#===============================================================================
# @file   FindGMSH.cmake
#
# @author Nicolas Richart <nicolas.richart@epfl.ch>
#
# @date creation: Mon Dec 08 2014
# @date last modification: Tue Jan 19 2016
#
# @brief  Find gmsh and delacre the add_mesh macro
#
# @section LICENSE
#
# Copyright (©) 2015 EPFL (Ecole Polytechnique Fédérale de Lausanne) Laboratory
# (LSMS - Laboratoire de Simulation en Mécanique des Solides)
#
# Akantu is free  software: you can redistribute it and/or  modify it under the
# terms  of the  GNU Lesser  General Public  License as  published by  the Free
# Software Foundation, either version 3 of the License, or (at your option) any
# later version.
#
# Akantu is  distributed in the  hope that it  will be useful, but  WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A  PARTICULAR PURPOSE. See  the GNU  Lesser General  Public License  for more
# details.
#
# You should  have received  a copy  of the GNU  Lesser General  Public License
# along with Akantu. If not, see <http://www.gnu.org/licenses/>.
#
#===============================================================================

find_program(GMSH gmsh
  DOC "The mesh generetor gmsh")

mark_as_advanced(GMSH)

if (GMSH)
  execute_process(COMMAND ${GMSH} --version
    ERROR_VARIABLE GMSH_VERSION
    ERROR_STRIP_TRAILING_WHITESPACE)
endif()

find_package(PackageHandleStandardArgs)
find_package_handle_standard_args(GMSH
  REQUIRED_VARS GMSH
  VERSION_VAR GMSH_VERSION)

#===============================================================================
function(ADD_MESH MESH_TARGET GEO_FILE)
  if(NOT GMSH_FOUND)
    return()
  endif()
  set(arguments
    ${MESH_TARGET} ${GEO_FILE}
    ${ARGN}
    )

  cmake_parse_arguments(_add_mesh
    ""
    "OUTPUT;DIM;ORDER"
    ""
    ${arguments}
    )

  if(NOT _add_mesh_DIM AND NOT _add_mesh_ORDER)
    list(GET _add_mesh_UNPARSED_ARGUMENTS 2 _add_mesh_DIM)
    list(GET _add_mesh_UNPARSED_ARGUMENTS 3 _add_mesh_ORDER)
  endif()

  if(NOT _add_mesh_DIM)
    set(_add_mesh_DIM 3)
  endif()

  if(NOT _add_mesh_ORDER)
    set(_add_mesh_ORDER 1)
  endif()
  
  set(_geo_file ${CMAKE_CURRENT_SOURCE_DIR}/${GEO_FILE})

  set(_r_geo_file "${GEO_FILE}")

  if(_add_mesh_OUTPUT)
    set(_msh_file ${CMAKE_CURRENT_BINARY_DIR}/${_add_mesh_OUTPUT})
    set(_r_msh_file "${_add_mesh_OUTPUT}")
  else(_add_mesh_OUTPUT)
    get_filename_component(_msh_file "${GEO_FILE}" NAME_WE)
    set(_r_msh_file "${_msh_file}.msh")
    set(_msh_file ${CMAKE_CURRENT_BINARY_DIR}/${_msh_file}.msh)
  endif(_add_mesh_OUTPUT)

  if(GMSH_VERSION VERSION_LESS 3.0.0)
    set(OPTIMIZE -optimize)
  endif()

  if(EXISTS ${_geo_file})
    add_custom_command(
      OUTPUT ${_msh_file}
      DEPENDS ${_geo_file}
      COMMAND ${GMSH}
      ARGS -${_add_mesh_DIM} -order ${_add_mesh_ORDER} ${OPTIMIZE} -o ${_msh_file} ${_geo_file} 2>&1 > /dev/null
      COMMENT "Generating the ${_add_mesh_DIM}D mesh ${_r_msh_file} (order ${_add_mesh_ORDER}) form the geometry ${_r_geo_file}"
      )

    add_custom_target(${MESH_TARGET}
      DEPENDS ${_msh_file})
    set_target_properties(${MESH_TARGET} PROPERTIES RESSOURCES ${_geo_file})
  else(EXISTS ${_geo_file})
    message(WARNING
      "File ${_geo_file} not found for target ${MESH_TARGET}")
  endif(EXISTS ${_geo_file})
endfunction()