// Package clock is a simple clock without date handling.
package clock
import (
	"strconv"
)
// Clock is simple clock.
type Clock struct {
	hour int
	min  int
}
// New constructs a new Clock with proper hour and minute values.
func New(hour, minute int) Clock {
	// handle hour turns because of mins
	if minute >= 0 {
		hour += minute / 60
	} else {
		hour += (minute+1)/60 - 1
	}
	// first normalize, then make it positive
	minute = minute % 60
	if minute < 0 {
		minute += 60
	}
	hour %= 24
	if hour < 0 {
		hour += 24
	}
	return Clock{hour: hour, min: minute}
}
// String returns Clock in "hh:mm" format.
func (c Clock) String() string {
	h := strconv.Itoa(c.hour)
	if c.hour < 10 {
		h = "0" + h
	}
	m := strconv.Itoa(c.min)
	if c.min < 10 {
		m = "0" + m
	}
	return h + ":" + m
}
// Add adds minutes to c.
func (c Clock) Add(minutes int) Clock {
	return New(c.hour, c.min+minutes)
}
// Subtract subtracts minutes from c.
func (c Clock) Subtract(minutes int) Clock {
	return New(c.hour, c.min-minutes)
}