rebar.config.script

%% -*- mode: erlang;erlang-indent-level: 4;indent-tabs-mode: nil -*-
%% ex: ts=4 sw=4 ft=erlang et
%%
ErtsPath = os:getenv("REBAR3_TARGET_INCLUDE_ERTS"),
SystemLibsPath = os:getenv("REBAR3_TARGET_SYSTEM_LIBS"),
Profile = case os:getenv("REBAR3_PROFILE") of
    false ->
        prod;
    Str ->
        list_to_atom(Str)
end,

Replace =
    fun
        Replace([Key], Value, Config0) ->
            Replace(Key, Value, Config0);

        Replace([H|T], Value, Config0) ->
            case lists:keyfind(H, 1, Config0) of
                false ->
                    error({key_not_found, [H, Config0]});
                {H, Config1} ->
                    NewValue = {H, Replace(T, Value, Config1)},
                    lists:keyreplace(H, 1, Config0, NewValue)
            end;

        Replace(Key, Value, Config) ->
            case lists:keyfind(Key, 1, Config) of
                false ->
                    Config;
                {Key, true} ->
                    NewValue = {Key, Value},
                    lists:keyreplace(Key, 1, Config, NewValue);
                {Key, _} ->
                    %% false or hardcoded Path, so we respect that
                    Config
            end
    end,

case {ErtsPath, SystemLibsPath} of
    {false, false} ->
        CONFIG;
    {Path, false} ->
        Replace([profiles, Profile, relx, include_erts], Path, CONFIG);
    {false, Path} ->
        Replace(profiles, [Profile, relx, system_libs], Path, CONFIG);
    {ErtsPath, SystemLibsPath} ->
        Replace(
            [profiles, Profile, relx, include_erts],
            ErtsPath,
            Replace(
                [profiles, Profile, relx, system_libs],
                SystemLibsPath,
                CONFIG
            )
        )
end.