// Copyright (c) 2019-2024 Alexander Medvednikov. All rights reserved.
// Use of this source code is governed by an MIT license
// that can be found in the LICENSE file.

module rand

#flag windows -Llibraries/bcrypt
#flag windows -lbcrypt
#include <bcrypt.h>

const status_success = 0x00000000
const bcrypt_use_system_preferred_rng = 0x00000002

// read returns an array of `bytes_needed` random bytes read from the OS.
pub fn read(bytes_needed int) ![]u8 {
    mut buffer := []u8{len: bytes_needed}
    // use bcrypt_use_system_preferred_rng because we passed null as algo
    status := C.BCryptGenRandom(0, buffer.data, bytes_needed, bcrypt_use_system_preferred_rng)
    if status != status_success {
        return &ReadError{}
    }
    return buffer
}