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

   Copyright (C) 2007-2018 Xceed Software Inc.

   This program is provided to you under the terms of the Microsoft Public
   License (Ms-PL) as published at http://wpftoolkit.codeplex.com/license 

   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

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

/**************************************************************************\
    Copyright Microsoft Corporation. All Rights Reserved.
\**************************************************************************/

namespace Microsoft.Windows.Shell
{
  using System;
  using System.Collections.Generic;
  using System.ComponentModel;
  using System.Diagnostics.CodeAnalysis;
  using System.Runtime.InteropServices;
  using System.Windows;
  using System.Windows.Media;
  using Standard;

  [SuppressMessage( "Microsoft.Design", "CA1001:TypesThatOwnDisposableFieldsShouldBeDisposable" )]
  public class SystemParameters2 : INotifyPropertyChanged
  {
    private delegate void _SystemMetricUpdate( IntPtr wParam, IntPtr lParam );

    [ThreadStatic]
    private static SystemParameters2 _threadLocalSingleton;

    private MessageWindow _messageHwnd;

    private bool _isGlassEnabled;
    private Color _glassColor;
    private SolidColorBrush _glassColorBrush;
    private Thickness _windowResizeBorderThickness;
    private Thickness _windowNonClientFrameThickness;
    private double _captionHeight;
    private Size _smallIconSize;
    private string _uxThemeName;
    private string _uxThemeColor;
    private bool _isHighContrast;
    private CornerRadius _windowCornerRadius;
    private Rect _captionButtonLocation;

    private readonly Dictionary<WM, List<_SystemMetricUpdate>> _UpdateTable;

    #region Initialization and Update Methods

    // Most properties exposed here have a way of being queried directly
    // and a way of being notified of updates via a window message.
    // This region is a grouping of both, for each of the exposed properties.

    private void _InitializeIsGlassEnabled()
    {
      IsGlassEnabled = NativeMethods.DwmIsCompositionEnabled();
    }

    private void _UpdateIsGlassEnabled( IntPtr wParam, IntPtr lParam )
    {
      // Neither the wParam or lParam are used in this case.
      _InitializeIsGlassEnabled();
    }

    private void _InitializeGlassColor()
    {
      bool isOpaque;
      uint color;
      NativeMethods.DwmGetColorizationColor( out color, out isOpaque );
      color |= isOpaque ? 0xFF000000 : 0;

      WindowGlassColor = Utility.ColorFromArgbDword( color );

      var glassBrush = new SolidColorBrush( WindowGlassColor );
      glassBrush.Freeze();

      WindowGlassBrush = glassBrush;
    }

    private void _UpdateGlassColor( IntPtr wParam, IntPtr lParam )
    {
      bool isOpaque = lParam != IntPtr.Zero;
      uint color = unchecked(( uint )( int )wParam.ToInt64());
      color |= isOpaque ? 0xFF000000 : 0;
      WindowGlassColor = Utility.ColorFromArgbDword( color );
      var glassBrush = new SolidColorBrush( WindowGlassColor );
      glassBrush.Freeze();
      WindowGlassBrush = glassBrush;
    }

    private void _InitializeCaptionHeight()
    {
      Point ptCaption = new Point( 0, NativeMethods.GetSystemMetrics( SM.CYCAPTION ) );
      WindowCaptionHeight = DpiHelper.DevicePixelsToLogical( ptCaption ).Y;
    }

    private void _UpdateCaptionHeight( IntPtr wParam, IntPtr lParam )
    {
      _InitializeCaptionHeight();
    }

    private void _InitializeWindowResizeBorderThickness()
    {
      Size frameSize = new Size(
          NativeMethods.GetSystemMetrics( SM.CXSIZEFRAME ),
          NativeMethods.GetSystemMetrics( SM.CYSIZEFRAME ) );
      Size frameSizeInDips = DpiHelper.DeviceSizeToLogical( frameSize );
      WindowResizeBorderThickness = new Thickness( frameSizeInDips.Width, frameSizeInDips.Height, frameSizeInDips.Width, frameSizeInDips.Height );
    }

