package config

import (
	"net"
	"path/filepath"
	"strconv"
)

const (
	PortPrimary   = 5032
	PortAlternate = 5033
	UpdatesSubdir = "updates"
)

// AlternateListenAddr returns the other blue-green port (5032 <-> 5033).
func AlternateListenAddr(current string) (string, error) {
	host, portStr, err := net.SplitHostPort(current)
	if err != nil {
		return "", err
	}
	if host == "" {
		host = "0.0.0.0"
	}
	port, err := strconv.Atoi(portStr)
	if err != nil {
		return "", err
	}
	next := PortAlternate
	if port == PortAlternate {
		next = PortPrimary
	}
	return net.JoinHostPort(host, strconv.Itoa(next)), nil
}

func UpdatesDir() (string, error) {
	base, err := InstallDir()
	if err != nil {
		return "", err
	}
	return filepath.Join(base, UpdatesSubdir), nil
}