-module(tinman_ffi).

-export([platform/0, is_windows/0, arch/0, version/0, hostname/0, endianness/0,
         used_memory/0, cpu_count/0, available_parallelism/0, runtime/0, runtime_version/0,
         is_online/0, is_tty/0, is_test/0, process_id/0, libc_type/0, read_file/1, file_exists/1,
         os_cmd/1, env/1]).

platform() ->
    case os:type() of
        {unix, Unix} ->
            atom_to_binary(Unix);
        {Family, _} ->
            atom_to_binary(Family)
    end.

is_windows() ->
    case os:type() of
        {win32, _} ->
            true;
        _ ->
            false
    end.

arch() ->
    [Arch | _] =
        string:split(
            erlang:system_info(system_architecture), "-"),
    list_to_binary(Arch).

version() ->
    case os:version() of
        {Major, Minor, Patch} ->
            {ok, {version, Major, Minor, Patch}};
        _ ->
            {error, nil}
    end.

hostname() ->
    {ok, Hostname} = inet:gethostname(),
    list_to_binary(Hostname).

endianness() ->
    case erlang:system_info(endian) of
        big ->
            big_endian;
        little ->
            little_endian
    end.

used_memory() ->
    erlang:memory(total).

cpu_count() ->
    case erlang:system_info(logical_processors) of
        unknown ->
            {error, nil};
        Count ->
            {ok, Count}
    end.

available_parallelism() ->
    case erlang:system_info(logical_processors_available) of
        unknown ->
            erlang:system_info(schedulers_online);
        Count ->
            min(Count, erlang:system_info(schedulers_online))
    end.

runtime() ->
    list_to_binary(erlang:system_info(machine)).

runtime_version() ->
    list_to_binary(erlang:system_info(version)).

is_online() ->
    case inet:getifaddrs() of
        {ok, Interfaces} ->
            has_non_internal_interface(Interfaces);
        _ ->
            false
    end.

has_non_internal_interface([]) ->
    false;
has_non_internal_interface([{_Name, Props} | Rest]) ->
    case is_interface_online(Props) of
        true ->
            true;
        false ->
            has_non_internal_interface(Rest)
    end.

is_interface_online(Props) ->
    Flags = proplists:get_value(flags, Props, []),
    Internal = lists:member(loopback, Flags),
    HwAddr = proplists:get_value(hwaddr, Props),
    HasValidMac = HwAddr =/= undefined andalso HwAddr =/= [0, 0, 0, 0, 0, 0],
    not Internal andalso HasValidMac.

is_tty() ->
    case io:columns() of
        {ok, _} ->
            % Check io:getopts for stdin, stdout, and terminal flags
            Opts = io:getopts(),
            HasStdin = proplists:get_value(stdin, Opts, false),
            HasStdout = proplists:get_value(stdout, Opts, false),
            HasStdin and HasStdout;
        {error, _} ->
            false
    end.

is_test() ->
    try
        throw(check_stack)
    catch
        _:_:Stack ->
            case lists:reverse(Stack) of
                % Pattern 1: application_master -> *.start: from within app start, need to check the command line
                [{application_master, _, _, _}, {_UserModule, start, _, _} | _] ->
                    OsPid = os:getpid(),
                    PsCmd = "ps -p " ++ OsPid ++ " -o command=",
                    CommandLine = os:cmd(PsCmd),
                    string:str(CommandLine, "_test") > 0;
                % Pattern 2: *@@main.run_module -> *_test.main: directly in test start module
                [{MainModule, run_module, _, _}, {TestModule, main, _, _} | _] ->
                    gleam@string:ends_with(atom_to_binary(MainModule), <<"@@main">>)
                    andalso gleam@string:ends_with(atom_to_binary(TestModule), <<"_test">>);
                % Pattern 3: eunit_proc -> ... (called from within a test function)
                [{eunit_proc, _, _, _} | _] ->
                    true;
                _ ->
                    false
            end
    end.

%% -------------------- Process Information --------------------

process_id() ->
    list_to_integer(os:getpid()).

libc_type() ->
    case os:type() of
        {unix, linux} ->
            Arch = erlang:system_info(system_architecture),
            Parts = string:split(Arch, "-", all),
            case lists:member("musl", Parts) of
                true ->
                    {ok, musl};
                false ->
                    {ok, glibc}
            end;
        _ ->
            {error, nil}
    end.

read_file(Path) ->
    case file:read_file(Path) of
        {ok, Binary} ->
            {ok, Binary};
        {error, _} ->
            {error, nil}
    end.

file_exists(Path) ->
    case filelib:is_file(binary_to_list(Path)) of
        true ->
            true;
        false ->
            false
    end.

os_cmd(Command) ->
    Result = os:cmd(binary_to_list(Command)),
    list_to_binary(Result).

env(Name) ->
    case os:getenv(binary_to_list(Name)) of
        false ->
            <<>>;
        Value ->
            list_to_binary(Value)
    end.