added more checks to email verif

src/main/java/com/example/demo/controller/EmailController.java

@@ -20,16 +20,22 @@ public class EmailController {
     @Autowired
     private EmailService emailService;
     
+    @PostMapping("/check")
+    public ResponseEntity<?> check(@RequestParam String email){
+    	if (emailService.isValidEmail(email) == false) {
+            return ResponseEntity.status(429).body("Invalid Email Detected.");
+        }
+    	 return ResponseEntity.ok().build();
+    }
 
     @PostMapping("/send")
     public ResponseEntity<?> send(@RequestParam String email) {
-
+        try {
-        if (!otpStore.canResend(email)) {
-            return ResponseEntity.status(429).body("Please wait before requesting another code.");
-        }
-
             emailService.sendOtpEmail(email);
             return ResponseEntity.ok().build();
+        } catch (RuntimeException e) {
+            return ResponseEntity.status(500).body("Failed to send verification email.");
+        }
     }
 
     

src/main/java/com/example/demo/service/EmailService.java

@@ -1,9 +1,18 @@
 package com.example.demo.service;
 
+import java.util.Hashtable;
+
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.mail.MailException;
 import org.springframework.mail.SimpleMailMessage;
 import org.springframework.mail.javamail.JavaMailSender;
 import org.springframework.stereotype.Service;
+import javax.naming.directory.Attributes;
+import javax.naming.directory.DirContext;
+import javax.naming.directory.InitialDirContext;
+
+import jakarta.mail.internet.AddressException;
+import jakarta.mail.internet.InternetAddress;
 
 @Service
 public class EmailService {
@@ -29,6 +38,45 @@ public class EmailService {
             "The Thyme Crunch Team"
         );
 
+        try {
             mailSender.send(message);
+        } catch (MailException e) {
+            otpStore.clear(toEmail);
+            throw new RuntimeException("Failed to send email to: " + toEmail, e);
+        }
+    }
+    
+    public boolean isValidEmail(String email) {
+        if (email == null || email.isBlank()) return false;
+
+        String emailRegex = "^[A-Za-z0-9+_.-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,}$";
+        if (!email.matches(emailRegex)) return false;
+
+        try {
+            InternetAddress emailAddr = new InternetAddress(email, true);
+            emailAddr.validate();
+        } catch (AddressException ex) {
+            return false;
+        }
+
+        String domain = email.substring(email.indexOf('@') + 1);
+        return hasMxRecord(domain);
+    }
+    
+
+private boolean hasMxRecord(String domain) {
+    try {
+        Hashtable<String, String> env = new Hashtable<>();
+        env.put("java.naming.factory.initial", "com.sun.jndi.dns.DnsContextFactory");
+        env.put("java.naming.provider.url", "dns:");
+        env.put("com.sun.jndi.dns.timeout.initial", "2000");
+        env.put("com.sun.jndi.dns.timeout.retries", "1");
+
+        DirContext ctx = new InitialDirContext(env);
+        Attributes attrs = ctx.getAttributes(domain, new String[]{"MX"});
+        return attrs.get("MX") != null;
+    } catch (Exception e) {
+        return false;
     }
 }
+}

src/main/resources/templates/create-account.html

@@ -146,6 +146,18 @@ function isProfane(str) {
             const csrfHeader = document.querySelector('meta[name="_csrf_header"]').getAttribute('content');
 
             try {
+                const checkResponse = await fetch(`/api/email/check?email=${encodeURIComponent(email)}`, {
+                    method: "POST",
+                    headers: { [csrfHeader]: csrfToken }
+                });
+
+                if (!checkResponse.ok) {
+                    const errorText = await checkResponse.text();
+                    passwordError.style.color = "red";
+                    passwordError.textContent = errorText || "Invalid Email Detected.";
+                    return;
+                }
+
                 sessionStorage.setItem("pendingEmail", email);
                 sessionStorage.setItem("pendingUser", JSON.stringify({
                     username: name,
@@ -154,11 +166,17 @@ function isProfane(str) {
                     role: "ROLE_USER"
                 }));
 
-                await fetch(`/api/email/send?email=${encodeURIComponent(email)}`, {
+                const sendResponse = await fetch(`/api/email/send?email=${encodeURIComponent(email)}`, {
                     method: "POST",
                     headers: { [csrfHeader]: csrfToken }
                 });
                 
+                if (!sendResponse.ok) {
+                    passwordError.style.color = "red";
+                    passwordError.textContent = "Failed to send verification email. Please check your address.";
+                    return;
+                }
+
                 passwordError.style.color = "green";
                 passwordError.textContent = "Check your email for a verification code...";
                 setTimeout(function () {
@@ -171,6 +189,6 @@ function isProfane(str) {
                 console.error("Request error:", error);
             }
         }); 
-
     });   
+
 </script>