    private void _UpdateWindowResizeBorderThickness( IntPtr wParam, IntPtr lParam )
    {
      _InitializeWindowResizeBorderThickness();
    }

    private void _InitializeWindowNonClientFrameThickness()
    {
      Size frameSize = new Size(
          NativeMethods.GetSystemMetrics( SM.CXSIZEFRAME ),
          NativeMethods.GetSystemMetrics( SM.CYSIZEFRAME ) );
      Size frameSizeInDips = DpiHelper.DeviceSizeToLogical( frameSize );
      int captionHeight = NativeMethods.GetSystemMetrics( SM.CYCAPTION );
      double captionHeightInDips = DpiHelper.DevicePixelsToLogical( new Point( 0, captionHeight ) ).Y;
      WindowNonClientFrameThickness = new Thickness( frameSizeInDips.Width, frameSizeInDips.Height + captionHeightInDips, frameSizeInDips.Width, frameSizeInDips.Height );
    }

    private void _UpdateWindowNonClientFrameThickness( IntPtr wParam, IntPtr lParam )
    {
      _InitializeWindowNonClientFrameThickness();
    }

    private void _InitializeSmallIconSize()
    {
      SmallIconSize = new Size(
          NativeMethods.GetSystemMetrics( SM.CXSMICON ),
          NativeMethods.GetSystemMetrics( SM.CYSMICON ) );
    }

    private void _UpdateSmallIconSize( IntPtr wParam, IntPtr lParam )
    {
      _InitializeSmallIconSize();
    }

    private void _LegacyInitializeCaptionButtonLocation()
    {
      // This calculation isn't quite right, but it's pretty close.
      // I expect this is good enough for the scenarios where this is expected to be used.
      int captionX = NativeMethods.GetSystemMetrics( SM.CXSIZE );
      int captionY = NativeMethods.GetSystemMetrics( SM.CYSIZE );

      int frameX = NativeMethods.GetSystemMetrics( SM.CXSIZEFRAME ) + NativeMethods.GetSystemMetrics( SM.CXEDGE );
      int frameY = NativeMethods.GetSystemMetrics( SM.CYSIZEFRAME ) + NativeMethods.GetSystemMetrics( SM.CYEDGE );

      Rect captionRect = new Rect( 0, 0, captionX * 3, captionY );
      captionRect.Offset( -frameX - captionRect.Width, frameY );

      WindowCaptionButtonsLocation = captionRect;
    }

    [SuppressMessage( "Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands" )]
    private void _InitializeCaptionButtonLocation()
    {
      // There is a completely different way to do this on XP.
      if( !Utility.IsOSVistaOrNewer || !NativeMethods.IsThemeActive() )
      {
        _LegacyInitializeCaptionButtonLocation();
        return;
      }

      var tbix = new TITLEBARINFOEX { cbSize = Marshal.SizeOf( typeof( TITLEBARINFOEX ) ) };
      IntPtr lParam = Marshal.AllocHGlobal( tbix.cbSize );
      try
      {
        Marshal.StructureToPtr( tbix, lParam, false );
        // This might flash a window in the taskbar while being calculated.
        // WM_GETTITLEBARINFOEX doesn't work correctly unless the window is visible while processing.
        NativeMethods.ShowWindow( _messageHwnd.Handle, SW.SHOW );
        NativeMethods.SendMessage( _messageHwnd.Handle, WM.GETTITLEBARINFOEX, IntPtr.Zero, lParam );
        tbix = ( TITLEBARINFOEX )Marshal.PtrToStructure( lParam, typeof( TITLEBARINFOEX ) );
      }
      finally
      {
        NativeMethods.ShowWindow( _messageHwnd.Handle, SW.HIDE );
        Utility.SafeFreeHGlobal( ref lParam );
      }

