////////////////////////////////////////////////////////////////////////////////
/// 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_ATTRIBUTE_ACCESSOR_H
#define ARANGOD_AQL_ATTRIBUTE_ACCESSOR_H 1

#include "Basics/Common.h"
#include "Aql/AqlValue.h"
#include "Aql/types.h"

namespace arangodb {
class Transaction;

namespace aql {

class AqlItemBlock;
class ExpressionContext;
struct Variable;

/// @brief AttributeAccessor
class AttributeAccessor {
 public:
  AttributeAccessor(std::vector<std::string>&&, Variable const*);
  ~AttributeAccessor() = default;

  /// @brief execute the accessor
  AqlValue getSystem(arangodb::Transaction* trx, ExpressionContext* context, bool& mustDestroy);
  AqlValue getDynamic(arangodb::Transaction* trx, ExpressionContext* context, bool& mustDestroy);
    
 public:
  void replaceVariable(std::unordered_map<VariableId, Variable const*> const& replacements);
 
  bool isSystem() const {
    return (_type == EXTRACT_KEY || _type == EXTRACT_ID || _type == EXTRACT_FROM || _type == EXTRACT_TO);
  }

  bool isDynamic() const {
    return !isSystem();
  }

 private:
  enum AccessorType {
    EXTRACT_KEY,
    EXTRACT_ID,
    EXTRACT_FROM,
    EXTRACT_TO,
    EXTRACT_SINGLE,
    EXTRACT_MULTI
  };

  /// @brief the attribute names vector (e.g. [ "a", "b", "c" ] for a.b.c)
  std::vector<std::string> const _attributeParts;

  /// @brief the accessed variable
  Variable const* _variable;

  /// @brief type of the accessor
  AccessorType _type;
};

}  // namespace arangodb::aql
}  // namespace arangodb

#endif