/*************************************************************************************
   
   Toolkit for WPF

   Copyright (C) 2007-2025 Xceed Software Inc.

   This program is provided to you under the terms of the XCEED SOFTWARE, INC.
   COMMUNITY LICENSE AGREEMENT (for non-commercial use) as published at 
   https://github.com/xceedsoftware/wpftoolkit/blob/master/license.md 

   For more features, controls, and fast professional support,
   pick up the Plus Edition at https://xceed.com/xceed-toolkit-plus-for-wpf/

   Stay informed: follow @datagrid on Twitter or Like http://facebook.com/datagrids

  ***********************************************************************************/

using System;
using System.Linq;
using System.Windows;
using System.Runtime.InteropServices;
using System.Windows.Interop;
using System.Windows.Input;
using Xceed.Wpf.AvalonDock.Layout;
using Xceed.Wpf.AvalonDock.Themes;
using Standard;
using System.Windows.Threading;

namespace Xceed.Wpf.AvalonDock.Controls
{
  public abstract class LayoutFloatingWindowControl : Window, ILayoutControl
  {
    #region Members

    private ResourceDictionary currentThemeResourceDictionary; // = null
    private bool _isInternalChange; //false
    private ILayoutElement _model;
    private bool _attachDrag = false;
    private HwndSource _hwndSrc;
    private HwndSourceHook _hwndSrcHook;
    private DragService _dragService = null;
    private bool _internalCloseFlag = false;
    private bool _isClosing = false;

    #endregion

    #region Constructors

    static LayoutFloatingWindowControl()
    {
      LayoutFloatingWindowControl.ContentProperty.OverrideMetadata( typeof( LayoutFloatingWindowControl ), new FrameworkPropertyMetadata( null, null, new CoerceValueCallback( CoerceContentValue ) ) );
      AllowsTransparencyProperty.OverrideMetadata( typeof( LayoutFloatingWindowControl ), new FrameworkPropertyMetadata( false ) );
      ShowInTaskbarProperty.OverrideMetadata( typeof( LayoutFloatingWindowControl ), new FrameworkPropertyMetadata( false ) );
    }

    protected LayoutFloatingWindowControl( ILayoutElement model )
    {
      this.Loaded += new RoutedEventHandler( OnLoaded );
      this.Unloaded += new RoutedEventHandler( OnUnloaded );
      this.IsVisibleChanged += this.LayoutFloatingWindowControl_IsVisibleChanged;
      _model = model;
    }

    protected LayoutFloatingWindowControl( ILayoutElement model, bool isContentImmutable )
      : this( model )
    {
      this.IsContentImmutable = isContentImmutable;
    }

    #endregion

    #region Properties

    #region Model

    public abstract ILayoutElement Model
    {
      get;
    }

    #endregion

    #region IsContentImmutable

    public static readonly DependencyProperty IsContentImmutableProperty = DependencyProperty.Register( "IsContentImmutable", typeof( bool ), typeof( LayoutFloatingWindowControl ),
              new FrameworkPropertyMetadata( ( bool )false ) );

    public bool IsContentImmutable
    {
      get
      {
        return ( bool )GetValue( IsContentImmutableProperty );
      }
      private set
      {
        SetValue( IsContentImmutableProperty, value );
      }
    }

    #endregion

    #region IsDragging

    private static readonly DependencyPropertyKey IsDraggingPropertyKey = DependencyProperty.RegisterReadOnly( "IsDragging", typeof( bool ), typeof( LayoutFloatingWindowControl ),
            new FrameworkPropertyMetadata( ( bool )false, new PropertyChangedCallback( OnIsDraggingChanged ) ) );

    public static readonly DependencyProperty IsDraggingProperty = IsDraggingPropertyKey.DependencyProperty;

    public bool IsDragging
    {
      get
      {
        return ( bool )GetValue( IsDraggingProperty );
      }
    }

    protected void SetIsDragging( bool value )
    {
      SetValue( IsDraggingPropertyKey, value );
    }

    private static void OnIsDraggingChanged( DependencyObject d, DependencyPropertyChangedEventArgs e )
    {
      ( ( LayoutFloatingWindowControl )d ).OnIsDraggingChanged( e );
    }

    protected virtual void OnIsDraggingChanged( DependencyPropertyChangedEventArgs e )
    {
      if( ( bool )e.NewValue )
      {
        CaptureMouse();
      }
      else
      {
        ReleaseMouseCapture();
      }
    }

