/**
 * Copyright (c) Facebook, Inc. and its affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

#import <UIKit/UIScrollView.h>

#import <React/RCTAutoInsetsProtocol.h>
#import <React/RCTEventDispatcher.h>
#import <React/RCTScrollableProtocol.h>
#import <React/RCTView.h>

@protocol UIScrollViewDelegate;

@interface RCTScrollView : RCTView <UIScrollViewDelegate, RCTScrollableProtocol, RCTAutoInsetsProtocol>

- (instancetype)initWithEventDispatcher:(RCTEventDispatcher *)eventDispatcher NS_DESIGNATED_INITIALIZER;

/**
 * The `RCTScrollView` may have at most one single subview. This will ensure
 * that the scroll view's `contentSize` will be efficiently set to the size of
 * the single subview's frame. That frame size will be determined somewhat
 * efficiently since it will have already been computed by the off-main-thread
 * layout system.
 */
@property (nonatomic, readonly) UIView *contentView;

/**
 * If the `contentSize` is not specified (or is specified as {0, 0}, then the
 * `contentSize` will automatically be determined by the size of the subview.
 */
@property (nonatomic, assign) CGSize contentSize;

/**
 * The underlying scrollView (TODO: can we remove this?)
 */
@property (nonatomic, readonly) UIScrollView *scrollView;

@property (nonatomic, assign) UIEdgeInsets contentInset;
@property (nonatomic, assign) BOOL automaticallyAdjustContentInsets;
@property (nonatomic, assign) BOOL DEPRECATED_sendUpdatedChildFrames;
@property (nonatomic, assign) NSTimeInterval scrollEventThrottle;
@property (nonatomic, assign) BOOL centerContent;
@property (nonatomic, copy) NSDictionary *maintainVisibleContentPosition;
@property (nonatomic, assign) int snapToInterval;
@property (nonatomic, copy) NSArray<NSNumber *> *snapToOffsets;
@property (nonatomic, assign) BOOL snapToStart;
@property (nonatomic, assign) BOOL snapToEnd;
@property (nonatomic, copy) NSString *snapToAlignment;

// NOTE: currently these event props are only declared so we can export the
// event names to JS - we don't call the blocks directly because scroll events
// need to be coalesced before sending, for performance reasons.
@property (nonatomic, copy) RCTDirectEventBlock onScrollBeginDrag;
@property (nonatomic, copy) RCTDirectEventBlock onScroll;
@property (nonatomic, copy) RCTDirectEventBlock onScrollToTop;
@property (nonatomic, copy) RCTDirectEventBlock onScrollEndDrag;
@property (nonatomic, copy) RCTDirectEventBlock onMomentumScrollBegin;
@property (nonatomic, copy) RCTDirectEventBlock onMomentumScrollEnd;

@end

@interface RCTScrollView (Internal)

- (void)updateContentOffsetIfNeeded;

@end

@interface RCTEventDispatcher (RCTScrollView)

/**
 * Send a fake scroll event.
 */
- (void)sendFakeScrollEvent:(NSNumber *)reactTag;

@end