window(15).
max_reqs(10).
page_size(5).
total_pages(5).

api([[[a,10],[b,11],[c,12],[d,13],[e,14]],
     [[f,15],[g,16],[h,16],[i,17],[j,18]],
     [[k,19],[l,20],[m,21],[n,22],[o,23]],
     [[p,24],[q,25],[r,26],[s,27],[t,28]],
     [[u,29],[v,30],[w,31],[x,32],[y,33]]]).

elem(P,E,D) :-
  api_call_2(E,D,D0),
  assert(mydata(P,E,D0)).

mt_elem_handler(_,E,_) :- page_size(E),!.
mt_elem_handler(P,E,D) :-
  thread_create(elem(P,E,D),_),
  succ(E,E0),
  mt_elem_handler(P,E0,D).

page(P) :-
  api_call_1(P,D),
  mt_elem_handler(P,0,D).

mt_page_handler(P) :- total_pages(P),!.
mt_page_handler(P) :-
  thread_create(page(P),_),
  succ(P,P0),
  flag(count,Count,Count+1),
  rate_limit,
  mt_page_handler(P0).

main :-
  rate_limit_init,
  mt_page_handler(0).

api_call_1(Page,Page_data) :-
  atomic_concat("Page: ",Page,Log),
  writeln(Log),sleep(2),api(Data),
  nth0(Page,Data,Page_data).

api_call_2(Elem,Page_data,Elem_data) :-
  atomic_concat("Elem: ",Elem,Log),
  writeln(Log),
  sleep(2),
  nth0(Elem,Page_data,[_,Elem_data]).

rate_limit :-
  window(Window),
  req_rate(Limit),
  get_flag(count,Count),
  get_flag(time,Time),
  get_time(Time0),
  T_diff is Time0-Time,
  (( T_diff >= Window
   ; Count >= Limit )
 -> Sleep is (Window+1)-T_diff,
    atomic_concat("RL: ",Sleep,Log),
    writeln(Log),
    sleep(Sleep),
    writeln("Resuming..."),
    get_time(Time1),
    flag(count,_,0),
    flag(time,_,Time1)
  ;
    writeln("RL Miss") ).

rate_limit_init :-
  get_time(Time),
  set_flag(time,Time),
  set_flag(count,0),
  max_reqs(MR),
  page_size(PS),
  Rate is MR/(PS+1),
  floor(Rate,Limit),
  assert(req_rate(Limit)).

:- dynamic mydata/3.