-module(z_syslog_app).

-behaviour(application).

-export([
    start/0,
    start/2,
    stop/1
]).

%%====================================================================
%% API
%%====================================================================

start() ->
    ensure_started(zotonic_mod_syslog).

start(_StartType, _StartArgs) ->
    z_syslog_sup:start_link().

%%--------------------------------------------------------------------
stop(_State) ->
    ok.

-spec ensure_started(atom()) -> ok | {error, term()}.
ensure_started(App) ->
    case application:start(App) of
        ok ->
            ok;
        {error, {not_started, Dep}} ->
            case ensure_started(Dep) of
                ok -> ensure_started(App);
                {error, _} = Error -> Error
            end;
        {error, {already_started, App}} ->
            ok;
        {error, {Tag, Msg}} when is_list(Tag), is_list(Msg) ->
            {error, lists:flatten(io_lib:format("~s: ~s", [Tag, Msg]))};
        {error, {bad_return, {{M, F, Args}, Return}}} ->
            A = string:join([io_lib:format("~p", [A])|| A <- Args], ", "),
            {error, lists:flatten(
                        io_lib:format("~s failed to start due to a bad return value from call ~s:~s(~s):~n~p",
                                      [App, M, F, A, Return]))};
        {error, Reason} ->
            {error, Reason}
    end.