src/main/cpp/rocketmq/include/SendCallbacks.h

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */
#pragma once

#include <memory>
#include <system_error>

#include "absl/container/flat_hash_map.h"
#include "absl/synchronization/mutex.h"
#include "apache/rocketmq/v1/service.grpc.pb.h"
#include "opencensus/trace/span.h"

#include "TransactionImpl.h"
#include "rocketmq/AsyncCallback.h"
#include "rocketmq/ErrorCode.h"
#include "rocketmq/MQMessage.h"
#include "rocketmq/MQMessageQueue.h"

ROCKETMQ_NAMESPACE_BEGIN

using SendMessageRequest = apache::rocketmq::v1::SendMessageRequest;

class OnewaySendCallback : public SendCallback {
public:
  void onSuccess(SendResult& send_result) noexcept override;

  void onFailure(const std::error_code& ec) noexcept override;
};

OnewaySendCallback* onewaySendCallback();

class AwaitSendCallback : public SendCallback {
public:
  void onSuccess(SendResult& send_result) noexcept override;

  void onFailure(const std::error_code& ec) noexcept override;

  void await();

  explicit operator bool() const {
    return !ec_.operator bool();
  }

  const SendResult& sendResult() const {
    return send_result_;
  }

  const std::error_code& errorCode() const {
    return ec_;
  }

private:
  absl::Mutex mtx_;
  absl::CondVar cv_;
  bool completed_{false};
  SendResult send_result_;
  std::error_code ec_;
};

class ProducerImpl;

class RetrySendCallback : public SendCallback {
public:
  RetrySendCallback(std::weak_ptr<ProducerImpl> producer, MQMessage message, int max_attempt_times,
                    SendCallback* callback, std::vector<MQMessageQueue> candidates)
      : producer_(std::move(producer)), message_(std::move(message)), max_attempt_times_(max_attempt_times),
        callback_(callback), candidates_(std::move(candidates)), span_(opencensus::trace::Span::BlankSpan()) {
  }

  void onSuccess(SendResult& send_result) noexcept override;

  void onFailure(const std::error_code& ec) noexcept override;

  MQMessage& message() {
    return message_;
  }

  int attemptTime() const {
    return attempt_times_;
  }

  const MQMessageQueue& messageQueue() const {
    int index = attempt_times_ % candidates_.size();
    return candidates_[index];
  }

  opencensus::trace::Span& span() {
    return span_;
  }

private:
  std::weak_ptr<ProducerImpl> producer_;
  MQMessage message_;
  int attempt_times_{0};
  int max_attempt_times_;
  SendCallback* callback_{nullptr};

  /**
   * @brief Once the first publish attempt failed, the following routable
   * message queues are employed.
   *
   */
  std::vector<MQMessageQueue> candidates_;

  /**
   * @brief The on-going span. Should be terminated in the callback functions.
   */
  opencensus::trace::Span span_;
};

ROCKETMQ_NAMESPACE_END