// Copyright 2022 Google LLC
//
// 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
//
//      http://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.
//
////////////////////////////////////////////////////////////////////////////////

package com.google.crypto.tink;

import static com.google.common.truth.Truth.assertThat;
import static java.util.concurrent.TimeUnit.DAYS;
import static org.junit.Assert.assertNotNull;

import com.google.crypto.tink.proto.KeyData;
import com.google.protobuf.ByteString;
import java.security.GeneralSecurityException;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

/** Thread safety tests for {@link Registry}. */
@RunWith(JUnit4.class)
public final class RegistryMultithreadTest {
  private static class TestKeyManager implements KeyManager<Aead> {
    public TestKeyManager(String typeUrl) {
      this.typeUrl = typeUrl;
    }

    private final String typeUrl;

    @Override
    public Aead getPrimitive(ByteString serializedKey) throws GeneralSecurityException {
      throw new UnsupportedOperationException("Not needed for test");
    }

    @Override
    public KeyData newKeyData(ByteString serializedKeyFormat) throws GeneralSecurityException {
      throw new UnsupportedOperationException("Not needed for test");
    }

    @Override
    public String getKeyType() {
      return this.typeUrl;
    }

    @Override
    public Class<Aead> getPrimitiveClass() {
      return Aead.class;
    }
  }

  private static final int REPETITIONS = 200;

  @Test
  public void registerAndGetKeyManager_works() throws Exception {
    ExecutorService threadPool = Executors.newFixedThreadPool(4);
    List<Future<?>> futures = new ArrayList<>();
    Registry.registerKeyManager(new TestKeyManager("KeyManagerStart"), false);
    futures.add(
        threadPool.submit(
            () -> {
              try {
                for (int i = 0; i < REPETITIONS; ++i) {
                  Registry.registerKeyManager(new TestKeyManager("KeyManager" + i), false);
                }
              } catch (GeneralSecurityException e) {
                throw new RuntimeException(e);
              }
            }));
    futures.add(
        threadPool.submit(
            () -> {
              try {
                for (int i = 0; i < REPETITIONS; ++i) {
                  assertNotNull(Registry.getUntypedKeyManager("KeyManagerStart"));
                }
              } catch (GeneralSecurityException e) {
                throw new RuntimeException(e);
              }
            }));

    threadPool.shutdown();
    // Wait forever: if the test times out we will notice independently.
    assertThat(threadPool.awaitTermination(1, DAYS)).isTrue();
    for (int i = 0; i < futures.size(); ++i) {
      futures.get(i).get(); // This will throw an exception if the thread threw an exception.
    }
  }

  // TODO(tholenst): Epxand the test coverage for primitive wrappers and catalogues.
}