#
#  Copyright 2009-2016, Jack Poulson
#  All rights reserved.
#
#  This file is part of Elemental and is under the BSD 2-Clause License,
#  which can be found in the LICENSE file in the root directory, or at
#  http://opensource.org/licenses/BSD-2-Clause
#
include(ExternalProject)
include(ElLibraryName)

if(NOT EL_FORCE_METIS_BUILD)
  message(STATUS "Searching for previously installed METIS")
  find_package(METIS)
endif()

if(METIS_FOUND)
  # find_package returns 'METIS_LIBRARIES' but METIS's CMakeLists.txt
  # returns 'METIS_LIBS'
  set(METIS_LIBS ${METIS_LIBRARIES})

  set(EXTERNAL_LIBS ${EXTERNAL_LIBS} ${METIS_LIBS})
  message(STATUS "Including ${METIS_INCLUDE_DIRS} for external METIS")
  include_directories(${METIS_INCLUDE_DIRS})
  set(EL_HAVE_METIS TRUE)

elseif(NOT EL_PREVENT_METIS_DOWNLOAD)
  if(NOT DEFINED METIS_URL)
    set(METIS_URL https://github.com/scibuilder/Metis.git)
  endif()
  message(STATUS "Will pull METIS from ${METIS_URL}")

  set(METIS_SOURCE_DIR ${PROJECT_BINARY_DIR}/download/metis/source)
  set(METIS_BINARY_DIR ${PROJECT_BINARY_DIR}/download/metis/build)

  option(METIS_PCRE OFF)
  if(MSVC OR MINGW)
    option(METIS_GKREGEX "Use GKlib's internal regex?" ON)
  else()
    option(METIS_GKREGEX "Use GKlib's internal regex?" OFF)
  endif()

  ExternalProject_Add(project_metis 
    PREFIX ${CMAKE_INSTALL_PREFIX}
    GIT_REPOSITORY ${METIS_URL}
    STAMP_DIR  ${METIS_BINARY_DIR}/stamp
    SOURCE_DIR ${METIS_SOURCE_DIR}
    BINARY_DIR ${METIS_BINARY_DIR}
    TMP_DIR    ${METIS_BINARY_DIR}/tmp
    UPDATE_COMMAND "" 
    CMAKE_ARGS 
      -D PCRE=${METIS_PCRE}
      -D GKREGEX=${METIS_GKREGEX}
      -D CMAKE_C_COMPILER=${CMAKE_C_COMPILER}
      -D CMAKE_C_FLAGS=${CMAKE_C_FLAGS}
      -D CMAKE_INSTALL_PREFIX=${CMAKE_INSTALL_PREFIX}
      -D BUILD_SHARED_LIBS=${BUILD_SHARED_LIBS}
      -D CMAKE_EXECUTABLE_SUFFIX_C=${CMAKE_EXECUTABLE_SUFFIX_C}
      -D CMAKE_MACOSX_RPATH=${CMAKE_MACOSX_RPATH}
      -D CMAKE_SKIP_BUILD_RPATH=${CMAKE_SKIP_BUILD_RPATH}
      -D CMAKE_BUILD_WITH_INSTALL_RPATH=${CMAKE_BUILD_WITH_INSTALL_RPATH}
      -D CMAKE_INSTALL_RPATH_USE_LINK_PATH=${CMAKE_INSTALL_RPATH_USE_LINK_PATH} 
      -D CMAKE_INSTALL_RPATH=${CMAKE_INSTALL_RPATH}
    INSTALL_DIR ${CMAKE_INSTALL_PREFIX}
  )

  # Extract the installation directory
  ExternalProject_Get_Property(project_metis install_dir)
  set(METIS_INCLUDE_DIRS "${install_dir}/include")

  # Add a target for libmetis (either shared or static)
  add_library(libmetis ${LIBRARY_TYPE} IMPORTED)
  El_library_name(metis_name metis)
  set(METIS_LIB ${install_dir}/lib/${metis_name})
  set_property(TARGET libmetis PROPERTY IMPORTED_LOCATION ${METIS_LIB})

  set(METIS_LIBS ${METIS_LIB})
  set(EL_BUILT_METIS TRUE)

  set(EXTERNAL_LIBS ${EXTERNAL_LIBS} ${METIS_LIBS})
  message(STATUS "Including ${METIS_INCLUDE_DIRS} for external METIS")
  include_directories(${METIS_INCLUDE_DIRS})
  set(EL_HAVE_METIS TRUE)
else()
  set(EL_HAVE_METIS FALSE)
endif()