unit CocoaWSCommon;

{$mode objfpc}{$H+}
{$modeswitch objectivec1}

interface

uses
  Types,
  CocoaAll,
  Classes, Controls, SysUtils,
  //
  WSControls, LCLType, LMessages, LCLProc, Graphics, Forms,
  CocoaPrivate, CocoaGDIObjects, CocoaCaret, CocoaUtils, LCLMessageGlue;

type
  { TLCLCommonCallback }

  TLCLCommonCallback = class(TObject, ICommonCallBack)
  private
    class var
      // Store state of key modifiers so that we can emulate keyup/keydown
      // of keys like control, option, command, caps lock, shift
      PrevKeyModifiers: NSUInteger;
    var
      FPropStorage: TStringList;
      FContext: TCocoaContext;
      FHasCaret: Boolean;
      FTarget: TWinControl;
    function GetHasCaret: Boolean;
    procedure SetHasCaret(AValue: Boolean);
  protected
    class function CocoaModifiersToKeyState(AModifiers: NSUInteger): PtrInt; static;
    class function CocoaPressedMouseButtonsToKeyState(AMouseButtons: NSUInteger): PtrInt; static;
    procedure OffsetMousePos(var Point: NSPoint);
  public
    Owner: NSObject;
    class constructor Create;
    constructor Create(AOwner: NSObject; ATarget: TWinControl); virtual;
    destructor Destroy; override;
    function GetPropStorage: TStringList;
    function GetContext: TCocoaContext;
    function GetTarget: TObject;
    function MouseUpDownEvent(Event: NSEvent): Boolean; virtual;
    function KeyEvent(Event: NSEvent): Boolean; virtual;
    procedure MouseClick; virtual;
    function MouseMove(Event: NSEvent): Boolean; virtual;
    procedure frameDidChange; virtual;
    procedure boundsDidChange; virtual;
    procedure BecomeFirstResponder; virtual;
    procedure ResignFirstResponder; virtual;
    function DeliverMessage(var Msg): LRESULT; virtual; overload;
    function DeliverMessage(Msg: Cardinal; WParam: WParam; LParam: LParam): LResult; virtual; overload;
    procedure Draw(ControlContext: NSGraphicsContext; const bounds, dirty: NSRect); virtual;
    function ResetCursorRects: Boolean; virtual;

    property HasCaret: Boolean read GetHasCaret write SetHasCaret;
    property Target: TWinControl read FTarget;
  end;

  TLCLCommonCallBackClass = class of TLCLCommonCallBack;

  { TCocoaWSWinControl }

  TCocoaWSWinControl = class(TWSWinControl)
  published
    class function CreateHandle(const AWinControl: TWinControl;
      const AParams: TCreateParams): TLCLIntfHandle; override;
    class procedure DestroyHandle(const AWinControl: TWinControl); override;
    class procedure SetText(const AWinControl: TWinControl; const AText: String); override;
    class function GetText(const AWinControl: TWinControl; var AText: String): Boolean; override;
    class function GetTextLen(const AWinControl: TWinControl; var ALength: Integer): Boolean; override;

    class function  GetClientBounds(const AWincontrol: TWinControl; var ARect: TRect): Boolean; override;
    class function  GetClientRect(const AWincontrol: TWinControl; var ARect: TRect): Boolean; override;
    class procedure GetPreferredSize(const AWinControl: TWinControl; var PreferredWidth, PreferredHeight: integer; WithThemeSpace: Boolean); override;
    class procedure SetBounds(const AWinControl: TWinControl; const ALeft, ATop, AWidth, AHeight: Integer); override;
    class procedure SetCursor(const AWinControl: TWinControl; const ACursor: HCursor); override;
    class procedure SetFont(const AWinControl: TWinControl; const AFont: TFont); override;
    class procedure ShowHide(const AWinControl: TWinControl); override;
  end;


  { TLCLCustomControlCallback }

  TLCLCustomControlCallback = class(TLCLCommonCallback)
  public
    function MouseUpDownEvent(Event: NSEvent): Boolean; override;
  end;

  { TCocoaWSCustomControl }

  TCocoaWSCustomControl = class(TWSCustomControl)
  published
    class function CreateHandle(const AWinControl: TWinControl;
      const AParams: TCreateParams): TLCLIntfHandle; override;
  end;

const
  DblClickThreshold = 3;// max Movement between two clicks of a DblClick

// Utility WS functions

function AllocCustomControl(const AWinControl: TWinControl): TCocoaCustomControl;
function EmbedInScrollView(AView: NSView): TCocoaScrollView;

implementation

uses
  CocoaInt;

