const { randomBytes } = require('crypto')

const ID_LENGTH = 64

const escape = string => string
    .replace(/\+/g, '-')
    .replace(/\//g, '_')
    .replace(/=/g, '')

module.exports = async () => new Promise((resolve, reject) => {
    randomBytes(ID_LENGTH, (error, bytes) => {
        if (error) {
            reject(error)
        } else {
            const [ seconds, nanoseconds ] = process.hrtime()
            resolve(escape(
                crypto
                    .createHash('sha512')
                    .update(`${bytes.toString('base64')}${seconds}${nanoseconds}`)
                    .digest('base64')
            ))
        }
    })
}