package domain

import (
	"fmt"
	"time"
)

// ClockTime é um horário do dia (HH:MM), guardado em minutos desde 00:00.
type ClockTime int

func ParseClock(value string) (ClockTime, error) {
	if len(value) != 5 || value[2] != ':' {
		return 0, fmt.Errorf("horário inválido %q (use HH:MM)", value)
	}
	digits := [4]byte{value[0], value[1], value[3], value[4]}
	for _, d := range digits {
		if d < '0' || d > '9' {
			return 0, fmt.Errorf("horário inválido %q (use HH:MM)", value)
		}
	}
	hour := int(digits[0]-'0')*10 + int(digits[1]-'0')
	minute := int(digits[2]-'0')*10 + int(digits[3]-'0')
	if hour > 23 || minute > 59 {
		return 0, fmt.Errorf("horário inválido %q", value)
	}
	return ClockTime(hour*60 + minute), nil
}

func MustParseClock(value string) ClockTime {
	c, err := ParseClock(value)
	if err != nil {
		panic(err)
	}
	return c
}

func (c ClockTime) String() string {
	return fmt.Sprintf("%02d:%02d", int(c)/60, int(c)%60)
}

// On devolve o instante desse horário na data (AAAA-MM-DD) e fuso informados.
func (c ClockTime) On(day string, loc *time.Location) time.Time {
	date, err := time.ParseInLocation(DateLayout, day, loc)
	if err != nil {
		return time.Time{}
	}
	return time.Date(date.Year(), date.Month(), date.Day(), int(c)/60, int(c)%60, 0, 0, loc)
}

// ClockOf devolve o horário do dia de t no fuso informado.
func ClockOf(t time.Time, loc *time.Location) ClockTime {
	local := t.In(loc)
	return ClockTime(local.Hour()*60 + local.Minute())
}