{$I mackeycodes.inc}

function AllocCustomControl(const AWinControl: TWinControl): TCocoaCustomControl;
begin
  if not Assigned(AWinControl) then
    Exit(nil);
  Result := TCocoaCustomControl(TCocoaCustomControl.alloc).init;
  Result.callback := TLCLCommonCallback.Create(Result, AWinControl);
end;

function EmbedInScrollView(AView: NSView): TCocoaScrollView;
var
  r: TRect;
  p: NSView;
begin
  if not Assigned(AView) then
    Exit(nil);
  r := AView.lclFrame;
  p := AView.superview;
  Result := TCocoaScrollView.alloc.initWithFrame(NSNullRect);
  if Assigned(p) then p.addSubView(Result);
  Result.lclSetFrame(r);
  Result.setDocumentView(AView);
  SetViewDefaults(Result);
end;

{ TLCLCustomControlCallback }

function TLCLCustomControlCallback.MouseUpDownEvent(Event: NSEvent): Boolean;
begin
  inherited MouseUpDownEvent(Event);
  Result := True;
end;


{ TLCLCommonCallback }

function TLCLCommonCallback.GetHasCaret: Boolean;
begin
  Result := FHasCaret;
end;

procedure TLCLCommonCallback.SetHasCaret(AValue: Boolean);
begin
  FHasCaret := AValue;
end;

class function TLCLCommonCallback.CocoaModifiersToKeyState(AModifiers: NSUInteger): PtrInt;
begin
  Result := 0;
  if AModifiers and NSShiftKeyMask <> 0 then
    Result := Result or MK_SHIFT;
  if AModifiers and NSControlKeyMask <> 0 then
    Result := Result or MK_CONTROL;
  if AModifiers and NSAlternateKeyMask <> 0 then
    Result := Result or $20000000;
end;

class function TLCLCommonCallback.CocoaPressedMouseButtonsToKeyState(AMouseButtons: NSUInteger): PtrInt;
begin
  Result := 0;
  if AMouseButtons and (1 shl 0) <> 0 then
    Result := Result or MK_LBUTTON;
  if AMouseButtons and (1 shl 1) <> 0 then
    Result := Result or MK_RBUTTON;
  if AMouseButtons and (1 shl 2) <> 0 then
    Result := Result or MK_MBUTTON;
  if AMouseButtons and (1 shl 3) <> 0 then
    Result := Result or MK_XBUTTON1;
  if AMouseButtons and (1 shl 4) <> 0 then
    Result := Result or MK_XBUTTON2;
end;

procedure TLCLCommonCallback.OffsetMousePos(var Point: NSPoint);
begin
  if Owner.isKindOfClass(NSWindow) then
    Point.y := NSWindow(Owner).contentView.bounds.size.height - Point.y
  else
  if Owner.isKindOfClass(NSView) then
  begin
    Point := NSView(Owner).convertPoint_fromView(Point, nil);
    Point.y := NSView(Owner).bounds.size.height - Point.y;
  end;
end;

class constructor TLCLCommonCallback.Create;
begin
  PrevKeyModifiers := 0;
end;

constructor TLCLCommonCallback.Create(AOwner: NSObject; ATarget: TWinControl);
begin
  inherited Create;
  Owner := AOwner;
  FTarget := ATarget;
  FContext := nil;
  FHasCaret := False;
  FPropStorage := TStringList.Create;
  FPropStorage.Sorted := True;
  FPropStorage.Duplicates := dupAccept;
end;

destructor TLCLCommonCallback.Destroy;
begin
  FContext.Free;
  FPropStorage.Free;
  FTarget := nil;
  inherited Destroy;
end;

function TLCLCommonCallback.GetPropStorage: TStringList;
begin
  Result := FPropStorage;
end;

function TLCLCommonCallback.GetContext: TCocoaContext;
begin
  Result := FContext;
end;

function TLCLCommonCallback.GetTarget: TObject;
begin
  Result := Target;
end;

function TLCLCommonCallback.MouseUpDownEvent(Event: NSEvent): Boolean;
const
  // array of clickcount x buttontype
  MSGKIND: array[0..3, 1..4] of Integer =
  (
    (LM_LBUTTONDOWN, LM_LBUTTONDBLCLK, LM_LBUTTONTRIPLECLK, LM_LBUTTONQUADCLK),
    (LM_RBUTTONDOWN, LM_RBUTTONDBLCLK, LM_RBUTTONTRIPLECLK, LM_RBUTTONQUADCLK),
    (LM_MBUTTONDOWN, LM_MBUTTONDBLCLK, LM_MBUTTONTRIPLECLK, LM_MBUTTONQUADCLK),
    (LM_XBUTTONDOWN, LM_XBUTTONDBLCLK, LM_XBUTTONTRIPLECLK, LM_XBUTTONQUADCLK)
  );
  MSGKINDUP: array[0..3] of Integer = (LM_LBUTTONUP, LM_RBUTTONUP, LM_MBUTTONUP, LM_XBUTTONUP);

var
  Msg: TLMMouse;
  MousePos: NSPoint;
  MButton: NSInteger;

  function CheckMouseButtonDown(AButton: Integer): Cardinal;
  var
    ClickCount: Integer;
  begin
    ClickCount := Event.clickCount;
    if ClickCount > 4 then
      ClickCount := 1;

