-module(ebb_worker).

-export([start_link/3, start_link/4, stop/1]).

-export([worker/3, worker/5]).
-export([worker_traced/3, worker_traced/5]).

start_link(Func, Args, Receiver) ->
    try
	spawn_link(?MODULE, worker, [Func, Args, Receiver])
    of
	Pid -> {ok, Pid}
    catch
	Error -> Error
    end.

start_link(distributed, Func, Args, Receiver) ->
    Node = ebb_work_manager:available_node(),
    start_link(node(), Node, Func, Args, Receiver).
start_link(Root, Node, Func, Args, Receiver) ->
    try
	Result = spawn_link(Node, ?MODULE, worker,
			    [Root, Node, Func, Args, Receiver]),
	ebb_work_manager:start_work(Node),
	Result
    of
	Pid -> {ok, Pid}
    catch
	Error -> Error
    end.

worker(Func, Args, Receiver) ->
    ebb_event:return(Receiver, apply(Func, Args)).

worker(Root, Node, Func, Args, Receiver) ->
    ebb_event:return(Receiver, apply(Func, Args)),
    ebb_work_manager:work_finished(Root, Node).

trace(Node, Worker, Args) ->
    Ref = make_ref(),
    io:format("~p<< ~p worker thread start~n", [Node, Ref]),
    {_, _, Start} = erlang:now(),
    apply(Worker, Args),
    {_, _, Finish} = erlang:now(),
    io:format("~p>> ~p worker thread finish (~p usec)~n",
	      [Node, Ref, Finish-Start]).

worker_traced(Func, Args, Receiver) ->
    trace(node(), fun worker/3, [Func, Args, Receiver]).

worker_traced(Root, Node, Func, Args, Receiver) ->
    trace(Node, fun worker/5, [Root, Node, Func, Args, Receiver]).

stop(Worker) ->
    exit(Worker, kill).