//=============================================================================
//
//  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 2015 National Technology & Engineering Solutions of Sandia, LLC (NTESS).
//  Copyright 2015 UT-Battelle, LLC.
//  Copyright 2015 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_cont_ArrayHandleConcatenate_h
#define vtk_m_cont_ArrayHandleConcatenate_h

#include <vtkm/cont/ArrayHandle.h>

namespace vtkm
{
namespace cont
{
namespace internal
{

template <typename PortalType1, typename PortalType2>
class VTKM_ALWAYS_EXPORT ArrayPortalConcatenate
{
public:
  using ValueType = typename PortalType1::ValueType;

  VTKM_EXEC_CONT
  ArrayPortalConcatenate()
    : portal1()
    , portal2()
  {
  }

  VTKM_EXEC_CONT
  ArrayPortalConcatenate(const PortalType1& p1, const PortalType2& p2)
    : portal1(p1)
    , portal2(p2)
  {
  }

  // Copy constructor
  template <typename OtherP1, typename OtherP2>
  VTKM_EXEC_CONT ArrayPortalConcatenate(const ArrayPortalConcatenate<OtherP1, OtherP2>& src)
    : portal1(src.GetPortal1())
    , portal2(src.GetPortal2())
  {
  }

  VTKM_EXEC_CONT
  vtkm::Id GetNumberOfValues() const
  {
    return this->portal1.GetNumberOfValues() + this->portal2.GetNumberOfValues();
  }

  VTKM_EXEC_CONT
  ValueType Get(vtkm::Id index) const
  {
    if (index < this->portal1.GetNumberOfValues())
      return this->portal1.Get(index);
    else
      return this->portal2.Get(index - this->portal1.GetNumberOfValues());
  }

  VTKM_EXEC_CONT
  void Set(vtkm::Id index, const ValueType& value) const
  {
    if (index < this->portal1.GetNumberOfValues())
      this->portal1.Set(index, value);
    else
      this->portal2.Set(index - this->portal1.GetNumberOfValues(), value);
  }

  VTKM_EXEC_CONT
  const PortalType1& GetPortal1() const { return this->portal1; }

  VTKM_EXEC_CONT
  const PortalType2& GetPortal2() const { return this->portal2; }

private:
  PortalType1 portal1;
  PortalType2 portal2;
}; // class ArrayPortalConcatenate

} // namespace internal

template <typename ArrayHandleType1, typename ArrayHandleType2>
class StorageTagConcatenate
{
};

namespace internal
{

template <typename ArrayHandleType1, typename ArrayHandleType2>
class Storage<typename ArrayHandleType1::ValueType,
              StorageTagConcatenate<ArrayHandleType1, ArrayHandleType2>>
{
public:
  using ValueType = typename ArrayHandleType1::ValueType;
  using PortalType = ArrayPortalConcatenate<typename ArrayHandleType1::PortalControl,
                                            typename ArrayHandleType2::PortalControl>;
  using PortalConstType = ArrayPortalConcatenate<typename ArrayHandleType1::PortalConstControl,
                                                 typename ArrayHandleType2::PortalConstControl>;

  VTKM_CONT
  Storage()
    : valid(false)
  {
  }

  VTKM_CONT
  Storage(const ArrayHandleType1& a1, const ArrayHandleType2& a2)
    : array1(a1)
    , array2(a2)
    , valid(true){};

  VTKM_CONT
  PortalConstType GetPortalConst() const
  {
    VTKM_ASSERT(this->valid);
    return PortalConstType(this->array1.GetPortalConstControl(),
                           this->array2.GetPortalConstControl());
  }

  VTKM_CONT
  PortalType GetPortal()
  {
    VTKM_ASSERT(this->valid);
    return PortalType(this->array1.GetPortalControl(), this->array2.GetPortalControl());
  }

  VTKM_CONT
  vtkm::Id GetNumberOfValues() const
  {
    VTKM_ASSERT(this->valid);
    return this->array1.GetNumberOfValues() + this->array2.GetNumberOfValues();
  }

  VTKM_CONT
  void Allocate(vtkm::Id vtkmNotUsed(numberOfValues))
  {
    throw vtkm::cont::ErrorInternal("ArrayHandleConcatenate should not be allocated explicitly. ");
  }

  VTKM_CONT
  void Shrink(vtkm::Id numberOfValues)
  {
    VTKM_ASSERT(this->valid);
    if (numberOfValues < this->array1.GetNumberOfValues())
    {
      this->array1.Shrink(numberOfValues);
      this->array2.Shrink(0);
    }
    else
      this->array2.Shrink(numberOfValues - this->array1.GetNumberOfValues());
  }

  VTKM_CONT
  void ReleaseResources()
  {
    VTKM_ASSERT(this->valid);
    this->array1.ReleaseResources();
    this->array2.ReleaseResources();
  }