    Result := MSGKIND[AButton][ClickCount];
  end;
begin
  Result := False; // allow cocoa to handle message

  if Assigned(Target) and (not (csDesigning in Target.ComponentState) and not Owner.lclIsEnabled) then
    Exit;

  // idea of multi click implementation is taken from gtk

  FillChar(Msg, SizeOf(Msg), #0);

  MousePos := Event.locationInWindow;
  OffsetMousePos(MousePos);

  Msg.Keys := CocoaModifiersToKeyState(Event.modifierFlags) or CocoaPressedMouseButtonsToKeyState(Event.pressedMouseButtons);

  Msg.XPos := Round(MousePos.X);
  Msg.YPos := Round(MousePos.Y);

  MButton := event.buttonNumber;
  if MButton >= 3 then
  begin
    // high word of XButton messages indicate the X button which is pressed
    Msg.Keys := Msg.Keys or (MButton - 2) shl 16;
    MButton := 3;
  end;


  case Event.type_ of
    NSLeftMouseDown,
    NSRightMouseDown,
    NSOtherMouseDown:
    begin
      Msg.Msg := CheckMouseButtonDown(MButton);

      NotifyApplicationUserInput(Target, Msg.Msg);
      Result := DeliverMessage(Msg) <> 0;
    end;
    NSLeftMouseUp,
    NSRightMouseUp,
    NSOtherMouseUp:
    begin
      Msg.Msg := MSGKINDUP[MButton];

      NotifyApplicationUserInput(Target, Msg.Msg);
      Result := DeliverMessage(Msg) <> 0;
    end;
  end;
end;

function TLCLCommonCallback.KeyEvent(Event: NSEvent): Boolean;
var
  UTF8VKCharacter: TUTF8Char; // char without modifiers, used for VK_ key value
  UTF8Character: TUTF8Char;   // char to send via IntfUtf8KeyPress
  KeyChar : char;          // Ascii char, when possible (xx_(SYS)CHAR)
  VKKeyChar: char;         // Ascii char without modifiers
  SendChar: boolean;       // Should we send char?
  VKKeyCode: word;         // VK_ code
  IsSysKey: Boolean;       // Is alt (option) key down?
  KeyData: PtrInt;         // Modifiers (ctrl, alt, mouse buttons...)


(*
  Mac keycodes handling is not so straight. For an explanation, see
  mackeycodes.inc
  In this function, we do the following:
   1) Get the raw keycode, if it is a known "non-printable" key, translate it
      to a known VK_ keycode.
      This will be reported via xx_KeyDown/KeyUP messages only, and we can stop
      here.
   2) else, we must send both KeyDown/KeyUp and IntfUTF8KeyPress/xx_(SYS)CHAR
      So, get the unicode character and the "ascii" character (note: if it's
      not a true ascii character (>127) use the Mac character).
    2a) Try to determine a known VK_ keycode (e.g: VK_A, VK_SPACE and so on)
    2b) If no VK_ keycode exists, use a dummy keycode to trigger LCL events
        (see later in the code for a more in depth explanation)
*)

  function TranslateMacKeyCode : boolean;
  var
    KeyCode: word;
  begin
    Result := False;
    SendChar := False;
    VKKeyCode := VK_UNKNOWN;

    IsSysKey := (Event.modifierFlags and NSCommandKeyMask) <> 0;
    KeyData := (Ord(Event.isARepeat) + 1) or Event.keyCode shl 16;
    KeyCode := Event.keyCode;

    //non-printable keys (see mackeycodes.inc)
    //for these keys, only send keydown/keyup (not char or UTF8KeyPress)
    case KeyCode of
      MK_F1       : VKKeyCode:=VK_F1;
      MK_F2       : VKKeyCode:=VK_F2;
      MK_F3       : VKKeyCode:=VK_F3;
      MK_F4       : VKKeyCode:=VK_F4;
      MK_F5       : VKKeyCode:=VK_F5;
      MK_F6       : VKKeyCode:=VK_F6;
      MK_F7       : VKKeyCode:=VK_F7;
      MK_F8       : VKKeyCode:=VK_F8;
      MK_F9       : VKKeyCode:=VK_F9;
      MK_F10      : VKKeyCode:=VK_F10;
      MK_F11      : VKKeyCode:=VK_F11;
      MK_F12      : VKKeyCode:=VK_F12;
      MK_F13      : VKKeyCode:=VK_SNAPSHOT;
      MK_F14      : VKKeyCode:=VK_SCROLL;
      MK_F15      : VKKeyCode:=VK_PAUSE;
      MK_POWER    : VKKeyCode:=VK_SLEEP; //?
      MK_TAB      : VKKeyCode:=VK_TAB; //strangely enough, tab is "non printable"
      MK_INS      : VKKeyCode:=VK_INSERT;
      MK_DEL      : VKKeyCode:=VK_DELETE;
      MK_HOME     : VKKeyCode:=VK_HOME;
      MK_END      : VKKeyCode:=VK_END;
      MK_PAGUP    : VKKeyCode:=VK_PRIOR;
      MK_PAGDN    : VKKeyCode:=VK_NEXT;
      MK_UP       : VKKeyCode:=VK_UP;
      MK_DOWN     : VKKeyCode:=VK_DOWN;
      MK_LEFT     : VKKeyCode:= VK_LEFT;
      MK_RIGHT    : VKKeyCode:= VK_RIGHT;
      MK_NUMLOCK  : VKKeyCode:= VK_NUMLOCK;
    end;

