%% -------------------------------------------------------------------
%%
%% riak_core: Core Riak Application
%%
%% Copyright (c) 2007-2010 Basho Technologies, Inc.  All Rights Reserved.
%%
%% This file is provided to you under the Apache License,
%% Version 2.0 (the "License"); you may not use this file
%% except in compliance with the License.  You may obtain
%% a copy of the License at
%%
%%   http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing,
%% software distributed under the License is distributed on an
%% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
%% KIND, either express or implied.  See the License for the
%% specific language governing permissions and limitations
%% under the License.
%%
%% -------------------------------------------------------------------

-module(riak_core_app).

-behaviour(application).

%% Application callbacks
-export([start/2, stop/1]).

%% ===================================================================
%% Application callbacks
%% ===================================================================

start(_StartType, _StartArgs) ->
    ok = validate_ring_state_directory_exists(),

    start_riak_core_sup().

stop(_State) ->
    logger:info("Stopped application riak_core", []),
    ok.

validate_ring_state_directory_exists() ->
    riak_core_util:start_app_deps(riak_core),
    {ok, RingStateDir} = application:get_env(riak_core, ring_state_dir),
    case filelib:ensure_dir(filename:join(RingStateDir, "dummy")) of
        ok ->
            ok;
        {error, RingReason} ->
            logger:critical(
              "Ring state directory ~p does not exist, " "and could not be created: ~p",
              [RingStateDir, riak_core_util:posix_error(RingReason)]),
            throw({error, invalid_ring_state_dir})
    end.


start_riak_core_sup() ->
    %% Spin up the supervisor; prune ring files as necessary
    case riak_core_sup:start_link() of
        {ok, Pid} ->
            ok = register_applications(),
            ok = add_ring_event_handler(),

            {ok, Pid};
        {error, Reason} ->
            {error, Reason}
    end.

register_applications() ->
    ok.

add_ring_event_handler() ->
    ok = riak_core_ring_events:add_guarded_handler(riak_core_ring_handler, []).