//

// ASPagerNode.h

// AsyncDisplayKit

//

// Created by Levi McCallum on 12/7/15.

// Copyright © 2015 Facebook. All rights reserved.

//

#import <AsyncDisplayKit/ASCollectionNode.h>

@class ASPagerNode;

@class ASPagerFlowLayout;

@protocol ASPagerNodeDataSource <NSObject>

/**

* This method replaces -collectionView:numberOfItemsInSection:

*

* @param pagerNode The sender.

*

*

* @returns The total number of pages that can display in the pagerNode.

*/

- (NSInteger)numberOfPagesInPagerNode:(ASPagerNode *)pagerNode;

@optional

/**

* This method replaces -collectionView:nodeForItemAtIndexPath:

*

* @param pagerNode The sender.

*

* @param index The index of the requested node.

*

* @returns a node for display at this index. This will be called on the main thread and should

* not implement reuse (it will be called once per row). Unlike UICollectionView's version,

* this method is not called when the row is about to display.

*/

- (ASCellNode *)pagerNode:(ASPagerNode *)pagerNode nodeAtIndex:(NSInteger)index;

/**

* This method replaces -collectionView:nodeBlockForItemAtIndexPath:

* This method takes precedence over pagerNode:nodeAtIndex: if implemented.

*

* @param pagerNode The sender.

*

* @param index The index of the requested node.

*

* @returns a block that creates the node for display at this index.

* Must be thread-safe (can be called on the main thread or a background

* queue) and should not implement reuse (it will be called once per row).

*/

- (ASCellNodeBlock)pagerNode:(ASPagerNode *)pagerNode nodeBlockAtIndex:(NSInteger)index;

/**

* Provides the constrained size range for measuring the node at the index path.

*

* @param pagerNode The sender.

*

* @param indexPath The index path of the node.

*

* @returns A constrained size range for layout the node at this index path.

*/

- (ASSizeRange)pagerNode:(ASPagerNode *)pagerNode constrainedSizeForNodeAtIndexPath:(NSIndexPath *)indexPath;

@end

@interface ASPagerNode : ASCollectionNode

// Configures a default horizontal, paging flow layout with 0 inter-item spacing.

- (instancetype)init;

// Initializer with custom-configured flow layout properties.

- (instancetype)initWithCollectionViewLayout:(ASPagerFlowLayout *)flowLayout;

// Data Source is required, and uses a different protocol from ASCollectionNode.

- (void)setDataSource:(id <ASPagerNodeDataSource>)dataSource;

- (id <ASPagerNodeDataSource>)dataSource;

// Delegate is optional, and uses the same protocol as ASCollectionNode.

// This includes UIScrollViewDelegate as well as most methods from UICollectionViewDelegate, like willDisplay...

@property (nonatomic, weak) id <ASCollectionDelegate> delegate;

// The underlying ASCollectionView object.

@property (nonatomic, readonly) ASCollectionView *view;

- (void)scrollToPageAtIndex:(NSInteger)index animated:(BOOL)animated;

@end