# - 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(WARNING "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(WARNING "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_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()