package wallet import "errors" var ErrDependencyUnavailable = errors.New("dependency unavailable") type Service struct { repo *Repository } func NewService(repo *Repository) *Service { return &Service{repo: repo} } func (s *Service) Account(userID uint64) (*AccountDTO, error) { if s.repo == nil { return nil, ErrDependencyUnavailable } return s.repo.Account(userID) } func (s *Service) Ledger(userID uint64) ([]LedgerDTO, error) { if s.repo == nil { return nil, ErrDependencyUnavailable } return s.repo.Ledger(userID) }