#import <AsyncDisplayKit/ASScrollNode.h>

#import <AsyncDisplayKit/ASDisplayNodeExtras.h>

#import <AsyncDisplayKit/ASDisplayNode+FrameworkPrivate.h>

#import <AsyncDisplayKit/ASDisplayNode+FrameworkSubclasses.h>

#import <AsyncDisplayKit/ASLayout.h>

#import <AsyncDisplayKit/_ASDisplayLayer.h>

@interface ASScrollView : UIScrollView

@implementation ASScrollView

+ (Class)layerClass

{

return [_ASDisplayLayer class];

}

- (ASScrollNode *)scrollNode

{

return (ASScrollNode *)ASViewToDisplayNode(self);

}

#pragma mark - _ASDisplayView behavior substitutions

- (void)willMoveToWindow:(UIWindow *)newWindow

{

ASDisplayNode *node = self.scrollNode; // Create strong reference to weak ivar.

BOOL visible = (newWindow != nil);

if (visible && !node.inHierarchy) {

[node __enterHierarchy];

}

}

- (void)didMoveToWindow

{

ASDisplayNode *node = self.scrollNode; // Create strong reference to weak ivar.

BOOL visible = (self.window != nil);

if (!visible && node.inHierarchy) {

[node __exitHierarchy];

}

}

@implementation ASScrollNode

{

ASScrollDirection _scrollableDirections;

BOOL _automaticallyManagesContentSize;

CGSize _contentCalculatedSizeFromLayout;

}

@dynamic view;

- (instancetype)init

{

if (self = [super init]) {

[self setViewBlock:^UIView *{ return [[ASScrollView alloc] init]; }];

}

return self;

}

- (ASLayout *)calculateLayoutThatFits:(ASSizeRange)constrainedSize

restrictedToSize:(ASLayoutElementSize)size

relativeToParentSize:(CGSize)parentSize

{

ASDN::MutexLocker l(__instanceLock__); // Lock for using our instance variables.

ASSizeRange contentConstrainedSize = constrainedSize;

if (ASScrollDirectionContainsVerticalDirection(_scrollableDirections)) {

contentConstrainedSize.max.height = CGFLOAT_MAX;

}

if (ASScrollDirectionContainsHorizontalDirection(_scrollableDirections)) {

contentConstrainedSize.max.width = CGFLOAT_MAX;

}

ASLayout *layout = [super calculateLayoutThatFits:contentConstrainedSize

restrictedToSize:size

relativeToParentSize:parentSize];

if (_automaticallyManagesContentSize) {

// To understand this code, imagine we're containing a horizontal stack set within a vertical table node.

// Our parentSize is fixed ~375pt width, but 0 - INF height. Our stack measures 1000pt width, 50pt height.

// In this case, we want our scrollNode.bounds to be 375pt wide, and 50pt high. ContentSize 1000pt, 50pt.

// We can achieve this behavior by: 1. Always set contentSize to layout.size. 2. Set bounds to parentSize,

// unless one dimension is not defined, in which case adopt the contentSize for that dimension.

_contentCalculatedSizeFromLayout = layout.size;

CGSize selfSize = parentSize;

if (ASPointsValidForLayout(selfSize.width) == NO) {

selfSize.width = _contentCalculatedSizeFromLayout.width;

}

if (ASPointsValidForLayout(selfSize.height) == NO) {

selfSize.height = _contentCalculatedSizeFromLayout.height;

}

// Don't provide a position, as that should be set by the parent.

layout = [ASLayout layoutWithLayoutElement:self

size:selfSize

sublayouts:layout.sublayouts];

}

return layout;

}

- (void)layout

{

[super layout];

ASDN::MutexLocker l(__instanceLock__); // Lock for using our two instance variables.

if (_automaticallyManagesContentSize) {

CGSize contentSize = _contentCalculatedSizeFromLayout;

if (ASIsCGSizeValidForLayout(contentSize) == NO) {

NSLog(@"%@ calculated a size in its layout spec that can't be applied to .contentSize: %@. Applying parentSize (scrollNode's bounds) instead: %@.", self, NSStringFromCGSize(contentSize), NSStringFromCGSize(self.calculatedSize));

contentSize = self.calculatedSize;

}

self.view.contentSize = contentSize;

}

}

- (BOOL)automaticallyManagesContentSize

{

ASDN::MutexLocker l(__instanceLock__);

return _automaticallyManagesContentSize;

}

- (void)setAutomaticallyManagesContentSize:(BOOL)automaticallyManagesContentSize

{

ASDN::MutexLocker l(__instanceLock__);

_automaticallyManagesContentSize = automaticallyManagesContentSize;

if (_automaticallyManagesContentSize == YES

&& ASScrollDirectionContainsVerticalDirection(_scrollableDirections) == NO

&& ASScrollDirectionContainsHorizontalDirection(_scrollableDirections) == NO) {

// Set the @default value, for more user-friendly behavior of the most

// common use cases of .automaticallyManagesContentSize.

_scrollableDirections = ASScrollDirectionVerticalDirections;

}

}

- (ASScrollDirection)scrollableDirections

{

ASDN::MutexLocker l(__instanceLock__);

return _scrollableDirections;

}

- (void)setScrollableDirections:(ASScrollDirection)scrollableDirections

{

ASDN::MutexLocker l(__instanceLock__);

_scrollableDirections = scrollableDirections;

}