##============================================================================
##  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.
##============================================================================

include(CMakeParseArguments)

include(VTKmDeviceAdapters)
include(VTKmCPUVectorization)
include(VTKmMPI)

#-----------------------------------------------------------------------------
# INTERNAL FUNCTIONS
# No promises when used from outside VTK-m

#-----------------------------------------------------------------------------
# Utility to build a kit name from the current directory.
function(vtkm_get_kit_name kitvar)
  # Will this always work?  It should if ${CMAKE_CURRENT_SOURCE_DIR} is
  # built from ${VTKm_SOURCE_DIR}.
  string(REPLACE "${VTKm_SOURCE_DIR}/" "" dir_prefix ${CMAKE_CURRENT_SOURCE_DIR})
  string(REPLACE "/" "_" kit "${dir_prefix}")
  set(${kitvar} "${kit}" PARENT_SCOPE)
  # Optional second argument to get dir_prefix.
  if (${ARGC} GREATER 1)
    set(${ARGV1} "${dir_prefix}" PARENT_SCOPE)
  endif (${ARGC} GREATER 1)
endfunction(vtkm_get_kit_name)

#-----------------------------------------------------------------------------
function(vtkm_pyexpander_generated_file generated_file_name)
  # If pyexpander is available, add targets to build and check
  if(PYEXPANDER_FOUND AND PYTHONINTERP_FOUND)
    add_custom_command(
      OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/${generated_file_name}.checked
      COMMAND ${CMAKE_COMMAND}
        -DPYTHON_EXECUTABLE=${PYTHON_EXECUTABLE}
        -DPYEXPANDER_COMMAND=${PYEXPANDER_COMMAND}
        -DSOURCE_FILE=${CMAKE_CURRENT_SOURCE_DIR}/${generated_file_name}
        -DGENERATED_FILE=${CMAKE_CURRENT_BINARY_DIR}/${generated_file_name}
        -P ${VTKm_CMAKE_MODULE_PATH}/testing/VTKmCheckPyexpander.cmake
      MAIN_DEPENDENCY ${CMAKE_CURRENT_SOURCE_DIR}/${generated_file_name}.in
      DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/${generated_file_name}
      COMMENT "Checking validity of ${generated_file_name}"
      )
    add_custom_target(check_${generated_file_name} ALL
      DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/${generated_file_name}.checked
      )
  endif()
endfunction(vtkm_pyexpander_generated_file)

#-----------------------------------------------------------------------------
function(vtkm_generate_export_header lib_name)
  # Get the location of this library in the directory structure
  # export headers work on the directory structure more than the lib_name
  vtkm_get_kit_name(kit_name dir_prefix)

  # Now generate a header that holds the macros needed to easily export
  # template classes. This
  string(TOUPPER ${kit_name} BASE_NAME_UPPER)
  set(EXPORT_MACRO_NAME "${BASE_NAME_UPPER}")

  set(EXPORT_IS_BUILT_STATIC 0)
  get_target_property(is_static ${lib_name} TYPE)
  if(${is_static} STREQUAL "STATIC_LIBRARY")
    #If we are building statically set the define symbol
    set(EXPORT_IS_BUILT_STATIC 1)
  endif()
  unset(is_static)

  get_target_property(EXPORT_IMPORT_CONDITION ${lib_name} DEFINE_SYMBOL)
  if(NOT EXPORT_IMPORT_CONDITION)
    #set EXPORT_IMPORT_CONDITION to what the DEFINE_SYMBOL would be when
    #building shared
    set(EXPORT_IMPORT_CONDITION ${kit_name}_EXPORTS)
  endif()


  configure_file(
      ${VTKm_SOURCE_DIR}/CMake/VTKmExportHeaderTemplate.h.in
      ${VTKm_BINARY_DIR}/include/${dir_prefix}/${kit_name}_export.h
    @ONLY)

  if(NOT VTKm_INSTALL_ONLY_LIBRARIES)
    install(FILES ${VTKm_BINARY_DIR}/include/${dir_prefix}/${kit_name}_export.h
      DESTINATION ${VTKm_INSTALL_INCLUDE_DIR}/${dir_prefix}
      )
  endif()
endfunction(vtkm_generate_export_header)

