include_guard()

find_program(GLIB_MKENUMS_BIN
  NAMES "glib-mkenums"
  REQUIRED
)

function(target_add_glib_enums TARGET)
  set(SINGLE_VALUE_ARGS
    "HEADER_TEMPLATE"
    "OUTPUT_NAME"
    "SOURCE_TEMPLATE"
  )
  set(MULTI_VALUE_ARGS "HEADERS")
  cmake_parse_arguments(
    PARSE_ARGV 1
    ""
    "${OPTIONS}"
    "${SINGLE_VALUE_ARGS}"
    "${MULTI_VALUE_ARGS}"
  )

  if(NOT TARGET "${TARGET}")
    message(FATAL_ERROR "GlibMkenums: Target '${TARGET}' does not exist")
  endif()

  if(NOT _HEADERS)
    message(FATAL_ERROR "GlibMkenums: No headers to be parsed were specified")
  endif()

  if(NOT _HEADER_TEMPLATE)
    message(STATUS "GlibMkenums: no header template was provided, skipping header generation")
    set(_SKIP_HEADER YES)
  endif()

  if(NOT _SOURCE_TEMPLATE)
    message(STATUS "GlibMkenums: no source template was provided, skipping header generation")
    set(_SKIP_SOURCE YES)
  endif()

  if(NOT _OUTPUT_NAME)
    message(FATAL_ERROR "GlibMkenums: No output name was specified")
  endif()

  if(_SKIP_HEADER AND _SKIP_SOURCE)
    message(AUTHOR_WARNING "GlibMkenums: No templates were specified, skipping all generation")
    return()
  endif()

  set(SOURCE_FILE "${CMAKE_CURRENT_SOURCE_DIR}/src/${_OUTPUT_NAME}.c")
  set(HEADER_FILE "${CMAKE_CURRENT_SOURCE_DIR}/src/${_OUTPUT_NAME}.h")

  if(NOT _SKIP_HEADER)
    add_custom_command(OUTPUT
      ${HEADER_FILE}
      WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
      COMMAND "${GLIB_MKENUMS_BIN}"
      ARGS
      "--template=${_HEADER_TEMPLATE}"
      "--output=${HEADER_FILE}"
      ${_HEADERS}
      VERBATIM
      COMMENT "Generating enum interface header"
      DEPENDS
      ${_HEADERS}
      ${_HEADER_TEMPLATE}
    )
  endif()

  if(NOT _SKIP_SOURCE)
    add_custom_command(OUTPUT
      ${SOURCE_FILE}
      WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
      COMMAND "${GLIB_MKENUMS_BIN}"
      ARGS
      "--template=${_SOURCE_TEMPLATE}"
      "--output=${SOURCE_FILE}"
      ${_HEADERS}
      VERBATIM
      COMMENT "Generating enum interface source"
      DEPENDS
      ${_HEADERS}
      ${_SOURCE_TEMPLATE}
    )
  endif()

  target_sources("${TARGET}" PRIVATE
    "${SOURCE_FILE}"
  )

  if(NOT _SKIP_HEADER)
    target_sources("${TARGET}" PUBLIC
      FILE_SET HEADERS
      FILES
      "${HEADER_FILE}"
    )
  endif()

endfunction()