender, ExecutedRoutedEventArgs e)
        {
            ToggleVisibility (MainMenuBar);
        }

        private void HideToolBarExec (object sender, ExecutedRoutedEventArgs e)
        {
            ToggleVisibility (MainToolBar);
        }

        static void ToggleVisibility (UIElement item)
        {
            var status = item.Visibility;
            if (Visibility.Visible == status)
                item.Visibility = Visibility.Collapsed;
            else
                item.Visibility = Visibility.Visible;
        }

        private void OnDropEvent (object sender, DragEventArgs e)
        {
            try
            {
                if (!e.Data.GetDataPresent (DataFormats.FileDrop))
                    return;
                var files = (string[])e.Data.GetData (DataFormats.FileDrop);
                if (!files.Any())
                    return;
                var filename = files.First();
                try
                {
                    OpenFileOrDir (filename);
                }
                catch (Exception X)
                {
                    VFS.FullPath = new string[] { Path.GetDirectoryName (filename) };
                    var vm = new DirectoryViewModel (VFS.FullPath, VFS.GetFiles(), VFS.IsVirtual);
                    PushViewModel (vm);
                    filename = Path.GetFileName (filename);
                    lv_SelectItem (filename);
                    SetStatusText (string.Format("{0}: {1}", filename, X.Message));
                }
            }
            catch (Exception X)
            {
                Trace.WriteLine (X.Message, "Drop event failed");
            }
        }
    }

    public class SortModeToBooleanConverter : IValueConverter
    {
        public object Convert (object value, Type targetType, object parameter, CultureInfo culture)
        {
            string actual_mode = value as string;
            string check_mode = parameter as string;
            if (string.IsNullOrEmpty (check_mode))
                return string.IsNullOrEmpty (actual_mode);
            return check_mode.Equals (actual_mode);
        }

        public object ConvertBack (object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }

    public class BooleanToCollapsedVisibilityConverter : IValueConverter
    {
        #region IValueConverter Members

        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            //reverse conversion (false=>Visible, true=>collapsed) on any given parameter
            bool input = (null == parameter) ? (bool)value : !((bool)value);
            return (input) ? Visibility.Visible : Visibility.Collapsed;
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }

        #endregion
    }

    public static class Commands
    {
        public static readonly RoutedCommand OpenItem = new RoutedCommand();
        public static readonly RoutedCommand OpenFile = new RoutedCommand();
        public static readonly RoutedCommand OpenRecent = new RoutedCommand();
        public static readonly RoutedCommand ExtractItem = new RoutedCommand();
        public static readonly RoutedCommand CreateArchive = new RoutedCommand();
        public static readonly RoutedCommand SortBy = new RoutedCommand();
        public static readonly RoutedCommand Exit = new RoutedCommand();
        public static readonly RoutedCommand About = new RoutedCommand();
        public static readonly RoutedCommand CheckUpdates = new RoutedCommand();
        public static readonly RoutedCommand GoBack = new RoutedCommand();
        public static readonly RoutedCommand GoForward = new RoutedCommand();
        public static readonly RoutedCommand DeleteItem = new RoutedCommand();
        public static readonly RoutedCommand RenameItem = new RoutedCommand();
        public static readonly RoutedCommand ExploreItem = new RoutedCommand();
        public static readonly RoutedCommand ConvertMedia = new RoutedCommand();
        public static readonly RoutedCommand Refresh = new RoutedCommand();
        public static readonly RoutedCommand Browse = new RoutedCommand();
        public static readonly RoutedCommand FitWindow = new RoutedCommand();
        public static readonly RoutedCommand HideStatusBar = new RoutedCommand();
        public static readonly RoutedCommand HideMenuBar = new RoutedCommand();
        public static readonly RoutedCommand HideToolBar = new RoutedCommand();
        public static readonly RoutedCommand AddSelection = new RoutedCommand();
        public static readonly RoutedCommand SelectAll = new RoutedCommand();
        public static readonly RoutedCommand SetFileType = new RoutedCommand();
        public static readonly RoutedCommand NextItem = new RoutedCommand();
        public static readonly RoutedCommand CopyNames = new RoutedCommand();
    }
}