    #endregion

    #region CloseInitiatedByUser

    protected bool CloseInitiatedByUser
    {
      get
      {
        return !_internalCloseFlag;
      }
    }

    #endregion

    #region KeepContentVisibleOnClose

    internal bool KeepContentVisibleOnClose
    {
      get;
      set;
    }

    #endregion

    #region IsMaximized

    public static readonly DependencyProperty IsMaximizedProperty = DependencyProperty.Register( "IsMaximized", typeof( bool ), typeof( LayoutFloatingWindowControl ),
              new FrameworkPropertyMetadata( ( bool )false ) );

    public bool IsMaximized
    {
      get
      {
        return ( bool )GetValue( IsMaximizedProperty );
      }
      private set
      {
        SetValue( IsMaximizedProperty, value );
        UpdatePositionAndSizeOfPanes();
      }
    }


    protected override void OnStateChanged( EventArgs e )
    {
      if( !_isInternalChange )
      {
        if( this.WindowState == WindowState.Maximized )
        {
          this.UpdateMaximizedState( true );
        }
        else
        {
          if( this.IsMaximized )
          {
            this.WindowState = WindowState.Maximized;
          }
        }
      }

      if( this.WindowState == WindowState.Normal )
      {
        this.UpdatePositionAndSizeOfPanes();
      }

      base.OnStateChanged( e );
    }

    #endregion

    #region ResizeBorderThickness

    public static readonly DependencyProperty ResizeBorderThicknessProperty = DependencyProperty.Register(
        "ResizeBorderThickness",
        typeof( Thickness ),
        typeof( LayoutFloatingWindowControl ),
        new FrameworkPropertyMetadata( new Thickness( 10 ) ) );

    public Thickness ResizeBorderThickness
    {
      get
      {
        return ( Thickness )GetValue( ResizeBorderThicknessProperty );
      }
      set
      {
        SetValue( ResizeBorderThicknessProperty, value );
      }
    }

    #endregion

    #endregion

    #region Overrides

    protected override void OnClosing( System.ComponentModel.CancelEventArgs e )
    {
      if( this.CloseInitiatedByUser && !this.KeepContentVisibleOnClose )
      {
        // model.CanClose is false, can we hide ?
        if( !this.CanClose() )
        {
          // Cancel the closing because we are hiding or nothing to do on (Alt + F4).
          e.Cancel = true;
          if( this.CanHide() )
          {
            // Just hiding.
            this.DoHide();
          }
        }
      }

      base.OnClosing( e );
    }

    protected override void OnClosed( EventArgs e )
    {
      var root = ( this.Model != null ) ? this.Model.Root : null;
      if( root != null )
      {
        if( root.Manager != null )
        {
          root.Manager.RemoveFloatingWindow( this );
        }
        root.CollectGarbage();
      }

      if( this.Content != null )
      {
        if( _hwndSrc != null )
        {
          _hwndSrc.RemoveHook( _hwndSrcHook );
          _hwndSrc.Dispose();
          _hwndSrc = null;
        }
      }

      base.OnClosed( e );

      if( !this.CloseInitiatedByUser && ( root != null ) )
      {
        root.FloatingWindows.Remove( this.Model as LayoutFloatingWindow );
      }

