////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed 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.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Jan Steemann
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGOD_STORAGE_ENGINE_TRANSACTION_STATE_H
#define ARANGOD_STORAGE_ENGINE_TRANSACTION_STATE_H 1

#include "Basics/Common.h"
#include "Basics/Result.h"
#include "Basics/SmallVector.h"
#include "Cluster/ServerState.h"
#include "Transaction/Hints.h"
#include "Transaction/Options.h"
#include "Transaction/Status.h"
#include "VocBase/AccessMode.h"
#include "VocBase/voc-types.h"

#ifdef ARANGODB_ENABLE_MAINTAINER_MODE

#define LOG_TRX(trx, level)  \
  LOG_TOPIC(TRACE, arangodb::Logger::TRANSACTIONS) << "#" << trx->id() << "." << level << " (" << transaction::statusString(trx->status()) << "): " 

#else

#define LOG_TRX(...) while (0) LOG_TOPIC(TRACE, arangodb::Logger::TRANSACTIONS)

#endif

struct TRI_vocbase_t;

namespace arangodb {
namespace transaction {
class Methods;
struct Options;
}
class TransactionCollection;

/// @brief transaction type
class TransactionState {
 public:
  TransactionState() = delete;
  TransactionState(TransactionState const&) = delete;
  TransactionState& operator=(TransactionState const&) = delete;

  TransactionState(TRI_vocbase_t* vocbase, transaction::Options const&);
  virtual ~TransactionState();

  bool isRunningInCluster() const { return ServerState::isRunningInCluster(_serverRole); }
  bool isDBServer() const { return ServerState::isDBServer(_serverRole); }
  bool isCoordinator() const { return ServerState::isCoordinator(_serverRole); }

  transaction::Options& options() { return _options; }
  transaction::Options const& options() const { return _options; }
  TRI_vocbase_t* vocbase() const { return _vocbase; }
  TRI_voc_tid_t id() const { return _id; }
  transaction::Status status() const { return _status; }
  bool isRunning() const { return _status == transaction::Status::RUNNING; }

  int increaseNesting() { return ++_nestingLevel; }
  int decreaseNesting() { 
    TRI_ASSERT(_nestingLevel > 0);
    return --_nestingLevel; 
  }
  int nestingLevel() const { return _nestingLevel; }
  bool isTopLevelTransaction() const { return _nestingLevel == 0; }
  bool isEmbeddedTransaction() const { return !isTopLevelTransaction(); }

  double timeout() const { return _options.lockTimeout; }
  void timeout(double value) { 
    if (value > 0.0) {
      _options.lockTimeout = value;
    } 
  }

  bool waitForSync() const { return _options.waitForSync; }
  void waitForSync(bool value) { _options.waitForSync = value; }

  bool allowImplicitCollections() const { return _options.allowImplicitCollections; }
  void allowImplicitCollections(bool value) { _options.allowImplicitCollections = value; }

  std::vector<std::string> collectionNames() const;

  /// @brief return the collection from a transaction
  TransactionCollection* collection(TRI_voc_cid_t cid, AccessMode::Type accessType);

  /// @brief add a collection to a transaction
  int addCollection(TRI_voc_cid_t cid, AccessMode::Type accessType, int nestingLevel, bool force);

  /// @brief make sure all declared collections are used & locked
  Result ensureCollections(int nestingLevel = 0);

  /// @brief use all participating collections of a transaction
  Result useCollections(int nestingLevel);
  
  /// @brief release collection locks for a transaction
  int unuseCollections(int nestingLevel);
  
  int lockCollections();
  
  /// @brief whether or not a transaction consists of a single operation
  bool isSingleOperation() const {
    return hasHint(transaction::Hints::Hint::SINGLE_OPERATION);
  }

  /// @brief update the status of a transaction
  void updateStatus(transaction::Status status);
  
  /// @brief whether or not a specific hint is set for the transaction
  bool hasHint(transaction::Hints::Hint hint) const { return _hints.has(hint); }
  
  /// @brief set a hint for the transaction
  void setHint(transaction::Hints::Hint hint) { _hints.set(hint); }

  /// @brief begin a transaction
  virtual arangodb::Result beginTransaction(transaction::Hints hints) = 0;

  /// @brief commit a transaction
  virtual arangodb::Result commitTransaction(transaction::Methods* trx) = 0;

  /// @brief abort a transaction
  virtual arangodb::Result abortTransaction(transaction::Methods* trx) = 0;

  virtual bool hasFailedOperations() const = 0;
  
  TransactionCollection* findCollection(TRI_voc_cid_t cid) const;
  
  void setType(AccessMode::Type type);

 protected:
  /// @brief find a collection in the transaction's list of collections
  TransactionCollection* findCollection(TRI_voc_cid_t cid, size_t& position) const;

  /// @brief whether or not a transaction is read-only
  bool isReadOnlyTransaction() const {
    return (_type == AccessMode::Type::READ);
  }

  /// @brief release collection locks for a transaction
  int releaseCollections();

  /// @brief clear the query cache for all collections that were modified by
  /// the transaction
  void clearQueryCache();

 protected:
  TRI_vocbase_t* _vocbase;            // vocbase
  TRI_voc_tid_t _id;                  // local trx id
  AccessMode::Type _type;             // access type (read|write)
  transaction::Status _status;        // current status
 
  SmallVector<TransactionCollection*>::allocator_type::arena_type _arena; // memory for collections
  SmallVector<TransactionCollection*> _collections; // list of participating collections
  
  ServerState::RoleEnum const _serverRole;  // role of the server

  transaction::Hints _hints;          // hints;
  int _nestingLevel;

  transaction::Options _options;
};

}

#endif