//
//  WRChapterPageCount.h
//  WeRead (微信读书)
//
//  Reverse-engineered header reconstruction.
//  Pagination calculator. Manages NSRange for each page within a chapter.
//  Computes page breaks based on the typeset attributed string and the
//  available drawing area.
//

#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

// ============================================================================
#pragma mark - WRChapterPageCount
// ============================================================================

@interface WRChapterPageCount : NSObject

// ---- Ivars from binary: NSString, NSString, NSString, NSArray ----

/// The book identifier this page count data belongs to.
@property (nonatomic, copy, nullable) NSString *bookId;

/// The chapter identifier.
@property (nonatomic, copy, nullable) NSString *chapterId;

/// A cache key string combining book and chapter info for disk caching.
@property (nonatomic, copy, nullable) NSString *cacheKey;

/// Array of NSValue-wrapped NSRange values, one per page.
/// Each range is a character range within the chapter's attributed string.
@property (nonatomic, strong, nullable) NSArray<NSValue *> *pageRanges;

/// Total number of pages in this chapter.
@property (nonatomic, assign, readonly) NSUInteger totalPages;

// ============================================================================
#pragma mark - Class Methods
// ============================================================================

/// Generates a cache key string for storing/retrieving pagination data
/// for the given book. The key encodes the book ID and current typesetter
/// settings (font size, line spacing, etc.) so pagination is invalidated
/// when settings change.
///
/// @param bookId The book identifier.
/// @return A unique cache key string, e.g., @"weread_pagcount_{bookId}_{fontSize}_{lineSpacing}".
+ (NSString *)currentCacheKeyWithBookId:(NSString *)bookId;

/// Calculates the page ranges from a page info dictionary.
/// The page info dictionary typically comes from the server or from local
/// layout computation and contains raw range data.
///
/// @param pageInfo Dictionary with pagination data (e.g., @"ranges" key containing
///                 an array of {location, length} dictionaries).
/// @return An array of NSValue-wrapped NSRange values.
+ (NSArray<NSValue *> *)rangeValueWithPageInfo:(NSDictionary *)pageInfo;

// ============================================================================
#pragma mark - Instance Methods
// ============================================================================

/// Returns the character range for the specified page index.
- (NSRange)rangeForPageAtIndex:(NSUInteger)pageIndex;

/// Returns the page index that contains the given character index.
- (NSUInteger)pageIndexForCharacterIndex:(NSUInteger)charIndex;

/// Recalculates page ranges for the given attributed string and drawing area.
///
/// @param attributedString The typeset chapter content.
/// @param drawingSize      The available drawing area size (points).
/// @param margins          Content insets / margins.
- (void)recalculatePageRangesForAttributedString:(NSAttributedString *)attributedString
                                     drawingSize:(CGSize)drawingSize
                                         margins:(UIEdgeInsets)margins;

@end

NS_ASSUME_NONNULL_END