import choice from './choice';
import randHex from './randHex';

/**
 * Returns pseudo-random guid (UUID v4)
 * IMPORTANT: it's not totally "safe" since randHex/choice uses Math.random
 * by default and sequences can be predicted in some cases. See the
 * "random/random" documentation for more info about it and how to replace
 * the default PRNG.
 */
function guid(): string {
    return (
        randHex(8) +
        '-' +
        randHex(4) +
        '-' +
        // v4 UUID always contain "4" at this position to specify it was
        // randomly generated
        '4' +
        randHex(3) +
        '-' +
        // v4 UUID always contain chars [a,b,8,9] at this position
        choice(8, 9, 'a', 'b') +
        randHex(3) +
        '-' +
        randHex(12)
    );
}
export default guid;