fix: code review fixes

Author: kacperzolkiewski

ios/EnrichedTextInputView.mm

@@ -1223,7 +1223,10 @@ - (bool)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range r
     [h3Style handleNewlinesInRange:range replacementText:text] ||
     [ZeroWidthSpaceUtils handleBackspaceInRange:range replacementText:text input:self] ||
     [ParagraphAttributesUtils handleBackspaceInRange:range replacementText:text input:self] ||
-    // this callback HAS TO be always evaluated last
+    // CRITICAL: This callback HAS TO be always evaluated last.
+    //
+    // This function is the "Generic Fallback": if no specific style claims the backspace action
+    // to change its state, only then do we proceed to physically delete the newline and merge paragraphs.
     [ParagraphAttributesUtils handleNewlineBackspaceInRange:range replacementText:text input:self]
   ) {
     [self anyTextMayHaveBeenModified];

ios/styles/CodeBlockStyle.mm

@@ -137,7 +137,7 @@ - (BOOL)handleBackspaceInRange:(NSRange)range replacementText:(NSString *)text {
 
 - (BOOL)styleCondition:(id _Nullable)value :(NSRange)range {
   NSParagraphStyle *paragraph = (NSParagraphStyle *)value;
-  return paragraph != nullptr && paragraph.textLists.count == 1 && [paragraph.textLists.firstObject.markerFormat isEqual:@"codeblock"];
+  return paragraph != nullptr && paragraph.textLists.count == 1 && [paragraph.textLists.firstObject.markerFormat isEqualToString:@"codeblock"];
 }
 
 - (BOOL)detectStyle:(NSRange)range {

ios/styles/H1Style.mm

@@ -3,7 +3,7 @@
 
 @implementation H1Style
 + (StyleType)getStyleType { return H1; }
-+ (BOOL)isParagraphStyle { return NO; }
++ (BOOL)isParagraphStyle { return YES; }
 - (CGFloat)getHeadingFontSize { return [((EnrichedTextInputView *)input)->config h1FontSize]; }
 - (BOOL)isHeadingBold {
   return [((EnrichedTextInputView *)input)->config h1Bold];

ios/styles/H2Style.mm

@@ -3,7 +3,7 @@
 
 @implementation H2Style
 + (StyleType)getStyleType { return H2; }
-+ (BOOL)isParagraphStyle { return NO; }
++ (BOOL)isParagraphStyle { return YES; }
 - (CGFloat)getHeadingFontSize { return [((EnrichedTextInputView *)input)->config h2FontSize]; }
 - (BOOL)isHeadingBold {
   return [((EnrichedTextInputView *)input)->config h2Bold];

ios/styles/H3Style.mm

@@ -3,7 +3,7 @@
 
 @implementation H3Style
 + (StyleType)getStyleType { return H3; }
-+ (BOOL)isParagraphStyle { return NO; }
++ (BOOL)isParagraphStyle { return YES; }
 - (CGFloat)getHeadingFontSize { return [((EnrichedTextInputView *)input)->config h3FontSize]; }
 - (BOOL)isHeadingBold {
   return [((EnrichedTextInputView *)input)->config h3Bold];

ios/styles/LinkStyle.mm

@@ -297,7 +297,7 @@ - (void)handleAutomaticLinks:(NSString *)word inRange:(NSRange)wordRange {
     return;
   }
 
-  // we don't recognize links among codeblock
+  // we don't recognize links in codeblocks
   if ([codeBlockStyle anyOccurence:wordRange]) {
     return;
   }

ios/utils/ParagraphAttributesUtils.mm

@@ -37,27 +37,14 @@ + (BOOL)handleBackspaceInRange:(NSRange)range replacementText:(NSString *)text i
 