    if VKKeyCode <> VK_UNKNOWN then
    begin
      //stop here, we won't send char or UTF8KeyPress
      Result := True;
      Exit;
    end;

    // check non-translated characters
    UTF8VKCharacter := NSStringToString(Event.charactersIgnoringModifiers);
    if Length(UTF8VKCharacter) > 0 then
    begin
      if UTF8VKCharacter[1] <= #127 then
        VKKeyChar := UTF8VKCharacter[1];
    end;

    //printable keys
    //for these keys, send char or UTF8KeyPress
    UTF8Character := NSStringToString(Event.characters);

    if Length(UTF8Character) > 0 then
    begin
      SendChar := True;

      if Utf8Character[1] <= #127 then
        KeyChar := Utf8Character[1];

      // the VKKeyCode is independent of the modifier
      // => use the VKKeyChar instead of the KeyChar
      case VKKeyChar of
        'a'..'z': VKKeyCode:=VK_A+ord(VKKeyChar)-ord('a');
        'A'..'Z': VKKeyCode:=ord(VKKeyChar);
        #27     : VKKeyCode:=VK_ESCAPE;
        #8      : VKKeyCode:=VK_BACK;
        ' '     : VKKeyCode:=VK_SPACE;
        #13     : VKKeyCode:=VK_RETURN;
        '0'..'9':
          case KeyCode of
            MK_NUMPAD0: VKKeyCode:=VK_NUMPAD0;
            MK_NUMPAD1: VKKeyCode:=VK_NUMPAD1;
            MK_NUMPAD2: VKKeyCode:=VK_NUMPAD2;
            MK_NUMPAD3: VKKeyCode:=VK_NUMPAD3;
            MK_NUMPAD4: VKKeyCode:=VK_NUMPAD4;
            MK_NUMPAD5: VKKeyCode:=VK_NUMPAD5;
            MK_NUMPAD6: VKKeyCode:=VK_NUMPAD6;
            MK_NUMPAD7: VKKeyCode:=VK_NUMPAD7;
            MK_NUMPAD8: VKKeyCode:=VK_NUMPAD8;
            MK_NUMPAD9: VKKeyCode:=VK_NUMPAD9
            else VKKeyCode:=ord(VKKeyChar);
          end;
        else
        case KeyCode of
          MK_PADDIV  : VKKeyCode:=VK_DIVIDE;
          MK_PADMULT : VKKeyCode:=VK_MULTIPLY;
          MK_PADSUB  : VKKeyCode:=VK_SUBTRACT;
          MK_PADADD  : VKKeyCode:=VK_ADD;
          MK_PADDEC  : VKKeyCode:=VK_DECIMAL;
          MK_BACKSPACE:
            begin
              VKKeyCode := VK_BACK;
              VKKeyChar := #8;
              UTF8Character := #8;
            end;
          MK_PADENTER:
            begin
              VKKeyCode:=VK_RETURN;
              VKKeyChar:=#13;
              UTF8Character:=VKKeyChar;
            end;
          MK_TILDE: VKKeyCode := VK_OEM_3;
          MK_MINUS: VKKeyCode := VK_OEM_MINUS;
          MK_EQUAL: VKKeyCode := VK_OEM_PLUS;
          MK_BACKSLASH:    VKKeyCode := VK_OEM_5;
          MK_LEFTBRACKET:  VKKeyCode := VK_OEM_4;
          MK_RIGHTBRACKET: VKKeyCode := VK_OEM_6;
          MK_SEMICOLON:    VKKeyCode := VK_OEM_1;
          MK_QUOTE:  VKKeyCode := VK_OEM_7;
          MK_COMMA:  VKKeyCode := VK_OEM_COMMA;
          MK_PERIOD: VKKeyCode := VK_OEM_PERIOD;
          MK_SLASH:  VKKeyCode := VK_OEM_2;
        end;
      end;

