/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkCocoaGLView.mm

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/

#import <Cocoa/Cocoa.h>
#import "vtkCocoaMacOSXSDKCompatibility.h" // Needed to support old SDKs

#import "vtkCocoaGLView.h"
#import "vtkCocoaRenderWindow.h"
#import "vtkCocoaRenderWindowInteractor.h"
#import "vtkCommand.h"

//----------------------------------------------------------------------------
// Private
@interface vtkCocoaGLView()
@property(readwrite, retain, nonatomic) NSTrackingArea *rolloverTrackingArea;
@end

@implementation vtkCocoaGLView

//----------------------------------------------------------------------------
// Private
- (void)emptyMethod:(id)sender
{
  (void)sender;
}

//----------------------------------------------------------------------------
@synthesize rolloverTrackingArea = _rolloverTrackingArea;

//----------------------------------------------------------------------------
// Overridden (from NSView).
// designated initializer
- (id)initWithFrame:(NSRect)frameRect
{
  self = [super initWithFrame:frameRect];
  if (self)
  {
    // Force Cocoa into "multi threaded mode" because VTK spawns pthreads.
    // Apple's docs say: "If you intend to use Cocoa calls, you must force
    // Cocoa into its multithreaded mode before detaching any POSIX threads.
    // To do this, simply detach an NSThread and have it promptly exit.
    // This is enough to ensure that the locks needed by the Cocoa
    // frameworks are put in place"
    if ([NSThread isMultiThreaded] == NO)
    {
      [NSThread detachNewThreadSelector:@selector(emptyMethod:)
                               toTarget:self
                             withObject:nil];
    }
  }
  return self;
}

//----------------------------------------------------------------------------
- (vtkCocoaRenderWindow *)getVTKRenderWindow
{
  return _myVTKRenderWindow;
}

//----------------------------------------------------------------------------
- (void)setVTKRenderWindow:(vtkCocoaRenderWindow *)theVTKRenderWindow
{
  _myVTKRenderWindow = theVTKRenderWindow;
}

//----------------------------------------------------------------------------
- (vtkCocoaRenderWindowInteractor *)getInteractor
{
  if (_myVTKRenderWindow)
  {
    return (vtkCocoaRenderWindowInteractor *)_myVTKRenderWindow->GetInteractor();
  }
  else
  {
    return nullptr;
  }
}

//----------------------------------------------------------------------------
// Overridden (from NSView).
- (void)drawRect:(NSRect)theRect
{
  (void)theRect;

  if (_myVTKRenderWindow && _myVTKRenderWindow->GetMapped())
  {
    _myVTKRenderWindow->Render();
  }
}

//----------------------------------------------------------------------------
// Overridden (from NSView).
- (void)updateTrackingAreas
{
  //clear out the old tracking area
  NSTrackingArea *trackingArea = [self rolloverTrackingArea];
  if (trackingArea)
  {
    [self removeTrackingArea:trackingArea];
  }

  //create a new tracking area
  NSRect rect = [self visibleRect];
  NSTrackingAreaOptions opts = (NSTrackingMouseEnteredAndExited |
                                NSTrackingMouseMoved |
                                NSTrackingActiveAlways);
  trackingArea = [[NSTrackingArea alloc] initWithRect:rect
                                              options:opts
                                                owner:self
                                             userInfo:nil];
  [self addTrackingArea:trackingArea];
  [self setRolloverTrackingArea:trackingArea];
#if !VTK_OBJC_IS_ARC
  [trackingArea release];
#endif

  [super updateTrackingAreas];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (BOOL)acceptsFirstResponder
{
  return YES;
}

//----------------------------------------------------------------------------
// For generating keysyms that are compatible with other VTK interactors
static const char *vtkMacCharCodeToKeySymTable[128] = {
  nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
  nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
  "space", "exclam", "quotedbl", "numbersign",
  "dollar", "percent", "ampersand", "quoteright",
  "parenleft", "parenright", "asterisk", "plus",
  "comma", "minus", "period", "slash",
  "0", "1", "2", "3", "4", "5", "6", "7",
  "8", "9", "colon", "semicolon", "less", "equal", "greater", "question",
  "at", "A", "B", "C", "D", "E", "F", "G",
  "H", "I", "J", "K", "L", "M", "N", "O",
  "P", "Q", "R", "S", "T", "U", "V", "W",
  "X", "Y", "Z", "bracketleft",
  "backslash", "bracketright", "asciicircum", "underscore",
  "quoteleft", "a", "b", "c", "d", "e", "f", "g",
  "h", "i", "j", "k", "l", "m", "n", "o",
  "p", "q", "r", "s", "t", "u", "v", "w",
  "x", "y", "z", "braceleft", "bar", "braceright", "asciitilde", "Delete",
};

