LinkRenderer.m

#import "LinkRenderer.h"
#import "FontUtils.h"
#import "RenderContext.h"
#import "RendererFactory.h"
#import "StyleConfig.h"
#import <React/RCTFont.h>

@implementation LinkRenderer {
  __weak RendererFactory *_rendererFactory;
  StyleConfig *_config;
}

- (instancetype)initWithRendererFactory:(id)rendererFactory config:(id)config
{
  self = [super init];
  if (self) {
    _rendererFactory = rendererFactory;
    _config = (StyleConfig *)config;
  }
  return self;
}

#pragma mark - Rendering

- (void)renderNode:(MarkdownASTNode *)node into:(NSMutableAttributedString *)output context:(RenderContext *)context
{
  NSUInteger start = output.length;

  // 1. Render children first to establish base attributes
  [_rendererFactory renderChildrenOfNode:node into:output context:context];

  NSRange range = NSMakeRange(start, output.length - start);
  if (range.length == 0)
    return;

  // 2. Extract configuration
  NSString *url = node.attributes[@"url"] ?: @"";
  RCTUIColor *linkColor = [_config linkColor];
  NSNumber *underlineStyle = @([_config linkUnderline] ? NSUnderlineStyleSingle : NSUnderlineStyleNone);
  NSString *linkFontFamily = [_config linkFontFamily];

  // 3. Apply core link functionality (non-destructive)
  [output addAttribute:NSLinkAttributeName value:url range:range];

  // 4. Optimize visual attributes via enumeration to avoid redundant updates
  [output enumerateAttributesInRange:range
                             options:NSAttributedStringEnumerationLongestEffectiveRangeNotRequired
                          usingBlock:^(NSDictionary<NSAttributedStringKey, id> *attrs, NSRange subrange, BOOL *stop) {
                            NSMutableDictionary *newAttributes = [NSMutableDictionary dictionary];

                            // Only apply link color if the subrange isn't already colored by the link style
                            if (linkColor && ![attrs[NSForegroundColorAttributeName] isEqual:linkColor]) {
                              newAttributes[NSForegroundColorAttributeName] = linkColor;
                              newAttributes[NSUnderlineColorAttributeName] = linkColor;
                            }

                            // Only update underline style if it differs from the config
                            if (![attrs[NSUnderlineStyleAttributeName] isEqual:underlineStyle]) {
                              newAttributes[NSUnderlineStyleAttributeName] = underlineStyle;
                            }

                            if (linkFontFamily.length > 0) {
                              UIFont *currentFont = attrs[NSFontAttributeName];
                              if (currentFont) {
                                UIFont *linkFont = [RCTFont updateFont:currentFont
                                                            withFamily:linkFontFamily
                                                                  size:nil
                                                                weight:nil
                                                                 style:nil
                                                               variant:nil
                                                       scaleMultiplier:1.0];
                                if (linkFont && ![currentFont isEqual:linkFont]) {
                                  newAttributes[NSFontAttributeName] = linkFont;
                                }
                              }
                            }

                            if (newAttributes.count > 0) {
                              [output addAttributes:newAttributes range:subrange];
                            }
                          }];

  // 5. Register for touch handling
  [context registerLinkRange:range url:url];
}

@end