feat: add Replay Mode

web/src/app/_components/messages-block.tsx

@@ -1,8 +1,15 @@
 // Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
 // SPDX-License-Identifier: MIT
 
+import { useSearchParams } from "next/navigation";
 import { useCallback, useRef, useState } from "react";
 
+import {
+  Card,
+  CardDescription,
+  CardHeader,
+  CardTitle,
+} from "~/components/ui/card";
 import type { Option } from "~/core/messages";
 import { sendMessage, useStore } from "~/core/store";
 import { cn } from "~/lib/utils";
@@ -10,10 +17,12 @@ import { cn } from "~/lib/utils";
 import { ConversationStarter } from "./conversation-starter";
 import { InputBox } from "./input-box";
 import { MessageListView } from "./message-list-view";
+import { RainbowText } from "./rainbow-text";
 
 export function MessagesBlock({ className }: { className?: string }) {
   const messageCount = useStore((state) => state.messageIds.length);
   const responding = useStore((state) => state.responding);
+  const replaying = useSearchParams().get("replay") !== null;
   const abortControllerRef = useRef<AbortController | null>(null);
   const [feedback, setFeedback] = useState<{ option: Option } | null>(null);
   const handleSend = useCallback(
@@ -56,22 +65,39 @@ export function MessagesBlock({ className }: { className?: string }) {
         onFeedback={handleFeedback}
         onSendMessage={handleSend}
       />
-      <div className="relative flex h-42 shrink-0 pb-4">
-        {!responding && messageCount === 0 && (
-          <ConversationStarter
-            className="absolute top-[-218px] left-0"
+      {!replaying ? (
+        <div className="relative flex h-42 shrink-0 pb-4">
+          {!responding && messageCount === 0 && (
+            <ConversationStarter
+              className="absolute top-[-218px] left-0"
+              onSend={handleSend}
+            />
+          )}
+          <InputBox
+            className="h-full w-full"
+            responding={responding}
+            feedback={feedback}
             onSend={handleSend}
+            onCancel={handleCancel}
+            onRemoveFeedback={handleRemoveFeedback}
           />
-        )}
-        <InputBox
-          className="h-full w-full"
-          responding={responding}
-          feedback={feedback}
-          onSend={handleSend}
-          onCancel={handleCancel}
-          onRemoveFeedback={handleRemoveFeedback}
-        />
-      </div>
+        </div>
+      ) : (
+        <div className="flex h-42 w-full items-center justify-center">
+          <Card className="w-full">
+            <CardHeader>
+              <CardTitle>
+                <RainbowText animated={responding}>Replay Mode</RainbowText>
+              </CardTitle>
+              <CardDescription>
+                <RainbowText animated={responding}>
+                  DeerFlow is now replaying the conversation...
+                </RainbowText>
+              </CardDescription>
+            </CardHeader>
+          </Card>
+        </div>
+      )}
     </div>
   );
 }

web/src/app/page.tsx

@@ -5,10 +5,11 @@
 
 import { GithubOutlined } from "@ant-design/icons";
 import Link from "next/link";
-import { useMemo } from "react";
+import { useEffect, useMemo } from "react";
 
 import { Button } from "~/components/ui/button";
-import { useStore } from "~/core/store";
+import { useReplay } from "~/core/replay";
+import { sendMessage, useStore } from "~/core/store";
 import { cn } from "~/lib/utils";
 
 import { Logo } from "./_components/logo";
@@ -19,11 +20,17 @@ import { Tooltip } from "./_components/tooltip";
 import { SettingsDialog } from "./_settings/dialogs/settings-dialog";
 
 export default function HomePage() {
+  const { isReplay } = useReplay();
   const openResearchId = useStore((state) => state.openResearchId);
   const doubleColumnMode = useMemo(
     () => openResearchId !== null,
     [openResearchId],
   );
+  useEffect(() => {
+    if (isReplay) {
+      void sendMessage();
+    }
+  }, [isReplay]);
   return (
     <div className="flex h-full w-full justify-center">
       <header className="fixed top-0 left-0 flex h-12 w-full w-screen items-center justify-between px-4">