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 FORCE)
else()
  set(DOXYGEN_FOUND OFF CACHE FORCE)
endif()


function(add_doxygen_target)
  if (DOXYGEN_FOUND)
    set(options)
    set(oneValueArgs TARGET_NAME IN OUT)
    set(multiValueArgs)

    cmake_parse_arguments(_DOXYGEN "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})

    configure_file(${_DOXYGEN_IN} ${_DOXYGEN_OUT} @ONLY)
    message("Doxygen build started")

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