Create endpoint for google oauth, generate JWT token, save to DB by email

src/main/java/com/faf223/expensetrackerfaf/service/AuthenticationService.java

@@ -17,6 +17,7 @@ import org.springframework.security.authentication.AuthenticationManager;
 import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
 import org.springframework.security.core.userdetails.UserDetails;
 import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.security.oauth2.core.user.OAuth2User;
 import org.springframework.stereotype.Service;
 
 import java.util.Optional;
@@ -30,6 +31,7 @@ public class AuthenticationService {
     private final PasswordEncoder passwordEncoder;
     private final JwtService jwtService;
     private final AuthenticationManager authenticationManager;
+    private final PasswordGenerator passwordGenerator;
 
     public AuthenticationResponse register(RegisterRequest request) {
 
@@ -53,6 +55,58 @@ public class AuthenticationService {
                 .build();
     }
 
+    public AuthenticationResponse register(OAuth2User oAuth2User) {
+        String userEmail = oAuth2User.getAttribute("email");
+
+        // Check if the user is already registered
+        Optional<Credential> existingCredential = credentialRepository.findByEmail(userEmail);
+        if (existingCredential.isPresent()) {
+            UserDetails userDetails = new PersonDetails(existingCredential.get());
+            String jwtToken = jwtService.generateToken(userDetails);
+            String refreshToken = jwtService.generateRefreshToken(userDetails);
+
+            return AuthenticationResponse.builder()
+                    .accessToken(jwtToken)
+                    .refreshToken(refreshToken)
+                    .build();
+        }
+
+        // Extract user details from OAuth2User
+        String givenName = oAuth2User.getAttribute("given_name");
+        String familyName = oAuth2User.getAttribute("family_name");
+        String email = oAuth2User.getAttribute("email");
+
+        // Create a new User entity and save it to the database
+        User user = User.builder()
+                .firstName(givenName)
+                .lastName(familyName)
+                .username(email) // You can adjust the username as needed
+                .build();
+
+        String randomPassword = passwordGenerator.generateRandomPassword(8);
+
+        user.setPassword(passwordEncoder.encode(randomPassword));
+
+        userRepository.save(user);
+        Credential credential = new Credential(user, email, passwordEncoder.encode(randomPassword));
+        credentialRepository.save(credential);
+
+        UserDetails userDetails = new PersonDetails(credential);
+        String jwtToken = jwtService.generateToken(userDetails);
+        String refreshToken = jwtService.generateRefreshToken(userDetails);
+
+        System.out.println("New user: " + user);
+        System.out.println("New credentials: " + credential);
+
+        // Return the registered user's authentication response
+        return AuthenticationResponse.builder()
+                .accessToken(jwtToken)
+                .refreshToken(refreshToken)
+                .build();
+    }
+
+
+
     public AuthenticationResponse authenticate(AuthenticationRequest request) {
         authenticationManager.authenticate(new UsernamePasswordAuthenticationToken(request.getEmail(), request.getPassword()));
 

src/main/java/com/faf223/expensetrackerfaf/service/PasswordGenerator.java

@@ -0,0 +1,18 @@
+package com.faf223.expensetrackerfaf.service;
+
+import org.springframework.stereotype.Service;
+
+import java.security.SecureRandom;
+import java.util.Base64;
+
+@Service
+public class PasswordGenerator {
+
+    private final SecureRandom secureRandom = new SecureRandom();
+
+    public String generateRandomPassword(int length) {
+        byte[] randomBytes = new byte[length];
+        secureRandom.nextBytes(randomBytes);
+        return Base64.getUrlEncoder().withoutPadding().encodeToString(randomBytes);
+    }
+}