/**
 * TensorExpression.h
 *
 * Author: hedaoyuan (hedaoyuan@baidu.com)
 * Created on: 2016-06-06
 *
 * Copyright (c) Baidu.com, Inc. All Rights Reserved
 *
 */

#pragma once
#include <cstddef>
#include <stdint.h>
#include "paddle/utils/TypeDefs.h"
#include "paddle/utils/Logging.h"
#include "hl_tensor_ops.h"

namespace paddle {

template<class OP, typename ExprType, class T> class TensorConstant;
template<class OP, typename ExprType, class T> class TensorUnaryOp;
template<
class OP, typename LhsType, typename RhsType, class T> class TensorBinaryOp;
template<
typename ExprType1,
typename ExprType2,
typename ExprType3,
class T> class TensorTernaryOp;

/**
 * \brief Tensor base class.
 * 
 * This is the base class of all Tensor and Expression class.
 */
template<typename Derived, class T>
class TensorExpression {
public:
  /**
   * Element wise unary expression.
   */
  template<typename UnaryOp>
  const TensorUnaryOp<UnaryOp, const Derived, T>
  unaryExpression(const UnaryOp& op) const {
    return TensorUnaryOp<UnaryOp, const Derived, T>(op, derived());
  }

  const TensorUnaryOp<hppl::unary::add_scale<T>, const Derived, T>
  operator+(T p) const {
    return unaryExpression(hppl::unary::add_scale<T>(p));
  }

  const TensorUnaryOp<hppl::unary::sub_scale<T>, const Derived, T>
  operator-(T p) const {
    return unaryExpression(hppl::unary::sub_scale<T>(p));
  }

  const TensorUnaryOp<hppl::unary::mul_scale<T>, const Derived, T>
  operator*(T p) const {
    return unaryExpression(hppl::unary::mul_scale<T>(p));
  }

  const TensorUnaryOp<hppl::unary::div_scale<T>, const Derived, T>
  operator/(T p) const {
    return unaryExpression(hppl::unary::div_scale<T>(p));
  }

  const TensorUnaryOp<hppl::unary::neg<T>, const Derived, T>
  operator-() const {
    return unaryExpression(hppl::unary::neg<T>());
  }

  const TensorUnaryOp<hppl::unary::exp_op<T>, const Derived, T>
  exp() const {
    return unaryExpression(hppl::unary::exp_op<T>());
  }

  const TensorUnaryOp<hppl::unary::log_op<T>, const Derived, T>
  log() const {
    return unaryExpression(hppl::unary::log_op<T>());
  }

  const TensorUnaryOp<hppl::unary::sqrt_op<T>, const Derived, T>
  sqrt() const {
    return unaryExpression(hppl::unary::sqrt_op<T>());
  }

  const TensorUnaryOp<hppl::unary::square<T>, const Derived, T>
  square() const {
    return unaryExpression(hppl::unary::square<T>());
  }

  const TensorUnaryOp<hppl::unary::reciprocal<T>, const Derived, T>
  reciprocal() const {
    return unaryExpression(hppl::unary::reciprocal<T>());
  }

  const TensorUnaryOp<hppl::unary::abs<T>, const Derived, T>
  abs() const {
    return unaryExpression(hppl::unary::abs<T>());
  }

  const TensorUnaryOp<hppl::unary::sign<T>, const Derived, T>
  sign() const {
    return unaryExpression(hppl::unary::sign<T>());
  }

  const TensorUnaryOp<hppl::unary::pow_op<T>, const Derived, T>
  pow(T p) const {
    return unaryExpression(hppl::unary::pow_op<T>(p));
  }

  const TensorUnaryOp<hppl::unary::min<T>, const Derived, T>
  min(T p) const {
    return unaryExpression(hppl::unary::min<T>(p));
  }

  const TensorUnaryOp<hppl::unary::max<T>, const Derived, T>
  max(T p) const {
    return unaryExpression(hppl::unary::max<T>(p));
  }

