module rand

// init initializes the default RNG.
fn init() {
    default_rng = new_default()
}

fn internal_fill_buffer_from_set(mut _ PRNG, _ string, mut _ []u8) {
    panic('todo')
}

// fn internal_string_from_set(mut rng PRNG, charset string, len int) string {
fn internal_string_from_set(mut _ PRNG, charset string, len int) string {
    result := ''
    #
    #const characters = charset.str;
    #const charactersLength = characters.length;
    #for (let i = 0;i < len.val;i++)
    #result.str += characters.charAt(Math.random() * charactersLength);

    _ = charset
    _ = len

    return result
}

const ulid_encoding = '0123456789ABCDEFGHJKMNPQRSTVWXYZ'

fn internal_ulid_at_millisecond(mut rng PRNG, unix_time_milli u64) string {
    mut buf := []u8{cap: 27}
    mut t := unix_time_milli
    mut i := 9
    for i >= 0 {
        buf[i] = ulid_encoding[int(t & 0x1f)]
        t = t >> 5
        i--
    }

    mut x := rng.u64()
    i = 10
    for i < 19 {
        buf[i] = ulid_encoding[int(x & 0x1f)]

        x = x >> 5
        i++
    }

    x = rng.u64()
    for i < 26 {
        buf[i] = ulid_encoding[int(x & 0x1f)]
        x = x >> 5
        i++
    }

    res := ''
    println(buf)
    #res.str = buf.arr.arr.map(String.fromCharCode).join('')

    return res
}

fn read_internal(mut rng PRNG, mut buf []u8) {
    for i in 0 .. buf.len {
        buf[i] = rng.u8()
    }
}