      this.BringFocusOnDockingManager();
    }

    protected override void OnInitialized( EventArgs e )
    {
      CommandBindings.Add( new CommandBinding( Microsoft.Windows.Shell.SystemCommands.CloseWindowCommand,
          new ExecutedRoutedEventHandler( ( s, args ) => Microsoft.Windows.Shell.SystemCommands.CloseWindow( ( Window )args.Parameter ) ) ) );
      CommandBindings.Add( new CommandBinding( Microsoft.Windows.Shell.SystemCommands.MaximizeWindowCommand,
          new ExecutedRoutedEventHandler( ( s, args ) => Microsoft.Windows.Shell.SystemCommands.MaximizeWindow( ( Window )args.Parameter ) ) ) );
      CommandBindings.Add( new CommandBinding( Microsoft.Windows.Shell.SystemCommands.MinimizeWindowCommand,
          new ExecutedRoutedEventHandler( ( s, args ) => Microsoft.Windows.Shell.SystemCommands.MinimizeWindow( ( Window )args.Parameter ) ) ) );
      CommandBindings.Add( new CommandBinding( Microsoft.Windows.Shell.SystemCommands.RestoreWindowCommand,
          new ExecutedRoutedEventHandler( ( s, args ) => Microsoft.Windows.Shell.SystemCommands.RestoreWindow( ( Window )args.Parameter ) ) ) );
      //Debug.Assert(this.Owner != null);
      base.OnInitialized( e );
    }

    protected override void OnKeyDown( KeyEventArgs e )
    {
      var root = this.Model.Root;
      if( root != null )
      {
        if( root.Manager.AllowMovingFloatingWindowWithKeyboard )
        {
          switch( e.Key )
          {
            case Key.Left:
              this.Left -= 25;
              break;
            case Key.Right:
              this.Left += 25;
              break;
            case Key.Up:
              this.Top -= 25;
              break;
            case Key.Down:
              this.Top += 25;
              break;
          }
        }
      }

      base.OnKeyDown( e );
    }

    protected override void OnPreviewKeyDown( KeyEventArgs e )
    {
      if( Keyboard.IsKeyDown( Key.LeftCtrl ) || Keyboard.IsKeyDown( Key.RightCtrl ) )
      {
        if( e.IsDown && e.Key == Key.Tab )
        {
          if( ( this.Model != null ) && ( this.Model.Root != null ) )
          {
            var manager = this.Model.Root.Manager;
            if( manager != null )
            {
              if( !manager.IsNavigatorWindowActive )
              {
                manager.ShowNavigatorWindow();
                e.Handled = true;
              }
            }
          }
        }
      }

      base.OnPreviewKeyDown( e );
    }


    #endregion

    #region Internal Methods

    internal virtual void UpdateThemeResources( Theme oldTheme = null )
    {
      if( oldTheme != null )
      {
        if( oldTheme is DictionaryTheme )
        {
          if( currentThemeResourceDictionary != null )
          {
            Resources.MergedDictionaries.Remove( currentThemeResourceDictionary );
            currentThemeResourceDictionary = null;
          }
        }
        else
        {
          var resourceDictionaryToRemove =
              Resources.MergedDictionaries.FirstOrDefault( r => r.Source == oldTheme.GetResourceUri() );
          if( resourceDictionaryToRemove != null )
            Resources.MergedDictionaries.Remove(
                resourceDictionaryToRemove );
        }
      }

      var manager = _model.Root.Manager;
      if( manager.Theme != null )
      {
        if( manager.Theme is DictionaryTheme )
        {
          currentThemeResourceDictionary = ( ( DictionaryTheme )manager.Theme ).ThemeResourceDictionary;
          Resources.MergedDictionaries.Add( currentThemeResourceDictionary );
        }
        else
        {
          Resources.MergedDictionaries.Add( new ResourceDictionary() { Source = manager.Theme.GetResourceUri() } );
        }
      }
    }

    protected virtual bool CanClose( object parameter = null )
    {
      return false;
    }

    protected virtual bool CanHide( object parameter = null )
    {
      return false;
    }

    protected virtual void DoHide()
    {
    }

    internal void AttachDrag( bool onActivated = true )
    {
      if( onActivated )
      {
        _attachDrag = true;
        this.Activated += new EventHandler( OnActivated );
      }
      else
      {
        IntPtr windowHandle = new WindowInteropHelper( this ).Handle;
        IntPtr lParam = new IntPtr( ( ( int )Left & ( int )0xFFFF ) | ( ( ( int )Top ) << 16 ) );
        Win32Helper.SendMessage( windowHandle, Win32Helper.WM_NCLBUTTONDOWN, new IntPtr( Win32Helper.HT_CAPTION ), lParam );
      }
    }

