/*************************************************************************************

Grid physics library, www.github.com/paboyle/Grid

Source file: ./lib/lattice/Lattice_ET.h

Copyright (C) 2015

Author: Azusa Yamaguchi <ayamaguc@staffmail.ed.ac.uk>
Author: Peter Boyle <paboyle@ph.ed.ac.uk>
Author: neo <cossu@post.kek.jp>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

See the full license in the file "LICENSE" in the top level distribution
directory
*************************************************************************************/
			   /*  END LEGAL */
#ifndef GRID_LATTICE_ET_H
#define GRID_LATTICE_ET_H

#include <iostream>
#include <tuple>
#include <typeinfo>
#include <vector>

NAMESPACE_BEGIN(Grid);

////////////////////////////////////////////////////
// Predicated where support
////////////////////////////////////////////////////
template <class iobj, class vobj, class robj>
inline vobj predicatedWhere(const iobj &predicate, const vobj &iftrue,
                            const robj &iffalse) {
  typename std::remove_const<vobj>::type ret;

  typedef typename vobj::scalar_object scalar_object;
  typedef typename vobj::scalar_type scalar_type;
  typedef typename vobj::vector_type vector_type;

  const int Nsimd = vobj::vector_type::Nsimd();

  std::vector<Integer> mask(Nsimd);
  std::vector<scalar_object> truevals(Nsimd);
  std::vector<scalar_object> falsevals(Nsimd);

  extract(iftrue, truevals);
  extract(iffalse, falsevals);
  extract<vInteger, Integer>(TensorRemove(predicate), mask);

  for (int s = 0; s < Nsimd; s++) {
    if (mask[s]) falsevals[s] = truevals[s];
  }

  merge(ret, falsevals);
  return ret;
}

////////////////////////////////////////////
// recursive evaluation of expressions; Could
// switch to generic approach with variadics, a la
// Antonin's Lat Sim but the repack to variadic with popped
// from tuple is hideous; C++14 introduces std::make_index_sequence for this
////////////////////////////////////////////

// leaf eval of lattice ; should enable if protect using traits

template <typename T>
using is_lattice = std::is_base_of<LatticeBase, T>;

template <typename T>
using is_lattice_expr = std::is_base_of<LatticeExpressionBase, T>;

template <typename T> using is_lattice_expr = std::is_base_of<LatticeExpressionBase,T >;

//Specialization of getVectorType for lattices
template<typename T>
struct getVectorType<Lattice<T> >{
  typedef typename Lattice<T>::vector_object type;
};
 
template<class sobj>
inline sobj eval(const unsigned int ss, const sobj &arg)
{
  return arg;
}
template <class lobj>
inline const lobj &eval(const unsigned int ss, const Lattice<lobj> &arg) {
  return arg[ss];
}

// handle nodes in syntax tree
template <typename Op, typename T1>
auto inline eval(
		 const unsigned int ss,
		 const LatticeUnaryExpression<Op, T1> &expr)  // eval one operand
  -> decltype(expr.first.func(eval(ss, std::get<0>(expr.second)))) {
  return expr.first.func(eval(ss, std::get<0>(expr.second)));
}

template <typename Op, typename T1, typename T2>
auto inline eval(
		 const unsigned int ss,
		 const LatticeBinaryExpression<Op, T1, T2> &expr)  // eval two operands
  -> decltype(expr.first.func(eval(ss, std::get<0>(expr.second)),
			      eval(ss, std::get<1>(expr.second)))) {
  return expr.first.func(eval(ss, std::get<0>(expr.second)),
                         eval(ss, std::get<1>(expr.second)));
}

template <typename Op, typename T1, typename T2, typename T3>
auto inline eval(const unsigned int ss,
                 const LatticeTrinaryExpression<Op, T1, T2, T3>
		 &expr)  // eval three operands
  -> decltype(expr.first.func(eval(ss, std::get<0>(expr.second)),
			      eval(ss, std::get<1>(expr.second)),
			      eval(ss, std::get<2>(expr.second)))) {
  return expr.first.func(eval(ss, std::get<0>(expr.second)),
                         eval(ss, std::get<1>(expr.second)),
                         eval(ss, std::get<2>(expr.second)));
}

