////////////////////////////////////////////////////////////////////////////////
/// 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
////////////////////////////////////////////////////////////////////////////////

#include "ClusterEdgeCursor.h"

#include "Cluster/ClusterMethods.h"
#include "Cluster/ClusterTraverser.h"
#include "Transaction/Helpers.h"
#include "Transaction/Methods.h"
#include "VocBase/TraverserCache.h"

#include <velocypack/Slice.h>
#include <velocypack/velocypack-aliases.h>

using ClusterEdgeCursor = arangodb::traverser::ClusterEdgeCursor;
using StringRef = arangodb::StringRef;

ClusterEdgeCursor::ClusterEdgeCursor(
    StringRef vertexId, uint64_t depth,
    arangodb::traverser::ClusterTraverser* traverser)
    : _position(0),
      _resolver(traverser->_trx->resolver()),
      _traverser(traverser) {
  transaction::BuilderLeaser leased(traverser->_trx);

  transaction::BuilderLeaser b(traverser->_trx);
  b->add(VPackValuePair(vertexId.data(), vertexId.length(),
                        VPackValueType::String));

  fetchEdgesFromEngines(traverser->_dbname, traverser->_engines, b->slice(),
                        depth, traverser->_edges, _edgeList,
                        traverser->_datalake, *(leased.get()),
                        traverser->_filteredPaths, traverser->_readDocuments);
}

bool ClusterEdgeCursor::next(
    std::function<void(StringRef const&, VPackSlice, size_t)> callback) {
  if (_position < _edgeList.size()) {
    VPackSlice edge = _edgeList[_position];
    std::string eid =
        transaction::helpers::extractIdString(_resolver, edge, VPackSlice());
    StringRef persId =
        _traverser->traverserCache()->persistString(StringRef(eid));
    callback(persId, edge, _position);
    ++_position;
    return true;
  }
  return false;
}

void ClusterEdgeCursor::readAll(
    std::function<void(StringRef const&, VPackSlice, size_t&)> callback) {
  for (auto const& edge : _edgeList) {
    std::string eid =
        transaction::helpers::extractIdString(_resolver, edge, VPackSlice());
    StringRef persId =
        _traverser->traverserCache()->persistString(StringRef(eid));
    callback(persId, edge, _position);
  }
}