feat: add audit log with email notification (#26)

backend/internal/service/email_service.go

@@ -0,0 +1,67 @@
+package service
+
+import (
+	"errors"
+	"fmt"
+	"github.com/stonith404/pocket-id/backend/internal/common"
+	"net/smtp"
+	"os"
+	"strings"
+)
+
+type EmailService struct {
+	appConfigService *AppConfigService
+}
+
+func NewEmailService(appConfigService *AppConfigService) *EmailService {
+	return &EmailService{
+		appConfigService: appConfigService}
+}
+
+// Send sends an email notification
+func (s *EmailService) Send(toEmail, title, templateName string, templateParameters map[string]interface{}) error {
+	// Check if SMTP settings are set
+	if s.appConfigService.DbConfig.EmailEnabled.Value != "true" {
+		return errors.New("email not enabled")
+	}
+
+	// Construct the email message
+	subject := fmt.Sprintf("Subject: %s\n", title)
+	subject += "From: " + s.appConfigService.DbConfig.SmtpFrom.Value + "\n"
+	subject += "To: " + toEmail + "\n"
+	subject += "Content-Type: text/html; charset=UTF-8\n"
+
+	body, err := os.ReadFile(fmt.Sprintf("./email-templates/%s.html", templateName))
+	bodyString := string(body)
+	if err != nil {
+		return fmt.Errorf("failed to read email template: %w", err)
+	}
+
+	// Replace template parameters
+	templateParameters["appName"] = s.appConfigService.DbConfig.AppName.Value
+	templateParameters["appUrl"] = common.EnvConfig.AppURL
+	
+	for key, value := range templateParameters {
+		bodyString = strings.ReplaceAll(bodyString, fmt.Sprintf("{{%s}}", key), fmt.Sprintf("%v", value))
+	}
+
+	emailBody := []byte(subject + bodyString)
+
+	// Set up the authentication information.
+	auth := smtp.PlainAuth("", s.appConfigService.DbConfig.SmtpUser.Value, s.appConfigService.DbConfig.SmtpPassword.Value, s.appConfigService.DbConfig.SmtpHost.Value)
+
+	// Send the email
+	err = smtp.SendMail(
+		s.appConfigService.DbConfig.SmtpHost.Value+":"+s.appConfigService.DbConfig.SmtpPort.Value,
+		auth,
+		s.appConfigService.DbConfig.SmtpFrom.Value,
+		[]string{toEmail},
+		emailBody,
+	)
+
+	if err != nil {
+		return fmt.Errorf("failed to send email: %w", err)
+	}
+
+	return nil
+}