-module(ecron_monitor).
-behaviour(gen_server).

-export([start_link/2]).

-export([init/1, handle_call/3, handle_cast/2, handle_info/2]).

start_link(Name, Jobs) ->
    gen_server:start_link(Name, ?MODULE, [Jobs], []).

init([Jobs]) ->
    case ecron_tick:parse_crontab(Jobs, []) of
        {ok, [_ | _]} ->
            erlang:process_flag(trap_exit, true),
            ok = net_kernel:monitor_nodes(true),
            {ok, undefined, 5};
        {stop, Reason} -> {stop, Reason}
    end.

handle_call(_Request, _From, State) ->
    {reply, error, State}.

handle_cast(_Request, State) ->
    {noreply, State}.

handle_info(Reason, State) ->
    QuorumSize = application:get_env(ecron, cluster_quorum_size, 1),
    {ResL, _BadNodes} = rpc:multicall(nodes(visible), erlang, whereis, [ecron], 6000),
    Healthy = lists:foldl(fun(Pid, Acc) -> case is_pid(Pid) of true -> Acc + 1; false -> Acc end end, 1, ResL),
    case Healthy >= QuorumSize of
        true ->
            {ok, Pid} = ecron_sup:start_global(Reason),
            link(Pid);
        false -> ecron_sup:stop_global(Reason)
    end,
    {noreply, State}.