      if VKKeyCode = VK_UNKNOWN then
      begin
        // There is no known VK_ code for this characther. Use a dummy keycode
        // (E8, which is unused by Windows) so that KeyUp/KeyDown events will be
        // triggered by LCL.
        // Note: we can't use the raw mac keycode, since it could collide with
        // well known VK_ keycodes (e.g on my italian ADB keyboard, keycode for
        // "&egrave;" is 33, which is the same as VK_PRIOR)
        VKKeyCode := $E8;
      end;
      Result := True;
    end;
  end;

  function LCLCharToMacEvent(const AUTF8Char: AnsiString): Boolean;
  begin
    if AUTF8Char = '' then
      Exit;
    // TODO
  end;

  function HandleKeyDown: Boolean;
  var
    KeyMsg: TLMKeyDown;
    CharMsg: TLMChar;
    OrigChar: AnsiString;
  begin
    Result := True;

    // create the CN_KEYDOWN message
    FillChar(KeyMsg, SizeOf(KeyMsg), 0);
    if IsSysKey then
      KeyMsg.Msg := CN_SYSKEYDOWN
    else
      KeyMsg.Msg := CN_KEYDOWN;
    KeyMsg.KeyData := KeyData;
    KeyMsg.CharCode := VKKeyCode;

    // is the key combination help key (Cmd + ?)
    if SendChar and IsSysKey and (UTF8Character = '?') then
      Application.ShowHelpForObject(Target);

    // widget can filter some keys from being send to cocoa control
    //if Widget.FilterKeyPress(IsSysKey, UTF8Character) then Result := noErr;

    //Send message to LCL
    if VKKeyCode <> VK_UNKNOWN then
    begin
      if (DeliverMessage(KeyMsg) <> 0) or (KeyMsg.CharCode = VK_UNKNOWN) then
      begin
        // the LCL handled the key
        NotifyApplicationUserInput(Target, KeyMsg.Msg);
        Exit;
      end;

      // Here is where we (interface) can do something with the key
      // Call the standard handler. Only Up/Down events are notified.
      //Widget.ProcessKeyEvent(KeyMsg);

      //Send a LM_(SYS)KEYDOWN
      if IsSysKey then
        KeyMsg.Msg := LM_SYSKEYDOWN
      else
        KeyMsg.Msg := LM_KEYDOWN;
      if (DeliverMessage(KeyMsg) <> 0) or (KeyMsg.CharCode = VK_UNKNOWN) then
      begin
        NotifyApplicationUserInput(Target, KeyMsg.Msg);
        Exit;
      end;
    end;

    //We should send a character
    if SendChar then
    begin
      // send the UTF8 keypress
      OrigChar := UTF8Character;
      if Target.IntfUTF8KeyPress(UTF8Character, 1, IsSysKey) then
      begin
        // the LCL has handled the key
        Exit;
      end;
      if OrigChar <> UTF8Character then
        LCLCharToMacEvent(UTF8Character);

      // create the CN_CHAR / CN_SYSCHAR message
      FillChar(CharMsg, SizeOf(CharMsg), 0);
      if IsSysKey then
        CharMsg.Msg := CN_SYSCHAR
      else
        CharMsg.Msg := CN_CHAR;
      CharMsg.KeyData := KeyData;
      CharMsg.CharCode := ord(KeyChar);

      //Send message to LCL
      if (DeliverMessage(CharMsg) <> 0) or (CharMsg.CharCode=VK_UNKNOWN) then
      begin
        // the LCL handled the key
        NotifyApplicationUserInput(Target, CharMsg.Msg);
        Exit;
      end;

      if CharMsg.CharCode <> ord(KeyChar) then
        LCLCharToMacEvent(Char(CharMsg.CharCode));

      //Send a LM_(SYS)CHAR
      if IsSysKey then
        CharMsg.Msg := LM_SYSCHAR
      else
        CharMsg.Msg := LM_CHAR;

      if DeliverMessage(CharMsg) <> 0 then
      begin
        // the LCL handled the key
        NotifyApplicationUserInput(Target, CharMsg.Msg);
        Exit;
      end;
    end;
    Result := False;
  end;

  function HandleKeyUp: Boolean;
  var
    KeyMsg: TLMKeyUp;
  begin
    Result := True;

    // create the CN_KEYUP message
    FillChar(KeyMsg, SizeOf(KeyMsg), 0);
    if IsSysKey then
      KeyMsg.Msg := CN_SYSKEYUP
    else
      KeyMsg.Msg := CN_KEYUP;
    KeyMsg.KeyData := KeyData;
    KeyMsg.CharCode := VKKeyCode;

    //Send message to LCL
    if VKKeyCode <> VK_UNKNOWN then
    begin
      if (DeliverMessage(KeyMsg) <> 0) or (KeyMsg.CharCode = VK_UNKNOWN) then
      begin
        // the LCL has handled the key
        NotifyApplicationUserInput(Target, KeyMsg.Msg);
        Exit;
      end;