    protected virtual IntPtr FilterMessage( IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled )
    {
      handled = false;

      switch( msg )
      {
        case Win32Helper.NCCALCSIZE:
          if( wParam != IntPtr.Zero )
          {
            handled = true;
            var client = ( RECT )Marshal.PtrToStructure( lParam, typeof( RECT ) );
            client.Bottom -= 1;
            Marshal.StructureToPtr( client, lParam, false );
          }
          break;

        //case Win32Helper.WM_NCHITTEST:
        //  {
        //    handled = true;
        //    //var htLocation = DefWindowProc( hwnd, msg, wParam, lParam ).ToInt32();
        //    //switch( htLocation )
        //    //{
        //    //  case (int)HitTestResult.HTBOTTOM:
        //    //  case (int)HitTestResult.HTBOTTOMLEFT:
        //    //  case (int)HitTestResult.HTBOTTOMRIGHT:
        //    //  case (int)HitTestResult.HTLEFT:
        //    //  case (int)HitTestResult.HTRIGHT:
        //    //  case (int)HitTestResult.HTTOP:
        //    //  case (int)HitTestResult.HTTOPLEFT:
        //    //  case (int)HitTestResult.HTTOPRIGHT:
        //    //    htLocation = (int)HitTestResult.HTBORDER;
        //  }
        //  break;

        case Win32Helper.WM_ACTIVATE:
          if( ( ( int )wParam & 0xFFFF ) == Win32Helper.WA_INACTIVE )
          {
            if( lParam == this.GetParentWindowHandle() )
            {
              Win32Helper.SetActiveWindow( _hwndSrc.Handle );
              handled = true;
            }
          }
          break;
        case Win32Helper.WM_EXITSIZEMOVE:
          UpdatePositionAndSizeOfPanes();

          if( _dragService != null )
          {
            bool dropFlag;
            var mousePosition = this.TransformToDeviceDPI( Win32Helper.GetMousePosition() );
            _dragService.Drop( mousePosition, out dropFlag );
            _dragService = null;
            SetIsDragging( false );

            if( dropFlag )
              InternalClose();
          }

          break;
        case Win32Helper.WM_MOVING:
          {
            UpdateDragPosition();
            if( this.IsMaximized )
            {
              this.UpdateMaximizedState( false );
            }
          }
          break;
        case Win32Helper.WM_LBUTTONUP: //set as handled right button click on title area (after showing context menu)
          if( _dragService != null && Mouse.LeftButton == MouseButtonState.Released )
          {
            _dragService.Abort();
            _dragService = null;
            SetIsDragging( false );
          }
          break;
        case Win32Helper.WM_SYSCOMMAND:
          int command = ( int )wParam & 0xFFF0;
          if( command == Win32Helper.SC_MAXIMIZE || command == Win32Helper.SC_RESTORE )
          {
            UpdateMaximizedState( command == Win32Helper.SC_MAXIMIZE );
          }
          break;
      }



      return IntPtr.Zero;
    }

    internal void InternalClose()
    {
      _internalCloseFlag = true;
      if( !_isClosing )
      {
        _isClosing = true;

        // Added Dispatcher to prevent InvalidOperationException issue in reference to bug case 
        // Azure case #2106
        Dispatcher.BeginInvoke( new Action( () =>
        {
          this.Close();
        } ), DispatcherPriority.Send );
      }
    }

    internal void BringFocusOnDockingManager()
    {
      // Prevent focus lost on MainWindow when closing floatingWindows.
      if( this.Owner != null )
      {
        this.Owner.Focus();
      }
      else
      {
        if( ( this.Model != null ) && ( this.Model.Root != null ) && ( this.Model.Root.Manager != null ) )
        {
          var firstUIElement = this.Model.Root.Manager.FindVisualChildren<UIElement>().Where( control => control.Focusable ).FirstOrDefault();
          if( firstUIElement != null )
          {
            firstUIElement.Focus();
          }
        }
      }
    }

