# - Try to find ESMF
#
# Requires setting ESMFMKFILE to the filepath of esmf.mk. If this is NOT set,
# then ESMF_FOUND will always be FALSE. If ESMFMKFILE exists, then ESMF_FOUND=TRUE
# and all ESMF makefile variables will be set in the global scope. Optionally,
# set ESMF_MKGLOBALS to a string list to filter makefile variables. For example,
# to globally scope only ESMF_LIBSDIR and ESMF_APPSDIR variables, use this CMake
# command in CMakeLists.txt:
#
#   set(ESMF_MKGLOBALS "LIBSDIR" "APPSDIR")


# Add the ESMFMKFILE path to the cache if defined as system env variable
if (DEFINED ENV{ESMFMKFILE} AND NOT DEFINED ESMFMKFILE)
  set(ESMFMKFILE $ENV{ESMFMKFILE} CACHE FILEPATH "Path to ESMF mk file")
endif ()

# Found the mk file and ESMF exists on the system
if (EXISTS ${ESMFMKFILE})
  set(ESMF_FOUND TRUE CACHE BOOL "ESMF mk file found" FORCE)
  # Did not find the ESMF mk file
else()
  set(ESMF_FOUND FALSE CACHE BOOL "ESMF mk file NOT found" FORCE)
  # Best to warn users that without the mk file there is no way to find ESMF
  if (NOT DEFINED ESMFMKFILE)
    message(FATAL_ERROR "ESMFMKFILE not defined. This is the path to esmf.mk file. \
Without this filepath, ESMF_FOUND will always be FALSE.")
  endif ()
endif()

# Only parse the mk file if it is found
if (ESMF_FOUND)
  # Read the mk file
  file(STRINGS "${ESMFMKFILE}" esmfmkfile_contents)
  # Parse each line in the mk file
  foreach(str ${esmfmkfile_contents})
    # Only consider uncommented lines
    string(REGEX MATCH "^[^#]" def ${str})
    # Line is not commented
    if (def)
      # Extract the variable name
      string(REGEX MATCH "^[^=]+" esmf_varname ${str})
      # Extract the variable's value
      string(REGEX MATCH "=.+$" esmf_vardef ${str})
      # Only for variables with a defined value
      if (esmf_vardef)
        # Get rid of the assignment string
        string(SUBSTRING ${esmf_vardef} 1 -1 esmf_vardef)
        # Remove whitespace
        string(STRIP ${esmf_vardef} esmf_vardef)
        # A string or single-valued list
        if(NOT DEFINED ESMF_MKGLOBALS)
          # Set in global scope
          set(${esmf_varname} ${esmf_vardef})
          # Don't display by default in GUI
          mark_as_advanced(esmf_varname)
        else() # Need to filter global promotion
          foreach(m ${ESMF_MKGLOBALS})
            string(FIND ${esmf_varname} ${m} match)
            # Found the string
            if(NOT ${match} EQUAL -1)
              # Promote to global scope
              set(${esmf_varname} ${esmf_vardef})
              # Don't display by default in the GUI
              mark_as_advanced (esmf_varname)
              # No need to search for the current string filter
              break()
            endif()
          endforeach()
        endif()
      endif()
    endif()
  endforeach()

  separate_arguments(ESMF_F90COMPILEPATHS NATIVE_COMMAND ${ESMF_F90COMPILEPATHS})
  foreach (ITEM ${ESMF_F90COMPILEPATHS})
     string(REGEX REPLACE "^-I" "" ITEM "${ITEM}")
     list(APPEND tmp ${ITEM})
  endforeach()
  set(ESMF_F90COMPILEPATHS ${tmp})

  add_library(esmf UNKNOWN IMPORTED)
  # Look for static library, if not found try dynamic library
  find_library(esmf_lib NAMES libesmf.a PATHS ${ESMF_LIBSDIR})
  if(esmf_lib MATCHES "esmf_lib-NOTFOUND")
    message(STATUS "Static ESMF library not found, searching for dynamic library instead")
    find_library(esmf_lib NAMES esmf_fullylinked PATHS ${ESMF_LIBSDIR})
    if(esmf_lib MATCHES "esmf_lib-NOTFOUND")
      message(FATAL_ERROR "Neither the dynamic nor the static ESMF library was found")
    else()
      message(STATUS "Found ESMF library: ${esmf_lib}")
    endif()
    set(ESMF_INTERFACE_LINK_LIBRARIES "")
  else()
    # When linking the static library, also need the ESMF linker flags; strip any leading/trailing whitespaces
    string(STRIP "${ESMF_F90ESMFLINKRPATHS} ${ESMF_F90ESMFLINKPATHS} ${ESMF_F90LINKPATHS} ${ESMF_F90LINKLIBS} ${ESMF_F90LINKOPTS}" ESMF_INTERFACE_LINK_LIBRARIES)
    message(STATUS "Found ESMF library: ${esmf_lib}")
  endif()

  set_target_properties(esmf PROPERTIES
    IMPORTED_LOCATION ${esmf_lib}
    INTERFACE_INCLUDE_DIRECTORIES "${ESMF_F90COMPILEPATHS}"
    INTERFACE_LINK_LIBRARIES "${ESMF_INTERFACE_LINK_LIBRARIES}")

endif()