      //Here is where we (interface) can do something with the key
      //Call the standard handler.
      //Widget.ProcessKeyEvent(KeyMsg);

      //Send a LM_(SYS)KEYUP
      if IsSysKey then
        KeyMsg.Msg := LM_SYSKEYUP
      else
        KeyMsg.Msg := LM_KEYUP;
      if DeliverMessage(KeyMsg) <> 0 then
      begin
        // the LCL handled the key
        NotifyApplicationUserInput(Target, KeyMsg.Msg);
        Exit;
      end;
    end;
    Result := False;
  end;

  function HandleFlagsChanged: Boolean;
  var
    CurMod, Diff: NSUInteger;
  begin
    Result := False;
    SendChar := False;
    CurMod := Event.modifierFlags;
    //see what changed. we only care of bits 16 through 20
    Diff := (PrevKeyModifiers xor CurMod) and $1F0000;

    case Diff of
      0          : Exit;  //nothing (that we cared of) changed
      NSControlKeyMask   : VKKeyCode := VK_CONTROL; //command mapped to control
      NSShiftKeyMask     : VKKeyCode := VK_SHIFT;
      NSAlphaShiftKeyMask: VKKeyCode := VK_CAPITAL; //caps lock
      NSAlternateKeyMask : VKKeyCode := VK_MENU;    //option is alt
      NSCommandKeyMask   : VKKeyCode := VK_LWIN;    //meta... map to left Windows Key?
    end;

    //diff is now equal to the mask of the bit that changed, so we can determine
    //if this change is a keydown (PrevKeyModifiers didn't have the bit set) or
    //a keyup (PrevKeyModifiers had the bit set)
    if (PrevKeyModifiers and Diff) = 0 then
      Result := HandleKeyDown
    else
      Result := HandleKeyUp;

    PrevKeyModifiers := CurMod;
  end;

begin
  case Event.type_ of
    NSKeyDown:
      begin
        if not TranslateMacKeyCode then
          Exit(True);
        Result := HandleKeyDown;
      end;
    NSKeyUp:
      begin
        if not TranslateMacKeyCode then
          Exit(True);
        Result := HandleKeyUp;
      end;
    NSFlagsChanged:
      Result := HandleFlagsChanged;
  else
    Result := False;
  end;
end;

procedure TLCLCommonCallback.MouseClick;
begin
  LCLSendClickedMsg(Target);
end;

function TLCLCommonCallback.MouseMove(Event: NSEvent): Boolean;
var
  Msg: TLMMouseMove;
  MousePos: NSPoint;
begin
  Result := False; // allow cocoa to handle message

  if Assigned(Target) and (not (csDesigning in Target.ComponentState) and not Owner.lclIsEnabled) then
    Exit;

  MousePos := Event.locationInWindow;
  OffsetMousePos(MousePos);

  FillChar(Msg, SizeOf(Msg), #0);
  Msg.Msg := LM_MOUSEMOVE;
  Msg.Keys := CocoaModifiersToKeyState(Event.modifierFlags) or CocoaPressedMouseButtonsToKeyState(Event.pressedMouseButtons);
  Msg.XPos := Round(MousePos.X);
  Msg.YPos := Round(MousePos.Y);

  NotifyApplicationUserInput(Target, Msg.Msg);
  Result := DeliverMessage(Msg) <> 0;
end;

procedure TLCLCommonCallback.frameDidChange;
begin
  boundsDidChange;
end;

procedure TLCLCommonCallback.boundsDidChange;
var
  NewBounds, OldBounds: TRect;
  PosMsg: TLMWindowPosChanged;
  Resized, Moved, ClientResized: Boolean;
  SizeType: Integer;
begin
  NewBounds := Owner.lclFrame;

  // send window pos changed
  PosMsg.Msg := LM_WINDOWPOSCHANGED;
  PosMsg.Result := 0;
  New(PosMsg.WindowPos);
  try
    with PosMsg.WindowPos^ do
    begin
      hWndInsertAfter := 0;
      x := NewBounds.Left;
      y := NewBounds.Right;
      cx := NewBounds.Right - NewBounds.Left;
      cy := NewBounds.Bottom - NewBounds.Top;
      flags := 0;
    end;
    LCLMessageGlue.DeliverMessage(Target, PosMsg);
  finally
    Dispose(PosMsg.WindowPos);
  end;

  OldBounds := Target.BoundsRect;

  Resized :=
    (OldBounds.Right - OldBounds.Left <> NewBounds.Right - NewBounds.Left) or
    (OldBounds.Bottom - OldBounds.Top <> NewBounds.Bottom - NewBounds.Top);
  Moved :=
    (OldBounds.Left <> NewBounds.Left) or
    (OldBounds.Top <> NewBounds.Top);

