if 'api' not in get_option('documentation')
    subdir_done()
endif

doxygen = find_program('doxygen', required: false)
if not doxygen.found()
    error('Program "doxygen" not found or not executable. Try building with -Ddocumentation=false')
endif

mainpage = vcs_tag(command: ['git', 'log', '-1', '--format=%h'],
                   fallback: 'unknown',
                   input: 'mainpage.dox',
                   output: 'mainpage.dox',
                   replace_string: '__GIT_VERSION__',
)

src_doxygen = files(
    # style files
    'doxygen-awesome.css',
) + [libei_headers, libeis_headers, liboeffis_headers]

doxyfiles = []
foreach f: src_doxygen
    df = configure_file(input: f,
                        output: '@PLAINNAME@',
                        copy: true,
    )
    doxyfiles += [df]
endforeach

doc_config = configuration_data()
doc_config.set('PACKAGE_NAME', meson.project_name())
doc_config.set('PACKAGE_VERSION', meson.project_version())
doc_config.set('builddir', meson.current_build_dir())

doxyfile = configure_file(input: 'libei.doxygen.in',
                          output: 'libei.doxygen',
                          configuration: doc_config,
)

custom_target('doxygen',
              input: [ doxyfile, mainpage ] + src_doxygen + doxyfiles,
              output: [ 'doc' ],
              command: [ doxygen, doxyfile ],
              install: false,
              depends: [ mainpage ],
              build_by_default: true,
)