      // TITLEBARINFOEX has information relative to the screen.  We need to convert the containing rect
      // to instead be relative to the top-right corner of the window.
      RECT rcAllCaptionButtons = RECT.Union( tbix.rgrect_CloseButton, tbix.rgrect_MinimizeButton );
      // For all known themes, the RECT for the maximize box shouldn't add anything to the union of the minimize and close boxes.
      Assert.AreEqual( rcAllCaptionButtons, RECT.Union( rcAllCaptionButtons, tbix.rgrect_MaximizeButton ) );

      RECT rcWindow = NativeMethods.GetWindowRect( _messageHwnd.Handle );

      // Reorient the Top/Right to be relative to the top right edge of the Window.
      var deviceCaptionLocation = new Rect(
          rcAllCaptionButtons.Left - rcWindow.Width - rcWindow.Left,
          rcAllCaptionButtons.Top - rcWindow.Top,
          rcAllCaptionButtons.Width,
          rcAllCaptionButtons.Height );

      Rect logicalCaptionLocation = DpiHelper.DeviceRectToLogical( deviceCaptionLocation );

      WindowCaptionButtonsLocation = logicalCaptionLocation;
    }

    private void _UpdateCaptionButtonLocation( IntPtr wParam, IntPtr lParam )
    {
      _InitializeCaptionButtonLocation();
    }

    private void _InitializeHighContrast()
    {
      HIGHCONTRAST hc = NativeMethods.SystemParameterInfo_GetHIGHCONTRAST();
      HighContrast = ( hc.dwFlags & HCF.HIGHCONTRASTON ) != 0;
    }

    private void _UpdateHighContrast( IntPtr wParam, IntPtr lParam )
    {
      _InitializeHighContrast();
    }

    private void _InitializeThemeInfo()
    {
      if( !NativeMethods.IsThemeActive() )
      {
        UxThemeName = "Classic";
        UxThemeColor = "";
        return;
      }

      string name;
      string color;
      string size;
      NativeMethods.GetCurrentThemeName( out name, out color, out size );

      // Consider whether this is the most useful way to expose this...
      UxThemeName = System.IO.Path.GetFileNameWithoutExtension( name );
      UxThemeColor = color;
    }

    private void _UpdateThemeInfo( IntPtr wParam, IntPtr lParam )
    {
      _InitializeThemeInfo();
    }

    private void _InitializeWindowCornerRadius()
    {
      // The radius of window corners isn't exposed as a true system parameter.
      // It instead is a logical size that we're approximating based on the current theme.
      // There aren't any known variations based on theme color.
      Assert.IsNeitherNullNorEmpty( UxThemeName );

      // These radii are approximate.  The way WPF does rounding is different than how
      //     rounded-rectangle HRGNs are created, which is also different than the actual
      //     round corners on themed Windows.  For now we're not exposing anything to
      //     mitigate the differences.
      var cornerRadius = default( CornerRadius );

      // This list is known to be incomplete and very much not future-proof.
      // On XP there are at least a couple of shipped themes that this won't catch,
      // "Zune" and "Royale", but WPF doesn't know about these either.
      // If a new theme was to replace Aero, then this will fall back on "classic" behaviors.
      // This isn't ideal, but it's not the end of the world.  WPF will generally have problems anyways.
      switch( UxThemeName.ToUpperInvariant() )
      {
        case "LUNA":
          cornerRadius = new CornerRadius( 6, 6, 0, 0 );
          break;
        case "AERO":
          // Aero has two cases.  One with glass and one without...
          if( NativeMethods.DwmIsCompositionEnabled() )
          {
            cornerRadius = new CornerRadius( 8 );
          }
          else
          {
            cornerRadius = new CornerRadius( 6, 6, 0, 0 );
          }
          break;
        case "CLASSIC":
        case "ZUNE":
        case "ROYALE":
        default:
          cornerRadius = new CornerRadius( 0 );
          break;
      }

