Go date.Date

date.go

package date

import (
	"database/sql/driver"
	"encoding/json"
	"errors"
	"fmt"
	"time"
)

// DateFormat is date format
const DateFormat = "2006-01-02"

// Date is date time
type Date struct {
	time time.Time
}

// Now is get today
func Now() Date {
	return Date{
		time: time.Now(),
	}
}

func (d Date) String() string {
	y, m, day := d.time.Date()
	return fmt.Sprintf("%04d-%02d-%02d", y, m, day)
}

// Value is implement database/sql/driver
func (d Date) Value() (driver.Value, error) {
	return d.time, nil
}

// Scan is implement database/sql/driver
func (d *Date) Scan(src interface{}) error {
	source, ok := src.(time.Time)
	if !ok {
		return errors.New("Incompatible type for Date")
	}
	d.time = source
	return nil
}

// UnmarshalJSON - implement Unmarshaler
func (d *Date) UnmarshalJSON(b []byte) error {
	var tmp string
	err := json.Unmarshal(b, &tmp)
	if err != nil {
		return err
	}
	d.time, err = time.Parse(DateFormat, tmp)
	if err != nil {
		return err
	}
	return nil
}

// MarshalJSON - implement Marshaler
func (d *Date) MarshalJSON() ([]byte, error) {
	return []byte(fmt.Sprintf(`"%v"`, d.String())), nil
}

// After reports whether the date instant t is after u.
func (d Date) After(u Date) bool {
	return d.time.After(u.time)
}

// Before reports whether the date instant t is before u.
func (d Date) Before(u Date) bool {
	return d.time.Before(u.time)
}