cmake: add DOWNLOAD_MSCG option

  enable_language(C)

endif()

if(PKG_KOKKOS OR PKG_MSCG)

if(PKG_KOKKOS)

  # starting with CMake 3.1 this is all you have to do to enforce C++11

  set(CMAKE_CXX_STANDARD 11) # C++11...

  set(CMAKE_CXX_STANDARD_REQUIRED ON) #...is required...

endif()

if(PKG_MSCG)

  find_package(GSL REQUIRED)

  set(LAMMPS_LIB_MSCG_BIN_DIR ${LAMMPS_LIB_BINARY_DIR}/mscg)

  set(MSCG_TARBALL ${LAMMPS_LIB_MSCG_BIN_DIR}/MS-CG-master.zip)

  set(LAMMPS_LIB_MSCG_BIN_DIR ${LAMMPS_LIB_MSCG_BIN_DIR}/MSCG-release-master/src)

  if(NOT EXISTS ${LAMMPS_LIB_MSCG_BIN_DIR})

    if(NOT EXISTS ${MSCG_TARBALL})

      message(STATUS "Downloading ${MSCG_TARBALL}")

      file(DOWNLOAD

        https://github.com/uchicago-voth/MSCG-release/archive/master.zip

        ${MSCG_TARBALL} SHOW_PROGRESS) #EXPECTED_MD5 cannot be due due to master

    endif()

    message(STATUS "Unpacking ${MSCG_TARBALL}")

    execute_process(COMMAND ${CMAKE_COMMAND} -E tar xvf ${MSCG_TARBALL}

      WORKING_DIRECTORY ${LAMMPS_LIB_BINARY_DIR}/mscg)

  endif()

  file(GLOB MSCG_SOURCES ${LAMMPS_LIB_MSCG_BIN_DIR}/*.cpp)

  add_library(mscg STATIC ${MSCG_SOURCES})

  list(APPEND LAMMPS_LINK_LIBS mscg)

  target_compile_options(mscg PRIVATE -DDIMENSION=3 -D_exclude_gromacs=1)

  target_include_directories(mscg PUBLIC ${LAMMPS_LIB_MSCG_BIN_DIR})

  target_link_libraries(mscg ${GSL_LIBRARIES} ${LAPACK_LIBRARIES})

  option(DOWNLOAD_MSCG "Download latte (instead of using the system's one)" OFF)

  if(DOWNLOAD_MSCG)

    include(ExternalProject)

    if(NOT LAPACK_FOUND)

      set(EXTRA_MSCG_OPTS "-DLAPACK_LIBRARIES=${CMAKE_CURRENT_BINARY_DIR}/liblinalg.a")

    endif()

    ExternalProject_Add(mscg_build

      URL https://github.com//uchicago-voth/MSCG-release/archive/1.7.3.1.tar.gz

      URL_MD5 8c45e269ee13f60b303edd7823866a91

      SOURCE_SUBDIR src/CMake

      CMAKE_ARGS -DCMAKE_INSTALL_PREFIX=<INSTALL_DIR> -DCMAKE_POSITION_INDEPENDENT_CODE=${CMAKE_POSITION_INDEPENDENT_CODE} ${EXTRA_MSCG_OPTS}

      )

    ExternalProject_get_property(mscg_build INSTALL_DIR)

    set(MSCG_LIBRARIES ${INSTALL_DIR}/${CMAKE_INSTALL_LIBDIR}/libmxcg.a)

    set(MSCG_INCLUDE_DIRS ${INSTALL_DIR}/include)

    list(APPEND LAMMPS_DEPS mscg_build)

    if(NOT LAPACK_FOUND)

      add_dependencies(mscg_build linalg)

    endif()

  else()

    find_package(MSCG)

    if(NOT MSCG_FOUND)

      message(FATAL_ERROR "MSCG not found, help CMake to find it by setting MSCG_LIBRARY and MSCG_INCLUDE_DIRS, or set DOWNLOAD_MSCG=ON to download it")

    endif()

  endif()

  list(APPEND LAMMPS_LINK_LIBS ${MSCG_LIBRARIES})

  include_directories(${MSCG_INCLUDE_DIRS})

endif()

if(PKG_COMPRESS)

# - Find mscg

# Find the native MSCG headers and libraries.

#

#  MSCG_INCLUDE_DIRS - where to find mscg.h, etc.

#  MSCG_LIBRARIES    - List of libraries when using mscg.

#  MSCG_FOUND        - True if mscg found.

#

find_path(MSCG_INCLUDE_DIR mscg.h PATH_SUFFIXES mscg)

find_library(MSCG_LIBRARY NAMES mscg)

set(MSCG_LIBRARIES ${MSCG_LIBRARY})

set(MSCG_INCLUDE_DIRS ${MSCG_INCLUDE_DIR})

include(FindPackageHandleStandardArgs)

# handle the QUIETLY and REQUIRED arguments and set MSCG_FOUND to TRUE

# if all listed variables are TRUE

find_package_handle_standard_args(MSCG DEFAULT_MSG MSCG_LIBRARY MSCG_INCLUDE_DIR)

mark_as_advanced(MSCG_INCLUDE_DIR MSCG_LIBRARY )