  const TensorUnaryOp<hppl::unary::cmp_eq<T>, const Derived, T>
  operator==(T p) const {
    return unaryExpression(hppl::unary::cmp_eq<T>(p));
  }

  const TensorUnaryOp<hppl::unary::cmp_ne<T>, const Derived, T>
  operator!=(T p) const {
    return unaryExpression(hppl::unary::cmp_ne<T>(p));
  }

  const TensorUnaryOp<hppl::unary::cmp_le<T>, const Derived, T>
  operator<=(T p) const {
    return unaryExpression(hppl::unary::cmp_le<T>(p));
  }

  const TensorUnaryOp<hppl::unary::cmp_lt<T>, const Derived, T>
  operator<(T p) const {
    return unaryExpression(hppl::unary::cmp_lt<T>(p));
  }

  const TensorUnaryOp<hppl::unary::cmp_ge<T>, const Derived, T>
  operator>=(T p) const {
    return unaryExpression(hppl::unary::cmp_ge<T>(p));
  }

  const TensorUnaryOp<hppl::unary::cmp_gt<T>, const Derived, T>
  operator>(T p) const {
    return unaryExpression(hppl::unary::cmp_gt<T>(p));
  }

  const TensorUnaryOp<hppl::unary::and_op<T>, const Derived, T>
  operator&&(T p) const {
    return unaryExpression(hppl::unary::and_op<T>(p));
  }

  const TensorUnaryOp<hppl::unary::or_op<T>, const Derived, T>
  operator||(T p) const {
    return unaryExpression(hppl::unary::or_op<T>(p));
  }

  /**
   * Element wise binary expression.
   */
  template<typename BinaryOp, typename ExpressionType>
  const TensorBinaryOp<BinaryOp, const Derived, const ExpressionType, T>
  binaryExpression(const BinaryOp& op, const ExpressionType& expr) const {
    return TensorBinaryOp<BinaryOp, const Derived, const ExpressionType, T>(
      op, derived(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::cmp_eq<T>, const Derived, const ExpressionType, T>
  operator==(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::cmp_eq<T>(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::cmp_ne<T>, const Derived, const ExpressionType, T>
  operator!=(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::cmp_ne<T>(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::cmp_le<T>, const Derived, const ExpressionType, T>
  operator<=(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::cmp_le<T>(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::cmp_lt<T>, const Derived, const ExpressionType, T>
  operator<(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::cmp_lt<T>(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::cmp_ge<T>, const Derived, const ExpressionType, T>
  operator>=(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::cmp_ge<T>(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::cmp_gt<T>, const Derived, const ExpressionType, T>
  operator>(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::cmp_gt<T>(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::and_op<T>, const Derived, const ExpressionType, T>
  operator&&(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::and_op<T>(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::or_op<T>, const Derived, const ExpressionType, T>
  operator||(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::or_op<T>(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::add<T>, const Derived, const ExpressionType, T>
  operator+(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::add<T>(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::sub<T>, const Derived, const ExpressionType, T>
  operator-(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::sub<T>(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::mul<T>, const Derived, const ExpressionType, T>
  operator*(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::mul<T>(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::div<T>, const Derived, const ExpressionType, T>
  operator/(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::div<T>(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::min<T>, const Derived, const ExpressionType, T>
  min(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::min<T>(), expr);
  }

  template<typename ExpressionType>
  const TensorBinaryOp<
    hppl::binary::max<T>, const Derived, const ExpressionType, T>
  max(const ExpressionType& expr) const {
    return binaryExpression(hppl::binary::max<T>(), expr);
  }

