////////////////////////////////////////////////////////////////////////////////
/// 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 Michael Hackstein
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGOD_EDGE_COLLECTION_INFO_H
#define ARANGOD_EDGE_COLLECTION_INFO_H 1

#include "VocBase/Traverser.h"

namespace arangodb {
class Transaction;

namespace traverser {

////////////////////////////////////////////////////////////////////////////////
/// @brief Information required internally of the traverser.
///        Used to easily pass around collections.
///        Also offer abstraction to extract edges.
////////////////////////////////////////////////////////////////////////////////

class EdgeCollectionInfo {

 private:
  //////////////////////////////////////////////////////////////////////////////
  /// @brief the underlying transaction
  //////////////////////////////////////////////////////////////////////////////

  arangodb::Transaction* _trx;

  //////////////////////////////////////////////////////////////////////////////
  /// @brief edge collection name
  //////////////////////////////////////////////////////////////////////////////

  std::string _collectionName;

  //////////////////////////////////////////////////////////////////////////////
  /// @brief index id
  //////////////////////////////////////////////////////////////////////////////

  arangodb::Transaction::IndexHandle _indexId;

  //////////////////////////////////////////////////////////////////////////////
  /// @brief Temporary builder for index search values
  ///        NOTE: Single search builder is NOT thread-save
  //////////////////////////////////////////////////////////////////////////////

  VPackBuilder _searchBuilder;

  std::string _weightAttribute;

  double _defaultWeight;

  TRI_edge_direction_e _forwardDir;

  TRI_edge_direction_e _backwardDir;

  std::vector<arangodb::traverser::TraverserExpression*> _unused;

 public:

  EdgeCollectionInfo(arangodb::Transaction* trx,
                     std::string const& collectionName,
                     TRI_edge_direction_e const direction,
                     std::string const& weightAttribute,
                     double defaultWeight);

////////////////////////////////////////////////////////////////////////////////
/// @brief Get edges for the given direction and start vertex.
////////////////////////////////////////////////////////////////////////////////

  std::unique_ptr<arangodb::OperationCursor> getEdges(std::string const&);

  std::unique_ptr<arangodb::OperationCursor> getEdges(arangodb::velocypack::Slice const&);

////////////////////////////////////////////////////////////////////////////////
/// @brief Get edges for the given direction and start vertex. On Coordinator.
////////////////////////////////////////////////////////////////////////////////

  int getEdgesCoordinator(arangodb::velocypack::Slice const&,
                          arangodb::velocypack::Builder&);

////////////////////////////////////////////////////////////////////////////////
/// @brief Get edges for the given direction and start vertex. Reverse version
////////////////////////////////////////////////////////////////////////////////

  std::unique_ptr<arangodb::OperationCursor> getReverseEdges(std::string const&);

  std::unique_ptr<arangodb::OperationCursor> getReverseEdges(arangodb::velocypack::Slice const&);

////////////////////////////////////////////////////////////////////////////////
/// @brief Get edges for the given direction and start vertex. Reverse version on Coordinator.
////////////////////////////////////////////////////////////////////////////////

  int getReverseEdgesCoordinator(arangodb::velocypack::Slice const&,
                                 arangodb::velocypack::Builder&);

  double weightEdge(arangodb::velocypack::Slice const);
  
  arangodb::Transaction* trx() const { return _trx; }

////////////////////////////////////////////////////////////////////////////////
/// @brief Return name of the wrapped collection
////////////////////////////////////////////////////////////////////////////////

  std::string const& getName() const; 

};

}
}

#endif