// This file is part of the guuid package
//
// (c) Dreamans <dreamans@163.com>
//
// For the full copyright and license information, please view the LICENSE
// file that was distributed with this source code.

package guuid

import (
	"crypto/md5"
	"os"
	"strconv"
	"strings"
)

var machineId []byte = machineHash()

func machineHash() (machHash []byte) {
	posixPID := posixPid()
	machineName := machineHostname()
	randId := rand()
	machine := strings.Join([]string{
		machineName,
		strconv.Itoa(posixPID),
		uint32ToHexString(randId),
	}, ",")

	md5Ctx := md5.New()
	md5Ctx.Write([]byte(machine))
	machHash = md5Ctx.Sum(nil)
	return
}

func machineHostname() string {
	host, err := os.Hostname()
	if err != nil {
		host = "localhost"
	}
	return host
}

func posixPid() int {
	return int(os.Getpid())
}