      WindowCornerRadius = cornerRadius;
    }

    private void _UpdateWindowCornerRadius( IntPtr wParam, IntPtr lParam )
    {
      // Neither the wParam or lParam are used in this case.
      _InitializeWindowCornerRadius();
    }


    #endregion

    /// <summary>
    /// Private constructor.  The public way to access this class is through the static Current property.
    /// </summary>
    private SystemParameters2()
    {
      // This window gets used for calculations about standard caption button locations
      // so it has WS_OVERLAPPEDWINDOW as a style to give it normal caption buttons.
      // This window may be shown during calculations of caption bar information, so create it at a location that's likely offscreen.
      _messageHwnd = new MessageWindow( ( CS )0, WS.OVERLAPPEDWINDOW | WS.DISABLED, ( WS_EX )0, new Rect( -16000, -16000, 100, 100 ), "", _WndProc );
      _messageHwnd.Dispatcher.ShutdownStarted += ( sender, e ) => Utility.SafeDispose( ref _messageHwnd );

      // Fixup the default values of the DPs.
      _InitializeIsGlassEnabled();
      _InitializeGlassColor();
      _InitializeCaptionHeight();
      _InitializeWindowNonClientFrameThickness();
      _InitializeWindowResizeBorderThickness();
      _InitializeCaptionButtonLocation();
      _InitializeSmallIconSize();
      _InitializeHighContrast();
      _InitializeThemeInfo();
      // WindowCornerRadius isn't exposed by true system parameters, so it requires the theme to be initialized first.
      _InitializeWindowCornerRadius();

      _UpdateTable = new Dictionary<WM, List<_SystemMetricUpdate>>
            {
                { WM.THEMECHANGED,
                    new List<_SystemMetricUpdate>
                    {
                        _UpdateThemeInfo,
                        _UpdateHighContrast,
                        _UpdateWindowCornerRadius,
                        _UpdateCaptionButtonLocation, } },
                { WM.SETTINGCHANGE,
                    new List<_SystemMetricUpdate>
                    {
                        _UpdateCaptionHeight,
                        _UpdateWindowResizeBorderThickness,
                        _UpdateSmallIconSize,
                        _UpdateHighContrast,
                        _UpdateWindowNonClientFrameThickness,
                        _UpdateCaptionButtonLocation, } },
                { WM.DWMNCRENDERINGCHANGED, new List<_SystemMetricUpdate> { _UpdateIsGlassEnabled } },
                { WM.DWMCOMPOSITIONCHANGED, new List<_SystemMetricUpdate> { _UpdateIsGlassEnabled } },
                { WM.DWMCOLORIZATIONCOLORCHANGED, new List<_SystemMetricUpdate> { _UpdateGlassColor } },
            };
    }

    public static SystemParameters2 Current
    {
      get
      {
        if( _threadLocalSingleton == null )
        {
          _threadLocalSingleton = new SystemParameters2();
        }
        return _threadLocalSingleton;
      }
    }

    private IntPtr _WndProc( IntPtr hwnd, WM msg, IntPtr wParam, IntPtr lParam )
    {
      // Don't do this if called within the SystemParameters2 constructor
      if( _UpdateTable != null )
      {
        List<_SystemMetricUpdate> handlers;
        if( _UpdateTable.TryGetValue( msg, out handlers ) )
        {
          Assert.IsNotNull( handlers );
          foreach( var handler in handlers )
          {
            handler( wParam, lParam );
          }
        }
      }

      return NativeMethods.DefWindowProc( hwnd, msg, wParam, lParam );
    }

    public bool IsGlassEnabled
    {
      get
      {
        // return _isGlassEnabled;
        // It turns out there may be some lag between someone asking this
        // and the window getting updated.  It's not too expensive, just always do the check.
        return NativeMethods.DwmIsCompositionEnabled();
      }
      private set
      {
        if( value != _isGlassEnabled )
        {
          _isGlassEnabled = value;
          _NotifyPropertyChanged( "IsGlassEnabled" );
        }
      }
    }