//////////////////////////////////////////////////////////////////////////
// Obtain the grid from an expression, ensuring conformable. This must follow a
// tree recursion
//////////////////////////////////////////////////////////////////////////
template <class T1,
          typename std::enable_if<is_lattice<T1>::value, T1>::type * = nullptr>
inline void GridFromExpression(GridBase *&grid, const T1 &lat)  // Lattice leaf
{
  if (grid) {
    conformable(grid, lat._grid);
  }
  grid = lat._grid;
}
template <class T1,
          typename std::enable_if<!is_lattice<T1>::value, T1>::type * = nullptr>
inline void GridFromExpression(GridBase *&grid,
                               const T1 &notlat)  // non-lattice leaf
{}
template <typename Op, typename T1>
inline void GridFromExpression(GridBase *&grid,
                               const LatticeUnaryExpression<Op, T1> &expr) {
  GridFromExpression(grid, std::get<0>(expr.second));  // recurse
}

template <typename Op, typename T1, typename T2>
inline void GridFromExpression(
			       GridBase *&grid, const LatticeBinaryExpression<Op, T1, T2> &expr) {
  GridFromExpression(grid, std::get<0>(expr.second));  // recurse
  GridFromExpression(grid, std::get<1>(expr.second));
}
template <typename Op, typename T1, typename T2, typename T3>
inline void GridFromExpression(
			       GridBase *&grid, const LatticeTrinaryExpression<Op, T1, T2, T3> &expr) {
  GridFromExpression(grid, std::get<0>(expr.second));  // recurse
  GridFromExpression(grid, std::get<1>(expr.second));
  GridFromExpression(grid, std::get<2>(expr.second));
}

//////////////////////////////////////////////////////////////////////////
// Obtain the CB from an expression, ensuring conformable. This must follow a
// tree recursion
//////////////////////////////////////////////////////////////////////////
template <class T1,
          typename std::enable_if<is_lattice<T1>::value, T1>::type * = nullptr>
inline void CBFromExpression(int &cb, const T1 &lat)  // Lattice leaf
{
  if ((cb == Odd) || (cb == Even)) {
    assert(cb == lat.Checkerboard());
  }
  cb = lat.Checkerboard();
  //  std::cout<<GridLogMessage<<"Lattice leaf cb "<<cb<<std::endl;
}
template <class T1,
          typename std::enable_if<!is_lattice<T1>::value, T1>::type * = nullptr>
inline void CBFromExpression(int &cb, const T1 &notlat)  // non-lattice leaf
{
  //  std::cout<<GridLogMessage<<"Non lattice leaf cb"<<cb<<std::endl;
}
template <typename Op, typename T1>
inline void CBFromExpression(int &cb,
                             const LatticeUnaryExpression<Op, T1> &expr) {
  CBFromExpression(cb, std::get<0>(expr.second));  // recurse
  //  std::cout<<GridLogMessage<<"Unary node cb "<<cb<<std::endl;
}

template <typename Op, typename T1, typename T2>
inline void CBFromExpression(int &cb,
                             const LatticeBinaryExpression<Op, T1, T2> &expr) {
  CBFromExpression(cb, std::get<0>(expr.second));  // recurse
  CBFromExpression(cb, std::get<1>(expr.second));
  //  std::cout<<GridLogMessage<<"Binary node cb "<<cb<<std::endl;
}
template <typename Op, typename T1, typename T2, typename T3>
inline void CBFromExpression(
			     int &cb, const LatticeTrinaryExpression<Op, T1, T2, T3> &expr) {
  CBFromExpression(cb, std::get<0>(expr.second));  // recurse
  CBFromExpression(cb, std::get<1>(expr.second));
  CBFromExpression(cb, std::get<2>(expr.second));
  //  std::cout<<GridLogMessage<<"Trinary node cb "<<cb<<std::endl;
}

