open Format

type t = string
type level = int

let loggers = [ "top-down-run"; "top-down-approx"; "result-set"; "level2-jit"; "res-jit"; "grammar"; "twopass";"transition" ]
let active_loggers : (t, int) Hashtbl.t = Hashtbl.create 17
let margin = List.fold_left (fun m l -> max m (String.length l)) 0 loggers
let available () = loggers

let is_logger s = List.mem s loggers
let level s = try Hashtbl.find active_loggers s with Not_found -> 0
let is_active s = Hashtbl.mem active_loggers s
let activate s lvl = if not (is_active s) then Hashtbl.add active_loggers s lvl
let deactivate s = Hashtbl.remove active_loggers s

let logger_output = ref err_formatter
let set_output f = logger_output := f

let log t l fmt =
  if l <= level t
  then begin
    pp_open_hovbox !logger_output (margin + 3);
    fprintf !logger_output "%-.*s : " margin t;
    kfprintf (fun _ ->
      pp_close_box !logger_output ();
      fprintf !logger_output "@?@\n";
    ) !logger_output fmt
  end
  else
    ifprintf !logger_output fmt

let print ppf fmt =
  pp_open_hovbox ppf 0;
  kfprintf (fun _ ->
    pp_close_box ppf ();
    fprintf ppf "@?")
    ppf fmt