feat: support message creation from url query (#960)

components/chat.tsx

@@ -2,7 +2,7 @@
 
 import type { Attachment, UIMessage } from 'ai';
 import { useChat } from '@ai-sdk/react';
-import { useState } from 'react';
+import { useEffect, useState } from 'react';
 import useSWR, { useSWRConfig } from 'swr';
 import { ChatHeader } from '@/components/chat-header';
 import type { Vote } from '@/lib/db/schema';
@@ -16,6 +16,7 @@ import { unstable_serialize } from 'swr/infinite';
 import { getChatHistoryPaginationKey } from './sidebar-history';
 import { toast } from './toast';
 import type { Session } from 'next-auth';
+import { useSearchParams } from 'next/navigation';
 
 export function Chat({
   id,
@@ -66,6 +67,23 @@ export function Chat({
     },
   });
 
+  const searchParams = useSearchParams();
+  const query = searchParams.get('query');
+
+  const [hasAppendedQuery, setHasAppendedQuery] = useState(false);
+
+  useEffect(() => {
+    if (query && !hasAppendedQuery) {
+      append({
+        role: 'user',
+        content: query,
+      });
+
+      setHasAppendedQuery(true);
+      window.history.replaceState({}, '', `/chat/${id}`);
+    }
+  }, [query, append, hasAppendedQuery, id]);
+
   const { data: votes } = useSWR<Array<Vote>>(
     messages.length >= 2 ? `/api/vote?chatId=${id}` : null,
     fetcher,