feat(backend): refactor chat stream logic into useChatStream hook and remove unused chatStream utility

Author: NarwhalChen

frontend/src/hooks/useChatStream.ts

@@ -4,7 +4,6 @@ import { CREATE_CHAT } from '@/graphql/request';
 import { Message } from '@/const/MessageType';
 import { toast } from 'sonner';
 import { logger } from '@/app/log/logger';
-import { startChatStream } from '@/utils/chatStream';
 import { useAuthContext } from '@/providers/AuthProvider';
 
 interface UseChatStreamProps {
@@ -63,14 +62,84 @@ export const useChatStream = ({
     },
   });
 
+  const startChatStream = async (
+    targetChatId: string,
+    message: string,
+    model: string,
+    stream: boolean = false // Default to non-streaming for better performance
+  ): Promise<string> => {
+    if (!token) {
+      throw new Error('Not authenticated');
+    }
+
+    const response = await fetch('/api/chat', {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json',
+        Authorization: `Bearer ${token}`,
+      },
+      body: JSON.stringify({
+        chatId: targetChatId,
+        message,
+        model,
+        stream,
+      }),
+    });
+
+    if (!response.ok) {
+      throw new Error(
+        `Network response was not ok: ${response.status} ${response.statusText}`
+      );
+    }
+    // TODO: Handle streaming responses properly
+    // if (stream) {
+    //   // For streaming responses, aggregate the streamed content
+    //   let fullContent = '';
+    //   const reader = response.body?.getReader();
+    //   if (!reader) {
+    //     throw new Error('No reader available');
+    //   }
+
+    //   while (true) {
+    //     const { done, value } = await reader.read();
+    //     if (done) break;
+
+    //     const text = new TextDecoder().decode(value);
+    //     const lines = text.split('\n\n');
+
+    //     for (const line of lines) {
+    //       if (line.startsWith('data: ')) {
+    //         const data = line.slice(5);
+    //         if (data === '[DONE]') break;
+    //         try {
+    //           const { content } = JSON.parse(data);
+    //           if (content) {
+    //             fullContent += content;
+    //           }
+    //         } catch (e) {
+    //           console.error('Error parsing SSE data:', e);
+    //         }
+    //       }
+    //     }
+    //   }
+    //   return fullContent;
+    // } else {
+    //   // For non-streaming responses, return the content directly
+    //   const data = await response.json();
+    //   return data.content;
+    // }
+
+    const data = await response.json();
+    return data.content;
+  };
+
   const handleChatResponse = async (targetChatId: string, message: string) => {
     try {
       setInput('');
       const response = await startChatStream(
         targetChatId,
         message,
-        selectedModel,
-        token
+        selectedModel
       );
 
       setMessages((prev) => [
@@ -147,5 +216,6 @@ export const useChatStream = ({
     stop,
     isStreaming: loadingSubmit,
     currentChatId,
+    startChatStream,
   };
 };