use ethereum_serai::crypto::*;
use frost::curve::Secp256k1;
use k256::{
  elliptic_curve::{bigint::ArrayEncoding, ops::Reduce, sec1::ToEncodedPoint},
  ProjectivePoint, Scalar, U256,
};

#[test]
fn test_ecrecover() {
  use k256::ecdsa::{
    recoverable::Signature,
    signature::{Signer, Verifier},
    SigningKey, VerifyingKey,
  };
  use rand_core::OsRng;

  let private = SigningKey::random(&mut OsRng);
  let public = VerifyingKey::from(&private);

  const MESSAGE: &'static [u8] = b"Hello, World!";
  let sig: Signature = private.sign(MESSAGE);
  public.verify(MESSAGE, &sig).unwrap();

  assert_eq!(
    ecrecover(hash_to_scalar(MESSAGE), sig.as_ref()[64], *sig.r(), *sig.s()).unwrap(),
    address(&ProjectivePoint::from(public))
  );
}

#[test]
fn test_signing() {
  use frost::{
    algorithm::Schnorr,
    tests::{algorithm_machines, key_gen, sign},
  };
  use rand_core::OsRng;

  let keys = key_gen::<_, Secp256k1>(&mut OsRng);
  let _group_key = keys[&1].group_key();

  const MESSAGE: &'static [u8] = b"Hello, World!";

  let algo = Schnorr::<Secp256k1, EthereumHram>::new();
  let _sig = sign(
    &mut OsRng,
    algo.clone(),
    keys.clone(),
    algorithm_machines(&mut OsRng, Schnorr::<Secp256k1, EthereumHram>::new(), &keys),
    MESSAGE,
  );
}

#[test]
fn test_ecrecover_hack() {
  use frost::{
    algorithm::Schnorr,
    tests::{algorithm_machines, key_gen, sign},
  };
  use rand_core::OsRng;

  let keys = key_gen::<_, Secp256k1>(&mut OsRng);
  let group_key = keys[&1].group_key();
  let group_key_encoded = group_key.to_encoded_point(true);
  let group_key_compressed = group_key_encoded.as_ref();
  let group_key_x = Scalar::from_uint_reduced(U256::from_be_slice(&group_key_compressed[1 .. 33]));

  const MESSAGE: &'static [u8] = b"Hello, World!";
  let hashed_message = keccak256(MESSAGE);
  let chain_id = U256::ONE;

  let full_message = &[chain_id.to_be_byte_array().as_slice(), &hashed_message].concat();

  let algo = Schnorr::<Secp256k1, EthereumHram>::new();
  let sig = sign(
    &mut OsRng,
    algo.clone(),
    keys.clone(),
    algorithm_machines(&mut OsRng, algo, &keys),
    full_message,
  );

  let (sr, er) =
    preprocess_signature_for_ecrecover(hashed_message, &sig.R, sig.s, &group_key, chain_id);
  let q = ecrecover(sr, group_key_compressed[0] - 2, group_key_x, er).unwrap();
  assert_eq!(q, address(&sig.R));
}