  VTKM_CONT
  const ArrayHandleType1& GetArray1() const
  {
    VTKM_ASSERT(this->valid);
    return this->array1;
  }

  VTKM_CONT
  const ArrayHandleType2& GetArray2() const
  {
    VTKM_ASSERT(this->valid);
    return this->array2;
  }

private:
  ArrayHandleType1 array1;
  ArrayHandleType2 array2;
  bool valid;
}; // class Storage

template <typename ArrayHandleType1, typename ArrayHandleType2, typename Device>
class ArrayTransfer<typename ArrayHandleType1::ValueType,
                    StorageTagConcatenate<ArrayHandleType1, ArrayHandleType2>,
                    Device>
{
public:
  using ValueType = typename ArrayHandleType1::ValueType;

private:
  using StorageTag = StorageTagConcatenate<ArrayHandleType1, ArrayHandleType2>;
  using StorageType = vtkm::cont::internal::Storage<ValueType, StorageTag>;

public:
  using PortalControl = typename StorageType::PortalType;
  using PortalConstControl = typename StorageType::PortalConstType;

  using PortalExecution =
    ArrayPortalConcatenate<typename ArrayHandleType1::template ExecutionTypes<Device>::Portal,
                           typename ArrayHandleType2::template ExecutionTypes<Device>::Portal>;
  using PortalConstExecution =
    ArrayPortalConcatenate<typename ArrayHandleType1::template ExecutionTypes<Device>::PortalConst,
                           typename ArrayHandleType2::template ExecutionTypes<Device>::PortalConst>;

  VTKM_CONT
  ArrayTransfer(StorageType* storage)
    : array1(storage->GetArray1())
    , array2(storage->GetArray2())
  {
  }

  VTKM_CONT
  vtkm::Id GetNumberOfValues() const
  {
    return this->array1.GetNumberOfValues() + this->array2.GetNumberOfValues();
  }

  VTKM_CONT
  PortalConstExecution PrepareForInput(bool vtkmNotUsed(updateData))
  {
    return PortalConstExecution(this->array1.PrepareForInput(Device()),
                                this->array2.PrepareForInput(Device()));
  }

  VTKM_CONT
  PortalExecution PrepareForInPlace(bool vtkmNotUsed(updateData))
  {
    return PortalExecution(this->array1.PrepareForInPlace(Device()),
                           this->array2.PrepareForInPlace(Device()));
  }

  VTKM_CONT
  PortalExecution PrepareForOutput(vtkm::Id vtkmNotUsed(numberOfValues))
  {
    throw vtkm::cont::ErrorInternal("ArrayHandleConcatenate is derived and read-only. ");
  }

  VTKM_CONT
  void RetrieveOutputData(StorageType* vtkmNotUsed(storage)) const
  {
    // not need to implement
  }

  VTKM_CONT
  void Shrink(vtkm::Id numberOfValues)
  {
    if (numberOfValues < this->array1.GetNumberOfValues())
    {
      this->array1.Shrink(numberOfValues);
      this->array2.Shrink(0);
    }
    else
      this->array2.Shrink(numberOfValues - this->array1.GetNumberOfValues());
  }

  VTKM_CONT
  void ReleaseResources()
  {
    this->array1.ReleaseResourcesExecution();
    this->array2.ReleaseResourcesExecution();
  }

private:
  ArrayHandleType1 array1;
  ArrayHandleType2 array2;
};
}
}
} // namespace vtkm::cont::internal

namespace vtkm
{
namespace cont
{

template <typename ArrayHandleType1, typename ArrayHandleType2>
class ArrayHandleConcatenate
  : public vtkm::cont::ArrayHandle<typename ArrayHandleType1::ValueType,
                                   StorageTagConcatenate<ArrayHandleType1, ArrayHandleType2>>
{
public:
  VTKM_ARRAY_HANDLE_SUBCLASS(
    ArrayHandleConcatenate,
    (ArrayHandleConcatenate<ArrayHandleType1, ArrayHandleType2>),
    (vtkm::cont::ArrayHandle<typename ArrayHandleType1::ValueType,
                             StorageTagConcatenate<ArrayHandleType1, ArrayHandleType2>>));

protected:
  using StorageType = vtkm::cont::internal::Storage<ValueType, StorageTag>;

public:
  VTKM_CONT
  ArrayHandleConcatenate(const ArrayHandleType1& array1, const ArrayHandleType2& array2)
    : Superclass(StorageType(array1, array2))
  {
  }
};

template <typename ArrayHandleType1, typename ArrayHandleType2>
VTKM_CONT ArrayHandleConcatenate<ArrayHandleType1, ArrayHandleType2> make_ArrayHandleConcatenate(
  const ArrayHandleType1& array1,
  const ArrayHandleType2& array2)
{
  return ArrayHandleConcatenate<ArrayHandleType1, ArrayHandleType2>(array1, array2);
}
}
} // namespace vtkm::cont

#endif //vtk_m_cont_ArrayHandleConcatenate_h
