////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2018 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 Andrey Abramov
/// @author Vasiliy Nabatchikov
////////////////////////////////////////////////////////////////////////////////

#ifndef ARANGOD_IRESEARCH__IRESEARCH_EXPRESSION_CONTEXT_H
#define ARANGOD_IRESEARCH__IRESEARCH_EXPRESSION_CONTEXT_H 1

#include "Aql/ExecutionNode.h"
#include "Aql/InputAqlItemRow.h"
#include "Aql/QueryExpressionContext.h"
#include "Basics/Exceptions.h"

namespace arangodb {

namespace aql {
class AqlItemBlock;
struct AstNode;
class ExecutionEngine;
}  // namespace aql

namespace iresearch {

class IResearchViewNode;

///////////////////////////////////////////////////////////////////////////////
/// @struct ViewExpressionContextBase
/// @brief FIXME remove this struct once IResearchView will be able to evaluate
///        epxressions with loop variable in SEARCH expressions
///////////////////////////////////////////////////////////////////////////////
struct ViewExpressionContextBase : public aql::QueryExpressionContext {
  explicit ViewExpressionContextBase(arangodb::aql::Query* query)
      : aql::QueryExpressionContext(query) {}

  aql::AstNode const* _expr{};  // for troubleshooting
};                              // ViewExpressionContextBase

///////////////////////////////////////////////////////////////////////////////
/// @struct ViewExpressionContext
///////////////////////////////////////////////////////////////////////////////
struct ViewExpressionContext final : public ViewExpressionContextBase {
  using VarInfoMap = std::unordered_map<aql::VariableId, aql::ExecutionNode::VarInfo>;

  ViewExpressionContext(aql::Query* query, aql::RegisterId numRegs,
                        aql::Variable const& outVar,
                        VarInfoMap const& varInfoMap, int nodeDepth)
      : ViewExpressionContextBase(query),
        _numRegs(numRegs),
        _outVar(outVar),
        _varInfoMap(varInfoMap),
        _nodeDepth(nodeDepth) {}

  virtual size_t numRegisters() const override;

  virtual aql::AqlValue const& getRegisterValue(size_t i) const override {
    THROW_ARANGO_EXCEPTION(TRI_ERROR_NOT_IMPLEMENTED);
  }

  virtual aql::Variable const* getVariable(size_t i) const override {
    THROW_ARANGO_EXCEPTION(TRI_ERROR_NOT_IMPLEMENTED);
  }

  virtual aql::AqlValue getVariableValue(aql::Variable const* variable, bool doCopy,
                                         bool& mustDestroy) const override;

  inline aql::Variable const& outVariable() const noexcept { return _outVar; }
  inline VarInfoMap const& varInfoMap() const noexcept { return _varInfoMap; }
  inline int nodeDepth() const noexcept { return _nodeDepth; }

  aql::InputAqlItemRow _inputRow{aql::CreateInvalidInputRowHint{}};
  aql::RegisterId const _numRegs;
  aql::Variable const& _outVar;
  VarInfoMap const& _varInfoMap;
  int const _nodeDepth;
};  // ViewExpressionContext

}  // namespace iresearch
}  // namespace arangodb

#endif  // ARANGOD_IRESEARCH__IRESEARCH_EXPRESSION_CONTEXT_H 1