  /**
   * Element wise ternary expression.
   *
   * ternary conditional operator(?: operator).
   * The conditional expression returns one of two values depending on
   * the result of derived expression.
   * If derived expression evaluates to true, then expression1 is evaluated.
   * If derived expression evaluates to false, then expression2 is evaluated.
   */
  template<typename ExprType1, typename ExprType2>
  const TensorTernaryOp<const Derived, const ExprType1, const ExprType2, T>
  condition(const ExprType1& expr1, const ExprType2& expr2) const {
    return TensorTernaryOp<const Derived, const ExprType1, const ExprType2, T>
      (derived(), expr1, expr2);
  }

  template<typename ExprType>
  const TensorTernaryOp<
    const Derived,
    const TensorConstant<hppl::unary::constant<T>, const Derived, T>,
    const ExprType,
    T>
  condition(T p, const ExprType& expr) const {
    return condition(constant(p), expr);
  }

  template<typename ExprType>
  const TensorTernaryOp<
    const Derived,
    const ExprType,
    const TensorConstant<hppl::unary::constant<T>, const Derived, T>,
    T>
  condition(const ExprType& expr, T p) const {
    return condition(expr, constant(p));
  }

  const TensorTernaryOp<
    const Derived,
    const TensorConstant<hppl::unary::constant<T>, const Derived, T>,
    const TensorConstant<hppl::unary::constant<T>, const Derived, T>,
    T>
  condition(T p1, T p2) const {
    return condition(constant(p1), constant(p2));
  }

  const TensorConstant<hppl::unary::constant<T>, const Derived, T>
  constant(T p) const {
    return TensorConstant<hppl::unary::constant<T>, const Derived, T>
      (hppl::unary::constant<T>(p), derived());
  }

protected:
  const Derived& derived() const { return *static_cast<const Derived*>(this); }
};

/**
 * \brief Unary Operator Expression
 */
template<class OP, typename ExprType, class T>
class TensorUnaryOp
    : public TensorExpression<TensorUnaryOp<OP, ExprType, T>, T> {
public:
  explicit TensorUnaryOp(const OP op, const ExprType& expr)
    : op_(op), expr_(expr) {}

  const OP op_;
  const ExprType expr_;
};

/**
 * \brief Binary Operator Expression
 */
template<class OP, typename LhsType, typename RhsType, class T>
class TensorBinaryOp
    : public TensorExpression<TensorBinaryOp<OP, LhsType, RhsType, T>, T> {
public:
  explicit TensorBinaryOp(const OP op, const LhsType& lhs, const RhsType& rhs)
    : op_(op), lhs_(lhs), rhs_(rhs) {}

  const OP op_;
  const LhsType lhs_;
  const RhsType rhs_;
};

/**
 * \brief Ternary Operator Expression
 */
template<typename ExprType1, typename ExprType2, typename ExprType3, class T>
class TensorTernaryOp
    : public TensorExpression<
        TensorTernaryOp<ExprType1, ExprType2, ExprType3, T>, T> {
public:
  explicit TensorTernaryOp(
    const ExprType1& expr1, const ExprType2& expr2, const ExprType3& expr3)
    : expr1_(expr1), expr2_(expr2), expr3_(expr3) {}

  const ExprType1 expr1_;
  const ExprType2 expr2_;
  const ExprType3 expr3_;
};

/**
 * \brief Constant Expression
 */
template<class OP, typename ExprType, class T>
class TensorConstant
    : public TensorExpression<TensorConstant<OP, ExprType, T>, T> {
public:
  explicit TensorConstant(const OP op, const ExprType& expr)
    : op_(op), expr_(expr) {}

  const OP op_;
  const ExprType expr_;
};

/**
 * \brief operator+ overload
 * \return a unary operator expression
 */
template<typename Derived, class T>
const TensorUnaryOp<hppl::unary::add_scale<T>, const Derived, T>
operator+(T p, const TensorExpression<Derived, T>& expr) {
  return expr + p;
}

/**
 * \brief operator* overload
 * \return a unary operator expression
 */
template<typename Derived, class T>
const TensorUnaryOp<hppl::unary::mul_scale<T>, const Derived, T>
operator*(T p, const TensorExpression<Derived, T>& expr) {
  return expr * p;
}

}  // namespace paddle

#include "TensorApply.h"
#include "TensorEvaluate.h"