fix: more accurate selection with zero width spaces on iOS (#191)

Fixed the new selection when zero width spaces are added or removed and
the adding/removing of them was within the user selection.

Author: szydlovsky

ios/styles/BlockQuoteStyle.mm

@@ -141,8 +141,8 @@ - (BOOL)handleBackspaceInRange:(NSRange)range replacementText:(NSString *)text {
     }
     NSRange nonNewlineRange = [nonNewlineVal rangeValue];
     if(NSEqualRanges(range, nonNewlineRange)) {
-      [self removeAttributes:range];
       [TextInsertionUtils replaceText:text at:range additionalAttributes:nullptr input:_input withSelection:YES];
+      [self removeAttributes:NSMakeRange(range.location, 0)];
       return YES;
     }
   }

ios/styles/OrderedListStyle.mm

@@ -153,8 +153,8 @@ - (BOOL)handleBackspaceInRange:(NSRange)range replacementText:(NSString *)text {
     }
     NSRange nonNewlineRange = [nonNewlineVal rangeValue];
     if(NSEqualRanges(range, nonNewlineRange)) {
-      [self removeAttributes:range];
       [TextInsertionUtils replaceText:text at:range additionalAttributes:nullptr input:_input withSelection:YES];
+      [self removeAttributes:NSMakeRange(range.location, 0)];
       return YES;
     }
   }

ios/styles/UnorderedListStyle.mm

@@ -153,8 +153,8 @@ - (BOOL)handleBackspaceInRange:(NSRange)range replacementText:(NSString *)text {
     }
     NSRange nonNewlineRange = [nonNewlineVal rangeValue];
     if(NSEqualRanges(range, nonNewlineRange)) {
-      [self removeAttributes:range];
       [TextInsertionUtils replaceText:text at:range additionalAttributes:nullptr input:_input withSelection:YES];
+      [self removeAttributes:NSMakeRange(range.location, 0)];
       return YES;
     }
   }

ios/utils/ZeroWidthSpaceUtils.mm

@@ -52,19 +52,23 @@ + (void)removeSpacesIfNeededinInput:(EnrichedTextInputView *)input {
 
   // do the removing
   NSInteger offset = 0;
-  NSInteger postRemoveOffset = 0;
+  NSInteger postRemoveLocationOffset = 0;
+  NSInteger postRemoveLengthOffset = 0;
   for(NSNumber *index in indexesToBeRemoved) {
     NSRange replaceRange = NSMakeRange([index integerValue] + offset, 1);
     [TextInsertionUtils replaceText:@"" at:replaceRange additionalAttributes:nullptr input:input withSelection:NO];
     offset -= 1;
     if([index integerValue] < preRemoveSelection.location) {
-      postRemoveOffset -= 1;
+      postRemoveLocationOffset -= 1;
+    }
+    if([index integerValue] >= preRemoveSelection.location && [index integerValue] < NSMaxRange(preRemoveSelection)) {
+      postRemoveLengthOffset -= 1;
     }
   }
 
   // fix the selection if needed
   if([input->textView isFirstResponder]) {
-    input->textView.selectedRange = NSMakeRange(preRemoveSelection.location + postRemoveOffset, preRemoveSelection.length);
+    input->textView.selectedRange = NSMakeRange(preRemoveSelection.location + postRemoveLocationOffset, preRemoveSelection.length + postRemoveLengthOffset);
   }
 }
 
@@ -93,13 +97,17 @@ + (void)addSpacesIfNeededinInput:(EnrichedTextInputView *)input {
 
   // do the replacing
   NSInteger offset = 0;
-  NSInteger postAddOffset = 0;
+  NSInteger postAddLocationOffset = 0;
+  NSInteger postAddLengthOffset = 0;
   for(NSNumber *index in indexesToBeInserted) {
     NSRange replaceRange = NSMakeRange([index integerValue] + offset, 1);
     [TextInsertionUtils replaceText:@"\u200B\n" at:replaceRange additionalAttributes:nullptr input:input withSelection:NO];
     offset += 1;
     if([index integerValue] < preAddSelection.location) {
-      postAddOffset += 1;
+      postAddLocationOffset += 1;
+    }
+    if([index integerValue] >= preAddSelection.location && [index integerValue] < NSMaxRange(preAddSelection)) {
+      postAddLengthOffset += 1;
     }
   }
 
@@ -112,7 +120,7 @@ + (void)addSpacesIfNeededinInput:(EnrichedTextInputView *)input {
 
   // fix the selection if needed
   if([input->textView isFirstResponder]) {
-    input->textView.selectedRange = NSMakeRange(preAddSelection.location + postAddOffset, preAddSelection.length);
+    input->textView.selectedRange = NSMakeRange(preAddSelection.location + postAddLocationOffset, preAddSelection.length + postAddLengthOffset);
   }
 }