////////////////////////////////////////////////////////////////////////////////
/// 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 Max Neunhoeffer
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGOD_AQL_CLUSTER_BLOCKS_H
#define ARANGOD_AQL_CLUSTER_BLOCKS_H 1

#include "Aql/ClusterNodes.h"
#include "Aql/ExecutionBlock.h"
#include "Aql/ExecutionState.h"
#include "Basics/Result.h"

#include <velocypack/Builder.h>

#include <cstdint>
#include <string>
#include <unordered_map>
#include <utility>
#include <vector>

namespace arangodb {

namespace httpclient {
class SimpleHttpResult;
}

namespace transaction {
class Methods;
}

namespace aql {
class AqlItemBlock;
struct Collection;
class ExecutionEngine;
class ExecutionNode;

class BlocksWithClients : public ExecutionBlock {
 public:
  BlocksWithClients(ExecutionEngine* engine, ExecutionNode const* ep,
                    std::vector<std::string> const& shardIds);

  ~BlocksWithClients() override = default;

 public:
  /// @brief shutdown
  std::pair<ExecutionState, Result> shutdown(int) override;

  std::pair<ExecutionState, bool> getBlock(size_t atMost);

  /// @brief getSome: shouldn't be used, use skipSomeForShard
  std::pair<ExecutionState, SharedAqlItemBlockPtr> getSome(size_t atMost) final;

  /// @brief skipSome: shouldn't be used, use skipSomeForShard
  std::pair<ExecutionState, size_t> skipSome(size_t atMost) final;

  /// @brief getSomeForShard
  virtual std::pair<ExecutionState, SharedAqlItemBlockPtr> getSomeForShard(
      size_t atMost, std::string const& shardId) = 0;

  /// @brief skipSomeForShard
  virtual std::pair<ExecutionState, size_t> skipSomeForShard(size_t atMost,
                                                             std::string const& shardId) = 0;

  std::tuple<ExecutionState, size_t, SharedAqlItemBlockPtr> execute(AqlCallStack stack) override;

 protected:
  /// @brief getClientId: get the number <clientId> (used internally)
  /// corresponding to <shardId>
  size_t getClientId(std::string const& shardId) const;

  /// @brief _shardIdMap: map from shardIds to clientNrs
  std::unordered_map<std::string, size_t> _shardIdMap;

  /// @brief _nrClients: total number of clients
  size_t _nrClients;

  /// @brief type of distribution that this nodes follows.
  ScatterNode::ScatterType _type;

 private:
  bool _wasShutdown;
};

}  // namespace aql
}  // namespace arangodb

#endif