//----------------------------------------------------------------------------
// For generating keysyms that are compatible with other VTK interactors
static const char *vtkMacKeyCodeToKeySymTable[128] = {
  nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
  nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
  nullptr, nullptr, nullptr, nullptr, "Return", nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
  "Tab", nullptr, nullptr, "Backspace", nullptr, "Escape", nullptr, nullptr,
  nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
  nullptr, "period", nullptr, "asterisk", nullptr, "plus", nullptr, "Clear",
  nullptr, nullptr, nullptr, "slash", "KP_Enter", nullptr, "minus", nullptr,
  nullptr, nullptr, "KP_0", "KP_1", "KP_2", "KP_3", "KP_4", "KP_5",
  "KP_6", "KP_7", nullptr, "KP_8", "KP_9", nullptr, nullptr, nullptr,
  "F5", "F6", "F7", "F3", "F8", nullptr, nullptr, nullptr,
  nullptr, "Snapshot", nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
  nullptr, nullptr, "Help", "Home", "Prior", "Delete", "F4", "End",
  "F2", "Next", "F1", "Left", "Right", "Down", "Up", nullptr,
};

//----------------------------------------------------------------------------
// Convert a Cocoa key event into a VTK key event
- (void)invokeVTKKeyEvent:(unsigned long)theEventId
               cocoaEvent:(NSEvent *)theEvent
{
  vtkCocoaRenderWindowInteractor *interactor = [self getInteractor];
  vtkCocoaRenderWindow *renWin =
    vtkCocoaRenderWindow::SafeDownCast([self getVTKRenderWindow]);

  if (!interactor || !renWin)
  {
    return;
  }

  // Get the location of the mouse event relative to this NSView's bottom
  // left corner.  Since this is NOT a mouse event, we can not use
  // locationInWindow.  Instead we get the mouse location at this instant,
  // which may not be the exact location of the mouse at the time of the
  // keypress, but should be quite close.  There seems to be no better way.
  // And, yes, vtk does sometimes need the mouse location even for key
  // events, example: pressing 'p' to pick the actor under the mouse.
  // Also note that 'mouseLoc' may have nonsense values if a key is pressed
  // while the mouse in not actually in the vtk view but the view is
  // first responder.
  NSPoint windowLoc = [[self window] mouseLocationOutsideOfEventStream];
  NSPoint viewLoc = [self convertPoint:windowLoc fromView:nil];
  NSPoint backingLoc = [self convertPointToBacking:viewLoc];

  NSUInteger flags = [theEvent modifierFlags];
  int shiftDown = ((flags & NSEventModifierFlagShift) != 0);
  int controlDown = ((flags & (NSEventModifierFlagControl | NSEventModifierFlagCommand)) != 0);
  int altDown = ((flags & NSEventModifierFlagOption) != 0);

  unsigned char charCode = '\0';
  const char *keySym = nullptr;

  NSEventType type = [theEvent type];
  BOOL isPress = (type == NSEventTypeKeyDown);

  if (type == NSEventTypeKeyUp || type == NSEventTypeKeyDown)
  {
    // Try to get the characters associated with the key event as an ASCII string.
    const char* keyedChars = [[theEvent characters] cStringUsingEncoding:NSASCIIStringEncoding];
    if (keyedChars)
    {
      charCode = static_cast<unsigned char>(keyedChars[0]);
    }
    // Get the virtual key code and convert it to a keysym as best we can.
    unsigned short macKeyCode = [theEvent keyCode];
    if (macKeyCode < 128)
    {
      keySym = vtkMacKeyCodeToKeySymTable[macKeyCode];
    }
    if (keySym == nullptr && charCode < 128)
    {
      keySym = vtkMacCharCodeToKeySymTable[charCode];
    }
  }
  else if (type == NSEventTypeFlagsChanged)
  {
    // Check to see what modifier flag changed.
    if (controlDown != interactor->GetControlKey())
    {
      keySym = "Control_L";
      isPress = (controlDown != 0);
    }
    else if (shiftDown != interactor->GetShiftKey())
    {
      keySym = "Shift_L";
      isPress = (shiftDown != 0);
    }
    else if (altDown != interactor->GetAltKey())
    {
      keySym = "Alt_L";
      isPress = (altDown != 0);
    }
    else
    {
      return;
    }

