//
//  ASCollectionLayoutState.h
//  Texture
//
//  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 /ASDK-Licenses directory of this source tree. An additional
//  grant of patent rights can be found in the PATENTS file in the same directory.
//
//  Modifications to this file made after 4/13/2017 are: Copyright (c) 2017-present,
//  Pinterest, Inc.  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
#import <AsyncDisplayKit/ASBaseDefines.h>

@class ASElementMap, ASCollectionElement, ASLayout;

NS_ASSUME_NONNULL_BEGIN

AS_SUBCLASSING_RESTRICTED
@interface ASCollectionLayoutState : NSObject

/// The elements used to calculate this object
@property (nonatomic, strong, readonly) ASElementMap *elements;

@property (nonatomic, assign, readonly) CGSize contentSize;

/// Element to layout attributes map. Should use weak pointers for elements.
@property (nonatomic, strong, readonly) NSMapTable<ASCollectionElement *, UICollectionViewLayoutAttributes *> *elementToLayoutArrtibutesMap;

- (instancetype)init __unavailable;

/**
 * Designated initializer.
 *
 * @param elements The elements used to calculate this object
 *
 * @param contentSize The content size of the collection's layout
 *
 * @param elementToLayoutArrtibutesMap Map between elements to their layout attributes. The map may contain all elements, or a subset of them and will be updated later. 
 * Also, it should have NSMapTableObjectPointerPersonality and NSMapTableWeakMemory as key options.
 */
- (instancetype)initWithElements:(ASElementMap *)elements contentSize:(CGSize)contentSize elementToLayoutArrtibutesMap:(NSMapTable<ASCollectionElement *, UICollectionViewLayoutAttributes *> *)elementToLayoutArrtibutesMap NS_DESIGNATED_INITIALIZER;

/**
 * Convenience initializer.
 *
 * @param elements The elements used to calculate this object
 *
 * @param layout The layout describes size and position of all elements, or a subset of them and will be updated later.
 *
 * @discussion The sublayouts that describe position of elements must be direct children of the root layout object parameter.
 */
- (instancetype)initWithElements:(ASElementMap *)elements layout:(ASLayout *)layout;

@end

NS_ASSUME_NONNULL_END