LayoutManagerExtension.mm

#import "LayoutManagerExtension.h"
#import <objc/runtime.h>
#import "EnrichedTextInputView.h"
#import "StyleHeaders.h"
#import "ParagraphsUtils.h"

@implementation NSLayoutManager (LayoutManagerExtension)

static void const *kInputKey = &kInputKey;

- (id)input {
  return objc_getAssociatedObject(self, kInputKey);
}

- (void)setInput:(id)value {
  objc_setAssociatedObject(
    self,
    kInputKey,
    value,
    OBJC_ASSOCIATION_RETAIN_NONATOMIC
  );
}

+ (void)load {
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    Class myClass = [NSLayoutManager class];
    SEL originalSelector = @selector(drawBackgroundForGlyphRange:atPoint:);
    SEL swizzledSelector = @selector(my_drawBackgroundForGlyphRange:atPoint:);
    Method originalMethod = class_getInstanceMethod(myClass, originalSelector);
    Method swizzledMethod = class_getInstanceMethod(myClass, swizzledSelector);
    
    BOOL didAddMethod = class_addMethod(myClass, originalSelector,
      method_getImplementation(swizzledMethod),
      method_getTypeEncoding(swizzledMethod)
    );
    
    if(didAddMethod) {
      class_replaceMethod(myClass, swizzledSelector,
        method_getImplementation(originalMethod),
        method_getTypeEncoding(originalMethod)
      );
    } else {
      method_exchangeImplementations(originalMethod, swizzledMethod);
    }
  });
}

- (void)my_drawBackgroundForGlyphRange:(NSRange)glyphRange atPoint:(CGPoint)origin {
  [self my_drawBackgroundForGlyphRange:glyphRange atPoint:origin];
  
  EnrichedTextInputView *typedInput = (EnrichedTextInputView *)self.input;
  if(typedInput == nullptr) { return; }
  
  BlockQuoteStyle *bqStyle = typedInput->stylesDict[@([BlockQuoteStyle getStyleType])];
  if(bqStyle == nullptr) { return; }
  
  NSRange inputRange = NSMakeRange(0, typedInput->textView.textStorage.length);
  
  // it isn't the most performant but we have to check for all the blockquotes each time and redraw them
  NSArray *allBlockquotes = [bqStyle findAllOccurences:inputRange];
  
  for(StylePair *pair in allBlockquotes) {
    NSRange paragraphRange = [typedInput->textView.textStorage.string paragraphRangeForRange:[pair.rangeValue rangeValue]];
    NSRange paragraphGlyphRange = [self glyphRangeForCharacterRange:paragraphRange actualCharacterRange:nullptr];
    [self enumerateLineFragmentsForGlyphRange:paragraphGlyphRange
      usingBlock:^(CGRect rect, CGRect usedRect, NSTextContainer * _Nonnull textContainer, NSRange glyphRange, BOOL * _Nonnull stop) {
        BOOL isRTL = [[RCTI18nUtil sharedInstance] isRTL];
        CGFloat width = [typedInput->config blockquoteBorderWidth];
        CGFloat height = rect.size.height;
      
        CGFloat x = 0;
        if (isRTL) {
          x = origin.x + rect.size.width - width;
        } else {
          x = origin.x;
        }
        CGFloat y = origin.y + rect.origin.y;
        
        CGRect lineRect = CGRectMake(x, y, width, height);
        [[typedInput->config blockquoteBorderColor] setFill];
        UIRectFill(lineRect);
      }
    ];
  }
    
  UnorderedListStyle *ulStyle = typedInput->stylesDict[@([UnorderedListStyle getStyleType])];
  OrderedListStyle *olStyle = typedInput->stylesDict[@([OrderedListStyle getStyleType])];
  if(ulStyle == nullptr || olStyle == nullptr) { return; }
  
  // also not the most performant but we redraw all the lists
  NSMutableArray *allLists = [[NSMutableArray alloc] init];
  [allLists addObjectsFromArray:[ulStyle findAllOccurences:inputRange]];
  [allLists addObjectsFromArray:[olStyle findAllOccurences:inputRange]];
  
  for(StylePair *pair in allLists) {
    NSParagraphStyle *pStyle = (NSParagraphStyle *)pair.styleValue;
    NSDictionary *markerAttributes = @{
      NSFontAttributeName: [typedInput->config orderedListMarkerFont],
      NSForegroundColorAttributeName: [typedInput->config orderedListMarkerColor]
    };
    