#-----------------------------------------------------------------------------
function(vtkm_install_headers dir_prefix)
  if(NOT VTKm_INSTALL_ONLY_LIBRARIES)
    set(hfiles ${ARGN})
    install(FILES ${hfiles}
      DESTINATION ${VTKm_INSTALL_INCLUDE_DIR}/${dir_prefix}
      )
  endif()
endfunction(vtkm_install_headers)


#-----------------------------------------------------------------------------
function(vtkm_declare_headers)
  vtkm_get_kit_name(name dir_prefix)
  vtkm_install_headers("${dir_prefix}" ${ARGN})
endfunction(vtkm_declare_headers)

#-----------------------------------------------------------------------------
# FORWARD FACING API

#-----------------------------------------------------------------------------
# Pass to consumers extra compile flags they need to add to CMAKE_CUDA_FLAGS
# to have CUDA compatibility.
#
# This is required as currently the -sm/-gencode flags when specified inside
# COMPILE_OPTIONS / target_compile_options are not propagated to the device
# linker. Instead they must be specified in CMAKE_CUDA_FLAGS
#
#
# add_library(lib_that_uses_vtkm ...)
# vtkm_add_cuda_flags(CMAKE_CUDA_FLAGS)
# target_link_libraries(lib_that_uses_vtkm PRIVATE vtkm_filter)
#
function(vtkm_get_cuda_flags settings_var)
  if(TARGET vtkm::cuda)
    get_property(arch_flags
      TARGET    vtkm::cuda
      PROPERTY  INTERFACE_CUDA_Architecture_Flags)
    set(${settings_var} "${${settings_var}} ${arch_flags}" PARENT_SCOPE)
  endif()
endfunction()


#-----------------------------------------------------------------------------
# Add a relevant information to target that wants to use VTK-m.
#
# This is a higher order function to allow build-systems that use VTK-m
# to compose add_library/add_executable and the required information to have
# VTK-m enabled.
#
# vtkm_add_target_information(
#   target
#   [ MODIFY_CUDA_FLAGS ]
#   [ EXTENDS_VTKM ]
#   [ DEVICE_SOURCES <source_list>
#   )
#
# Usage:
#   add_library(lib_that_uses_vtkm STATIC a.cxx)
#   vtkm_add_target_information(lib_that_uses_vtkm
#                               MODIFY_CUDA_FLAGS
#                               DEVICE_SOURCES a.cxx
#                               )
#   target_link_libraries(lib_that_uses_vtkm PRIVATE vtkm_filter)
#
#  MODIFY_CUDA_FLAGS: If enabled will add the required -arch=<ver> flags
#  that VTK-m was compiled with. This functionality is also provided by the
#  the standalone `vtkm_get_cuda_flags` function.
#
#  DEVICE_SOURCES: The collection of source files that are used by `target` that
#  need to be marked as going to a special compiler for certain device adapters
#  such as CUDA.
#
#  EXTENDS_VTKM: Some programming models have restrictions on how types can be extended.
#  For example CUDA doesn't allow device side calls across dynamic library boundaries,
#  and requires all polymorphic classes to be reachable at dynamic library/executable
#  link time.
#
#  To accommodate these restrictions we need to handle the following allowable
#  use-cases:
#   Object library: do nothing, zero restrictions
#   Executable: do nothing, zero restrictions
#   Static library: do nothing, zero restrictions
#   Dynamic library:
#     -> Wanting to extend VTK-m and provide these types to consumers. This
#     is supported when CUDA isn't enabled. Otherwise we need to ERROR!
#     -> Wanting to use VTK-m as implementation detail, doesn't expose VTK-m
#        types to consumers. This is supported no matter if CUDA is enabled.
#
#  For most consumers they can ignore the `EXTENDS_VTKM` property as the default
#  will be correct.
#
#
function(vtkm_add_target_information uses_vtkm_target)
  set(options MODIFY_CUDA_FLAGS EXTENDS_VTKM)
  set(multiValueArgs DEVICE_SOURCES)
  cmake_parse_arguments(VTKm_TI
    "${options}" "${oneValueArgs}" "${multiValueArgs}"
    ${ARGN}
    )