  ClientResized := False;

  // update client rect
  if Resized or Target.ClientRectNeedsInterfaceUpdate then
  begin
    Target.InvalidateClientRectCache(False);
    ClientResized := True;
  end;

  // then send a LM_SIZE message
  if Resized or ClientResized then
  begin
    LCLSendSizeMsg(Target, NewBounds.Right - NewBounds.Left,
      NewBounds.Bottom - NewBounds.Top, Owner.lclWindowState, True);
  end;

  // then send a LM_MOVE message
  if Moved then
  begin
    LCLSendMoveMsg(Target, NewBounds.Left,
      NewBounds.Top, Move_SourceIsInterface);
  end;
end;

procedure TLCLCommonCallback.BecomeFirstResponder;
begin
  LCLSendSetFocusMsg(Target);
end;

procedure TLCLCommonCallback.ResignFirstResponder;
begin
  LCLSendKillFocusMsg(Target);
end;

function TLCLCommonCallback.DeliverMessage(var Msg): LRESULT;
begin
  Result := LCLMessageGlue.DeliverMessage(Target, Msg);
end;

function TLCLCommonCallback.DeliverMessage(Msg: Cardinal; WParam: WParam; LParam: LParam): LResult;
var
  Message: TLMessage;
begin
  Message.Msg := Msg;
  Message.WParam := WParam;
  Message.LParam := LParam;
  Message.Result := 0;
  Result := DeliverMessage(Message);
end;

procedure TLCLCommonCallback.Draw(ControlContext: NSGraphicsContext;
  const bounds, dirty: NSRect);
var
  struct: TPaintStruct;
begin
  // todo: think more about draw call while previous draw still active
  if Assigned(FContext) then
    Exit;
  FContext := TCocoaContext.Create;
  try
    FContext.ctx := ControlContext;
    if FContext.InitDraw(Round(bounds.size.width), Round(bounds.size.height)) then
    begin
      FillChar(struct, SizeOf(TPaintStruct), 0);
      struct.hdc := HDC(FContext);
      NSToLCLRect(dirty, struct.rcPaint);
      LCLSendPaintMsg(Target, HDC(FContext), @struct);
      if FHasCaret then
        DrawCaret;
    end;
  finally
    FreeAndNil(FContext);
  end;
end;

function TLCLCommonCallback.ResetCursorRects: Boolean;
var
  ACursor: TCursor;
  View: NSView;
begin
  Result := False;
  if Owner.isKindOfClass_(NSWindow) then
    View := NSwindow(Owner).contentView
  else
  if Owner.isKindOfClass_(NSView) then
    View := NSView(Owner)
  else
    Exit;
  if not (csDesigning in Target.ComponentState) then
  begin
    ACursor := Screen.Cursor;
    if ACursor = crDefault then
    begin
      // traverse visible child controls
      ACursor := Target.Cursor;
    end;
    Result := ACursor <> crDefault;
    if Result then
      View.addCursorRect_cursor(View.visibleRect, TCocoaCursor(Screen.Cursors[ACursor]).Cursor);
  end;
end;

{ TCocoaWSWinControl }

class function TCocoaWSWinControl.CreateHandle(const AWinControl: TWinControl;
  const AParams: TCreateParams): TLCLIntfHandle;
begin
  Result := TCocoaWSCustomControl.CreateHandle(AWinControl, AParams);
end;

class procedure TCocoaWSWinControl.DestroyHandle(const AWinControl: TWinControl);
var
  obj: NSObject;
begin
  if not AWinControl.HandleAllocated then
    Exit;
  obj := NSObject(AWinControl.Handle);
  if obj.isKindOfClass_(NSView) then
    NSView(obj).removeFromSuperview;
  obj.release;
end;

class procedure TCocoaWSWinControl.SetText(const AWinControl: TWinControl; const AText: String);
var
  obj: NSObject;
begin
  if not AWinControl.HandleAllocated then
    Exit;
  obj := NSObject(AWinControl.Handle);
  if obj.isKindOfClass_(NSControl) then
    SetNSControlValue(NSControl(obj), AText);
end;

class function TCocoaWSWinControl.GetText(const AWinControl: TWinControl; var AText: String): Boolean;
var
  obj: NSObject;
begin
  Result := AWinControl.HandleAllocated;
  if not Result then
    Exit;
  obj := NSObject(AWinControl.Handle);
  Result := obj.isKindOfClass_(NSControl);
  if Result then
    AText := GetNSControlValue(NSControl(obj));
end;

class function TCocoaWSWinControl.GetTextLen(const AWinControl: TWinControl; var ALength: Integer): Boolean;
var
  obj: NSObject;
  s: NSString;
begin
  Result := AWinControl.HandleAllocated;
  if not Result then
    Exit;

