/**
 *   Copyright 2011-2015 Quickstep Technologies LLC.
 *   Copyright 2015 Pivotal Software, Inc.
 *
 *   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.
 **/

#ifndef QUICKSTEP_QUERY_OPTIMIZER_EXPRESSIONS_UNARY_EXPRESSION_HPP_
#define QUICKSTEP_QUERY_OPTIMIZER_EXPRESSIONS_UNARY_EXPRESSION_HPP_

#include <memory>
#include <string>
#include <unordered_map>
#include <vector>

#include "query_optimizer/expressions/AttributeReference.hpp"
#include "query_optimizer/expressions/ExprId.hpp"
#include "query_optimizer/expressions/Expression.hpp"
#include "query_optimizer/expressions/ExpressionType.hpp"
#include "query_optimizer/expressions/Scalar.hpp"
#include "types/operations/unary_operations/UnaryOperation.hpp"
#include "utility/Macros.hpp"

#include "glog/logging.h"

namespace quickstep {

class CatalogAttribute;
class Scalar;
class Type;

namespace optimizer {
namespace expressions {

/** \addtogroup OptimizerExpressions
 *  @{
 */

class UnaryExpression;
typedef std::shared_ptr<const UnaryExpression> UnaryExpressionPtr;

class UnaryExpression : public Scalar {
 public:
  ExpressionType getExpressionType() const override {
    return ExpressionType::kUnaryExpression;
  }

  std::string getName() const override;

  bool isConstant() const override { return operand_->isConstant(); }

  /**
   * @return The unary operator.
   */
  const UnaryOperation& operation() const { return operation_; }

  /**
   * @return The operand of the unary operator.
   */
  const ScalarPtr& operand() const { return operand_; }

  const Type& getValueType() const override {
    return *(operation_.resultTypeForArgumentType(operand_->getValueType()));
  }

  ExpressionPtr copyWithNewChildren(
      const std::vector<ExpressionPtr> &new_children) const override;

  std::vector<AttributeReferencePtr> getReferencedAttributes() const override {
    return operand_->getReferencedAttributes();
  }

  ::quickstep::Scalar* concretize(
      const std::unordered_map<ExprId, const CatalogAttribute*> &substitution_map) const override;

  /**
   * @brief Creates an immutable UnaryExpression.
   *
   * @param operation The unary operation.
   * @param operand The operand.
   * @return An immutable UnaryExpression that applies the operation to the
   *         operand.
   */
  static UnaryExpressionPtr Create(const UnaryOperation &operation,
                                   const ScalarPtr &operand) {
    return UnaryExpressionPtr(new UnaryExpression(operation, operand));
  }

 protected:
  void getFieldStringItems(
      std::vector<std::string> *inline_field_names,
      std::vector<std::string> *inline_field_values,
      std::vector<std::string> *non_container_child_field_names,
      std::vector<OptimizerTreeBaseNodePtr> *non_container_child_fields,
      std::vector<std::string> *container_child_field_names,
      std::vector<std::vector<OptimizerTreeBaseNodePtr>> *container_child_fields) const override;

 private:
  UnaryExpression(const UnaryOperation &operation,
                  const ScalarPtr &operand)
      : operation_(operation), operand_(operand) {
    DCHECK(operation_.canApplyToType(operand_->getValueType())) << toString();
    addChild(operand);
  }

  const UnaryOperation &operation_;
  ScalarPtr operand_;

  DISALLOW_COPY_AND_ASSIGN(UnaryExpression);
};

/** @} */

}  // namespace expressions
}  // namespace optimizer
}  // namespace quickstep

#endif /* QUICKSTEP_QUERY_OPTIMIZER_EXPRESSIONS_UNARY_EXPRESSION_HPP_ */