Enhance spam detection logic in contact form API

- Improved spam detection by integrating Gemini AI and heuristic checks, allowing for more accurate identification of spam messages.
- Updated logging to specify the source of spam detection (Gemini or heuristic) for better debugging and monitoring.
- Maintained existing functionality while enhancing the overall user experience in the contact form submission process.

src/pages/api/contact.ts

@@ -211,16 +211,20 @@ export const POST: APIRoute = async ({ request, clientAddress }) => {
       errors.disclaimer = 'Please check the required consent box before submitting';
     }
 
-    // Check for spam
-    if (isSpam(message, name, email)) {
-      errors.spam = 'Your message was flagged as potential spam. Please revise your message and try again.';
-    }
-
-    // Gemini AI spam detection
+    // Gemini AI spam detection FIRST
+    let spamDetected = false;
+    let spamReason = '';
     if (await isSpamWithGemini(message)) {
+      spamDetected = true;
+      spamReason = 'Gemini';
+    } else if (isSpam(message, name, email)) {
+      spamDetected = true;
+      spamReason = 'heuristic';
+    }
+    if (spamDetected) {
       const token = jwt.sign({ email, message }, MANUAL_REVIEW_SECRET, { expiresIn: '1h' });
       console.warn(
-        `[SPAM DETECTED by Gemini]`,
+        `[SPAM DETECTED by ${spamReason === 'Gemini' ? 'Gemini' : 'heuristic'}]`,
         { name, email, message, ip: request.headers.get('x-forwarded-for') }
       );
       return new Response(