  # Validate that following:
  #   - We are building with CUDA enabled.
  #   - We are building a VTK-m library or a library that wants cross library
  #     device calls.
  #
  # This is required as CUDA currently doesn't support device side calls across
  # dynamic library boundaries.
  if(TARGET vtkm::cuda)
    get_target_property(lib_type ${uses_vtkm_target} TYPE)
    get_target_property(requires_static vtkm::cuda INTERFACE_REQUIRES_STATIC_BUILDS)

    if(requires_static AND ${lib_type} STREQUAL "SHARED_LIBRARY")
      #We provide different error messages based on if we are building VTK-m
      #or being called by a consumer of VTK-m. We use PROJECT_NAME so that we
      #produce the correct error message when VTK-m is a subdirectory include
      #of another project
      if(PROJECT_NAME STREQUAL "VTKm")
        message(SEND_ERROR "${uses_vtkm_target} needs to be built STATIC as CUDA doesn't"
              " support virtual methods across dynamic library boundaries. You"
              " need to set the CMake option BUILD_SHARED_LIBS to `OFF`.")
      else()
        message(SEND_ERROR "${uses_vtkm_target} needs to be built STATIC as CUDA doesn't"
                " support virtual methods across dynamic library boundaries. You"
                " should either explicitly call add_library with the `STATIC` keyword"
                " or set the CMake option BUILD_SHARED_LIBS to `OFF`.")
      endif()
    endif()

    set_source_files_properties(${VTKm_TI_DEVICE_SOURCES} PROPERTIES LANGUAGE "CUDA")
  endif()

  set_target_properties(${uses_vtkm_target} PROPERTIES POSITION_INDEPENDENT_CODE ON)
  set_target_properties(${uses_vtkm_target} PROPERTIES CUDA_SEPARABLE_COMPILATION ON)

  if(VTKm_TI_MODIFY_CUDA_FLAGS)
    vtkm_get_cuda_flags(CMAKE_CUDA_FLAGS)
    set(CMAKE_CUDA_FLAGS ${CMAKE_CUDA_FLAGS} PARENT_SCOPE)
  endif()
endfunction()


#-----------------------------------------------------------------------------
# Add a VTK-m library. The name of the library will match the "kit" name
# (e.g. vtkm_rendering) unless the NAME argument is given.
#
# vtkm_library(
#   [ NAME <name> ]
#   [ OBJECT | STATIC | SHARED ]
#   SOURCES <source_list>
#   TEMPLATE_SOURCES <.hxx >
#   HEADERS <header list>
#   [ DEVICE_SOURCES <source_list> ]
#   )
function(vtkm_library)
  set(options OBJECT STATIC SHARED)
  set(oneValueArgs NAME)
  set(multiValueArgs SOURCES HEADERS TEMPLATE_SOURCES DEVICE_SOURCES)
  cmake_parse_arguments(VTKm_LIB
    "${options}" "${oneValueArgs}" "${multiValueArgs}"
    ${ARGN}
    )

  if(NOT VTKm_LIB_NAME)
    message(FATAL_ERROR "vtkm library must have an explicit name")
  endif()
  set(lib_name ${VTKm_LIB_NAME})

