remove resend and use custom email client

.env.include.example

@@ -14,7 +14,11 @@ JWT_EXPIRY=168h
 
 MAILER_SMTP_HOST=
 MAILER_SMTP_PORT=
+MAILER_IMAP_HOST=
+MAILER_IMAP_PORT=
 MAILER_USERNAME=
 MAILER_PASSWORD=
 MAILER_EMAIL_FROM=
 MAILER_ENVELOPE_FROM=
+MAILER_SUPPORT_EMAIL=
+MAILER_SUPPORT_ENVELOPE_FROM=

go.mod

@@ -6,12 +6,13 @@ require (
 	github.com/Oudwins/tailwind-merge-go v0.2.1
 	github.com/a-h/templ v0.3.960
 	github.com/alexedwards/argon2id v1.0.0
+	github.com/emersion/go-imap v1.2.1
 	github.com/golang-jwt/jwt/v5 v5.2.2
 	github.com/jackc/pgx/v5 v5.7.6
 	github.com/jmoiron/sqlx v1.4.0
 	github.com/joho/godotenv v1.5.1
 	github.com/pressly/goose/v3 v3.26.0
-	github.com/resend/resend-go/v2 v2.28.0
+	github.com/wneessen/go-mail v0.7.2
 	modernc.org/sqlite v1.40.1
 )
 
@@ -28,6 +29,7 @@ require (
 	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/elastic/go-sysinfo v1.15.4 // indirect
 	github.com/elastic/go-windows v1.0.2 // indirect
+	github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21 // indirect
 	github.com/fatih/color v1.18.0 // indirect
 	github.com/fsnotify/fsnotify v1.9.0 // indirect
 	github.com/go-faster/city v1.0.1 // indirect
@@ -70,9 +72,9 @@ require (
 	golang.org/x/exp v0.0.0-20250620022241-b7579e27df2b // indirect
 	golang.org/x/mod v0.27.0 // indirect
 	golang.org/x/net v0.43.0 // indirect
-	golang.org/x/sync v0.16.0 // indirect
+	golang.org/x/sync v0.17.0 // indirect
 	golang.org/x/sys v0.36.0 // indirect
-	golang.org/x/text v0.28.0 // indirect
+	golang.org/x/text v0.29.0 // indirect
 	golang.org/x/tools v0.36.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20240123012728-ef4313101c80 // indirect
 	google.golang.org/grpc v1.62.1 // indirect

