#import "CustomView.h"

#import "CustomLayer.h"

#import "vtkRenderer.h"
#import "vtkCocoaRenderWindow.h"
#import "vtkCocoaRenderWindowInteractor.h"

@implementation CustomView

// ----------------------------------------------------------------------------
// Designated initializer
- (instancetype)initWithFrame:(NSRect)frameRect
{
  self = [super initWithFrame:frameRect];
  if (self)
  {
    // nothing to do... add something if you need to
  }

  return self;
}

// ----------------------------------------------------------------------------
// Designated initializer
- (nullable instancetype)initWithCoder:(NSCoder *)coder
{
  self = [super initWithCoder:coder];
  if (self)
  {
    // nothing to do... add something if you need to
  }

  return self;
}

#pragma mark -

// ----------------------------------------------------------------------------
- (void)initializeVTKSupport
{
  // The usual vtk object creation.
  vtkRenderer* ren = vtkRenderer::New();
  vtkRenderWindow* renWin = vtkRenderWindow::New();
  vtkRenderWindowInteractor* renWinInt = vtkRenderWindowInteractor::New();

  // The cast should never fail, but we do it anyway, as
  // it's more correct to do so.
  vtkCocoaRenderWindow* cocoaRenWin = vtkCocoaRenderWindow::SafeDownCast(renWin);

  if (ren && cocoaRenWin && renWinInt)
  {
    //
    [self setRenderer:ren];
    [self setRenderWindow:cocoaRenWin];
    [self setRenderWindowInteractor:renWinInt];

    // This is special to our usage of vtk.  To prevent vtk
    // from creating an NSWindow and NSView automatically (its
    // default behaviour) we tell vtk that they exist already.
    // The APIs names are a bit misleading, due to the cross
    // platform nature of vtk, but this usage is correct.
    NSWindow* parentWindow = [self window];
    assert(parentWindow);
    cocoaRenWin->SetRootWindow((__bridge void*)parentWindow);
    cocoaRenWin->SetWindowId((__bridge void*)self);

    // The usual vtk connections.
    cocoaRenWin->AddRenderer(ren);
    renWinInt->SetRenderWindow(cocoaRenWin);

    // Initialize now so we are ready when the OS asks us to draw.
    if (!renWinInt->GetInitialized())
    {
      renWinInt->Initialize();
    }
  }
}

// ----------------------------------------------------------------------------
- (void)cleanUpVTKSupport
{
  vtkRenderer* ren = [self renderer];
  vtkRenderWindow* renWin = [self renderWindow];
  vtkRenderWindowInteractor* renWinInt = [self renderWindowInteractor];

  if (ren)
  {
    ren->Delete();
  }
  if (renWin)
  {
    renWin->Delete();
  }
  if (renWinInt)
  {
    renWinInt->Delete();
  }

  [self setRenderer:nil];
  [self setRenderWindow:nil];
  [self setRenderWindowInteractor:nil];
}

#pragma mark -

// ----------------------------------------------------------------------------
- (void)initializeLayerSupport
{
  // Make sure we don't do this twice.
  assert([[self layer] isKindOfClass:[CustomLayer class]] == NO);

  NSRect viewBounds = [self bounds];

  // Create the CustomLayer.
  CustomLayer* layer = [CustomLayer layer];
  [layer setName:@"CustomLayer"];
  [layer setAnchorPoint:CGPointZero];
  [layer setPosition:CGPointZero];
  [layer setBounds:viewBounds];
  [layer setMasksToBounds:YES];
  [layer setNeedsDisplayOnBoundsChange:YES];
  [layer setOpaque:YES];
  [layer setCustomView:self];

  // If the view has been connected to a window use the window's backing scale factor as its content scale.
  NSWindow* window = [self window];
  if (window)
  {
    double backingScaleFactor = [window backingScaleFactor];
    [layer setContentsScale:backingScaleFactor];
    [self modifyDPIForBackingScaleFactor:backingScaleFactor];
  }

  // Newly created layers are generally invalidated after creation, and so must be told to redraw.
  [layer setNeedsDisplay];

  // Make us a layer-hosting (not layer-backed) view.
  [self setLayer:layer];
  [self setWantsLayer:YES];
}

#pragma mark - Backing Property Change

// ---------------------------------------------------------------------------------------------------------------
- (void)modifyDPIForBackingScaleFactor:(double)backingScaleFactor
{
  vtkCocoaRenderWindow* renderWindow = [self renderWindow];
  if (renderWindow)
  {
    // DPI has been hardcoded to 72 but in order to cater for text rendering discrepancies with vtkTextActors for instance we must adjust the scaling factor per NSWindow.
    renderWindow->SetDPI((int)lround(72.0 * backingScaleFactor));
  }
}

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

  if (inNewWindow)
  {
    CGFloat backingScaleFactor = [inNewWindow backingScaleFactor];
    assert(backingScaleFactor >= 1.0);

    // If the layer exists set its content scale to the window's backing scale factor otherwise it will eventually get set when the layer is created (see 'initializeLayerSupport').
    [[self layer] setContentsScale:backingScaleFactor];

    // Update the rendering DPI per window.
    [self modifyDPIForBackingScaleFactor:backingScaleFactor];
  }
}

// ---------------------------------------------------------------------------------------------------------------
- (void)viewDidChangeBackingProperties
{
  [super viewDidChangeBackingProperties];

  NSWindow* window = [self window];
  if (window)
  {
    CGFloat backingScaleFactor = [[self window] backingScaleFactor];
    assert(backingScaleFactor >= 1.0);

    // If the layer exists set its content scale to the window's backing scale factor otherwise when it's ready and the backing property changes (i.e moving between screens that differ in resolution) it will be set.
    [[self layer] setContentsScale:backingScaleFactor];

    // Update the rendering DPI per window.
    [self modifyDPIForBackingScaleFactor:backingScaleFactor];
  }
}

@end
