use base64::Engine;
use base64::engine::general_purpose::URL_SAFE_NO_PAD;
use rand::RngCore;
use rand::rngs::OsRng;
use sha2::{Digest, Sha256};

pub fn random_b64url(len: usize) -> String {
    let mut bytes = vec![0u8; len];
    OsRng.fill_bytes(&mut bytes);
    URL_SAFE_NO_PAD.encode(bytes)
}

pub fn sha256_hex(bytes: &[u8]) -> String {
    let digest = Sha256::digest(bytes);
    let mut out = String::with_capacity(digest.len() * 2);
    for byte in digest {
        use std::fmt::Write;
        let _ = write!(out, "{byte:02x}");
    }
    out
}