chat: enhance final response rendering with pinning logic and repositioning (microsoft#293597)

Author: tamuratak

src/vs/workbench/contrib/chat/browser/widget/chatListRenderer.ts

@@ -1169,8 +1169,10 @@ export class ChatListItemRenderer extends Disposable implements ITreeRenderer<Ch
 	private renderChatContentDiff(partsToRender: ReadonlyArray<IChatRendererContent | null>, contentForThisTurn: ReadonlyArray<IChatRendererContent>, element: IChatResponseViewModel, elementIndex: number, templateData: IChatListItemTemplate): void {
 		const renderedParts = templateData.renderedParts ?? [];
 		templateData.renderedParts = renderedParts;
+		const lastMarkdownIndex = partsToRender.findLastIndex(part => part?.kind === 'markdownContent');
 		partsToRender.forEach((partToRender, contentIndex) => {
 			const alreadyRenderedPart = templateData.renderedParts?.[contentIndex];
+			const isFinalAnswerPart = partToRender?.kind === 'markdownContent' && contentIndex === lastMarkdownIndex && element.isComplete;
 
 			if (!partToRender) {
 				// null=no change
@@ -1188,7 +1190,7 @@ export class ChatListItemRenderer extends Disposable implements ITreeRenderer<Ch
 					}
 					renderedParts[contentIndex] = alreadyRenderedPart;
 					return;
-				} else if (alreadyRenderedPart instanceof ChatThinkingContentPart && this.shouldPinPart(partToRender, element)) {
+				} else if (alreadyRenderedPart instanceof ChatThinkingContentPart && this.shouldPinPart(partToRender, element) && !isFinalAnswerPart) {
 					// keep existing thinking part if we are pinning it (combining tool calls into it)
 					renderedParts[contentIndex] = alreadyRenderedPart;
 					return;
@@ -1219,7 +1221,7 @@ export class ChatListItemRenderer extends Disposable implements ITreeRenderer<Ch
 
 			// combine tool invocations into thinking part if needed. render the tool, but do not replace the working spinner with the new part's dom node since it is already inside the thinking part.
 			const lastThinking = this.getLastThinkingPart(renderedParts);
-			if (lastThinking && (partToRender.kind === 'toolInvocation' || partToRender.kind === 'toolInvocationSerialized' || partToRender.kind === 'markdownContent' || partToRender.kind === 'textEditGroup' || partToRender.kind === 'hook') && this.shouldPinPart(partToRender, element)) {
+			if (lastThinking && (partToRender.kind === 'toolInvocation' || partToRender.kind === 'toolInvocationSerialized' || partToRender.kind === 'markdownContent' || partToRender.kind === 'textEditGroup' || partToRender.kind === 'hook') && this.shouldPinPart(partToRender, element) && !isFinalAnswerPart) {
 				const newPart = this.renderChatContentPart(partToRender, templateData, context);
 				if (newPart) {
 					renderedParts[contentIndex] = newPart;
@@ -1379,9 +1381,17 @@ export class ChatListItemRenderer extends Disposable implements ITreeRenderer<Ch
 
 	private diff(renderedParts: ReadonlyArray<IChatContentPart>, contentToRender: ReadonlyArray<IChatRendererContent>, element: ChatTreeItem): ReadonlyArray<IChatRendererContent | null> {
 		const diff: (IChatRendererContent | null)[] = [];
+		const elementIsComplete = isResponseVM(element) && element.isComplete;
+		const lastMarkdownContentIndex = contentToRender.findLastIndex(part => part.kind === 'markdownContent');
 		for (let i = 0; i < contentToRender.length; i++) {
 			const content = contentToRender[i];
 			const renderedPart = renderedParts[i];
+			const isFinalAnswerPart = content.kind === 'markdownContent' && i === lastMarkdownContentIndex && elementIsComplete;
+
+			if (isFinalAnswerPart && this.isRenderedPartInsideThinking(renderedPart)) {
+				diff.push(content);
+				continue;
+			}
 
 			if (!renderedPart || !renderedPart.hasSameContent(content, contentToRender.slice(i + 1), element)) {
 				diff.push(content);
@@ -1394,6 +1404,13 @@ export class ChatListItemRenderer extends Disposable implements ITreeRenderer<Ch
 		return diff;
 	}
 
+	private isRenderedPartInsideThinking(renderedPart: IChatContentPart | undefined): boolean {
+		if (!renderedPart?.domNode) {
+			return false;
+		}
+		return !!dom.findParentWithClass(renderedPart.domNode, 'chat-thinking-box');
+	}
+
 	private hasCodeblockUri(part: IChatRendererContent): boolean {
 		if (part.kind !== 'markdownContent') {
 			return false;