    internal bool IsClosing()
    {
      return _isClosing;
    }

    #endregion

    #region Private Methods

    private static object CoerceContentValue( DependencyObject sender, object content )
    {
      var lfwc = sender as LayoutFloatingWindowControl;
      if( lfwc != null )
      {
        if( lfwc.IsLoaded && lfwc.IsContentImmutable )
          return lfwc.Content;
        return content;
      }
      return null;
    }

    private void LayoutFloatingWindowControl_IsVisibleChanged( object sender, DependencyPropertyChangedEventArgs e )
    {
      if( ( bool )e.NewValue )
      {
      }
    }

    private void OnLoaded( object sender, RoutedEventArgs e )
    {
      this.Loaded -= new RoutedEventHandler( OnLoaded );

      this.SetParentToMainWindowOf( Model.Root.Manager );

      _hwndSrc = HwndSource.FromDependencyObject( this ) as HwndSource;
      _hwndSrcHook = new HwndSourceHook( FilterMessage );
      _hwndSrc.AddHook( _hwndSrcHook );

      // Restore maximize state
      var maximized = Model.Descendents().OfType<ILayoutElementForFloatingWindow>().Any( l => l.IsMaximized );
      UpdateMaximizedState( maximized );
    }

    private void OnUnloaded( object sender, RoutedEventArgs e )
    {
      this.Unloaded -= new RoutedEventHandler( OnUnloaded );

      if( _hwndSrc != null )
      {
        _hwndSrc.RemoveHook( _hwndSrcHook );
        InternalClose();
      }
    }

    private void OnActivated( object sender, EventArgs e )
    {
      this.Activated -= new EventHandler( OnActivated );

      if( _attachDrag && Mouse.LeftButton == MouseButtonState.Pressed )
      {
        IntPtr windowHandle = new WindowInteropHelper( this ).Handle;
        var mousePosition = this.PointToScreenDPI( Mouse.GetPosition( this ) );
        var clientArea = Win32Helper.GetClientRect( windowHandle );
        var windowArea = Win32Helper.GetWindowRect( windowHandle );

        Left = mousePosition.X - ( windowArea.Width - clientArea.Width ) / 2.0;
        Top = mousePosition.Y - ( windowArea.Height - clientArea.Height ) / 2.0;
        _attachDrag = false;

        IntPtr lParam = new IntPtr( ( ( int )mousePosition.X & ( int )0xFFFF ) | ( ( ( int )mousePosition.Y ) << 16 ) );
        Win32Helper.SendMessage( windowHandle, Win32Helper.WM_NCLBUTTONDOWN, new IntPtr( Win32Helper.HT_CAPTION ), lParam );
      }
    }

    private void UpdatePositionAndSizeOfPanes()
    {
      foreach( var posElement in Model.Descendents().OfType<ILayoutElementForFloatingWindow>() )
      {
        posElement.FloatingLeft = Left;
        posElement.FloatingTop = Top;
        posElement.FloatingWidth = Width;
        posElement.FloatingHeight = Height;
      }
    }

    private void UpdateMaximizedState( bool isMaximized )
    {
      foreach( var posElement in Model.Descendents().OfType<ILayoutElementForFloatingWindow>() )
      {
        posElement.IsMaximized = isMaximized;
      }
      IsMaximized = isMaximized;
      _isInternalChange = true;
      WindowState = isMaximized ? WindowState.Maximized : WindowState.Normal;
      _isInternalChange = false;
    }

    private void UpdateDragPosition()
    {
      if( _dragService == null )
      {
        _dragService = new DragService( this );
        SetIsDragging( true );
      }

      var mousePosition = this.TransformToDeviceDPI( Win32Helper.GetMousePosition() );
      _dragService.UpdateMouseLocation( mousePosition );
    }

    #endregion
  }
}