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

backend/internal/model/audit_log.go

@@ -0,0 +1,50 @@
+package model
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"errors"
+)
+
+type AuditLog struct {
+	Base
+
+	Event     AuditLogEvent
+	IpAddress string
+	UserAgent string
+	UserID    string
+	Data      AuditLogData
+}
+
+type AuditLogData map[string]string
+
+type AuditLogEvent string
+
+const (
+	AuditLogEventSignIn                 AuditLogEvent = "SIGN_IN"
+	AuditLogEventClientAuthorization    AuditLogEvent = "CLIENT_AUTHORIZATION"
+	AuditLogEventNewClientAuthorization AuditLogEvent = "NEW_CLIENT_AUTHORIZATION"
+)
+
+// Scan and Value methods for GORM to handle the custom type
+
+func (e *AuditLogEvent) Scan(value interface{}) error {
+	*e = AuditLogEvent(value.(string))
+	return nil
+}
+
+func (e AuditLogEvent) Value() (driver.Value, error) {
+	return string(e), nil
+}
+
+func (d *AuditLogData) Scan(value interface{}) error {
+	if v, ok := value.([]byte); ok {
+		return json.Unmarshal(v, d)
+	} else {
+		return errors.New("type assertion to []byte failed")
+	}
+}
+
+func (d AuditLogData) Value() (driver.Value, error) {
+	return json.Marshal(d)
+}