//
//  DTCoreTextLayouter.h
//  WeRead
//
//  Reverse-engineered from binary analysis
//  Based on DTCoreText open-source library, customized by WeRead
//
//  DTCoreText is an open-source library for rendering HTML with CoreText.
//  WeRead has customized it for their reading engine.
//

#import <Foundation/Foundation.h>
#import <CoreText/CoreText.h>

@class DTCoreTextLayoutFrame;
@class NSAttributedString;

NS_ASSUME_NONNULL_BEGIN

/**
 * DTCoreTextLayouter - CoreText typesetter wrapper.
 *
 * This is the original DTCoreText layouter class, customized by WeRead.
 * It wraps CTTypesetter and CTFramesetter to provide high-level
 * text layout functionality.
 *
 * Key features:
 * - Creates CTTypesetter from attributed string
 * - Manages typesetter lifecycle
 * - Produces DTCoreTextLayoutFrame objects
 * - Supports caching of layout frames
 * - Handles string updates efficiently
 */
@interface DTCoreTextLayouter : NSObject

#pragma mark - Properties

/** The attributed string to be laid out */
@property (nonatomic, strong, nullable) NSAttributedString *attributedString;

/** Cache for layout frames */
@property (nonatomic, strong, readonly) NSCache *layoutFrameCache;

/** Array of created layout frames */
@property (nonatomic, strong, readonly) NSMutableArray<DTCoreTextLayoutFrame *> *layoutFrames;

#pragma mark - Initialization

/**
 * Initialize with an attributed string.
 *
 * @param attributedString The text with styling attributes
 * @return Initialized layouter instance
 */
- (instancetype)initWithAttributedString:(NSAttributedString *)attributedString;

#pragma mark - Typesetter Management

/**
 * Returns the internal CTTypesetter.
 * Creates one if it doesn't exist.
 *
 * @return The CTTypesetter reference
 */
- (CTTypesetterRef)typesetter;

/**
 * Invalidates the current typesetter.
 * Called when the attributed string changes.
 */
- (void)invalidateTypesetter;

#pragma mark - Layout Frame Creation

/**
 * Create a layout frame for a given string range within the specified rect.
 *
 * @param range The range of the attributed string to lay out
 * @param frame The bounding rectangle for the layout
 * @return A new DTCoreTextLayoutFrame
 */
- (DTCoreTextLayoutFrame *)layoutFrameWithRange:(NSRange)range
                                          frame:(CGRect)frame;

/**
 * Suggest a line break for the given range and width.
 *
 * @param startIndex The starting index
 * @param width The available width
 * @return The suggested line break index
 */
- (NSUInteger)suggestLineBreakStartIndex:(NSUInteger)startIndex
                                   width:(CGFloat)width;

/**
 * Suggest a fitting string length for pagination.
 *
 * @param startIndex The starting index
 * @param constraints Size constraints
 * @return The suggested fitting length
 */
- (NSUInteger)stringIndexFittingLengthForWidth:(CGFloat)width
                                    startIndex:(NSUInteger)startIndex;

#pragma mark - Frame Caching

/**
 * Returns a cached layout frame for the given key.
 */
- (nullable DTCoreTextLayoutFrame *)cachedLayoutFrameForKey:(NSString *)key;

/**
 * Caches a layout frame with the given key.
 */
- (void)cacheLayoutFrame:(DTCoreTextLayoutFrame *)frame
                  forKey:(NSString *)key;

/**
 * Clears the layout frame cache.
 */
- (void)clearLayoutFrameCache;

@end

NS_ASSUME_NONNULL_END