////////////////////////////////////////////
// Unary operators and funcs
////////////////////////////////////////////
#define GridUnopClass(name, ret)					\
  template <class arg>							\
  struct name {								\
    static auto inline func(const arg a) -> decltype(ret) { return ret; } \
  };

GridUnopClass(UnarySub, -a);
GridUnopClass(UnaryNot, Not(a));
GridUnopClass(UnaryAdj, adj(a));
GridUnopClass(UnaryConj, conjugate(a));
GridUnopClass(UnaryTrace, trace(a));
GridUnopClass(UnaryTranspose, transpose(a));
GridUnopClass(UnaryTa, Ta(a));
GridUnopClass(UnaryProjectOnGroup, ProjectOnGroup(a));
GridUnopClass(UnaryReal, real(a));
GridUnopClass(UnaryImag, imag(a));
GridUnopClass(UnaryToReal, toReal(a));
GridUnopClass(UnaryToComplex, toComplex(a));
GridUnopClass(UnaryTimesI, timesI(a));
GridUnopClass(UnaryTimesMinusI, timesMinusI(a));
GridUnopClass(UnaryAbs, abs(a));
GridUnopClass(UnarySqrt, sqrt(a));
GridUnopClass(UnaryRsqrt, rsqrt(a));
GridUnopClass(UnarySin, sin(a));
GridUnopClass(UnaryCos, cos(a));
GridUnopClass(UnaryAsin, asin(a));
GridUnopClass(UnaryAcos, acos(a));
GridUnopClass(UnaryLog, log(a));
GridUnopClass(UnaryExp, exp(a));

////////////////////////////////////////////
// Binary operators
////////////////////////////////////////////
#define GridBinOpClass(name, combination)			\
  template <class left, class right>				\
  struct name {							\
    static auto inline func(const left &lhs, const right &rhs)	\
      -> decltype(combination) const {				\
      return combination;					\
    }								\
  }
GridBinOpClass(BinaryAdd, lhs + rhs);
GridBinOpClass(BinarySub, lhs - rhs);
GridBinOpClass(BinaryMul, lhs *rhs);
GridBinOpClass(BinaryDiv, lhs /rhs);

GridBinOpClass(BinaryAnd, lhs &rhs);
GridBinOpClass(BinaryOr, lhs | rhs);
GridBinOpClass(BinaryAndAnd, lhs &&rhs);
GridBinOpClass(BinaryOrOr, lhs || rhs);

////////////////////////////////////////////////////
// Trinary conditional op
////////////////////////////////////////////////////
#define GridTrinOpClass(name, combination)				\
  template <class predicate, class left, class right>			\
  struct name {								\
    static auto inline func(const predicate &pred, const left &lhs,	\
                            const right &rhs) -> decltype(combination) const { \
      return combination;						\
    }									\
  }

GridTrinOpClass(
		TrinaryWhere,
		(predicatedWhere<predicate, typename std::remove_reference<left>::type,
		 typename std::remove_reference<right>::type>(pred, lhs,
							      rhs)));

////////////////////////////////////////////
// Operator syntactical glue
////////////////////////////////////////////

#define GRID_UNOP(name) name<decltype(eval(0, arg))>
#define GRID_BINOP(name) name<decltype(eval(0, lhs)), decltype(eval(0, rhs))>
#define GRID_TRINOP(name)						\
  name<decltype(eval(0, pred)), decltype(eval(0, lhs)), decltype(eval(0, rhs))>

#define GRID_DEF_UNOP(op, name)						\
  template <typename T1,						\
            typename std::enable_if<is_lattice<T1>::value ||		\
				    is_lattice_expr<T1>::value,         \
                                    T1>::type * = nullptr>		\
  inline auto op(const T1 &arg)						\
    ->decltype(LatticeUnaryExpression<GRID_UNOP(name), const T1 &>(	\
								   std::make_pair(GRID_UNOP(name)(), std::forward_as_tuple(arg)))) { \
    return LatticeUnaryExpression<GRID_UNOP(name), const T1 &>(		\
							       std::make_pair(GRID_UNOP(name)(), std::forward_as_tuple(arg))); \
  }

