package auxid

import (
	"math/rand"
	"sync"
	"time"
)

func init() {
	rand.Seed(time.Now().UnixNano())
}

var (
	idMtx  sync.Mutex
	lastID int64
)

func GenID() int64 {
	// 53 bit limit for js
	// See https://stackoverflow.com/questions/1379934/large-numbers-erroneously-rounded-in-javascript
	idMtx.Lock()
	defer idMtx.Unlock()
	for {
		id := (time.Now().UnixNano() / 1000) // - 10000000000000
		if id != lastID {
			lastID = id
			return id
		}
		time.Sleep(1 * time.Microsecond)
	}
	//10467328383814
}