/************************************************************************
 *
 * Copyright (c) 2016 Alibaba.com, Inc. All Rights Reserved
 * $Id:  witness.h,v 1.0 12/20/2016 07:15:45 PM jarry.zj(jarry.zj@alibaba-inc.com) $
 *
 ************************************************************************/

/**
 * @file witness.h
 * @author jarry.zj(jarry.zj@alibaba-inc.com)
 * @date 12/20/2016 07:15:45 PM
 * @version 1.0
 * @brief Witness node in paxos protocol
 *
 **/

#ifndef ALICONSENSUS_INCLUDE_WITNESS_H_
#define ALICONSENSUS_INCLUDE_WITNESS_H_

#include <mutex>
#include <condition_variable>
#include <memory>
#include <string>
#include "consensus.h"
#include "mem_paxos_log.h"
#include "service.h"
#include "thread_timer.h"

extern easy_log_level_t easy_log_level;
#define PRINT_TIME() do {struct timeval tv;if (easy_log_level>=EASY_LOG_INFO) {gettimeofday(&tv, NULL);printf("TS:%ld.%06ld ",tv.tv_sec, tv.tv_usec);std::cout<<std::flush;}} while (0)
namespace alisql {

class Witness : public Consensus {
public:
  Witness(std::string addr, std::shared_ptr<MemPaxosLog> log, uint64_t clusterId = 0,
          uint64_t ioThreadCnt = 4, uint64_t workThreadCnt = 4);
  virtual ~Witness();

  /* Callback for witness */
  virtual int onAppendLog(PaxosMsg *msg, PaxosMsg *rsp);

  /* functions do not need to implement */
  virtual int onRequestVote(PaxosMsg *msg, PaxosMsg *rsp);
  virtual int onRequestVoteResponce(PaxosMsg *msg) {return 0;}
  virtual int onAppendLogSendFail(PaxosMsg *msg, uint64_t *newId= nullptr) {return 0;}
  virtual int onAppendLogResponce(PaxosMsg *msg) {return 0;}
  virtual int requestVote(bool force) {return 0;}
  virtual uint64_t replicateLog(LogEntry &entry) {return 0;}
  virtual int appendLog(const bool needLock) {return 0;}
  virtual int onLeaderCommand(PaxosMsg *msg, PaxosMsg *rsp);
  virtual int onLeaderCommandResponce(PaxosMsg *msg) {return 0;};
  virtual int onClusterIdNotMatch(PaxosMsg *msg){return 0;};
  virtual int onMsgPreCheck(PaxosMsg *msg, PaxosMsg *rsp) {return 0;}
  virtual int onMsgPreCheckFailed(PaxosMsg *msg) {return 0;}

  void updateAppliedIndex(uint64_t index);
  const uint64_t getCommitIndex() {return commitIndex_;}
  void setCommitIndex(uint64_t ci) {commitIndex_ = ci;}
  uint64_t getLastLogIndex() {return log_->getLastLogIndex();}
  uint64_t getCurrentLeader() {return leaderId_;}
  std::shared_ptr<MemPaxosLog> getLog() {return log_;}
  virtual uint64_t getClusterId() {return clusterId_.load();}
  virtual int setClusterId(uint64_t ci) {clusterId_.store(ci); return 0;}

  virtual void setLeaderChangeCb(std::function<void(uint64_t leaderId)> cb);
  bool isShutdown() {return shutdown_.load();}
  void resetLastLogIndex(uint64_t lli);

  static bool debugWitnessTest;

  protected:
  std::shared_ptr<MemPaxosLog> log_; /* MemPaxosLog is required */
  std::shared_ptr<Service> srv_;

  /* timeout unit is ms */
  uint64_t currentTerm_;
  uint64_t commitIndex_;
  std::atomic<uint64_t> appliedIndex_;
  uint64_t leaderId_;
  uint64_t serverId;
  std::atomic<uint64_t> clusterId_;
  std::atomic<bool> shutdown_;

  mutable std::mutex lock_;

  /* user-defined async callback functions */
  std::function<void(uint64_t leaderId)> leaderChangeHandler_;

  private:
  Witness(const Witness &other);
  const Witness& operator =(const Witness &other);
};

} //namespace alisql

#endif /* ALICONSENSUS_INCLUDE_WITNESS_H_ */