// Copyright (c) 2011-2015, Francois Saint-Jacques
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
//       documentation and/or other materials provided with the distribution.
//     * Neither the name of the disruptor-- nor the
//       names of its contributors may be used to endorse or promote products
//       derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL FRANCOIS SAINT-JACQUES BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
// THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef DISRUPTOR_EVENT_PROCESSOR_H_  // NOLINT
#define DISRUPTOR_EVENT_PROCESSOR_H_  // NOLINT

#include <stdexcept>

#include "disruptor/ring_buffer.h"

namespace disruptor {

template <typename T>
class NoOpEventProcessor : public EventProcessorInterface<T> {
 public:
  NoOpEventProcessor(RingBuffer<T>* ring_buffer) : ring_buffer_(ring_buffer) {}

  virtual Sequence* GetSequence() { return ring_buffer_->GetSequencePtr(); }

  virtual void Halt() {}

  virtual void Run() {}

 private:
  RingBuffer<T>* ring_buffer_;
};

template <typename T>
class BatchEventProcessor : public EventProcessorInterface<T> {
 public:
  BatchEventProcessor(RingBuffer<T>* ring_buffer,
                      SequenceBarrierInterface* sequence_barrier,
                      EventHandlerInterface<T>* event_handler,
                      ExceptionHandlerInterface<T>* exception_handler)
      : running_(false),
        ring_buffer_(ring_buffer),
        sequence_barrier_(sequence_barrier),
        event_handler_(event_handler),
        exception_handler_(exception_handler) {}

  virtual Sequence* GetSequence() { return &sequence_; }

  virtual void Halt() {
    running_.store(false);
    sequence_barrier_->Alert();
  }

  virtual void Run() {
    if (running_.load()) throw std::runtime_error("Thread is already running");

    running_.store(true);
    sequence_barrier_->ClearAlert();
    event_handler_->OnStart();

    T* event = NULL;
    int64_t next_sequence = sequence_.sequence() + 1L;

    while (true) {
      try {
        int64_t available_sequence = sequence_barrier_->WaitFor(next_sequence);

        while (next_sequence <= available_sequence) {
          event = ring_buffer_->Get(next_sequence);
          event_handler_->OnEvent(next_sequence,
                                  next_sequence == available_sequence, event);
          next_sequence++;
        }

        sequence_.set_sequence(next_sequence - 1L);
      } catch (const AlertException& e) {
        if (!running_.load()) break;
      } catch (const std::exception& e) {
        exception_handler_->Handle(e, next_sequence, event);
        sequence_.set_sequence(next_sequence);
        next_sequence++;
      }
    }

    event_handler_->OnShutdown();
    running_.store(false);
  }

  void operator()() { Run(); }

 private:
  std::atomic<bool> running_;
  Sequence sequence_;

  RingBuffer<T>* ring_buffer_;
  SequenceBarrierInterface* sequence_barrier_;
  EventHandlerInterface<T>* event_handler_;
  ExceptionHandlerInterface<T>* exception_handler_;

  DISALLOW_COPY_MOVE_AND_ASSIGN(BatchEventProcessor);
};

};  // namespace disruptor

#endif  // DISRUPTOR_EVENT_PROCESSOR_H_ NOLINT