Authentication

Added JWT-token generation and verification into backend. When a user logs in or signs up it should generate a token.

src/main/java/ntnu/idatt2105/group44/trivioServer/config/AppConfig.java

+package ntnu.idatt2105.group44.trivioServer.config;
+
+import java.util.Collection;
+import java.util.Collections;
+import lombok.RequiredArgsConstructor;
+import ntnu.idatt2105.group44.trivioServer.exception.UserNotFoundException;
+import ntnu.idatt2105.group44.trivioServer.model.Role;
+import ntnu.idatt2105.group44.trivioServer.repository.UserRepository;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.security.core.GrantedAuthority;
+import org.springframework.security.core.authority.SimpleGrantedAuthority;
+import org.springframework.security.core.userdetails.User;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.core.userdetails.UserDetailsService;
+import org.springframework.security.core.userdetails.UsernameNotFoundException;
+import org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder;
+import org.springframework.security.crypto.password.PasswordEncoder;
+
+@RequiredArgsConstructor
+@Configuration
+public class AppConfig {
+
+  private final UserRepository userRepository;
+
+  @Bean
+  public UserDetailsService userDetailsService() {
+    return id -> {
+      // Load user details from the database using UserRepository
+      ntnu.idatt2105.group44.trivioServer.model.User user = userRepository.findById(Long.valueOf(id)).orElseThrow(() -> new UserNotFoundException(id));
+      if (user == null) {
+        throw new UsernameNotFoundException("User not found");
+      }
+
+      // Create UserDetails object from loaded user details
+      return User.builder()
+          .username(user.getUsername())
+          .password(user.getPassword())
+          .authorities(mapRolesToAuthorities(user.getRole()))
+          .build();
+    };
+  }
+  // Helper method to map roles to authorities
+  private Collection<? extends GrantedAuthority> mapRolesToAuthorities(Role role) {
+    return Collections.singletonList(new SimpleGrantedAuthority("ROLE_" + role));
+  }
+
+}