cosepo

-module(cosepo@directive).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([get_name/1, get_value/1, new_directive/2]).
-export_type([directive/0]).

-opaque directive() :: {directive, binary(), list(binary())}.

-spec get_name(directive()) -> binary().
get_name(Directive) ->
    erlang:element(2, Directive).

-spec get_value(directive()) -> list(binary()).
get_value(Directive) ->
    erlang:element(3, Directive).

-spec new_directive(binary(), list(binary())) -> {ok, directive()} |
    {error, binary()}.
new_directive(Name, Value) ->
    case gleam@list:find(
        [<<"base-uri"/utf8>>,
            <<"child-src"/utf8>>,
            <<"connect-src"/utf8>>,
            <<"default-src"/utf8>>,
            <<"font-src"/utf8>>,
            <<"form-action"/utf8>>,
            <<"frame-ancestors"/utf8>>,
            <<"frame-src"/utf8>>,
            <<"img-src"/utf8>>,
            <<"manifest-src"/utf8>>,
            <<"media-src"/utf8>>,
            <<"object-src"/utf8>>,
            <<"script-src"/utf8>>,
            <<"script-src-attr"/utf8>>,
            <<"script-src-elem"/utf8>>,
            <<"style-src"/utf8>>,
            <<"style-src-attr"/utf8>>,
            <<"style-src-elem"/utf8>>,
            <<"upgrade-insecure-requests"/utf8>>,
            <<"worker-src"/utf8>>],
        fun(X) -> X =:= Name end
    ) of
        {error, _} ->
            {error, <<Name/binary, " is not a valid directive name"/utf8>>};

        {ok, _} ->
            case Name of
                <<"upgrade-insecure-requests"/utf8>> ->
                    case Value of
                        [] ->
                            {ok, {directive, Name, Value}};

                        _ ->
                            {error,
                                <<"unexpected values for upgrade-insecure-requests directive"/utf8>>}
                    end;

                _ ->
                    {ok, {directive, Name, Value}}
            end
    end.