-module(rebar3_gpb_prv_compile).

-export([init/1,
         do/1,
         format_error/1]).

-define(PROVIDER, 'compile').
-define(DEPS, [{default, app_discovery}]).
-define(SHORT_DESC, "Automatically compile Google Protocol Buffer (.proto) ",
                    "files using the gpb compiler").
-define(DESC,"Configure gpb options (gbp_opts) in your rebar.config, e.g.\n"
             "  {gpb_opts,["
             "    {i, \"path/to/proto_dir\"},"
             "    {module_name_suffix, \"_pb\"},"
             "    {o_erl, \"path/to/out_src\"},"
             "    {o_hrl, \"path/to/out_include\"},"
             "    {strings_as_binaries, true},"
             "    type_specs]}).").

%% ===================================================================
%% Public API
%% ===================================================================
-spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
init(State) ->
    Provider = providers:create([
            {name, ?PROVIDER},            % The 'user friendly' name of the task
            {namespace, protobuf},
            {module, ?MODULE},            % The module implementation of the task
            {bare, true},                 % The task can be run by the user, always true
            {deps, ?DEPS},                % The list of dependencies
            {opts, []},                   % list of options understood by the plugin
            {example, "rebar3 protobuf compile"},
            {short_desc, ?SHORT_DESC},
            {desc, ?DESC}
    ]),
    {ok, rebar_state:add_provider(State, Provider)}.

-spec do(rebar_state:t()) -> {ok, rebar_state:t()}.
do(State) ->
    Apps = case rebar_state:current_app(State) of
            undefined ->
                rebar_state:project_apps(State);
            AppInfo ->
                [AppInfo]
           end,
    lists:foreach(fun(App) ->
                    rebar3_gpb_compiler:compile(App, State)
                  end, Apps),
    {ok, State}.

-spec format_error(any()) ->  iolist().
format_error(Reason) ->
    io_lib:format("~p", [Reason]).