/*
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

#import "OpenVulkanoViewController.h"

#pragma mark -
#pragma mark OpenVulkanoViewController

@implementation OpenVulkanoOrientationLockableViewController
-(id)init {
	[super init];
	_rotationLockedView = nil;
	return self;
}

-(void) viewDidLoad {
	[super viewDidLoad];
}

- (void)viewWillLayoutSubviews
{
	[super viewWillLayoutSubviews];
	if (_rotationLockedView != nil)
	{
		_rotationLockedView.center = CGPointMake(CGRectGetMidX(self.view.bounds), CGRectGetMidY(self.view.bounds));
	}
}

-(CGFloat)getOrientation {
	if (_rotationLockedView == nil) return 0;
	return [[_rotationLockedView.layer valueForKeyPath:@"transform.rotation.z"] floatValue];
}

-(void)setOrientation:(CGFloat)angle {
	if (_rotationLockedView != nil) {
		[_rotationLockedView.layer setValue:@(angle) forKeyPath:@"transform.rotation.z"];
	}
}

-(void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {
	[super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];

	if (_rotationLockedView != nil)
	{
		[coordinator animateAlongsideTransition:^(id <UIViewControllerTransitionCoordinatorContext> context) {
			CGAffineTransform deltaTransform = coordinator.targetTransform;
			CGFloat deltaAngle = atan2f(deltaTransform.b, deltaTransform.a);

			CGFloat currentRotation = [self getOrientation];
			// Adding a small value to the rotation angle forces the animation to occur in a the desired direction, preventing an issue where the view would appear to rotate 2PI radians during a rotation from LandscapeRight -> LandscapeLeft.
			currentRotation += -1 * deltaAngle + 0.0001;
			[self setOrientation:currentRotation];

		} completion:^(id <UIViewControllerTransitionCoordinatorContext> context) {
			// Integralize the transform to undo the extra 0.0001 added to the rotation angle.
			CGAffineTransform currentTransform = _rotationLockedView.transform;
			currentTransform.a = round(currentTransform.a);
			currentTransform.b = round(currentTransform.b);
			currentTransform.c = round(currentTransform.c);
			currentTransform.d = round(currentTransform.d);
			_rotationLockedView.transform = currentTransform;
		}];
	}
}
@end