find_program(clang-format_EXECUTABLE clang-format)
mark_as_advanced(clang-format_EXECUTABLE)

if(clang-format_EXECUTABLE)
  add_executable(clang-format IMPORTED)
  set_target_properties(clang-format PROPERTIES
    IMPORTED_LOCATION ${clang-format_EXECUTABLE})
endif()

unset(_CLANG_FORMAT)

function(add_autoformat_target target)
  get_target_property(source_dir ${target} SOURCE_DIR)
  get_target_property(sources ${target} SOURCES)
  foreach(source ${sources})
    get_property(generated SOURCE ${source} PROPERTY GENERATED)
    if(NOT ${generated})
      list(APPEND non_generated_sources ${source})
    endif()
  endforeach()
  add_custom_target(autoformat_${target}
    COMMAND clang-format -i -- ${non_generated_sources}
    WORKING_DIRECTORY ${source_dir}
    COMMENT "Autoformating sources of target ${target}"
    VERBATIM)
  if(NOT TARGET autoformat)
    add_custom_target(autoformat)
  endif()
  add_dependencies(autoformat autoformat_${target})
endfunction()