go.sum

@@ -59,6 +59,12 @@ github.com/elastic/go-sysinfo v1.15.4/go.mod h1:ZBVXmqS368dOn/jvijV/zHLfakWTYHBZ
 github.com/elastic/go-windows v1.0.0/go.mod h1:TsU0Nrp7/y3+VwE82FoZF8gC/XFg/Elz6CcloAxnPgU=
 github.com/elastic/go-windows v1.0.2 h1:yoLLsAsV5cfg9FLhZ9EXZ2n2sQFKeDYrHenkcivY4vI=
 github.com/elastic/go-windows v1.0.2/go.mod h1:bGcDpBzXgYSqM0Gx3DM4+UxFj300SZLixie9u9ixLM8=
+github.com/emersion/go-imap v1.2.1 h1:+s9ZjMEjOB8NzZMVTM3cCenz2JrQIGGo5j1df19WjTA=
+github.com/emersion/go-imap v1.2.1/go.mod h1:Qlx1FSx2FTxjnjWpIlVNEuX+ylerZQNFE5NsmKFSejY=
+github.com/emersion/go-message v0.15.0/go.mod h1:wQUEfE+38+7EW8p8aZ96ptg6bAb1iwdgej19uXASlE4=
+github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21 h1:OJyUGMJTzHTd1XQp98QTaHernxMYzRaOasRir9hUlFQ=
+github.com/emersion/go-sasl v0.0.0-20200509203442-7bfe0ed36a21/go.mod h1:iL2twTeMvZnrg54ZoPDNfJaJaqy0xIQFuBdrLsmspwQ=
+github.com/emersion/go-textwrapper v0.0.0-20200911093747-65d896831594/go.mod h1:aqO8z8wPrjkscevZJFVE1wXJrLpC5LtJG7fqLOsPb2U=
 github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1mIlRU8Am5FuJP05cCM98=
@@ -191,8 +197,6 @@ github.com/rekby/fixenv v0.6.1 h1:jUFiSPpajT4WY2cYuc++7Y1zWrnCxnovGCIX72PZniM=
 github.com/rekby/fixenv v0.6.1/go.mod h1:/b5LRc06BYJtslRtHKxsPWFT/ySpHV+rWvzTg+XWk4c=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec h1:W09IVJc94icq4NjY3clb7Lk8O1qJ8BdBEF8z0ibU0rE=
 github.com/remyoudompheng/bigfft v0.0.0-20230129092748-24d4a6f8daec/go.mod h1:qqbHyh8v60DhA7CoWK5oRCqLrMHRGoxYCSS9EjAz6Eo=
-github.com/resend/resend-go/v2 v2.28.0 h1:ttM1/VZR4fApBv3xI1TneSKi1pbfFsVrq7fXFlHKtj4=
-github.com/resend/resend-go/v2 v2.28.0/go.mod h1:3YCb8c8+pLiqhtRFXTyFwlLvfjQtluxOr9HEh2BwCkQ=
 github.com/rogpeppe/fastuuid v1.2.0/go.mod h1:jVj6XXZzXRy/MSR5jhDC/2q6DgLz+nrA6LYCDYWNEvQ=
 github.com/rogpeppe/go-internal v1.14.1 h1:UQB4HGPB6osV0SQTLymcB4TgvyWu6ZyliaW0tI/otEQ=
 github.com/rogpeppe/go-internal v1.14.1/go.mod h1:MaRKkUm5W0goXpeCfT7UZI6fk/L7L7so1lCWt35ZSgc=
@@ -218,6 +222,8 @@ github.com/tursodatabase/libsql-client-go v0.0.0-20240902231107-85af5b9d094d h1:
 github.com/tursodatabase/libsql-client-go v0.0.0-20240902231107-85af5b9d094d/go.mod h1:l8xTsYB90uaVdMHXMCxKKLSgw5wLYBwBKKefNIUnm9s=
 github.com/vertica/vertica-sql-go v1.3.3 h1:fL+FKEAEy5ONmsvya2WH5T8bhkvY27y/Ik3ReR2T+Qw=
 github.com/vertica/vertica-sql-go v1.3.3/go.mod h1:jnn2GFuv+O2Jcjktb7zyc4Utlbu9YVqpHH/lx63+1M4=
+github.com/wneessen/go-mail v0.7.2 h1:xxPnhZ6IZLSgxShebmZ6DPKh1b6OJcoHfzy7UjOkzS8=
+github.com/wneessen/go-mail v0.7.2/go.mod h1:+TkW6QP3EVkgTEqHtVmnAE/1MRhmzb8Y9/W3pweuS+k=
 github.com/xdg-go/pbkdf2 v1.0.0/go.mod h1:jrpuAogTd400dnrH08LKmI/xc1MbPOebTwRqcT5RDeI=
 github.com/xdg-go/scram v1.1.1/go.mod h1:RaEWvsqvNKKvBPvcKeFjrG2cJqOkHTiyTpzz23ni57g=
 github.com/xdg-go/stringprep v1.0.3/go.mod h1:W3f5j4i+9rC0kuIEJL0ky1VpHXQU3ocBgklLGvcBnW8=
@@ -291,8 +297,8 @@ golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.16.0 h1:ycBJEhp9p4vXvUZNszeOq0kGTPghopOL8q0fq3vstxw=
+golang.org/x/sync v0.17.0 h1:l60nONMj9l5drqw6jlhIELNv9I0A4OFgRsG9k2oT9Ug=
-golang.org/x/sync v0.16.0/go.mod h1:1dzgHSNfp02xaA81J2MS99Qcpr2w7fw1gpm99rleRqA=
+golang.org/x/sync v0.17.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -322,8 +328,8 @@ golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
 golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/text v0.9.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
 golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
-golang.org/x/text v0.28.0 h1:rhazDwis8INMIwQ4tpjLDzUhx6RlXqZNPEM0huQojng=
+golang.org/x/text v0.29.0 h1:1neNs90w9YzJ9BocxfsQNHKuAT4pkghyXc4nhZ6sJvk=
-golang.org/x/text v0.28.0/go.mod h1:U8nCwOR8jO/marOQ0QbDiOngZVEBB7MAiitBuMjXiNU=
+golang.org/x/text v0.29.0/go.mod h1:7MhJOA9CD2qZyOKYazxdYMF85OwPdEr9jTtBpO7ydH4=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190226205152-f727befe758c/go.mod h1:9Yl7xja0Znq3iFh3HoIrodX9oNMXvdceNzlUR8zjMvY=

internal/app/app.go

@@ -29,13 +29,13 @@ func New(cfg *config.Config) (*App, error) {
 		return nil, fmt.Errorf("failed to run migrations: %w", err)
 	}
 
