refactor: simplify chat fork flow

src/components/chat/AgentWorkspace.tsx

@@ -13,17 +13,12 @@ import { AgentTurn } from "./AgentTurn";
 import { TypingIndicator } from "./GlobalChatbox.parts";
 import type { PermissionReply } from "@/lib/chatStream";
 import type {
-  BranchGroup,
-  BranchState,
-  BranchTransition,
   Message,
   SpeechState,
 } from "./GlobalChatbox.types";
 
 type AgentWorkspaceProps = {
   messages: Message[];
-  branchGroups: BranchGroup[];
-  branchTransition: BranchTransition | null;
   isStreaming: boolean;
   bottomRef: React.RefObject<HTMLDivElement | null>;
   speakingMessageId: string | null;
@@ -33,15 +28,13 @@ type AgentWorkspaceProps = {
   onResumeSpeech: () => void;
   onStopSpeech: () => void;
   isTtsSupported: boolean;
-  onRegenerate: () => void;
-  onEditResubmit: (messageId: string, newContent: string) => void;
-  onCycleBranch: (rootMessageId: string, direction: -1 | 1) => void;
+  onRegenerate: (messageId: string) => void;
+  onCreateBranch: (messageId: string) => void;
   onReplyPermission: (requestId: string, reply: PermissionReply) => void;
 };
 
 type TurnListProps = {
   messages: Message[];
-  branchGroups: BranchGroup[];
   speakingMessageId: string | null;
   speechState: SpeechState;
   onSpeak: (messageId: string, text: string) => void;
@@ -49,9 +42,8 @@ type TurnListProps = {
   onResumeSpeech: () => void;
   onStopSpeech: () => void;
   isTtsSupported: boolean;
-  onRegenerate: () => void;
-  onEditResubmit: (messageId: string, newContent: string) => void;
-  onCycleBranch: (rootMessageId: string, direction: -1 | 1) => void;
+  onRegenerate: (messageId: string) => void;
+  onCreateBranch: (messageId: string) => void;
   onReplyPermission: (requestId: string, reply: PermissionReply) => void;
 };
 
@@ -61,7 +53,6 @@ const sameMessages = (left: Message[], right: Message[]) =>
 
 const TurnListInner = ({
   messages,
-  branchGroups,
   speakingMessageId,
   speechState,
   onSpeak,
@@ -70,45 +61,26 @@ const TurnListInner = ({
   onStopSpeech,
   isTtsSupported,
   onRegenerate,
-  onEditResubmit,
-  onCycleBranch,
+  onCreateBranch,
   onReplyPermission,
 }: TurnListProps) => {
-  const branchStateByRootId = React.useMemo(() => {
-    const next = new Map<string, BranchState>();
-    branchGroups.forEach((group) => {
-      if (group.branches.length > 1) {
-        next.set(group.rootMessageId, {
-          activeIndex: group.activeIndex,
-          total: group.branches.length,
-        });
-      }
-    });
-    return next;
-  }, [branchGroups]);
-
   return (
     <>
-      {messages.map((message) => {
-        const rootMessageId = message.branchRootId ?? message.id;
-        return (
-          <AgentTurn
-            key={rootMessageId}
-            message={message}
-            branchState={branchStateByRootId.get(rootMessageId)}
-            messageSpeechState={speakingMessageId === message.id ? speechState : "idle"}
-            onSpeak={onSpeak}
-            onPause={onPauseSpeech}
-            onResume={onResumeSpeech}
-            onStopSpeech={onStopSpeech}
-            isTtsSupported={isTtsSupported}
-            onRegenerate={onRegenerate}
-            onEditResubmit={onEditResubmit}
-            onCycleBranch={onCycleBranch}
-            onReplyPermission={onReplyPermission}
-          />
-        );
-      })}
+      {messages.map((message) => (
+        <AgentTurn
+          key={message.id}
+          message={message}
+          messageSpeechState={speakingMessageId === message.id ? speechState : "idle"}
+          onSpeak={onSpeak}
+          onPause={onPauseSpeech}
+          onResume={onResumeSpeech}
+          onStopSpeech={onStopSpeech}
+          isTtsSupported={isTtsSupported}
+          onRegenerate={onRegenerate}
+          onCreateBranch={onCreateBranch}
+          onReplyPermission={onReplyPermission}
+        />
+      ))}
     </>
   );
 };
@@ -117,7 +89,6 @@ const TurnList = React.memo(
   TurnListInner,
   (prevProps, nextProps) =>
     sameMessages(prevProps.messages, nextProps.messages) &&
-    prevProps.branchGroups === nextProps.branchGroups &&
     prevProps.speakingMessageId === nextProps.speakingMessageId &&
     prevProps.speechState === nextProps.speechState &&
     prevProps.onSpeak === nextProps.onSpeak &&
@@ -126,8 +97,7 @@ const TurnList = React.memo(
     prevProps.onStopSpeech === nextProps.onStopSpeech &&
     prevProps.isTtsSupported === nextProps.isTtsSupported &&
     prevProps.onRegenerate === nextProps.onRegenerate &&
-    prevProps.onEditResubmit === nextProps.onEditResubmit &&
-    prevProps.onCycleBranch === nextProps.onCycleBranch &&
+    prevProps.onCreateBranch === nextProps.onCreateBranch &&
     prevProps.onReplyPermission === nextProps.onReplyPermission,
 );
 
