nomino/generators.go

package nomino

import (
	"time"

	"github.com/google/uuid"
)

// Generator is a function that returns the "random" portion of the returned filename.
// Technically, it doesn't necessarily need to be random, and could be based on time, or a counter,
// for example.
type Generator func() (string, error)

// WithGenerator sets the specified generator
func WithGenerator(g Generator) Option {
	return func(c *config) {
		c.generator = g
	}
}

func uuidGen() (string, error) {
	u, err := uuid.NewRandom()
	if err != nil {
		return "", err
	}
	return u.String(), nil
}

// UUID generates a UUIDv4.
func UUID() Generator {
	return uuidGen
}

// FileTimestamp is the default format for WithTimestamp and WithTime
const FileTimestamp string = "2006-01-02_03-05-06-0700"

// Timestamp generates a a date and time for the current time.
// It is formatted accourding to FileTimestamp
func Timestamp() Generator {
	return TimestampWithFormat(FileTimestamp)
}

// TimestampWithFormat generates a date and time for the current time with the supplied format.
func TimestampWithFormat(f string) Generator {
	return FormattedTime(time.Now(), FileTimestamp)
}

// Time generates a date and time for the supplied time.
// It is formatted accourding to FileTimestamp
func Time(t time.Time) Generator {
	return FormattedTime(t, FileTimestamp)
}

// FormattedTime generates a date and time for the supplied time with the supplied format.
func FormattedTime(t time.Time, f string) Generator {
	return func() (string, error) {
		return t.Format(f), nil
	}
}

// FileTimestamp is the default format for WithTimestampUTC and WithTimeUTC
const FileTimestampNoTZ string = "2006-01-02_03-05-06"

// TimestampUTC generates a date and time for the current time in UTC without a timezone in the format.
func TimestampUTC() Generator {
	return TimeUTC(time.Now())
}

// TimeUTC generates a date and time for the supplied time in UTC without a timezone in the format.
func TimeUTC(t time.Time) Generator {
	return FormattedTime(t.UTC(), FileTimestampNoTZ)
}