package util

import (
	crand "crypto/rand"
	mrand "math/rand"
)

type src struct{}

func (s src) Int63() int64 {
	result := make([]byte, 8)
	_, err := crand.Read(result)
	if err != nil {
		panic(err)
	}
	return int64(result[0]&0x7F)<<56 |
		int64(result[1])<<48 |
		int64(result[2])<<40 |
		int64(result[3])<<32 |
		int64(result[4])<<24 |
		int64(result[5])<<16 |
		int64(result[6])<<8 |
		int64(result[7])<<0
}

func (s src) Seed(seed int64) {
	// We don't do seeds here.
}

var Rand = mrand.New(src{})

const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789+="

func RandomBase64(n int) string {
	b := make([]byte, n)
	for i := range b {
		b[i] = letterBytes[Rand.Intn(64)]
	}
	return string(b)
}