go-solid-single-responsibility-5dfc2e5da33fd7a8f2eebc59

employee.go

// Money represents currency in Thai Baht
type Money float64

// Employee is a person employed by a company
type Employee struct {
	// An amount to-be paid per working hour
	salaryPerHour Money

	// A total number of working hours of the employee
	workingHours int
}

// CalculatePay does calculating a total amount to-be paid to the employee
func (e Employee) CalculatePay() Money {
	return e.salaryPerHour * Money(e.workingHours)
}

// Save stores an employee data to the data storage
func (e Employee) Save() {
	fmt.Println("an employee data has been saved")
}

// ReportHours returns a number of working hours
func (e Employee) ReportHours() string {
	return fmt.Sprintf("an employee has been working %d hours so far...", e.workingHours)
}

refactored_employee.go

// Employee is an abstraction of all employee types.
type Employee interface {
	// Return an amount to-be paid per working hour
	SalaryPerHour() Money
	// Return a total number of working hours of the employee
	TotalWorkingHours() int
	// Return a number of working hours
	ReportHours() string
}

// An EmployeeDAO
type EmployeeDAO struct{}

// Save stores an employee data to the data storage
func (repo EmployeeDAO) Save(e Employee) error {
	fmt.Println("an employee data has been saved")
	return nil
}

// An EmployeePayment
type EmployeePayment struct{}

// CalculatePay does calculating a total amount to-be paid to the employee
func (p EmployeePayment) CalculatePay(e Employee) Money {
	return e.SalaryPerHour() * Money(e.TotalWorkingHours())
}

// DailyEmployee will be paid every day at the end of the day
type DailyEmployee struct {
	// An amount to-be paid per working hour
	salaryPerHour Money
	// A daily working hours
	dailyWorkingHours int
}

func (e DailyEmployee) SalaryPerHour() Money {
	return e.salaryPerHour
}

func (e DailyEmployee) TotalWorkingHours() int {
	return e.dailyWorkingHours
}

func (e DailyEmployee) ReportHours() string {
	return fmt.Sprintf("an employee has been working %d hours so far...", e.dailyWorkingHours)
}