//============================================================================
//  Copyright (c) Kitware, Inc.
//  All rights reserved.
//  See LICENSE.txt for details.
//  This software is distributed WITHOUT ANY WARRANTY; without even
//  the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
//  PURPOSE.  See the above copyright notice for more information.
//
//  Copyright 2014 National Technology & Engineering Solutions of Sandia, LLC (NTESS).
//  Copyright 2014 UT-Battelle, LLC.
//  Copyright 2014 Los Alamos National Security.
//
//  Under the terms of Contract DE-NA0003525 with NTESS,
//  the U.S. Government retains certain rights in this software.
//
//  Under the terms of Contract DE-AC52-06NA25396 with Los Alamos National
//  Laboratory (LANL), the U.S. Government retains certain rights in
//  this software.
//============================================================================
#ifndef vtk_m_worklet_Dispatcher_MapField_h
#define vtk_m_worklet_Dispatcher_MapField_h

#include <vtkm/worklet/WorkletMapField.h>
#include <vtkm/worklet/internal/DispatcherBase.h>

namespace vtkm
{
namespace worklet
{

/// \brief Dispatcher for worklets that inherit from \c WorkletMapField.
///
template <typename WorkletType>
class DispatcherMapField
  : public vtkm::worklet::internal::DispatcherBase<DispatcherMapField<WorkletType>,
                                                   WorkletType,
                                                   vtkm::worklet::WorkletMapField>
{
  using Superclass = vtkm::worklet::internal::DispatcherBase<DispatcherMapField<WorkletType>,
                                                             WorkletType,
                                                             vtkm::worklet::WorkletMapField>;
  using ScatterType = typename Superclass::ScatterType;

public:
  // If you get a compile error here about there being no appropriate constructor for ScatterType,
  // then that probably means that the worklet you are trying to execute has defined a custom
  // ScatterType and that you need to create one (because there is no default way to construct
  // the scatter). By convention, worklets that define a custom scatter type usually provide a
  // static method named MakeScatter that constructs a scatter object.
  VTKM_CONT
  DispatcherMapField(const WorkletType& worklet = WorkletType(),
                     const ScatterType& scatter = ScatterType())
    : Superclass(worklet, scatter)
  {
  }

  VTKM_CONT
  DispatcherMapField(const ScatterType& scatter)
    : Superclass(WorkletType(), scatter)
  {
  }

  template <typename Invocation>
  VTKM_CONT void DoInvoke(Invocation& invocation) const
  {
    // This is the type for the input domain
    using InputDomainType = typename Invocation::InputDomainType;

    // We can pull the input domain parameter (the data specifying the input
    // domain) from the invocation object.
    const InputDomainType& inputDomain = invocation.GetInputDomain();

    // For a DispatcherMapField, the inputDomain must be an ArrayHandle (or
    // an VariantArrayHandle that gets cast to one). The size of the domain
    // (number of threads/worklet instances) is equal to the size of the
    // array.
    auto numInstances = internal::scheduling_range(inputDomain);

    // A MapField is a pretty straightforward dispatch. Once we know the number
    // of invocations, the superclass can take care of the rest.
    this->BasicInvoke(invocation, numInstances);
  }
};
}
} // namespace vtkm::worklet

#endif //vtk_m_worklet_Dispatcher_MapField_h
