include_guard(GLOBAL)

if(${CMAKE_VERSION} VERSION_LESS "3.17.0")
  set(MYX_CMAKE_LIB_DOC_DIR_BACKPORT "${CMAKE_CURRENT_LIST_DIR}")
endif()

function(myx_doc_doxygen NAME)
  if(${CMAKE_VERSION} VERSION_LESS "3.17.0")
    set(CMAKE_CURRENT_FUNCTION_LIST_DIR ${MYX_CMAKE_LIB_DOC_DIR_BACKPORT})
  endif()

  find_package(Doxygen)
  if(DOXYGEN_FOUND)
    set(DOXYGEN_FOUND ON CACHE STRING "Doxygen documentation generator enabled" FORCE)
    set(DOXYGEN_EXECUTABLE "${DOXYGEN_EXECUTABLE}" CACHE STRING "Path to Doxygen executable")
  else()
    set(DOXYGEN_FOUND OFF CACHE STRING "Doxygen documentation generator disabled" FORCE)
  endif()

  set(target "myx-doc-doxygen-${NAME}")
  if(NOT DOXYGEN_FOUND)
    add_custom_target(${target} VERBATIM COMMENT "Doxygen is not found. Skipping target ${target} build")
    return()
  endif()

  if(TARGET ${target})
    myx_message_warning("Target ${target} already defined")
    return()
  endif()

  set(options)
  set(oneValueArgs HTML LATEX XML LANGUAGE DOXYFILE_TEMPLATE)
  set(multiValueArgs)

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

  if(NOT ARG_HTML)
    set(ARG_HTML NO)
  endif()
  if(NOT ARG_LATEX)
    set(ARG_LATEX NO)
  endif()
  if(NOT ARG_XML)
    set(ARG_XML YES)
  endif()
  if(NOT ARG_LANGUAGE)
    set(ARG_LANGUAGE "Russian")
  endif()
  if(NOT ARG_DOXYFILE_TEMPLATE OR NOT EXISTS "${ARG_DOXYFILE_TEMPLATE}")
    set(ARG_DOXYFILE_TEMPLATE "${CMAKE_CURRENT_FUNCTION_LIST_DIR}/Doxyfile.in")
  endif()
  if(NOT DOXYGEN_PROJECT_NAME)
    set(DOXYGEN_PROJECT_NAME ${PROJECT_NAME})
  endif()

  set(work_dir ${PROJECT_BINARY_DIR}/doc/doxygen)
  configure_file(${ARG_DOXYFILE_TEMPLATE} ${work_dir}/Doxyfile @ONLY)

  add_custom_target(${target}
    VERBATIM
    WORKING_DIRECTORY ${work_dir}
    COMMAND ${DOXYGEN_EXECUTABLE} ${work_dir}/Doxyfile
    COMMENT "Generating API documentation with Doxygen")
  if(ARG_HTML)
    install(DIRECTORY ${CMAKE_BINARY_DIR}/doc/doxygen/html/
            COMPONENT doc OPTIONAL
            DESTINATION ${CMAKE_INSTALL_DATADIR}/doc/doxygen)
  endif()
  if(NOT TARGET myx-doc-doxygen)
    add_custom_target(myx-doc-doxygen)
  endif()
  add_dependencies(myx-doc-doxygen ${target})
endfunction()