//

// ASPagerNode.h

// AsyncDisplayKit

//

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

//

// Copyright (c) 2014-present, Facebook, Inc. All rights reserved.

// This source code is licensed under the BSD-style license found in the

// LICENSE file in the root directory of this source tree. An additional grant

// of patent rights can be found in the PATENTS file in the same directory.

//

#import <AsyncDisplayKit/ASCollectionNode.h>

#import <AsyncDisplayKit/ASDataController.h>

@class ASPagerNode;

@class ASPagerFlowLayout;

NS_ASSUME_NONNULL_BEGIN

#define ASPagerNodeDataSource ASPagerDataSource

@protocol ASPagerDataSource <NSObject>

/**

* This method replaces -collectionView:numberOfItemsInSection:

*

* @param pagerNode The sender.

* @return 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.

* @return 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.

* @return 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;

@end

@protocol ASPagerDelegate <ASCollectionDelegate>

@optional

/**

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

*

* @param pagerNode The sender.

* @param index The index of the node.

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

*/

- (ASSizeRange)pagerNode:(ASPagerNode *)pagerNode constrainedSizeForNodeAtIndex:(NSInteger)index;

@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:(nullable id <ASPagerDataSource>)dataSource;

- (nullable id <ASPagerDataSource>)dataSource;

/**

* Delegate is optional.

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

*/

- (void)setDelegate:(nullable id <ASPagerDelegate>)delegate;

- (nullable id <ASPagerDelegate>)delegate;

/**

* The underlying ASCollectionView object.

*/

@property (nonatomic, readonly) ASCollectionView *view;

/**

* Returns the current page index

*/

@property (nonatomic, assign, readonly) NSInteger currentPageIndex;

/**

* Scroll the contents of the receiver to ensure that the page is visible

*/

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

/**

* Returns the node for the passed page index

*/

- (ASCellNode *)nodeForPageAtIndex:(NSInteger)index;

@end

NS_ASSUME_NONNULL_END