use crate::error::CryptoError;
use rsa::BigUint;
use rsa::Oaep;
use rsa::Pkcs1v15Encrypt;
use rsa::RsaPublicKey;
use rsa::pkcs8::DecodePublicKey;
use rsa::rand_core::OsRng;

// Steam Universe Public RSA key (DER-encoded SubjectPublicKeyInfo).
// Extracted from steamclient64.dll at 0x1394161d0.
// 1024-bit RSA, exponent 17 (0x11).
const STEAM_PUBLIC_KEY_DER: [u8; 160] = [
    0x30, 0x81, 0x9d, 0x30, 0x0d, 0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x01, 0x01,
    0x05, 0x00, 0x03, 0x81, 0x8b, 0x00, 0x30, 0x81, 0x87, 0x02, 0x81, 0x81, 0x00, 0xdf, 0xec, 0x1a,
    0xd6, 0x2c, 0x10, 0x66, 0x2c, 0x17, 0x35, 0x3a, 0x14, 0xb0, 0x7c, 0x59, 0x11, 0x7f, 0x9d, 0xd3,
    0xd8, 0x2b, 0x7a, 0xe3, 0xe0, 0x15, 0xcd, 0x19, 0x1e, 0x46, 0xe8, 0x7b, 0x87, 0x74, 0xa2, 0x18,
    0x46, 0x31, 0xa9, 0x03, 0x14, 0x79, 0x82, 0x8e, 0xe9, 0x45, 0xa2, 0x49, 0x12, 0xa9, 0x23, 0x68,
    0x73, 0x89, 0xcf, 0x69, 0xa1, 0xb1, 0x61, 0x46, 0xbd, 0xc1, 0xbe, 0xbf, 0xd6, 0x01, 0x1b, 0xd8,
    0x81, 0xd4, 0xdc, 0x90, 0xfb, 0xfe, 0x4f, 0x52, 0x73, 0x66, 0xcb, 0x95, 0x70, 0xd7, 0xc5, 0x8e,
    0xba, 0x1c, 0x7a, 0x33, 0x75, 0xa1, 0x62, 0x34, 0x46, 0xbb, 0x60, 0xb7, 0x80, 0x68, 0xfa, 0x13,
    0xa7, 0x7a, 0x8a, 0x37, 0x4b, 0x9e, 0xc6, 0xf4, 0x5d, 0x5f, 0x3a, 0x99, 0xf9, 0x9e, 0xc4, 0x3a,
    0xe9, 0x63, 0xa2, 0xbb, 0x88, 0x19, 0x28, 0xe0, 0xe7, 0x14, 0xc0, 0x42, 0x89, 0x02, 0x01, 0x11,
];

pub fn encrypt_with_steam_public_key(data: &[u8]) -> Result<Vec<u8>, CryptoError> {
    let public_key = RsaPublicKey::from_public_key_der(&STEAM_PUBLIC_KEY_DER)
        .map_err(|e| CryptoError::Rsa(rsa::Error::from(rsa::pkcs8::Error::from(e))))?;
    let mut rng = OsRng;
    public_key
        .encrypt(&mut rng, Oaep::new::<sha1_v10::Sha1>(), data)
        .map_err(CryptoError::Rsa)
}

pub fn encrypt_with_rsa_public_key(
    data: &[u8],
    modulus_hex: &str,
    exponent_hex: &str,
) -> Result<Vec<u8>, CryptoError> {
    let modulus =
        BigUint::parse_bytes(modulus_hex.as_bytes(), 16).ok_or(CryptoError::DecryptionFailed)?;
    let exponent =
        BigUint::parse_bytes(exponent_hex.as_bytes(), 16).ok_or(CryptoError::DecryptionFailed)?;
    let public_key = RsaPublicKey::new(modulus, exponent).map_err(CryptoError::Rsa)?;
    let mut rng = OsRng;
    public_key
        .encrypt(&mut rng, Pkcs1v15Encrypt, data)
        .map_err(CryptoError::Rsa)
}
