// Copyright 2025 The BoringSSL Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <cstring>

#include <benchmark/benchmark.h>

#include <openssl/base.h>
#include <openssl/bn.h>
#include <openssl/ec.h>
#include <openssl/ecdsa.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/mem.h>

#include "../crypto/internal.h"
#include "./internal.h"

BSSL_NAMESPACE_BEGIN
namespace {

static constexpr size_t kMaxSignature = 256;
static constexpr size_t kMaxDigestSize = 66;  // ceil(521 / 8) for P-521

void BM_SpeedECDSASign(benchmark::State &state, const EC_GROUP *group) {
  UniquePtr<EC_KEY> key(EC_KEY_new());
  if (!key || !EC_KEY_set_group(key.get(), group) ||
      !EC_KEY_generate_key(key.get())) {
    state.SkipWithError("keygen failed.");
    return;
  }

  const size_t digest_len = BN_num_bytes(EC_GROUP_get0_order(group));
  if (digest_len > kMaxDigestSize || ECDSA_size(key.get()) > kMaxSignature) {
    state.SkipWithError("key or digest is too large.");
    return;
  }

  uint8_t digest[kMaxDigestSize];
  OPENSSL_memset(digest, 42, digest_len);
  uint8_t out[kMaxSignature];

  for (auto _ : state) {
    unsigned out_len = 0;
    benchmark::ClobberMemory();
    benchmark::DoNotOptimize(digest);


    if (!ECDSA_sign(0, digest, digest_len, out, &out_len, key.get())) {
      state.SkipWithError("signing failed.");
      return;
    }

    benchmark::DoNotOptimize(out);
    benchmark::DoNotOptimize(out_len);
  }
}

void BM_SpeedECDSAVerify(benchmark::State &state, const EC_GROUP *group) {
  uint8_t digest[kMaxDigestSize];
  const size_t digest_len = BN_num_bytes(EC_GROUP_get0_order(group));
  if (digest_len > kMaxDigestSize) {
    state.SkipWithError("digest is too large.");
    return;
  }

  OPENSSL_memset(digest, 42, digest_len);

  // Declared outside of the loop to avoid running object destructor while
  // timing.
  UniquePtr<EC_KEY> key;
  uint8_t signature[kMaxSignature];
  unsigned sig_len;

  for (auto _ : state) {
    state.PauseTiming();

    key = UniquePtr<EC_KEY>(EC_KEY_new());
    if (!key || !EC_KEY_set_group(key.get(), group) ||
        !EC_KEY_generate_key(key.get())) {
      state.SkipWithError("keygen failed.");
      return;
    }

    if (ECDSA_size(key.get()) > kMaxSignature) {
      state.SkipWithError("key is too large.");
      return;
    }

    if (!ECDSA_sign(0, digest, digest_len, signature, &sig_len, key.get())) {
      state.SkipWithError("signing failed.");
      return;
    }

    benchmark::DoNotOptimize(signature);
    benchmark::DoNotOptimize(sig_len);
    benchmark::ClobberMemory();

    state.ResumeTiming();

    if (!ECDSA_verify(0, digest, digest_len, signature, sig_len, key.get())) {
      state.SkipWithError("verification failed.");
      return;
    }
  }
}

BSSL_BENCH_LAZY_REGISTER() {
  BENCHMARK_CAPTURE(BM_SpeedECDSASign, p224, EC_group_p224())
      ->Apply(bench::SetThreads);
  BENCHMARK_CAPTURE(BM_SpeedECDSASign, p256, EC_group_p256())
      ->Apply(bench::SetThreads);
  BENCHMARK_CAPTURE(BM_SpeedECDSASign, p384, EC_group_p384())
      ->Apply(bench::SetThreads);
  BENCHMARK_CAPTURE(BM_SpeedECDSASign, p521, EC_group_p521())
      ->Apply(bench::SetThreads);

  BENCHMARK_CAPTURE(BM_SpeedECDSAVerify, p224, EC_group_p224())
      ->Apply(bench::SetThreads);
  BENCHMARK_CAPTURE(BM_SpeedECDSAVerify, p256, EC_group_p256())
      ->Apply(bench::SetThreads);
  BENCHMARK_CAPTURE(BM_SpeedECDSAVerify, p384, EC_group_p384())
      ->Apply(bench::SetThreads);
  BENCHMARK_CAPTURE(BM_SpeedECDSAVerify, p521, EC_group_p521())
      ->Apply(bench::SetThreads);
}

}  // namespace
BSSL_NAMESPACE_END