%%   Copyright 2014 Frank Hunleth
%%
%%   Licensed 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.

%%% @doc
%%%  This module provides a supervisor for the target_syncer
%%%  module that does all of the syncing work on the remote.
%%% @end

-module(target_syncer_sup).

-behaviour(supervisor).

%% API
-export([start_link/0, start_child/1]).

%% Supervisor callbacks
-export([init/1]).

-define(SERVER, ?MODULE).

%%%===================================================================
%%% API functions
%%%===================================================================

%%--------------------------------------------------------------------
%% @doc
%% Starts the supervisor
%%
%% @spec start_link() -> {ok, Pid} | ignore | {error, Error}
%% @end
%%--------------------------------------------------------------------
start_link() ->
    supervisor:start_link({local, ?SERVER}, ?MODULE, []).

-spec start_child(atom()) ->
    {ok, undefined | pid()}
    | {ok, undefined | pid(), _}
    | {error, _}.
start_child(Node) ->
    % Make sure that the code is up to date on the remote
    Modules = [relsync_lib, target_syncer],
    [
        begin
            {Mod, Bin, File} = code:get_object_code(Module),
            {module, Mod} = rpc:call(Node, code, load_binary, [Mod, File, Bin], 5000)
        end
     || Module <- Modules
    ],

    % Start the supervisor
    AChild =
        {{target_syncer, Node}, {target_syncer, start_link, [Node]}, transient, 2000, worker, [
            target_syncer
        ]},
    supervisor:start_child(?SERVER, AChild).

%%%===================================================================
%%% Supervisor callbacks
%%%===================================================================

%%--------------------------------------------------------------------
%% @private
%% @doc
%% Whenever a supervisor is started using supervisor:start_link/[2,3],
%% this function is called by the new process to find out about
%% restart strategy, maximum restart frequency and child
%% specifications.
%%
%% @spec init(Args) -> {ok, {SupFlags, [ChildSpec]}} |
%%                     ignore |
%%                     {error, Reason}
%% @end
%%--------------------------------------------------------------------
init([]) ->
    RestartStrategy = one_for_one,
    MaxRestarts = 1000,
    MaxSecondsBetweenRestarts = 3600,

    SupFlags = {RestartStrategy, MaxRestarts, MaxSecondsBetweenRestarts},

    {ok, {SupFlags, []}}.

%%%===================================================================
%%% Internal functions
%%%===================================================================