@@ -249,8 +219,6 @@ const EmptyState = () => {
 
 export const AgentWorkspace = ({
   messages,
-  branchGroups,
-  branchTransition,
   isStreaming,
   bottomRef,
   speakingMessageId,
@@ -261,8 +229,7 @@ export const AgentWorkspace = ({
   onStopSpeech,
   isTtsSupported,
   onRegenerate,
-  onEditResubmit,
-  onCycleBranch,
+  onCreateBranch,
   onReplyPermission,
 }: AgentWorkspaceProps) => {
   const theme = useTheme();
@@ -274,18 +241,12 @@ export const AgentWorkspace = ({
     (!latestAssistant ||
       (latestAssistant.content.trim().length === 0 &&
         !(latestAssistant.artifacts?.length)));
-  const stableMessages = branchTransition
-    ? messages.slice(0, branchTransition.parentCount)
-    : messages;
-  const transitionMessages = branchTransition
-    ? messages.slice(branchTransition.parentCount)
-    : [];
   const streamingMessage =
-    !branchTransition && isStreaming && messages.at(-1)?.role === "assistant"
+    isStreaming && messages.at(-1)?.role === "assistant"
       ? messages.at(-1)
       : undefined;
   const historyMessages =
-    streamingMessage !== undefined ? messages.slice(0, -1) : stableMessages;
+    streamingMessage !== undefined ? messages.slice(0, -1) : messages;
 
   return (
     <Box
@@ -307,7 +268,6 @@ export const AgentWorkspace = ({
         <Box sx={{ display: "flex", flexDirection: "column", gap: 2 }}>
           <TurnList
             messages={historyMessages}
-            branchGroups={branchGroups}
             speakingMessageId={speakingMessageId}
             speechState={speechState}
             onSpeak={onSpeak}
@@ -316,15 +276,13 @@ export const AgentWorkspace = ({
             onStopSpeech={onStopSpeech}
             isTtsSupported={isTtsSupported}
             onRegenerate={onRegenerate}
-            onEditResubmit={onEditResubmit}
-            onCycleBranch={onCycleBranch}
+            onCreateBranch={onCreateBranch}
             onReplyPermission={onReplyPermission}
           />
 
           {streamingMessage ? (
             <TurnList
               messages={[streamingMessage]}
-              branchGroups={branchGroups}
               speakingMessageId={speakingMessageId}
               speechState={speechState}
               onSpeak={onSpeak}
@@ -333,40 +291,10 @@ export const AgentWorkspace = ({
               onStopSpeech={onStopSpeech}
               isTtsSupported={isTtsSupported}
               onRegenerate={onRegenerate}
-              onEditResubmit={onEditResubmit}
-              onCycleBranch={onCycleBranch}
+              onCreateBranch={onCreateBranch}
               onReplyPermission={onReplyPermission}
             />
           ) : null}
-
-          {branchTransition ? (
-            <AnimatePresence initial={false} mode="wait">
-              <motion.div
-                key={`${branchTransition.rootMessageId}:${branchTransition.activeBranchId}:${branchTransition.nonce}`}
-                initial={{ opacity: 0, y: 8 }}
-                animate={{ opacity: 1, y: 0 }}
-                exit={{ opacity: 0, y: -8 }}
-                transition={{ duration: 0.18, ease: "easeOut" }}
-                style={{ display: "flex", flexDirection: "column", gap: 16 }}
-              >
-                <TurnList
-                  messages={transitionMessages}
-                  branchGroups={branchGroups}
-                  speakingMessageId={speakingMessageId}
-                  speechState={speechState}
-                  onSpeak={onSpeak}
-                  onPauseSpeech={onPauseSpeech}
-                  onResumeSpeech={onResumeSpeech}
-                  onStopSpeech={onStopSpeech}
-                  isTtsSupported={isTtsSupported}
-                  onRegenerate={onRegenerate}
-                  onEditResubmit={onEditResubmit}
-                  onCycleBranch={onCycleBranch}
-                  onReplyPermission={onReplyPermission}
-                />
-              </motion.div>
-            </AnimatePresence>
-          ) : null}
         </Box>
       ) : null}