    theEventId = (isPress ?
                  vtkCommand::KeyPressEvent :
                  vtkCommand::KeyReleaseEvent);
  }
  else // No info from which to generate a VTK key event!
  {
    return;
  }

  if (keySym == nullptr)
  {
    keySym = "None";
  }

  interactor->SetEventInformation(static_cast<int>(backingLoc.x),
                                  static_cast<int>(backingLoc.y),
                                  controlDown, shiftDown,
                                  charCode, 1, keySym);
  interactor->SetAltKey(altDown);

  interactor->InvokeEvent(theEventId, nullptr);
  if (isPress && charCode != '\0')
  {
    interactor->InvokeEvent(vtkCommand::CharEvent, nullptr);
  }
}

//----------------------------------------------------------------------------
// Convert a Cocoa motion event into a VTK button event
- (void)invokeVTKMoveEvent:(unsigned long)theEventId
                cocoaEvent:(NSEvent *)theEvent
{
  vtkCocoaRenderWindowInteractor *interactor = [self getInteractor];
  vtkCocoaRenderWindow *renWin =
    vtkCocoaRenderWindow::SafeDownCast([self getVTKRenderWindow]);

  if (!interactor || !renWin)
  {
    return;
  }

  // Get the location of the mouse event relative to this NSView's bottom
  // left corner. Since this is a mouse event, we can use locationInWindow.
  NSPoint windowLoc = [theEvent locationInWindow];
  NSPoint viewLoc = [self convertPoint:windowLoc fromView:nil];
  NSPoint backingLoc = [self convertPointToBacking:viewLoc];

  NSUInteger flags = [theEvent modifierFlags];
  int shiftDown = ((flags & NSEventModifierFlagShift) != 0);
  int controlDown = ((flags & (NSEventModifierFlagControl | NSEventModifierFlagCommand)) != 0);
  int altDown = ((flags & NSEventModifierFlagOption) != 0);

  interactor->SetEventInformation(static_cast<int>(backingLoc.x),
                                  static_cast<int>(backingLoc.y),
                                  controlDown, shiftDown);
  interactor->SetAltKey(altDown);
  interactor->InvokeEvent(theEventId, nullptr);
}

//----------------------------------------------------------------------------
// Convert a Cocoa motion event into a VTK button event
- (void)invokeVTKButtonEvent:(unsigned long)theEventId
                  cocoaEvent:(NSEvent *)theEvent
{
  vtkCocoaRenderWindowInteractor *interactor = [self getInteractor];
  vtkCocoaRenderWindow *renWin =
    vtkCocoaRenderWindow::SafeDownCast([self getVTKRenderWindow]);

  if (!interactor || !renWin)
  {
    return;
  }

  // Get the location of the mouse event relative to this NSView's bottom
  // left corner. Since this is a mouse event, we can use locationInWindow.
  NSPoint windowLoc = [theEvent locationInWindow];
  NSPoint viewLoc = [self convertPoint:windowLoc fromView:nil];
  NSPoint backingLoc = [self convertPointToBacking:viewLoc];

  int clickCount = static_cast<int>([theEvent clickCount]);
  int repeatCount = ((clickCount > 1) ? clickCount - 1 : 0);

  NSUInteger flags = [theEvent modifierFlags];
  int shiftDown = ((flags & NSEventModifierFlagShift) != 0);
  int controlDown = ((flags & (NSEventModifierFlagControl | NSEventModifierFlagCommand)) != 0);
  int altDown = ((flags & NSEventModifierFlagOption) != 0);

  interactor->SetEventInformation(static_cast<int>(backingLoc.x),
                                  static_cast<int>(backingLoc.y),
                                  controlDown, shiftDown,
                                  0, repeatCount);
  interactor->SetAltKey(altDown);
  interactor->InvokeEvent(theEventId, nullptr);
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)keyDown:(NSEvent *)theEvent
{
  [self invokeVTKKeyEvent:vtkCommand::KeyPressEvent
               cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)keyUp:(NSEvent *)theEvent
{
  [self invokeVTKKeyEvent:vtkCommand::KeyReleaseEvent
               cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)flagsChanged:(NSEvent *)theEvent
{
  // what kind of event it is will be decided by invokeVTKKeyEvent
  [self invokeVTKKeyEvent:vtkCommand::AnyEvent
               cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)mouseMoved:(NSEvent *)theEvent
{
  // Note: this method will only be called if this view's NSWindow
  // is set to receive mouse moved events.  See setAcceptsMouseMovedEvents:
  // An NSWindow created by vtk automatically does accept such events.

