////////////////////////////////////////////////////////////////////////////////
/// 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 Dr. Frank Celler
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGOD_VOC_BASE_EDGE_COLLECTION_H
#define ARANGOD_VOC_BASE_EDGE_COLLECTION_H 1

#include "Basics/Common.h"
#include "Basics/Exceptions.h"
#include "VocBase/voc-types.h"
#include "VocBase/document-collection.h"

////////////////////////////////////////////////////////////////////////////////
/// @brief edge direction
////////////////////////////////////////////////////////////////////////////////

typedef enum {
  TRI_EDGE_ANY = 0,  // can only be used for searching
  TRI_EDGE_IN = 1,
  TRI_EDGE_OUT = 2
} TRI_edge_direction_e;

////////////////////////////////////////////////////////////////////////////////
/// @brief index entry for edges
////////////////////////////////////////////////////////////////////////////////

struct TRI_edge_header_t {
  TRI_edge_header_t(TRI_voc_cid_t cid, TRI_voc_key_t key)
      : _cid(cid), _key(key) {}

  TRI_voc_cid_t _cid;  // from or to, depending on the direction
  TRI_voc_key_t _key;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief edge index iterator
////////////////////////////////////////////////////////////////////////////////

struct TRI_edge_index_iterator_t {
  TRI_edge_index_iterator_t(TRI_edge_direction_e direction, TRI_voc_cid_t cid,
                            TRI_voc_key_t key)
      : _direction(direction), _edge(cid, nullptr) {
    TRI_ASSERT(key != nullptr);

    _edge._key = TRI_DuplicateString(TRI_UNKNOWN_MEM_ZONE, key);

    if (_edge._key == nullptr) {
      THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY);
    }
  }

  TRI_edge_index_iterator_t(TRI_edge_direction_e direction, TRI_voc_cid_t cid,
                            char const* key)
      : _direction(direction), _edge({cid, nullptr}) {
    TRI_ASSERT(key != nullptr);
    _edge._key = TRI_DuplicateString(TRI_UNKNOWN_MEM_ZONE, key);
    if (_edge._key == nullptr) {
      THROW_ARANGO_EXCEPTION(TRI_ERROR_OUT_OF_MEMORY);
    }
  }

  ~TRI_edge_index_iterator_t() {
    if (_edge._key != nullptr) {
      TRI_FreeString(TRI_UNKNOWN_MEM_ZONE, _edge._key);
    }
  }

  TRI_edge_direction_e const _direction;
  TRI_edge_header_t _edge;
};

////////////////////////////////////////////////////////////////////////////////
/// @brief looks up edges
////////////////////////////////////////////////////////////////////////////////

std::vector<TRI_doc_mptr_copy_t> TRI_LookupEdgesDocumentCollection(
    arangodb::Transaction*, struct TRI_document_collection_t*,
    TRI_edge_direction_e, TRI_voc_cid_t, TRI_voc_key_t const);

#endif