Update ai-routes.js

ai-routes.js

@@ -445,10 +445,13 @@ router.post('/chat', async (req, res) => {
     const systemInstruction = await buildUserContext(username, userRole, schoolId);
 
     // Build History
-    const geminiHistory = (history || []).map(msg => ({
-        role: msg.role,
-        parts: [{ text: msg.text || '' }]
-    }));
+    // Filter out messages with empty text to prevent API errors
+    const geminiHistory = (history || [])
+        .filter(msg => msg.text && msg.text.trim() !== '')
+        .map(msg => ({
+            role: msg.role,
+            parts: [{ text: msg.text }]
+        }));
 
     // Build Current Message Parts
     const currentParts = [];
@@ -478,8 +481,11 @@ router.post('/chat', async (req, res) => {
     }
 
     // Add Text if any (must have text if no media, or can accompany media)
-    if (text) {
+    if (text && text.trim()) {
         currentParts.push({ text: text });
+    } else if (audio) {
+        // Fix: If sending audio without text, add a prompt so the model knows what to do
+        currentParts.push({ text: "请听这段语音并回答。" });
     } else if (currentParts.length === 0) {
         // Fallback if empty
         currentParts.push({ text: "." });