Add email logging and SMTP health check

- Add structured logging for email sending (success/failure)
- Add HealthCheck method to EmailService interface
- Extend /health endpoint to include SMTP status
- Update all email service mocks to implement HealthCheck
- SMTP status shows: ok, error, or disabled

internal/application/commands/request_password_reset_test.go

@@ -85,6 +85,10 @@ func (m *mockRequestResetEmailService) Send(message services.EmailMessage) error
 	return nil
 }
 
+func (m *mockRequestResetEmailService) HealthCheck() error {
+	return nil
+}
+
 func TestRequestPasswordResetHandler_Success(t *testing.T) {
 	user := entities.NewUser("test@example.com", "hash")
 	user.ID = "user-123"

internal/application/commands/verify_email_test.go

@@ -65,6 +65,10 @@ func (m *mockEmailService) Send(message services.EmailMessage) error {
 	return nil
 }
 
+func (m *mockEmailService) HealthCheck() error {
+	return nil
+}
+
 func TestVerifyEmailHandler_Success(t *testing.T) {
 	token := "valid-token"
 	expiry := time.Now().Add(24 * time.Hour)

internal/domain/services/email_service.go

@@ -9,4 +9,5 @@ type EmailMessage struct {
 
 type EmailService interface {
 	Send(message EmailMessage) error
+	HealthCheck() error
 }

internal/infrastructure/email/smtp_service.go

@@ -3,6 +3,7 @@ package email
 import (
 	"crypto/tls"
 	"fmt"
+	"log"
 	"strings"
 	"time"
 
@@ -53,9 +54,11 @@ func (s *SMTPService) Send(message services.EmailMessage) error {
 	}
 
 	if err := s.sendWithRetry(dialer, m); err != nil {
+		log.Printf("[EMAIL] status=failed to=%s subject=%q error=%q", message.To, message.Subject, err.Error())
 		return fmt.Errorf("failed to send email: %w", err)
 	}
 
+	log.Printf("[EMAIL] status=sent to=%s subject=%q", message.To, message.Subject)
 	return nil
 }
 
@@ -103,3 +106,28 @@ func isConfigError(err error) bool {
 func (s *SMTPService) GetConfig() SMTPConfig {
 	return s.config
 }
+
+func (s *SMTPService) HealthCheck() error {
+	dialer := mail.NewDialer(s.config.Host, s.config.Port, s.config.Username, s.config.Password)
+	dialer.TLSConfig = &tls.Config{
+		ServerName: s.config.Host,
+	}
+
+	if s.config.Port == 465 {
+		dialer.SSL = true
+	}
+
+	smtpCloser, err := dialer.Dial()
+	if err != nil {
+		if isAuthError(err) {
+			return fmt.Errorf("SMTP authentication failed: %w", err)
+		}
+		if isConfigError(err) {
+			return fmt.Errorf("SMTP connection failed: %w", err)
+		}
+		return fmt.Errorf("SMTP error: %w", err)
+	}
+	defer smtpCloser.Close()
+
+	return nil
+}

internal/infrastructure/http/health_handlers.go

@@ -1,6 +1,7 @@
 package http
 
 import (
+	"apocapoc-api/internal/domain/services"
 	"database/sql"
 	"net/http"
 	"time"
@@ -9,18 +10,21 @@ import (
 var startTime = time.Now()
 
 type HealthHandlers struct {
-	db *sql.DB
+	db           *sql.DB
+	emailService services.EmailService
 }
 
-func NewHealthHandlers(db *sql.DB) *HealthHandlers {
+func NewHealthHandlers(db *sql.DB, emailService services.EmailService) *HealthHandlers {
 	return &HealthHandlers{
-		db: db,
+		db:           db,
+		emailService: emailService,
 	}
 }
 
 type HealthResponse struct {
 	Status   string `json:"status"`
 	Database string `json:"database"`
+	SMTP     string `json:"smtp"`
 	Uptime   string `json:"uptime"`
 }
 
@@ -34,6 +38,7 @@ type HealthResponse struct {
 // @Router /health [get]
 func (h *HealthHandlers) Health(w http.ResponseWriter, r *http.Request) {
 	dbStatus := "ok"
+	smtpStatus := "ok"
 	overallStatus := "ok"
 	statusCode := http.StatusOK
 
@@ -43,12 +48,25 @@ func (h *HealthHandlers) Health(w http.ResponseWriter, r *http.Request) {
 		statusCode = http.StatusServiceUnavailable
 	}
 
+	if h.emailService != nil {
+		if err := h.emailService.HealthCheck(); err != nil {
+			smtpStatus = "error"
+			if overallStatus != "degraded" {
+				overallStatus = "degraded"
+				statusCode = http.StatusServiceUnavailable
+			}
+		}
+	} else {
+		smtpStatus = "disabled"
+	}
+
 	uptime := time.Since(startTime)
 	uptimeStr := formatDuration(uptime)
 
 	response := HealthResponse{
 		Status:   overallStatus,
 		Database: dbStatus,
+		SMTP:     smtpStatus,
 		Uptime:   uptimeStr,
 	}
 

internal/infrastructure/http/integration_test.go

@@ -72,7 +72,7 @@ func setupTestServer(t *testing.T) *TestServer {
 	authHandlers := NewAuthHandlers(registerHandler, loginHandler, refreshTokenHandler, revokeTokenHandler, revokeAllTokensHandler, verifyEmailHandler, resendVerificationEmailHandler, requestPasswordResetHandler, resetPasswordHandler, jwtService, refreshTokenRepo, refreshTokenExpiry, translator)
 	habitHandlers := NewHabitHandlers(createHandler, getTodaysHandler, getUserHabitsHandler, getHabitByIDHandler, getHabitEntriesHandler, updateHandler, archiveHandler, markHandler, unmarkHandler, translator)
 	statsHandlers := NewStatsHandlers(getHabitStatsHandler, translator)
-	healthHandlers := NewHealthHandlers(db)
+	healthHandlers := NewHealthHandlers(db, nil)
 	userHandlers := NewUserHandlers(deleteUserHandler, translator)
 
 	router := NewRouter("http://localhost:3000", habitHandlers, authHandlers, statsHandlers, healthHandlers, userHandlers, jwtService, translator)