-	emailClient := service.NewResendClient(cfg.ResendKey)
+	emailClient := service.NewEmailClient(cfg.MailerSMTPHost, cfg.MailerSMTPPort, cfg.MailerIMAPHost, cfg.MailerIMAPPort, cfg.MailerUsername, cfg.MailerPassword)
 
 	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")
+	emailService := service.NewEmailService(emailClient, cfg.MailerEmailFrom, cfg.MailerEnvelopeFrom, cfg.MailerSupportFrom, cfg.MailerSupportEnvelopeFrom, cfg.AppURL, cfg.AppName, cfg.AppEnv == "development")
 
 	return &App{
 		Cfg:          cfg,

internal/config/config.go

@@ -3,6 +3,7 @@ package config
 import (
 	"log/slog"
 	"os"
+	"strconv"
 	"time"
 
 	"github.com/joho/godotenv"
@@ -23,11 +24,15 @@ type Config struct {
 	JWTExpiry time.Duration
 
 	MailerSMTPHost            string
-	MailerSMTPPort     string
+	MailerSMTPPort            int
+	MailerIMAPHost            string
+	MailerIMAPPort            int
 	MailerUsername            string
 	MailerPassword            string
 	MailerEmailFrom           string
 	MailerEnvelopeFrom        string
+	MailerSupportFrom         string
+	MailerSupportEnvelopeFrom string
 }
 
 func Load() *Config {
@@ -51,11 +56,15 @@ func Load() *Config {
 		JWTExpiry: envDuration("JWT_EXPIRY", 168*time.Hour), // 7 days default
 
 		MailerSMTPHost:            envString("MAILER_SMTP_HOST", ""),
-		MailerSMTPPort:     envString("MAILER_SMTP_PORT", ""),
+		MailerSMTPPort:            envInt("MAILER_SMTP_PORT", 587),
+		MailerIMAPHost:            envString("MAILER_IMAP_HOST", ""),
+		MailerIMAPPort:            envInt("MAILER_IMAP_PORT", 993),
 		MailerUsername:            envString("MAILER_USERNAME", ""),
 		MailerPassword:            envString("MAILER_PASSWORD", ""),
 		MailerEmailFrom:           envString("MAILER_EMAIL_FROM", ""),
 		MailerEnvelopeFrom:        envString("MAILER_ENVELOPE_FROM", ""),
+		MailerSupportFrom:         envString("MAILER_SUPPORT_EMAIL_FROM", ""),
+		MailerSupportEnvelopeFrom: envString("MAILER_SUPPORT_ENVELOPE_FROM", ""),
 	}
 
 	return cfg
@@ -89,6 +98,19 @@ func envString(key, def string) string {
 	return value
 }
 
+func envInt(key string, def int) int {
+	value, exists := os.LookupEnv(key)
+	if !exists {
+		return def
+	}
+	i, err := strconv.ParseInt(value, 10, 32)
+	if err != nil {
+		slog.Warn("config invalid integer, using default", "key", key, "value", value, "default", def)
+		return def
+	}
+	return int(i)
+}
+
 func envDuration(key string, def time.Duration) time.Duration {
 	value, ok := os.LookupEnv(key)
 	if !ok || value == "" {

internal/service/email.go

@@ -1,15 +1,20 @@
 package service
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"log/slog"
+	"time"
 
-	"github.com/resend/resend-go/v2"
+	"github.com/emersion/go-imap"
+	"github.com/emersion/go-imap/client"
+	"github.com/wneessen/go-mail"
 )
 
 type EmailParams struct {
 	From         string
+	EnvelopeFrom string
 	To           []string
 	Bcc          []string
 	Cc           []string
@@ -19,54 +24,125 @@ type EmailParams struct {
 	Html         string
 }
 
-type EmailClient interface {
+type EmailClient struct {
-	SendWithContext(ctx context.Context, params *EmailParams) (string, error)
+	smtpHost string
+	smtpPort int
+	imapHost string
+	imapPort int
+	username string
+	password string
 }
 
-type ResendClient struct {
+func NewEmailClient(smtpHost string, smtpPort int, imapHost string, imapPort int, username, password string) *EmailClient {
-	client *resend.Client
+	return &EmailClient{
+		smtpHost: smtpHost,
+		smtpPort: smtpPort,
+		imapHost: imapHost,
+		imapPort: imapPort,
+		username: username,
+		password: password,
+	}
 }
 