  obj := NSObject(AWinControl.Handle);
  Result := obj.isKindOfClass_(NSControl);
  if not Result then Exit;

  s := NSControl(obj).stringValue;
  if Assigned(s) then
    ALength := s.length
  else
    ALength := 0
end;

class function TCocoaWSWinControl.GetClientBounds(const AWincontrol: TWinControl; var ARect: TRect): Boolean;
begin
  Result := AWinControl.HandleAllocated;
  if Result then
    ARect := NSObject(AWinControl.Handle).lclClientFrame;
end;

class function TCocoaWSWinControl.GetClientRect(const AWincontrol: TWinControl; var ARect: TRect): Boolean;
begin
  Result:=(AWinControl.Handle<>0);
  if not Result then Exit;
  ARect:=NSObject(AWinControl.Handle).lclClientFrame;
end;

class procedure TCocoaWSWinControl.GetPreferredSize(
  const AWinControl: TWinControl; var PreferredWidth, PreferredHeight: integer;
  WithThemeSpace: Boolean);
var
  Obj: NSObject;
  Size: NSSize;
begin
  if AWinControl.HandleAllocated then
  begin
    Obj := NSObject(AWinControl.Handle);
{
    if Obj.isKindOfClass_(NSView) and obj.respondsToSelector(objcselector('fittingSize')) then
    begin
      Size := NSView(Obj).fittingSize;
      PreferredWidth := Round(Size.width);
      PreferredHeight := Round(Size.height);
    end;
}
  end;
end;

class procedure TCocoaWSWinControl.SetBounds(const AWinControl: TWinControl;
  const ALeft, ATop, AWidth, AHeight: Integer);
begin
  if AWinControl.HandleAllocated then
    NSObject(AWinControl.Handle).lclSetFrame(Bounds(ALeft, ATop, AWidth, AHeight));
end;

class procedure TCocoaWSWinControl.SetCursor(const AWinControl: TWinControl;
  const ACursor: HCursor);
var
  Obj: NSObject;
begin
  if (AWinControl.Handle <> 0) then
  begin
    Obj := NSObject(AWinControl.Handle);
    if Obj.isKindOfClass_(NSWindow) then
      NSWindow(Obj).resetCursorRects
    else
    if Obj.isKindOfClass_(NSView) then
      NSView(Obj).resetCursorRects;
  end;
end;

class procedure TCocoaWSWinControl.SetFont(const AWinControl: TWinControl; const AFont: TFont);
var
  Obj: NSObject;
  Cell: NSCell;
  Str: NSAttributedString;
  NewStr: NSMutableAttributedString;
  Dict: NSDictionary;
  Range: NSRange;
begin
  if (AWinControl.HandleAllocated) then
  begin
    Obj := NSObject(AWinControl.Handle);
    if Obj.isKindOfClass(NSScrollView) then
      Obj := NSScrollView(Obj).documentView;
    if Obj.isKindOfClass(NSControl) then
    begin
      Cell := NSCell(NSControl(Obj).cell);
      Cell.setFont(TCocoaFont(AFont.Reference.Handle).Font);
      // try to assign foreground color?
      Str := Cell.attributedStringValue;
      if Assigned(Str) then
      begin
        NewStr := NSMutableAttributedString.alloc.initWithAttributedString(Str);
        Range.location := 0;
        Range.length := NewStr.length;
        if AFont.Color = clDefault then
          NewStr.removeAttribute_range(NSForegroundColorAttributeName, Range)
        else
          NewStr.addAttribute_value_range(NSForegroundColorAttributeName, ColorToNSColor(ColorToRGB(AFont.Color)), Range);
        Cell.setAttributedStringValue(NewStr);
        NewStr.release;
      end;
    end
    else
    if Obj.isKindOfClass(NSText) then
    begin
      NSText(Obj).setFont(TCocoaFont(AFont.Reference.Handle).Font);
      if AFont.Color = clDefault then
        NSText(Obj).setTextColor(nil)
      else
        NSText(Obj).setTextColor(ColorToNSColor(ColorToRGB(AFont.Color)));
    end;
  end;
end;

class procedure TCocoaWSWinControl.ShowHide(const AWinControl: TWinControl);
begin
  if AWinControl.HandleAllocated then
    NSObject(AWinControl.Handle).lclSetVisible(AWinControl.HandleObjectShouldBeVisible);
end;

{ TCocoaWSCustomControl }

class function TCocoaWSCustomControl.CreateHandle(const AWinControl: TWinControl;
  const AParams: TCreateParams): TLCLIntfHandle;
var
  ctrl: TCocoaCustomControl;
begin
  ctrl := TCocoaCustomControl(TCocoaCustomControl.alloc.lclInitWithCreateParams(AParams));
  ctrl.callback := TLCLCustomControlCallback.Create(ctrl, AWinControl);
  Result := TLCLIntfHandle(ctrl);
end;

end.