    public Color WindowGlassColor
    {
      get
      {
        return _glassColor;
      }
      private set
      {
        if( value != _glassColor )
        {
          _glassColor = value;
          _NotifyPropertyChanged( "WindowGlassColor" );
        }
      }
    }

    public SolidColorBrush WindowGlassBrush
    {
      get
      {
        return _glassColorBrush;
      }
      private set
      {
        Assert.IsNotNull( value );
        Assert.IsTrue( value.IsFrozen );
        if( _glassColorBrush == null || value.Color != _glassColorBrush.Color )
        {
          _glassColorBrush = value;
          _NotifyPropertyChanged( "WindowGlassBrush" );
        }
      }
    }

    public Thickness WindowResizeBorderThickness
    {
      get
      {
        return _windowResizeBorderThickness;
      }
      private set
      {
        if( value != _windowResizeBorderThickness )
        {
          _windowResizeBorderThickness = value;
          _NotifyPropertyChanged( "WindowResizeBorderThickness" );
        }
      }
    }

    public Thickness WindowNonClientFrameThickness
    {
      get
      {
        return _windowNonClientFrameThickness;
      }
      private set
      {
        if( value != _windowNonClientFrameThickness )
        {
          _windowNonClientFrameThickness = value;
          _NotifyPropertyChanged( "WindowNonClientFrameThickness" );
        }
      }
    }

    public double WindowCaptionHeight
    {
      get
      {
        return _captionHeight;
      }
      private set
      {
        if( value != _captionHeight )
        {
          _captionHeight = value;
          _NotifyPropertyChanged( "WindowCaptionHeight" );
        }
      }
    }

    public Size SmallIconSize
    {
      get
      {
        return new Size( _smallIconSize.Width, _smallIconSize.Height );
      }
      private set
      {
        if( value != _smallIconSize )
        {
          _smallIconSize = value;
          _NotifyPropertyChanged( "SmallIconSize" );
        }
      }
    }

    [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "Ux" )]
    [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "Ux" )]
    public string UxThemeName
    {
      get
      {
        return _uxThemeName;
      }
      private set
      {
        if( value != _uxThemeName )
        {
          _uxThemeName = value;
          _NotifyPropertyChanged( "UxThemeName" );
        }
      }
    }

    [SuppressMessage( "Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "Ux" )]
    [SuppressMessage( "Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "Ux" )]
    public string UxThemeColor
    {
      get
      {
        return _uxThemeColor;
      }
      private set
      {
        if( value != _uxThemeColor )
        {
          _uxThemeColor = value;
          _NotifyPropertyChanged( "UxThemeColor" );
        }
      }
    }

    public bool HighContrast
    {
      get
      {
        return _isHighContrast;
      }
      private set
      {
        if( value != _isHighContrast )
        {
          _isHighContrast = value;
          _NotifyPropertyChanged( "HighContrast" );
        }
      }
    }

    public CornerRadius WindowCornerRadius
    {
      get
      {
        return _windowCornerRadius;
      }
      private set
      {
        if( value != _windowCornerRadius )
        {
          _windowCornerRadius = value;
          _NotifyPropertyChanged( "WindowCornerRadius" );
        }
      }
    }

    public Rect WindowCaptionButtonsLocation
    {
      get
      {
        return _captionButtonLocation;
      }
      private set
      {
        if( value != _captionButtonLocation )
        {
          _captionButtonLocation = value;
          _NotifyPropertyChanged( "WindowCaptionButtonsLocation" );
        }
      }
    }

    #region INotifyPropertyChanged Members

    private void _NotifyPropertyChanged( string propertyName )
    {
      Assert.IsNeitherNullNorEmpty( propertyName );
      var handler = PropertyChanged;
      if( handler != null )
      {
        handler( this, new PropertyChangedEventArgs( propertyName ) );
      }
    }

    public event PropertyChangedEventHandler PropertyChanged;

    #endregion
  }
}