    NSArray *paragraphs = [ParagraphsUtils getSeparateParagraphsRangesIn:typedInput->textView range:[pair.rangeValue rangeValue]];
    
    for(NSValue *paragraph in paragraphs) {
      NSRange paragraphGlyphRange = [self glyphRangeForCharacterRange:[paragraph rangeValue] actualCharacterRange:nullptr];
      
      [self enumerateLineFragmentsForGlyphRange:paragraphGlyphRange
        usingBlock:^(CGRect rect, CGRect usedRect, NSTextContainer *container, NSRange lineGlyphRange, BOOL *stop) {
          NSString *marker = [self markerForList:pStyle.textLists.firstObject charIndex:[self characterIndexForGlyphAtIndex:lineGlyphRange.location] input:typedInput];
          BOOL isRTL = [[RCTI18nUtil sharedInstance] isRTL];

          CGFloat textStartLeft = usedRect.origin.x;
          CGFloat textEndRight = usedRect.origin.x + usedRect.size.width;
          
          if(pStyle.textLists.firstObject.markerFormat == NSTextListMarkerDecimal) {
            CGFloat gapWidth = [typedInput->config orderedListGapWidth];
            CGFloat markerWidth = [marker sizeWithAttributes:markerAttributes].width;
            CGFloat markerX = 0;
            
            if (isRTL) {
              markerX = textEndRight + gapWidth;
            } else {
              markerX = textStartLeft - gapWidth - markerWidth / 2;
            }
            
            [marker drawAtPoint:CGPointMake(markerX, usedRect.origin.y + origin.y) withAttributes:markerAttributes];
          } else {
            CGFloat gapWidth = [typedInput->config unorderedListGapWidth];
            CGFloat bulletSize = [typedInput->config unorderedListBulletSize];
            CGFloat centerY = CGRectGetMidY(usedRect);
            CGFloat bulletX = 0;
                
            if (isRTL) {
              bulletX = textEndRight + gapWidth + (bulletSize / 2.0);
            } else {
              bulletX = textStartLeft - gapWidth - (bulletSize / 2.0);
            }
            
            CGContextRef context = UIGraphicsGetCurrentContext();
            CGContextSaveGState(context); {
              [[typedInput->config unorderedListBulletColor] setFill];
              CGContextAddArc(context, bulletX, centerY, bulletSize/2, 0, 2 * M_PI, YES);
              CGContextFillPath(context);
            }
            CGContextRestoreGState(context);
          }
          // only first line of a list gets its marker drawn
          *stop = YES;
        }
      ];
    }
  }
}

- (NSString *)markerForList:(NSTextList *)list charIndex:(NSUInteger)index input:(EnrichedTextInputView *)input {
  if(list.markerFormat == NSTextListMarkerDecimal) {
    NSString *fullText = input->textView.textStorage.string;
    NSInteger itemNumber = 1;
    
    NSRange currentParagraph = [fullText paragraphRangeForRange:NSMakeRange(index, 0)];
    if(currentParagraph.location > 0) {
      OrderedListStyle *olStyle = input->stylesDict[@([OrderedListStyle getStyleType])];
      
      NSInteger prevParagraphsCount = 0;
      NSInteger recentParagraphLocation = [fullText paragraphRangeForRange:NSMakeRange(currentParagraph.location - 1, 0)].location;
      
      // seek for previous lists
      while(true) {
        if([olStyle detectStyle:NSMakeRange(recentParagraphLocation, 0)]) {
          prevParagraphsCount += 1;
          
          if(recentParagraphLocation > 0) {
            recentParagraphLocation = [fullText paragraphRangeForRange:NSMakeRange(recentParagraphLocation - 1, 0)].location;
          } else {
            break;
          }
        } else {
          break;
        }
      }
      
      itemNumber = prevParagraphsCount + 1;
    }
    BOOL isRTL = [[RCTI18nUtil sharedInstance] isRTL];
    
    if (isRTL) {
      return [NSString stringWithFormat:@".%ld", (long)(itemNumber)];
    } else {
      return [NSString stringWithFormat:@"%ld.", (long)(itemNumber)];
    }
  } else {
    return @"•";
  }
}

@end