#define GRID_BINOP_LEFT(op, name)					\
  template <typename T1, typename T2,					\
            typename std::enable_if<is_lattice<T1>::value ||		\
				    is_lattice_expr<T1>::value,		\
                                    T1>::type * = nullptr>		\
  inline auto op(const T1 &lhs, const T2 &rhs)				\
    ->decltype(								\
	       LatticeBinaryExpression<GRID_BINOP(name), const T1 &, const T2 &>( \
										 std::make_pair(GRID_BINOP(name)(), \
												std::forward_as_tuple(lhs, rhs)))) { \
    return LatticeBinaryExpression<GRID_BINOP(name), const T1 &, const T2 &>( \
									     std::make_pair(GRID_BINOP(name)(), std::forward_as_tuple(lhs, rhs))); \
  }

#define GRID_BINOP_RIGHT(op, name)					\
  template <typename T1, typename T2,					\
            typename std::enable_if<!is_lattice<T1>::value &&		\
				    !is_lattice_expr<T1>::value,	\
                                    T1>::type * = nullptr,		\
            typename std::enable_if<is_lattice<T2>::value ||		\
				    is_lattice_expr<T2>::value,		\
                                    T2>::type * = nullptr>		\
  inline auto op(const T1 &lhs, const T2 &rhs)				\
    ->decltype(								\
	       LatticeBinaryExpression<GRID_BINOP(name), const T1 &, const T2 &>( \
										 std::make_pair(GRID_BINOP(name)(), \
												std::forward_as_tuple(lhs, rhs)))) { \
    return LatticeBinaryExpression<GRID_BINOP(name), const T1 &, const T2 &>( \
									     std::make_pair(GRID_BINOP(name)(), std::forward_as_tuple(lhs, rhs))); \
  }

#define GRID_DEF_BINOP(op, name)		\
  GRID_BINOP_LEFT(op, name);			\
  GRID_BINOP_RIGHT(op, name);

#define GRID_DEF_TRINOP(op, name)					\
  template <typename T1, typename T2, typename T3>			\
  inline auto op(const T1 &pred, const T2 &lhs, const T3 &rhs)		\
    ->decltype(								\
	       LatticeTrinaryExpression<GRID_TRINOP(name), const T1 &, const T2 &, \
	       const T3 &>(std::make_pair(				\
					  GRID_TRINOP(name)(), std::forward_as_tuple(pred, lhs, rhs)))) { \
    return LatticeTrinaryExpression<GRID_TRINOP(name), const T1 &, const T2 &, \
      const T3 &>(std::make_pair(					\
				 GRID_TRINOP(name)(), std::forward_as_tuple(pred, lhs, rhs))); \
  }
////////////////////////
// Operator definitions
////////////////////////

GRID_DEF_UNOP(operator-, UnarySub);
GRID_DEF_UNOP(Not, UnaryNot);
GRID_DEF_UNOP(operator!, UnaryNot);
GRID_DEF_UNOP(adj, UnaryAdj);
GRID_DEF_UNOP(conjugate, UnaryConj);
GRID_DEF_UNOP(trace, UnaryTrace);
GRID_DEF_UNOP(transpose, UnaryTranspose);
GRID_DEF_UNOP(Ta, UnaryTa);
GRID_DEF_UNOP(ProjectOnGroup, UnaryProjectOnGroup);
GRID_DEF_UNOP(real, UnaryReal);
GRID_DEF_UNOP(imag, UnaryImag);
GRID_DEF_UNOP(toReal, UnaryToReal);
GRID_DEF_UNOP(toComplex, UnaryToComplex);
GRID_DEF_UNOP(timesI, UnaryTimesI);
GRID_DEF_UNOP(timesMinusI, UnaryTimesMinusI);
GRID_DEF_UNOP(abs, UnaryAbs);  // abs overloaded in cmath C++98; DON'T do the
                               // abs-fabs-dabs-labs thing
GRID_DEF_UNOP(sqrt, UnarySqrt);
GRID_DEF_UNOP(rsqrt, UnaryRsqrt);
GRID_DEF_UNOP(sin, UnarySin);
GRID_DEF_UNOP(cos, UnaryCos);
GRID_DEF_UNOP(asin, UnaryAsin);
GRID_DEF_UNOP(acos, UnaryAcos);
GRID_DEF_UNOP(log, UnaryLog);
GRID_DEF_UNOP(exp, UnaryExp);

