Build post chat and attachment workflows

backend/internal/mail/smtp.go

@@ -0,0 +1,150 @@
+package mail
+
+import (
+	"crypto/tls"
+	"fmt"
+	"net"
+	"net/mail"
+	"net/smtp"
+	"strings"
+)
+
+type SMTPConfig struct {
+	Host     string
+	Port     string
+	User     string
+	Password string
+	From     string
+	FromName string
+}
+
+type Sender struct {
+	cfg SMTPConfig
+}
+
+func NewSender(cfg SMTPConfig) Sender {
+	if strings.TrimSpace(cfg.Port) == "" {
+		cfg.Port = "587"
+	}
+	return Sender{cfg: cfg}
+}
+
+func (s Sender) IsConfigured() bool {
+	return strings.TrimSpace(s.cfg.Host) != "" &&
+		strings.TrimSpace(s.cfg.Port) != "" &&
+		strings.TrimSpace(s.cfg.From) != ""
+}
+
+func (s Sender) SendInvitation(to string, invitationURL string) error {
+	subject := "Convite para acessar o Mira"
+	textBody := "Voce foi convidado para acessar o Mira.\n\nCrie sua senha pelo link abaixo:\n" + invitationURL + "\n\nEste convite expira em 7 dias."
+	htmlBody := `<p>Voce foi convidado para acessar o Mira.</p><p><a href="` + invitationURL + `">Criar minha senha</a></p><p>Este convite expira em 7 dias.</p>`
+
+	return s.send(to, subject, textBody, htmlBody)
+}
+
+func (s Sender) send(to string, subject string, textBody string, htmlBody string) error {
+	if !s.IsConfigured() {
+		return nil
+	}
+
+	from := mail.Address{Name: strings.TrimSpace(s.cfg.FromName), Address: strings.TrimSpace(s.cfg.From)}
+	recipient := mail.Address{Address: strings.TrimSpace(to)}
+	boundary := "mira-mail-boundary"
+	message := strings.Join([]string{
+		"From: " + from.String(),
+		"To: " + recipient.String(),
+		"Subject: " + subject,
+		"MIME-Version: 1.0",
+		"Content-Type: multipart/alternative; boundary=\"" + boundary + "\"",
+		"",
+		"--" + boundary,
+		"Content-Type: text/plain; charset=UTF-8",
+		"",
+		textBody,
+		"--" + boundary,
+		"Content-Type: text/html; charset=UTF-8",
+		"",
+		htmlBody,
+		"--" + boundary + "--",
+		"",
+	}, "\r\n")
+
+	host := strings.TrimSpace(s.cfg.Host)
+	port := strings.TrimSpace(s.cfg.Port)
+	addr := net.JoinHostPort(host, port)
+	var auth smtp.Auth
+	if strings.TrimSpace(s.cfg.User) != "" || strings.TrimSpace(s.cfg.Password) != "" {
+		auth = smtp.PlainAuth("", strings.TrimSpace(s.cfg.User), strings.TrimSpace(s.cfg.Password), host)
+	}
+
+	if port == "465" {
+		if err := sendMailTLS(addr, host, auth, from.Address, []string{recipient.Address}, []byte(message)); err != nil {
+			return fmt.Errorf("send smtp email: %w", err)
+		}
+		return nil
+	}
+
+	if err := sendMailStartTLS(addr, host, auth, from.Address, []string{recipient.Address}, []byte(message)); err != nil {
+		return fmt.Errorf("send smtp email: %w", err)
+	}
+	return nil
+}
+
+func sendMailStartTLS(addr string, host string, auth smtp.Auth, from string, to []string, message []byte) error {
+	client, err := smtp.Dial(addr)
+	if err != nil {
+		return err
+	}
+	defer client.Quit()
+
+	if ok, _ := client.Extension("STARTTLS"); ok {
+		if err := client.StartTLS(&tls.Config{ServerName: host, MinVersion: tls.VersionTLS12}); err != nil {
+			return err
+		}
+	}
+
+	return sendMailWithClient(client, auth, from, to, message)
+}
+
+func sendMailTLS(addr string, host string, auth smtp.Auth, from string, to []string, message []byte) error {
+	conn, err := tls.Dial("tcp", addr, &tls.Config{ServerName: host, MinVersion: tls.VersionTLS12})
+	if err != nil {
+		return err
+	}
+
+	client, err := smtp.NewClient(conn, host)
+	if err != nil {
+		_ = conn.Close()
+		return err
+	}
+	defer client.Quit()
+
+	return sendMailWithClient(client, auth, from, to, message)
+}
+
+func sendMailWithClient(client *smtp.Client, auth smtp.Auth, from string, to []string, message []byte) error {
+	if auth != nil {
+		if err := client.Auth(auth); err != nil {
+			return err
+		}
+	}
+	if err := client.Mail(from); err != nil {
+		return err
+	}
+	for _, recipient := range to {
+		if err := client.Rcpt(recipient); err != nil {
+			return err
+		}
+	}
+
+	writer, err := client.Data()
+	if err != nil {
+		return err
+	}
+	if _, err := writer.Write(message); err != nil {
+		_ = writer.Close()
+		return err
+	}
+	return writer.Close()
+}