////////////////////////////////////////////////////////////////////////////////
/// 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 Jan Christoph Uhde
////////////////////////////////////////////////////////////////////////////////

#include "ExecutorExpressionContext.h"
#include "Aql/AqlItemBlock.h"
#include "Aql/AqlValue.h"
#include "Aql/InputAqlItemRow.h"
#include "Aql/Variable.h"
#include "Basics/Exceptions.h"

using namespace arangodb::aql;

size_t ExecutorExpressionContext::numRegisters() const {
  return _inputRow.getNrRegisters();
}

AqlValue const& ExecutorExpressionContext::getRegisterValue(size_t i) const {
  return _inputRow.getValue(static_cast<arangodb::aql::RegisterId>(i));
}

Variable const* ExecutorExpressionContext::getVariable(size_t i) const {
  return (_vars)[i];
}

AqlValue ExecutorExpressionContext::getVariableValue(Variable const* variable, bool doCopy,
                                                     bool& mustDestroy) const {
  mustDestroy = false;

  auto const searchId = variable->id;
  size_t i = -1;  // size_t is guaranteed to be unsigned so the overflow is ok
  for (auto const* var : _vars) {
    TRI_ASSERT(var != nullptr);
    ++i;
    if (var->id == searchId) {
      TRI_ASSERT(i < _regs.size());
      if (doCopy) {
        mustDestroy = true;  // as we are copying
        return _inputRow.getValue((_regs)[i]).clone();
      }
      return _inputRow.getValue((_regs)[i]);
    }
  }

  std::string msg("variable not found '");
  msg.append(variable->name);
  msg.append("' in executeSimpleExpression()");
  THROW_ARANGO_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL, msg.c_str());
}