package util

import (
	"math/rand"
	"time"
)

var defaultLetters = []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")

// RandomString returns a random string with a fixed length
func RandomString(n int, allowedChars ...[]rune) string {
	var letters []rune

	if len(allowedChars) == 0 {
		letters = defaultLetters
	} else {
		letters = allowedChars[0]
	}

	b := make([]rune, n)
	for i := range b {
		b[i] = letters[rand.Intn(len(letters))]
	}

	return string(b)
}

func RandInt64(min, max int64) int64 {
	s := rand.NewSource(time.Now().UnixNano())
	r := rand.New(s)
	return min + r.Int63n(max-min+1)
}
func RandFloat64(min, max float64) float64 {
	s := rand.NewSource(time.Now().UnixNano())
	r := rand.New(s)

	return min + r.Float64()*(max-min)
}