-module(core_counters).
-export([inc/1, dec/1, get/1, read_and_reset/1]).

-define(TABLE, eventhub_counters).

inc(Key) ->
  try ets:update_counter(?TABLE, Key, {2, 1})  % позиция 2 — значение
  catch error:badarg ->
    ets:insert(?TABLE, {Key, 1})
  end.

dec(Key) ->
  try ets:update_counter(?TABLE, Key, {2, -1})
  catch error:badarg ->
    ets:insert(?TABLE, {Key, 0})
  end.

get(Key) ->
  case ets:lookup(?TABLE, Key) of
    [{Key, Val}] -> Val;
    [] -> 0
  end.

read_and_reset(Key) ->
  case ets:lookup(?TABLE, Key) of
    [{Key, Val}] ->
      ets:insert(?TABLE, {Key, 0}),
      Val;
    [] -> 0
  end.