/*
 *
 * Copyright 2018 gRPC 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
 *
 *     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.
 *
 */

#include <functional>
#include <mutex>

#include <grpcpp/channel.h>
#include <grpcpp/client_context.h>
#include <grpcpp/create_channel.h>
#include <grpcpp/generic/generic_stub.h>
#include <grpcpp/impl/codegen/proto_utils.h>
#include <grpcpp/server.h>
#include <grpcpp/server_builder.h>
#include <grpcpp/server_context.h>
#include <grpcpp/support/client_callback.h>

#include "src/proto/grpc/testing/echo.grpc.pb.h"
#include "test/core/util/test_config.h"
#include "test/cpp/end2end/test_service_impl.h"
#include "test/cpp/util/byte_buffer_proto_helper.h"

#include <gtest/gtest.h>

namespace grpc {
namespace testing {
namespace {

class ClientCallbackEnd2endTest : public ::testing::Test {
 protected:
  ClientCallbackEnd2endTest() {}

  void SetUp() override {
    ServerBuilder builder;
    builder.RegisterService(&service_);

    server_ = builder.BuildAndStart();
    is_server_started_ = true;
  }

  void ResetStub() {
    ChannelArguments args;
    channel_ = server_->InProcessChannel(args);
    stub_.reset(new GenericStub(channel_));
  }

  void TearDown() override {
    if (is_server_started_) {
      server_->Shutdown();
    }
  }

  void SendRpcs(int num_rpcs, bool maybe_except) {
    const grpc::string kMethodName("/grpc.testing.EchoTestService/Echo");
    grpc::string test_string("");
    for (int i = 0; i < num_rpcs; i++) {
      EchoRequest request;
      std::unique_ptr<ByteBuffer> send_buf;
      ByteBuffer recv_buf;
      ClientContext cli_ctx;

      test_string += "Hello world. ";
      request.set_message(test_string);
      send_buf = SerializeToByteBuffer(&request);

      std::mutex mu;
      std::condition_variable cv;
      bool done = false;
      stub_->experimental().UnaryCall(
          &cli_ctx, kMethodName, send_buf.get(), &recv_buf,
          [&request, &recv_buf, &done, &mu, &cv, maybe_except](Status s) {
            GPR_ASSERT(s.ok());

            EchoResponse response;
            EXPECT_TRUE(ParseFromByteBuffer(&recv_buf, &response));
            EXPECT_EQ(request.message(), response.message());
            std::lock_guard<std::mutex> l(mu);
            done = true;
            cv.notify_one();
#if GRPC_ALLOW_EXCEPTIONS
            if (maybe_except) {
              throw - 1;
            }
#endif
          });
      std::unique_lock<std::mutex> l(mu);
      while (!done) {
        cv.wait(l);
      }
    }
  }
  bool is_server_started_;
  std::shared_ptr<Channel> channel_;
  std::unique_ptr<grpc::GenericStub> stub_;
  TestServiceImpl service_;
  std::unique_ptr<Server> server_;
};

TEST_F(ClientCallbackEnd2endTest, SimpleRpc) {
  ResetStub();
  SendRpcs(1, false);
}

TEST_F(ClientCallbackEnd2endTest, SequentialRpcs) {
  ResetStub();
  SendRpcs(10, false);
}

#if GRPC_ALLOW_EXCEPTIONS
TEST_F(ClientCallbackEnd2endTest, ExceptingRpc) {
  ResetStub();
  SendRpcs(10, true);
}
#endif

}  // namespace
}  // namespace testing
}  // namespace grpc

int main(int argc, char** argv) {
  grpc_test_init(argc, argv);
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}