-func NewResendClient(apiKey string) *ResendClient {
+func (nc *EmailClient) SendWithContext(ctx context.Context, params *EmailParams) (string, error) {
-	var client *resend.Client
+	m := mail.NewMsg()
-	if apiKey != "" {
+	m.From(params.From)
-		client = resend.NewClient(apiKey)
+	m.EnvelopeFrom(params.EnvelopeFrom)
-	} else {
+	m.To(params.To...)
-		slog.Warn("cannot initialize Resend client with empty api key")
+	m.Subject(params.Subject)
-		return nil
+	m.SetBodyString(mail.TypeTextPlain, params.Text)
-	}
+	m.SetBodyString(mail.TypeTextHTML, params.Html)
-	return &ResendClient{client: client}
+	m.ReplyTo(params.ReplyTo)
+	m.SetDate()
+	m.SetMessageID()
+
+	msgID := m.GetMessageID()
+
+	var msgBuffer bytes.Buffer
+	if _, err := m.WriteTo(&msgBuffer); err != nil {
+		return "", fmt.Errorf("failed to buffer message: %w", err)
 	}
 
-func (c *ResendClient) SendWithContext(ctx context.Context, params *EmailParams) (string, error) {
+	smtpClient, err := nc.connectToSMTP()
-	res, err := c.client.Emails.SendWithContext(ctx, &resend.SendEmailRequest{
-		From:    params.From,
-		To:      params.To,
-		Bcc:     params.Bcc,
-		Cc:      params.Cc,
-		ReplyTo: params.ReplyTo,
-		Subject: params.Subject,
-		Text:    params.Text,
-		Html:    params.Html,
-	})
 	if err != nil {
-		return "", err
+		return "", fmt.Errorf("failed to connect to SMTP server: %w", err)
 	}
-	return res.Id, nil
+
+	err = smtpClient.DialAndSendWithContext(ctx, m)
+	if err != nil {
+		return "", fmt.Errorf("failed to send email: %w", err)
+	}
+
+	imapClient, err := nc.connectToIMAP()
+	if err != nil {
+		slog.Error("failed to establish connection with IMAP server", "error", err)
+		return msgID, nil
+	}
+	defer imapClient.Logout()
+
+	flags := []string{imap.SeenFlag}
+
+	folderName := "Sent"
+
+	literal := bytes.NewReader(msgBuffer.Bytes())
+
+	err = imapClient.Append(folderName, flags, time.Now(), literal)
+	if err != nil {
+		slog.Error("IMAP append failed", "error", err)
+	}
+
+	return msgID, nil
+}
+
+func (nc *EmailClient) connectToSMTP() (*mail.Client, error) {
+	smtpClient, err := mail.NewClient(
+		nc.smtpHost,
+		mail.WithPort(nc.smtpPort),
+		mail.WithSMTPAuth(mail.SMTPAuthPlain),
+		mail.WithUsername(nc.username),
+		mail.WithPassword(nc.password),
+		mail.WithTLSPolicy(mail.TLSMandatory),
+	)
+	return smtpClient, err
+}
+
+func (nc *EmailClient) connectToIMAP() (*client.Client, error) {
+	var c *client.Client
+	var err error
+
+	addr := fmt.Sprintf("%s:%d", nc.imapHost, nc.imapPort)
+
+	c, err = client.DialTLS(addr, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	err = c.Login(nc.username, nc.password)
+	if err != nil {
+		return nil, err
+	}
+
+	return c, nil
 }
 
 type EmailService struct {
-	client    EmailClient
+	client          *EmailClient
 	fromEmail       string
+	fromEnvelope    string
+	supportEmail    string
+	supportEnvelope string
 	isDev           bool
 	appURL          string
 	appName         string
 }
 
-func NewEmailService(client EmailClient, fromEmail, appURL, appName string, isDev bool) *EmailService {
+func NewEmailService(client *EmailClient, fromEmail, fromEnvelope, supportEmail, supportEnvelope, appURL, appName string, isDev bool) *EmailService {
 	return &EmailService{
 		client:          client,
 		fromEmail:       fromEmail,
+		fromEnvelope:    fromEnvelope,
+		supportEmail:    supportEmail,
+		supportEnvelope: supportEnvelope,
 		isDev:           isDev,
 		appURL:          appURL,
 		appName:         appName,
@@ -82,10 +158,6 @@ func (s *EmailService) SendMagicLinkEmail(email, token, name string) error {
 		return nil
 	}
 
-	if s.client == nil {
-		return fmt.Errorf("email service not configured (missing RESEND_API_KEY)")
-	}
-
 	params := &EmailParams{
 		From:    s.fromEmail,
 		To:      []string{email},