fix: submit to Brevo directly via fetch, remove API route

Co-authored-by: bobbyiliev <21223421+bobbyiliev@users.noreply.github.com>

Author: Copilot

app/api/newsletter/route.ts

@@ -5,6 +5,7 @@ import { motion, AnimatePresence } from 'framer-motion'
 import { BookOpen, X, Sparkles } from 'lucide-react'
 import { Button } from '@/components/ui/button'
 import Confetti from 'react-confetti'
+import { EMAIL_RE, submitToBrevo } from '@/lib/newsletter'
 
 export function BookPromotionPopup() {
   const [isVisible, setIsVisible] = useState(false)
@@ -63,14 +64,10 @@ export function BookPromotionPopup() {
   const handleSubscribe = async (e: React.FormEvent<HTMLFormElement>) => {
     e.preventDefault();
 
-    if (!email) return;
+    if (!email || !EMAIL_RE.test(email)) return;
 
     try {
-      await fetch('/api/newsletter', {
-        method: 'POST',
-        headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({ email }),
-      });
+      await submitToBrevo(email);
     } catch (err) {
       console.error('[newsletter] Popup subscription error:', err);
       // Proceed optimistically – show thank you regardless

components/book-promotion-popup.tsx

@@ -1,11 +1,10 @@
 'use client';
 
 import { useState } from 'react';
+import { EMAIL_RE, submitToBrevo } from '@/lib/newsletter';
 
 export type SubscribeStatus = 'idle' | 'loading' | 'success' | 'error';
 
-const EMAIL_RE = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
-
 export function useNewsletterSubscribe() {
   const [status, setStatus] = useState<SubscribeStatus>('idle');
 
@@ -16,12 +15,8 @@ export function useNewsletterSubscribe() {
     }
     setStatus('loading');
     try {
-      const res = await fetch('/api/newsletter', {
-        method: 'POST',
-        headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({ email }),
-      });
-      setStatus(res.ok ? 'success' : 'error');
+      await submitToBrevo(email);
+      setStatus('success');
     } catch {
       setStatus('error');
     }

hooks/use-newsletter-subscribe.ts

@@ -1,3 +1,24 @@
 /** Brevo subscription form URL. Public — safe to commit, no env var needed. */
 export const BREVO_FORM_URL =
   'https://66ce6dcc.sibforms.com/serve/MUIFABg_VUzhY-5kln8REbgjz0epYq6FtPckqwqsIG_s4FKBiVUqR9Q5SakKep9c2cHa2NEC1J02ps4tMUbaxssoB7MvwSggRvWktJJ7-LM9oWVRG3h0KhFHXsNOgoCSEo9OTB_CIp8JyRlALoSmEQOGpRoVYIYEq2LD0ikQ6T56zXVF8ZNc3tFBykMZGOxtLEfD7tap75LwptWPxg==';
+
+export const EMAIL_RE = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
+
+/**
+ * Submit an email to the Brevo hosted subscription form.
+ * Uses mode:'no-cors' because Brevo's endpoint doesn't emit CORS headers.
+ * The response is opaque, so any non-throwing fetch is treated as success.
+ */
+export async function submitToBrevo(email: string): Promise<void> {
+  const body = new URLSearchParams({
+    EMAIL: email.trim(),
+    email_address_check: '',
+    locale: 'en',
+  });
+  await fetch(BREVO_FORM_URL, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
+    body: body.toString(),
+    mode: 'no-cors',
+  });
+}