%% -*- erlang -*-
{ErlOpts0, Config0} =
    case lists:keytake(erl_opts, 1, CONFIG) of
        false -> {[], CONFIG};
        {value, {erl_opts, D}, Cfg0} -> {D, Cfg0}
    end,

ErlOpts =
    case list_to_integer(erlang:system_info(otp_release)) of
        N when N >= 27 ->
            %[warn_missing_doc, warn_missing_spec, warn_untyped_record | ErlOpts0];
            [warn_missing_spec, warn_untyped_record | ErlOpts0];
        _ ->
            ErlOpts0
    end,

{ExDoc0, Config1} =
    case lists:keytake(ex_doc, 1, Config0) of
        false -> {[], Config0};
        {value, {ex_doc, E}, Cfg1} -> {E, Cfg1}
    end,

SrcDir = "src/",

case file:list_dir(SrcDir) of
    {ok, SrcDirList} ->
        Dirs = lists:filter(
            fun(F) -> not filelib:is_regular(filename:join(SrcDir, F)) end,
            SrcDirList
        ),

        ModulesInDir = fun M(Dir) ->
            {ok, FileList} = file:list_dir(Dir),
            lists:flatmap(
                fun(File) ->
                    case filename:extension(File) of
                        ".erl" ->
                            Module = filename:basename(File, ".erl"),
                            [list_to_atom(Module)];
                        _ ->
                            case filelib:is_dir(filename:join(Dir, File)) of
                                true ->
                                    M(filename:join(Dir, File));
                                false ->
                                    []
                            end
                    end
                end,
                FileList
            )
        end,

        DirsInDir = fun(Dir) ->
            {ok, DirList} = file:list_dir(Dir),
            lists:filter(fun(F) -> not filelib:is_regular(filename:join(Dir, F)) end, DirList)
        end,

        GroupModules = lists:map(
            fun(Dir) ->
                {list_to_binary(Dir), lists:flatten(ModulesInDir(filename:join(SrcDir, Dir)))}
            end,
            Dirs
        ),

        ExDoc = [{groups_for_modules, GroupModules} | ExDoc0],

        [{ex_doc, ExDoc}, {erl_opts, ErlOpts} | Config1];
    {error, _} ->
        [{erl_opts, ErlOpts} | Config0]
end.