// Copyright 2021, Roman Gershman.  All rights reserved.
// See LICENSE for licensing terms.
//

#pragma once

#include <vector>

#include "server/common_types.h"

namespace dfly {

// Present in every server thread. This class differs from EngineShard. The latter manages
// state around engine shards while the former represents coordinator/connection state.
// There may be threads that handle engine shards but not IO, there may be threads that handle IO
// but not engine shards and there can be threads that handle both. This class is present only
// for threads that handle IO and owne coordination fibers.
class ServerState {  // public struct - to allow initialization.
  ServerState(const ServerState&) = delete;
  void operator=(const ServerState&) = delete;

 public:
  static ServerState* tlocal() {
    return &state_;
  }

  static ConnectionStats* tl_connection_stats() {
    return &state_.connection_stats;
  }

  ServerState();
  ~ServerState();

  ConnectionStats connection_stats;

  void TxCountInc() {
    ++live_transactions_;
  }

  void TxCountDec() {
    --live_transactions_;  // can go negative since we can start on one thread and end on another.
  }

  int64_t live_transactions() const {
    return live_transactions_;
  }

 private:
  int64_t live_transactions_ = 0;

  static thread_local ServerState state_;
};

}  // namespace dfly