  if(VTKm_LIB_OBJECT)
    set(VTKm_LIB_type OBJECT)
  elseif(VTKm_LIB_STATIC)
    set(VTKm_LIB_type STATIC)
  elseif(VTKm_LIB_SHARED)
    set(VTKm_LIB_type SHARED)
  endif()

  add_library(${lib_name}
              ${VTKm_LIB_type}
              ${VTKm_LIB_SOURCES}
              ${VTKm_LIB_HEADERS}
              ${VTKm_LIB_TEMPLATE_SOURCES}
              ${VTKm_LIB_DEVICE_SOURCES}
              )
  vtkm_add_target_information(${lib_name}
                              DEVICE_SOURCES ${VTKm_LIB_DEVICE_SOURCES}
                              )
  if(NOT VTKm_USE_DEFAULT_SYMBOL_VISIBILITY)
    set_property(TARGET ${lib_name} PROPERTY CUDA_VISIBILITY_PRESET "hidden")
    set_property(TARGET ${lib_name} PROPERTY CXX_VISIBILITY_PRESET "hidden")
  endif()
  #specify where to place the built library
  set_property(TARGET ${lib_name} PROPERTY ARCHIVE_OUTPUT_DIRECTORY ${VTKm_LIBRARY_OUTPUT_PATH})
  set_property(TARGET ${lib_name} PROPERTY LIBRARY_OUTPUT_DIRECTORY ${VTKm_LIBRARY_OUTPUT_PATH})
  set_property(TARGET ${lib_name} PROPERTY RUNTIME_OUTPUT_DIRECTORY ${VTKm_EXECUTABLE_OUTPUT_PATH})


  # allow the static cuda runtime find the driver (libcuda.dyllib) at runtime.
  if(APPLE)
    set_property(TARGET ${lib_name} PROPERTY BUILD_RPATH ${CMAKE_CUDA_IMPLICIT_LINK_DIRECTORIES})
  endif()

  # Setup the SOVERSION and VERSION information for this vtkm library
  set_property(TARGET ${lib_name} PROPERTY VERSION 1)
  set_property(TARGET ${lib_name} PROPERTY SOVERSION 1)

  # Support custom library suffix names, for other projects wanting to inject
  # their own version numbers etc.
  if(DEFINED VTKm_CUSTOM_LIBRARY_SUFFIX)
    set(_lib_suffix "${VTKm_CUSTOM_LIBRARY_SUFFIX}")
  else()
    set(_lib_suffix "-${VTKm_VERSION_MAJOR}.${VTKm_VERSION_MINOR}")
  endif()
  set_property(TARGET ${lib_name} PROPERTY OUTPUT_NAME ${lib_name}${_lib_suffix})

  #generate the export header and install it
  vtkm_generate_export_header(${lib_name})

  #install the headers
  vtkm_declare_headers(${VTKm_LIB_HEADERS}
                       ${VTKm_LIB_TEMPLATE_SOURCES})

  # When building libraries/tests that are part of the VTK-m repository inherit
  # the properties from vtkm_developer_flags. The flags are intended only for
  # VTK-m itself and are not needed by consumers. We will export
  # vtkm_developer_flags so consumer can use VTK-m's build flags if they so
  # desire
  if (VTKm_ENABLE_DEVELOPER_FLAGS)
    target_link_libraries(${lib_name} PUBLIC $<BUILD_INTERFACE:vtkm_developer_flags>)
  else()
    target_link_libraries(${lib_name} PRIVATE $<BUILD_INTERFACE:vtkm_developer_flags>)
  endif()

  #install the library itself
  install(TARGETS ${lib_name}
    EXPORT ${VTKm_EXPORT_NAME}
    ARCHIVE DESTINATION ${VTKm_INSTALL_LIB_DIR}
    LIBRARY DESTINATION ${VTKm_INSTALL_LIB_DIR}
    RUNTIME DESTINATION ${VTKm_INSTALL_BIN_DIR}
    )

endfunction(vtkm_library)