   // if the backspace removes the whole content of a paragraph (possibly more but has to start where the paragraph starts), we remove the typing attributes
   if(range.location == nonNewlineRange.location && range.length >= nonNewlineRange.length) {
-    // for lists and quotes we want to remove the characters but keep attribtues so that a zero width space appears here
+    // for lists, quotes and codeblocks we want to remove the characters but keep the attributes so that a zero width space appears here
     // so we do the removing manually and reapply attributes
-    if([ulStyle detectStyle:nonNewlineRange]) {
-      [TextInsertionUtils replaceText:text at:range additionalAttributes:nullptr input:typedInput withSelection:YES];
-      [ulStyle addAttributes:NSMakeRange(range.location, 0)];
-      return YES;
-    }
-    if([olStyle detectStyle:nonNewlineRange]) {
-      [TextInsertionUtils replaceText:text at:range additionalAttributes:nullptr input:typedInput withSelection:YES];
-      [olStyle addAttributes:NSMakeRange(range.location, 0)];
-      return YES;
-    }
-    if([bqStyle detectStyle:nonNewlineRange]) {
-      [TextInsertionUtils replaceText:text at:range additionalAttributes:nullptr input:typedInput withSelection:YES];
-      [bqStyle addAttributes:NSMakeRange(range.location, 0)];
-      return YES;
-    }
-    if([cbStyle detectStyle:nonNewlineRange]) {
-      [TextInsertionUtils replaceText:text at:range additionalAttributes:nullptr input:typedInput withSelection:YES];
-      [cbStyle addAttributes:NSMakeRange(range.location, 0)];
-      return YES;
+    NSArray *handledStyles = @[ulStyle, olStyle, bqStyle, cbStyle];
+    for(id<BaseStyleProtocol> style in handledStyles) {
+      if([style detectStyle:nonNewlineRange]) {
+        [TextInsertionUtils replaceText:text at:range additionalAttributes:nullptr input:typedInput withSelection:YES];
+        return YES;
+      }
     }
 
     // do the replacement manually
@@ -70,6 +57,23 @@ + (BOOL)handleBackspaceInRange:(NSRange)range replacementText:(NSString *)text i
   return NO;
 }
 
+/**
+ * Handles the specific case of backspacing a newline character, which results in merging two paragraphs.
+ *
+ * THE PROBLEM:
+ * When merging a bottom paragraph (Source) into a top paragraph (Destination), the bottom paragraph
+ * normally brings all its attributes with it. If the top paragraph is a restrictive style (like a CodeBlock),
+ * and the bottom paragraph contains a conflicting style (like an H1 Header), a standard merge would
+ * create an invalid state (e.g., a CodeBlock that is also a Header).
+ *
+ * THE SOLUTION:
+ * 1. Identifies the dominant style of the paragraph ABOVE the deleted newline (`leftParagraphStyle`).
+ * 2. Checks the paragraph BELOW the newline (`rightRange`) for any styles that conflict with or are blocked by the top style.
+ * 3. Explicitly removes those forbidden styles from the bottom paragraph *before* the merge occurs.
+ * 4. Performs the merge (deletes the newline).
+ *
+ * @return YES if the newline backspace was handled and sanitized; NO otherwise.
+ */
 + (BOOL)handleNewlineBackspaceInRange:(NSRange)range replacementText:(NSString *)text input:(id)input {
   EnrichedTextInputView *typedInput = (EnrichedTextInputView *)input;
   if(typedInput == nullptr) {

ios/utils/ZeroWidthSpaceUtils.mm

@@ -44,7 +44,7 @@ + (void)removeSpacesIfNeededinInput:(EnrichedTextInputView *)input {
       BlockQuoteStyle *bqStyle = input->stylesDict[@([BlockQuoteStyle getStyleType])];
       CodeBlockStyle *cbStyle = input->stylesDict[@([CodeBlockStyle getStyleType])];
 
-      // zero width spaces with no lists/blockquote styles on them get removed
+      // zero width spaces with no lists/blockquotes/codeblocks on them get removed
       if(![ulStyle detectStyle:characterRange] && ![olStyle detectStyle:characterRange] && ![bqStyle detectStyle:characterRange] && ![cbStyle detectStyle:characterRange]) {
         [indexesToBeRemoved addObject:@(characterRange.location)];
       }