#include<Kokkos_Core.hpp>

namespace Test {
namespace {

struct TestIsAsynchFunctor {
  Kokkos::View<double,TEST_EXECSPACE> atomic_test;
  TestIsAsynchFunctor(Kokkos::View<double,TEST_EXECSPACE> atomic_test_):atomic_test(atomic_test_){}

  KOKKOS_INLINE_FUNCTION
  void operator()(const int) const {
    Kokkos::atomic_add(&atomic_test(),1.0);
  }
};

template<class PolicyType, class ReduceFunctor>
void test_reduce_device_view(int64_t N, PolicyType policy, ReduceFunctor functor) {

     using ExecSpace = TEST_EXECSPACE;
     
     Kokkos::View<int64_t,TEST_EXECSPACE> result("Result");
     Kokkos::View<double,TEST_EXECSPACE> atomic_test("Atomic");
     int64_t reducer_result, view_result, scalar_result;

     
     Kokkos::Timer timer;     

     // Establish whether execspace is asynchronous
     Kokkos::parallel_for("Test::ReduceDeviceView::TestIsAsynch",Kokkos::RangePolicy<TEST_EXECSPACE>(0,1000000),
       TestIsAsynchFunctor(atomic_test));
     double time0 = timer.seconds();
     timer.reset();
     typename ExecSpace::execution_space().fence();
     double time_fence0 = timer.seconds(); 
     Kokkos::deep_copy(result,0);
     timer.reset();
     bool is_async = time0<time_fence0;

     // Test Reducer 

     Kokkos::parallel_reduce("Test::ReduceDeviceView::TestReducer",policy, functor, Kokkos::Sum<int64_t,TEST_EXECSPACE>(result));
     double time1 = timer.seconds();
     // Check whether it was asyncronous
     timer.reset();
     typename ExecSpace::execution_space().fence();
     double time_fence1 = timer.seconds();    
     Kokkos::deep_copy(reducer_result,result);    
     Kokkos::deep_copy(result,0);
     ASSERT_EQ(N,reducer_result); 
     timer.reset();
     
     
     // Test View 
     Kokkos::parallel_reduce("Test::ReduceDeviceView::TestView",policy, functor, result);
     double time2 = timer.seconds();
     // Check whether it was asyncronous
     timer.reset();
     typename ExecSpace::execution_space().fence();
     double time_fence2 = timer.seconds();    
     Kokkos::deep_copy(view_result,result);    
     Kokkos::deep_copy(result,0);
     ASSERT_EQ(N,view_result); 
     timer.reset();
     
     
     // Test Scalar
     Kokkos::parallel_reduce("Test::ReduceDeviceView::TestScalar",policy, functor, scalar_result);
     double time3 = timer.seconds();

     // Check whether it was asyncronous
     timer.reset();
     typename ExecSpace::execution_space().fence();
     double time_fence3 = timer.seconds();

     ASSERT_EQ(N,scalar_result); 
     if(is_async) {
       ASSERT_TRUE(time1<time_fence1);
     }
     if(is_async) {
       ASSERT_TRUE(time2<time_fence2);
       ASSERT_TRUE(time3>time_fence3);
     }
  }

struct RangePolicyFunctor {
  KOKKOS_INLINE_FUNCTION
  void operator() (const int, int64_t& lsum) const {
    lsum += 1;
  }
};

struct MDRangePolicyFunctor {
  KOKKOS_INLINE_FUNCTION
  void operator() (const int, const int, const int, int64_t& lsum) const {
    lsum += 1;
  }
};

struct TeamPolicyFunctor {
  int M;
  TeamPolicyFunctor(int M_):M(M_){}

  KOKKOS_INLINE_FUNCTION
  void operator() (const Kokkos::TeamPolicy<TEST_EXECSPACE>::member_type& team, int64_t& lsum) const {
    for(int i=team.team_rank(); i<M; i+=team.team_size())
      lsum += 1;
  }
};

} // namespace

TEST_F( TEST_CATEGORY, reduce_device_view_range_policy )
{
  int N=1000*1024*1024;
  test_reduce_device_view(N,Kokkos::RangePolicy<TEST_EXECSPACE>(0,N),RangePolicyFunctor());
}

TEST_F( TEST_CATEGORY, reduce_device_view_mdrange_policy )
{
  int N=1000*1024*1024;
  test_reduce_device_view(N,Kokkos::MDRangePolicy<TEST_EXECSPACE,Kokkos::Rank<3>>({0,0,0},{1000,1024,1024}),MDRangePolicyFunctor());
}

TEST_F( TEST_CATEGORY, reduce_device_view_team_policy )
{
  int N=1000*1024*1024;
  test_reduce_device_view(N,Kokkos::TeamPolicy<TEST_EXECSPACE>(1000*1024,Kokkos::AUTO),TeamPolicyFunctor(1024));
}

} // namespace Test