GRID_DEF_BINOP(operator+, BinaryAdd);
GRID_DEF_BINOP(operator-, BinarySub);
GRID_DEF_BINOP(operator*, BinaryMul);
GRID_DEF_BINOP(operator/, BinaryDiv);

GRID_DEF_BINOP(operator&, BinaryAnd);
GRID_DEF_BINOP(operator|, BinaryOr);
GRID_DEF_BINOP(operator&&, BinaryAndAnd);
GRID_DEF_BINOP(operator||, BinaryOrOr);

GRID_DEF_TRINOP(where, TrinaryWhere);

/////////////////////////////////////////////////////////////
// Closure convenience to force expression to evaluate
/////////////////////////////////////////////////////////////
template <class Op, class T1>
auto closure(const LatticeUnaryExpression<Op, T1> &expr)
  -> Lattice<decltype(expr.first.func(eval(0, std::get<0>(expr.second))))> {
  Lattice<decltype(expr.first.func(eval(0, std::get<0>(expr.second))))> ret(
									    expr);
  return ret;
}
template <class Op, class T1, class T2>
auto closure(const LatticeBinaryExpression<Op, T1, T2> &expr)
  -> Lattice<decltype(expr.first.func(eval(0, std::get<0>(expr.second)),
				      eval(0, std::get<1>(expr.second))))> {
  Lattice<decltype(expr.first.func(eval(0, std::get<0>(expr.second)),
                                   eval(0, std::get<1>(expr.second))))>
    ret(expr);
  return ret;
}
template <class Op, class T1, class T2, class T3>
auto closure(const LatticeTrinaryExpression<Op, T1, T2, T3> &expr)
  -> Lattice<decltype(expr.first.func(eval(0, std::get<0>(expr.second)),
				      eval(0, std::get<1>(expr.second)),
				      eval(0, std::get<2>(expr.second))))> {
  Lattice<decltype(expr.first.func(eval(0, std::get<0>(expr.second)),
                                   eval(0, std::get<1>(expr.second)),
                                   eval(0, std::get<2>(expr.second))))>
    ret(expr);
  return ret;
}

#undef GRID_UNOP
#undef GRID_BINOP
#undef GRID_TRINOP

#undef GRID_DEF_UNOP
#undef GRID_DEF_BINOP
#undef GRID_DEF_TRINOP
NAMESPACE_END(Grid);

#if 0
using namespace Grid;
        
int main(int argc,char **argv){
   
  Lattice<double> v1(16);
  Lattice<double> v2(16);
  Lattice<double> v3(16);

  BinaryAdd<double,double> tmp;
  LatticeBinaryExpression<BinaryAdd<double,double>,Lattice<double> &,Lattice<double> &> 
    expr(std::make_pair(tmp,
			std::forward_as_tuple(v1,v2)));
  tmp.func(eval(0,v1),eval(0,v2));

  auto var = v1+v2;
  std::cout<<GridLogMessage<<typeid(var).name()<<std::endl;

  v3=v1+v2;
  v3=v1+v2+v1*v2;
};

void testit(Lattice<double> &v1,Lattice<double> &v2,Lattice<double> &v3)
{
  v3=v1+v2+v1*v2;
}
#endif

#endif