-module(gmhc_counters).

-export([ initialize/0 ]).

-export([ add/1
        , add/2
        , add_read/1
        , add_read/2
        , get_value/1
        , values/0 ]).

counters() ->
    #{ connector => 1 }.

initialize() ->
    Counters = counters(),
    Size = map_size(Counters),
    CRef = counters:new(Size, []),
    put_counters(#{ref => CRef, counters => Counters}).

add(Counter) ->
    add(Counter, 1).

add(Counter, Incr) when is_integer(Incr), Incr >= 0 ->
    {CRef, Ix} = counter_ix(Counter),
    counters:add(CRef, Ix, Incr).

add_read(Counter) ->
    add_read(Counter, 1).

add_read(Counter, Incr) when is_integer(Incr), Incr >= 0 ->
    {CRef, Ix} = counter_ix(Counter),
    counters:add(CRef, Ix, Incr),
    counters:get(CRef, Ix).

get_value(Counter) ->
    {CRef, Ix} = counter_ix(Counter),
    counters:get(CRef, Ix).

values() ->
    #{ref := CRef, counters := Counters} = get_counters(),
    maps:map(fun(_,Ix) -> counters:get(CRef, Ix) end, Counters).
                     

counter_ix(Counter) ->
    #{ref := CRef, counters := #{Counter := Ix}} = get_counters(),
    {CRef, Ix}.

put_counters(C) ->
    persistent_term:put(?MODULE, C).

get_counters() ->
    persistent_term:get(?MODULE).