setup resend client for email service

internal/app/app.go

@@ -11,10 +11,11 @@ import (
 )
 
 type App struct {
-	Cfg         *config.Config
-	DB          *sqlx.DB
-	UserService *service.UserService
-	AuthService *service.AuthService
+	Cfg          *config.Config
+	DB           *sqlx.DB
+	UserService  *service.UserService
+	AuthService  *service.AuthService
+	EmailService *service.EmailService
 }
 
 func New(cfg *config.Config) (*App, error) {
@@ -28,16 +29,20 @@ func New(cfg *config.Config) (*App, error) {
 		return nil, fmt.Errorf("failed to run migrations: %w", err)
 	}
 
+	emailClient := service.NewResendClient(cfg.ResendKey)
+
 	userRepository := repository.NewUserRepository(database)
 
 	userService := service.NewUserService(userRepository)
 	authService := service.NewAuthService(userRepository)
+	emailService := service.NewEmailService(emailClient, cfg.EmailFrom, cfg.AppURL, cfg.AppName, cfg.AppEnv == "development")
 
 	return &App{
-		Cfg:         cfg,
-		DB:          database,
-		UserService: userService,
-		AuthService: authService,
+		Cfg:          cfg,
+		DB:           database,
+		UserService:  userService,
+		AuthService:  authService,
+		EmailService: emailService,
 	}, nil
 }
 

internal/config/config.go

@@ -20,6 +20,9 @@ type Config struct {
 
 	JWTSecret string
 	JWTExpiry time.Duration
+
+	EmailFrom string
+	ResendKey string
 }
 
 func Load() *Config {
@@ -40,6 +43,9 @@ func Load() *Config {
 
 		JWTSecret: envRequired("JWT_SECRET"),
 		JWTExpiry: envDuration("JWT_EXPIRY", 168*time.Hour), // 7 days default
+
+		EmailFrom: envString("EMAIL_FROM", ""),
+		ResendKey: envString("RESEND_KEY", ""),
 	}
 
 	return cfg

internal/service/email.go

@@ -1,6 +1,11 @@
 package service
 
-import "context"
+import (
+	"context"
+	"log/slog"
+
+	"github.com/resend/resend-go/v2"
+)
 
 type EmailParams struct {
 	From    string
@@ -13,6 +18,34 @@ type EmailClient interface {
 	SendWithContext(ctx context.Context, params EmailParams) (string, error)
 }
 
+type ResendClient struct {
+	client *resend.Client
+}
+
+func NewResendClient(apiKey string) *ResendClient {
+	var client *resend.Client
+	if apiKey != "" {
+		client = resend.NewClient(apiKey)
+	} else {
+		slog.Warn("cannot initialize Resend client with empty api key")
+		return nil
+	}
+	return &ResendClient{client: client}
+}
+
+func (c *ResendClient) SendWithContext(ctx context.Context, params EmailParams) (string, error) {
+	res, err := c.client.Emails.SendWithContext(ctx, &resend.SendEmailRequest{
+		From:    params.From,
+		To:      params.To,
+		Subject: params.Subject,
+		Text:    params.Text,
+	})
+	if err != nil {
+		return "", err
+	}
+	return res.Id, nil
+}
+
 type EmailService struct {
 	client    EmailClient
 	fromEmail string