refactor(core): reorganize code and implement logging

application/src/main/java/com/pablotj/restemailbridge/application/usecase/SendEmailUseCase.java

@@ -5,20 +5,47 @@ import com.pablotj.restemailbridge.application.port.EmailConfigurationPort;
 import com.pablotj.restemailbridge.domain.model.Email;
 import com.pablotj.restemailbridge.domain.repository.EmailRepository;
 import com.pablotj.restemailbridge.domain.service.EmailService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
+/**
+ * Use case for sending emails.
+ * <p>
+ * Retrieves the default recipient from EmailConfigurationPort, sends the email using EmailService,
+ * and persists it via EmailRepository.
+ */
 public class SendEmailUseCase {
+
+    private static final Logger log = LoggerFactory.getLogger(SendEmailUseCase.class);
+
     private final EmailConfigurationPort emailConfigurationPort;
     private final EmailService emailService;
     private final EmailRepository emailRepository;
 
-    public SendEmailUseCase(EmailConfigurationPort emailConfigurationPort, EmailService emailService, EmailRepository emailRepository) {
+    /**
+     * Constructor injecting required ports.
+     *
+     * @param emailConfigurationPort Port to retrieve configuration
+     * @param emailService           Service to send emails
+     * @param emailRepository        Repository to persist emails
+     */
+    public SendEmailUseCase(EmailConfigurationPort emailConfigurationPort,
+                            EmailService emailService,
+                            EmailRepository emailRepository) {
         this.emailConfigurationPort = emailConfigurationPort;
         this.emailService = emailService;
         this.emailRepository = emailRepository;
     }
 
+    /**
+     * Handles sending an email based on the provided DTO.
+     *
+     * @param emailDTO DTO containing from, subject, and body
+     */
     public void handle(EmailDTO emailDTO) {
         String to = emailConfigurationPort.getDefaultRecipient();
+        log.info("Sending email from {} to {}", emailDTO.from(), to);
+
         Email email = emailService.sendEmail(
                 Email.builder()
                         .from(emailDTO.from())
@@ -27,6 +54,8 @@ public class SendEmailUseCase {
                         .body(emailDTO.body())
                         .build()
         );
-        emailRepository.save(email);
+
+        emailRepository.save(email); // Persist the sent email
+        log.info("Email successfully sent and persisted to repository for recipient {}", to);
     }
-}
+}