  // Ignore motion outside the view in order to mimic other interactors
  NSPoint windowLoc = [theEvent locationInWindow];
  NSPoint viewLoc = [self convertPoint:windowLoc fromView:nil];
  if (NSPointInRect(viewLoc, [self visibleRect]))
  {
    [self invokeVTKMoveEvent:vtkCommand::MouseMoveEvent
                  cocoaEvent:theEvent];
  }
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)mouseDragged:(NSEvent *)theEvent
{
  [self invokeVTKMoveEvent:vtkCommand::MouseMoveEvent
                cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)rightMouseDragged:(NSEvent *)theEvent
{
  [self invokeVTKMoveEvent:vtkCommand::MouseMoveEvent
                cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)otherMouseDragged:(NSEvent *)theEvent
{
  [self invokeVTKMoveEvent:vtkCommand::MouseMoveEvent
                cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)mouseEntered:(NSEvent *)theEvent
{
  // Note: the mouseEntered/mouseExited events depend on the maintenance of
  // the tracking area (updateTrackingAreas).
  [self invokeVTKMoveEvent:vtkCommand::EnterEvent
                cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)mouseExited:(NSEvent *)theEvent
{
  [self invokeVTKMoveEvent:vtkCommand::LeaveEvent
                cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)scrollWheel:(NSEvent *)theEvent
{
  CGFloat dy = [theEvent deltaY];

  unsigned long eventId = 0;

  if (dy > 0)
  {
    eventId = vtkCommand::MouseWheelForwardEvent;
  }
  else if (dy < 0)
  {
    eventId = vtkCommand::MouseWheelBackwardEvent;
  }

  if (eventId != 0)
  {
    [self invokeVTKMoveEvent:eventId
                  cocoaEvent:theEvent];
  }
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)mouseDown:(NSEvent *)theEvent
{
  [self invokeVTKButtonEvent:vtkCommand::LeftButtonPressEvent
                  cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)rightMouseDown:(NSEvent *)theEvent
{
  [self invokeVTKButtonEvent:vtkCommand::RightButtonPressEvent
                  cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)otherMouseDown:(NSEvent *)theEvent
{
  [self invokeVTKButtonEvent:vtkCommand::MiddleButtonPressEvent
                  cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)mouseUp:(NSEvent *)theEvent
{
  [self invokeVTKButtonEvent:vtkCommand::LeftButtonReleaseEvent
                  cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)rightMouseUp:(NSEvent *)theEvent
{
  [self invokeVTKButtonEvent:vtkCommand::RightButtonReleaseEvent
                  cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Overridden (from NSResponder).
- (void)otherMouseUp:(NSEvent *)theEvent
{
  [self invokeVTKButtonEvent:vtkCommand::MiddleButtonReleaseEvent
                  cocoaEvent:theEvent];
}

//----------------------------------------------------------------------------
// Private
- (void)modifyDPIForBackingScaleFactorOfWindow:(/*nullable*/ NSWindow *)window
{
  if (window)
  {
    CGFloat backingScaleFactor = [window backingScaleFactor];
    assert(backingScaleFactor >= 1.0);

    vtkCocoaRenderWindow *renderWindow = [self getVTKRenderWindow];
    if (renderWindow)
    {
      // Ordinarily, DPI is hardcoded to 72, but in order for vtkTextActors
      // to have the correct apparent size, we adjust it per the NSWindow's
      // scaling factor.
      renderWindow->SetDPI(lround(72.0 * backingScaleFactor));
    }
  }
}

//----------------------------------------------------------------------------
// Overridden (from NSView).
- (void)viewWillMoveToWindow:(/*nullable*/ NSWindow*)inNewWindow
{
  [super viewWillMoveToWindow:inNewWindow];

  [self modifyDPIForBackingScaleFactorOfWindow:inNewWindow];
}

//----------------------------------------------------------------------------
// Overridden (from NSView).
- (void)viewDidChangeBackingProperties
{
  [super viewDidChangeBackingProperties];

  NSWindow *window = [self window];
  [self modifyDPIForBackingScaleFactorOfWindow:window];
}

@end
