fix: diff apply failed and edit app issues

Author: zhu-xiaowei

react-native/src/app/AppGalleryScreen.tsx

@@ -363,6 +363,7 @@ function AppGalleryScreen(): React.JSX.Element {
         navigation.navigate('Bedrock', {
           editAppCode: app.htmlCode,
           editAppName: app.name,
+          editTimestamp: Date.now(),
         });
       }
     }

react-native/src/chat/ChatScreen.tsx

@@ -102,6 +102,14 @@ const findLatestHtmlCode = (messages: SwiftChatMessage[]): string => {
   return '';
 };
 
+/**
+ * Check if any AI message has diffCode (for detecting failed diff apply case)
+ */
+const hasAnyDiffCode = (messages: SwiftChatMessage[]): boolean => {
+  const aiMessages = messages.filter(m => m.user._id === BOT_ID);
+  return aiMessages.some(msg => msg.diffCode);
+};
+
 const createBotMessage = (mode: string, isAppMode: boolean = false) => {
   return {
     _id: uuid.v4(),
@@ -132,6 +140,7 @@ function ChatScreen(): React.JSX.Element {
   const mode = route.params?.mode ?? currentMode;
   const editAppCode = route.params?.editAppCode;
   const editAppName = route.params?.editAppName;
+  const editTimestamp = route.params?.editTimestamp;
   const modeRef = useRef(mode);
   const isNovaSonic =
     getTextModel().modelId.includes('sonic') &&
@@ -261,6 +270,7 @@ function ChatScreen(): React.JSX.Element {
       setMessages([]);
       bedrockMessages.current = [];
       clearLatestHtmlCode();
+      setUsage(undefined);
       showKeyboard();
     }, [])
   );
@@ -354,8 +364,7 @@ function ChatScreen(): React.JSX.Element {
       const restoredHtmlCode = findLatestHtmlCode(msg as SwiftChatMessage[]);
       setLatestHtmlCode(restoredHtmlCode);
 
-      // If session has htmlCode, auto-select App prompt
-      if (restoredHtmlCode) {
+      if (restoredHtmlCode || hasAnyDiffCode(msg as SwiftChatMessage[])) {
         isAppModeRef.current = true;
         sendEventRef.current?.('selectAppPrompt');
       } else {
@@ -386,8 +395,9 @@ function ChatScreen(): React.JSX.Element {
 
   // editAppCode handler - for editing saved apps from AppGallery
   useEffect(() => {
-    if (editAppCode) {
+    if (editAppCode && editTimestamp) {
       startNewChat.current();
+      setUsage(undefined);
       setLatestHtmlCode(editAppCode);
       isAppModeRef.current = true;
       setTimeout(() => {
@@ -401,7 +411,7 @@ function ChatScreen(): React.JSX.Element {
         }
       }, 100);
     }
-  }, [editAppCode, editAppName, navigation]);
+  }, [editAppCode, editAppName, editTimestamp]);
 
   // deleteChat listener
   useEffect(() => {
@@ -441,7 +451,7 @@ function ChatScreen(): React.JSX.Element {
   // diffApplied listener for App mode - update message.htmlCode and save diffCode
   // Note: placeholder replacement is done in ChatStatus.Complete handler
   useEffect(() => {
-    if (event?.event === 'diffApplied' && event.params?.htmlCode) {
+    if (event?.event === 'diffApplied' && event.params?.diffCode) {
       const { htmlCode, diffCode } = event.params;
       setMessages(prevMessages => {
         // update isLastHtml for all messages
@@ -520,7 +530,7 @@ function ChatScreen(): React.JSX.Element {
       if (isAppModeRef.current && msg.htmlCode) {
         msg.text = replaceHtmlWithPlaceholder(msg.text, msg.htmlCode);
       }
-      if (isAppModeRef.current && msg.diffCode) {
+      if (isAppModeRef.current && msg.diffCode && msg.htmlCode) {
         msg.text = replaceDiffWithPlaceholder(msg.text, msg.diffCode);
       }
       saveCurrentMessages();

react-native/src/chat/component/markdown/HtmlCodeRenderer.tsx

@@ -84,7 +84,7 @@ const HtmlCodeRenderer = forwardRef<HtmlCodeRendererRef, HtmlCodeRendererProps>(
       undefined
     );
     const [hasLoadedCode, setHasLoadedCode] = useState(
-      () => !messageHtmlCode && !isCompleted
+      () => (!messageHtmlCode && !isCompleted) || Boolean(messageDiffCode)
     );
     const [webViewLoaded, setWebViewLoaded] = useState(false);
     const htmlRendererRef = useRef<HtmlPreviewRendererRef>(null);
@@ -134,6 +134,7 @@ const HtmlCodeRenderer = forwardRef<HtmlCodeRendererRef, HtmlCodeRendererProps>(
               setShowPreview(true);
               sendEvent('diffApplied', { htmlCode: result, diffCode: text });
             } else {
+              sendEvent('diffApplied', { htmlCode: undefined, diffCode: text });
               showInfo('Diff apply failed, please regenerate');
             }
           }

react-native/src/chat/util/ApplyDiff.ts

@@ -287,7 +287,6 @@ function findAllMatches(
   return positions;
 }
 
-
 /**
  * Find block position using three-layer fallback strategy
  */
@@ -358,7 +357,10 @@ function findBlockPosition(
   }
 
   // Last resort: removals only
-  if (removals.length >= 2) {
+  if (
+    removals.length >= 2 ||
+    (removals.length === 1 && removals[0].trim().length >= 5)
+  ) {
     pos = trimmedMatch(sourceLines, removals, startFrom);
     if (pos !== -1) {
       return pos;
@@ -565,7 +567,10 @@ export function applyDiff(
                 firstMiddleContext,
                 searchAfter
               );
-              if (middlePositions.length > 0 && middlePositions[0] < searchAfter + 100) {
+              if (
+                middlePositions.length > 0 &&
+                middlePositions[0] < searchAfter + 100
+              ) {
                 position = changePos;
                 break;
               }

react-native/src/chat/util/DiffUtils.ts

@@ -2,7 +2,7 @@
 export const HTML_CODE_PLACEHOLDER = '[HTML_OUTPUT_OMITTED]';
 
 // Placeholder for diff code block - diff has been applied, no need to send again
-export const DIFF_CODE_PLACEHOLDER = '[DIFF_CHANGES_OMITTED]';
+export const DIFF_CODE_PLACEHOLDER = '[PREVIOUS_DIFF_APPLIED]';
 
 // Global storage for latest HTML code in App mode
 let latestHtmlCode: string = '';

react-native/src/types/RouteTypes.ts

@@ -20,6 +20,7 @@ export type RouteParamList = {
     mode?: ChatMode;
     editAppCode?: string;
     editAppName?: string;
+    editTimestamp?: number;
   };
   Settings: NonNullable<unknown>;
   TokenUsage: NonNullable<unknown>;