set(DOXYGEN_FOUND AUTO CACHE STRING "Enable Doxygen documentation generator")
set_property(CACHE DOXYGEN_FOUND PROPERTY STRINGS ON OFF AUTO)

find_package(Doxygen)
if (DOXYGEN_FOUND)
  set(DOXYGEN_FOUND ON CACHE STRING "Doxygen documentation generator enabled" FORCE)
else()
  set(DOXYGEN_FOUND OFF CACHE STRING "Doxygen documentation generator disabled" FORCE)
endif()


function(add_doxygen_target)
  set(options)
  set(oneValueArgs TARGET_NAME DOXY_FILE OUTPUT_DIRECTORY LATEX HTML)
  set(multiValueArgs)

  cmake_parse_arguments(_DOXYGEN "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
  if (DOXYGEN_FOUND)
    set(GENERATE_XML NO)
    set(GENERATE_HTML NO)
    set(GENERATE_LATEX NO)
    if (_DOXYGEN_HTML)
      set(GENERATE_HTML YES)
    endif()
    if (_DOXYGEN_LATEX)
      set(GENERATE_LATEX YES)
    endif()

    configure_file(${_DOXYGEN_DOXY_FILE} ${_DOXYGEN_OUTPUT_DIRECTORY}/Doxyfile @ONLY)
    message("Doxygen build started")

    add_custom_target(${_DOXYGEN_TARGET_NAME} VERBATIM
      COMMAND ${DOXYGEN_EXECUTABLE} ${_DOXYGEN_OUTPUT_DIRECTORY}/Doxyfile
      WORKING_DIRECTORY ${_DOXYGEN_OUTPUT_DIRECTORY}
      COMMENT "Generating API documentation with Doxygen")
  else()
    add_custom_target(${_DOXYGEN_TARGET_NAME} VERBATIM
      COMMENT "Doxygen is not found. Skipping target ${_DOXYGEN_TARGET_NAME} build")
  endif()
endfunction()