////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2016 ArangoDB 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 Simon Grätzer
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGODB_PREGEL_ALGOS_SSSP_H
#define ARANGODB_PREGEL_ALGOS_SSSP_H 1

#include "Pregel/Algorithm.h"

namespace arangodb {
namespace pregel {
namespace algos {

/// Single Source Shortest Path. Uses integer attribute 'value', the source
/// should have
/// the value == 0, all others -1 or an undefined value
class SSSPAlgorithm : public Algorithm<int64_t, int64_t, int64_t> {
  std::string _sourceDocumentId, _resultField = "result";

 public:
  explicit SSSPAlgorithm(application_features::ApplicationServer& server, VPackSlice userParams)
      : Algorithm(server, "SSSP") {
    if (!userParams.isObject() || !userParams.hasKey("source")) {
      THROW_ARANGO_EXCEPTION_MESSAGE(
          TRI_ERROR_BAD_PARAMETER,
          "You need to specify the source document id");
    }
    _sourceDocumentId = userParams.get("source").copyString();
    VPackSlice slice = userParams.get("_resultField");
    if (slice.isString()) {
      _resultField = slice.copyString();
    }
  }

  bool supportsAsyncMode() const override { return true; }
  bool supportsCompensation() const override { return true; }

  GraphFormat<int64_t, int64_t>* inputFormat() const override;

  MessageFormat<int64_t>* messageFormat() const override {
    return new IntegerMessageFormat();
  }

  MessageCombiner<int64_t>* messageCombiner() const override {
    return new MinCombiner<int64_t>();
  }

  VertexComputation<int64_t, int64_t, int64_t>* createComputation(WorkerConfig const*) const override;
  VertexCompensation<int64_t, int64_t, int64_t>* createCompensation(WorkerConfig const*) const override;

  uint32_t messageBatchSize(WorkerConfig const& config, MessageStats const& stats) const override;
};
}  // namespace algos
}  // namespace pregel
}  // namespace arangodb
#endif