/**
 * 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.
 **/

#ifndef QUICKSTEP_TRANSACTION_TRANSACTION_HPP_
#define QUICKSTEP_TRANSACTION_TRANSACTION_HPP_

#include <cstddef>
#include <cstdint>
#include <functional>

namespace quickstep {
namespace transaction {

/** \addtogroup Transaction
 *  @{
 */

/**
 * @brief Type that represents id of a transaction.
 **/
typedef std::uint64_t transaction_id;

/**
 * @brief Enum class for transaction internal status.
 **/
enum class TransactionStatus {
  kRunning = 0,
  kAborted,
  kCommitted
};

/**
 * @brief Transaction
 **/
class Transaction {
 public:
  /**
   * @brief Constructor for Transaction.
   *
   * @param tid Id of this transaction.
   **/
  explicit Transaction(transaction_id tid)
    : tid_(tid) {
  }

  /**
   * @brief Getter for transaction id.
   *
   * @return Transaction id of this.
   **/
  inline transaction_id getTransactionId() const {
    return tid_;
  }

  /**
   * @brief Setter for the transaction status.
   *
   * @param status New status of the transaction.
   **/
  inline void setStatus(TransactionStatus status) {
    status_ = status_;
  }

  /**
   * @brief Getter for the transaction status.
   *
   * @return Status of the transaction.
   **/
  inline TransactionStatus getStatus() const {
    return status_;
  }

  /**
   * @brief Equality operator for Transaction class.
   *
   * @param other Other transaction to be compared with.
   * @return True if other tid and this tid are equal, false otherwise.
   **/
  inline bool operator==(const Transaction &other) const {
    return tid_ == other.tid_;
  }

  /**
   * @brief Helper hasher class for transaction.
   **/
  struct TransactionHasher {
    std::size_t operator()(const Transaction &transaction) const {
      return std::hash<transaction_id>()(transaction.tid_);
    }
  };

 private:
  // Unique id for the transaction.
  transaction_id tid_;

  // Transaction's running status.
  TransactionStatus status_;
};

/** @} */

}  // namespace transaction
}  // namespace quickstep

#endif  // QUICKSTEP_TRANSACTION_TRANSACTION_HPP_