feat: implement email sending functionality with SMTP and Resend fallback

- Added support for sending emails using SMTP configuration or Resend API as a fallback.
- Updated environment variables in .env_example for SMTP settings.
- Enhanced email confirmation process with improved error handling and fallback logic.
- Introduced a test script to validate email sending configuration and functionality.

viewer-frontend/scripts/test-email-sending.ts

@@ -1,4 +1,5 @@
 import { Resend } from 'resend';
+import nodemailer from 'nodemailer';
 import * as dotenv from 'dotenv';
 
 // Load environment variables
@@ -6,63 +7,96 @@ dotenv.config();
 
 const resend = new Resend(process.env.RESEND_API_KEY);
 
+function smtpEnabled(): boolean {
+  return Boolean(
+    process.env.SMTP_HOST &&
+      process.env.SMTP_USER &&
+      process.env.SMTP_PASS
+  );
+}
+
 async function testEmailSending() {
   console.log('🧪 Testing email sending configuration...\n');
   
   // Check environment variables
   console.log('📋 Environment Variables:');
+  console.log('  EMAIL_PROVIDER:', process.env.EMAIL_PROVIDER || 'smtp (default)');
+  console.log('  SMTP_HOST:', process.env.SMTP_HOST || '❌ NOT SET');
+  console.log('  SMTP_PORT:', process.env.SMTP_PORT || '465 (default)');
+  console.log('  SMTP_SECURE:', process.env.SMTP_SECURE || 'true (default)');
+  console.log('  SMTP_USER:', process.env.SMTP_USER || '❌ NOT SET');
+  console.log('  SMTP_FROM_EMAIL:', process.env.SMTP_FROM_EMAIL || '❌ NOT SET');
   console.log('  RESEND_API_KEY:', process.env.RESEND_API_KEY ? `${process.env.RESEND_API_KEY.substring(0, 10)}...` : '❌ NOT SET');
   console.log('  RESEND_FROM_EMAIL:', process.env.RESEND_FROM_EMAIL || '❌ NOT SET');
   console.log('  NEXTAUTH_URL:', process.env.NEXTAUTH_URL || '❌ NOT SET');
   console.log('');
-  
-  if (!process.env.RESEND_API_KEY) {
-    console.error('❌ RESEND_API_KEY is not set in .env file');
+
+  const toEmail = process.env.TEST_EMAIL_TO || process.env.SMTP_USER || process.env.RESEND_FROM_EMAIL;
+  if (!toEmail) {
+    console.error('❌ Set TEST_EMAIL_TO or SMTP_USER in .env to run this test.');
     process.exit(1);
   }
-  
-  if (!process.env.RESEND_FROM_EMAIL) {
-    console.error('❌ RESEND_FROM_EMAIL is not set in .env file');
+
+  if (smtpEnabled()) {
+    console.log('📤 Attempting SMTP test first...');
+    try {
+      const transporter = nodemailer.createTransport({
+        host: process.env.SMTP_HOST,
+        port: Number(process.env.SMTP_PORT || 465),
+        secure: (process.env.SMTP_SECURE || 'true').toLowerCase() === 'true',
+        auth: {
+          user: process.env.SMTP_USER,
+          pass: process.env.SMTP_PASS,
+        },
+      });
+
+      const smtpFromEmail = process.env.SMTP_FROM_EMAIL || process.env.SMTP_USER!;
+      const smtpFromName = process.env.SMTP_FROM_NAME;
+      const smtpReplyTo = process.env.SMTP_REPLY_TO || smtpFromEmail;
+      const smtpFrom = smtpFromName
+        ? `${smtpFromName} <${smtpFromEmail}>`
+        : smtpFromEmail;
+
+      const info = await transporter.sendMail({
+        from: smtpFrom,
+        to: toEmail,
+        replyTo: smtpReplyTo,
+        subject: 'SMTP test from PunimTag',
+        text: 'SMTP test email from PunimTag viewer frontend.',
+      });
+
+      console.log('✅ SMTP test sent successfully');
+      console.log('   Message ID:', info.messageId);
+      process.exit(0);
+    } catch (smtpError: any) {
+      console.error('⚠️  SMTP test failed, will try Resend fallback.');
+      console.error('   SMTP error:', smtpError.message);
+    }
+  } else {
+    console.log('ℹ️  SMTP config not set, skipping SMTP test.');
+  }
+
+  if (!process.env.RESEND_API_KEY || !process.env.RESEND_FROM_EMAIL) {
+    console.error('❌ Resend fallback not configured (RESEND_API_KEY/RESEND_FROM_EMAIL missing).');
     process.exit(1);
   }
-  
-  // Clean up the from email (remove quotes and spaces)
-  const fromEmail = process.env.RESEND_FROM_EMAIL.trim().replace(/^["']|["']$/g, '');
-  console.log('📧 Using FROM email:', fromEmail);
-  console.log('');
-  
-  // Test email sending
-  console.log('📤 Attempting to send test email...');
+
+  const resendFrom = process.env.RESEND_FROM_EMAIL.trim().replace(/^["']|["']$/g, '');
+  console.log('📤 Attempting Resend fallback test...');
   try {
     const result = await resend.emails.send({
-      from: fromEmail,
-      to: 'test@example.com', // This will fail but we'll see the error
-      subject: 'Test Email',
-      html: '<p>This is a test email</p>',
+      from: resendFrom,
+      to: toEmail,
+      subject: 'Resend fallback test from PunimTag',
+      html: '<p>Resend fallback test email from PunimTag viewer frontend.</p>',
     });
-    
-    console.log('✅ Email API call successful!');
-    console.log('Response:', JSON.stringify(result, null, 2));
+    if (result.error) {
+      throw new Error(result.error.message || 'Unknown Resend API error');
+    }
+    console.log('✅ Resend fallback test sent successfully');
+    console.log('   Email ID:', result.data?.id);
   } catch (error: any) {
-    console.error('❌ Error sending email:');
-    console.error('  Message:', error.message);
-    if (error.response) {
-      console.error('  Response:', JSON.stringify(error.response, null, 2));
-    }
-    
-    // Check for common errors
-    if (error.message?.includes('domain')) {
-      console.error('\n⚠️  Domain verification issue:');
-      console.error('  The email domain needs to be verified in Resend dashboard');
-      console.error('  For testing, use: onboarding@resend.dev');
-    }
-    
-    if (error.message?.includes('unauthorized') || error.message?.includes('Invalid API key')) {
-      console.error('\n⚠️  API Key issue:');
-      console.error('  Check that your RESEND_API_KEY is correct');
-      console.error('  Get a new key from: https://resend.com/api-keys');
-    }
-    
+    console.error('❌ Resend fallback failed:', error.message);
     process.exit(1);
   }
 }