/** DGui project file.

Copyright: Trogu Antonio Davide 2011-2013

License: $(HTTP boost.org/LICENSE_1_0.txt, Boost License 1.0).

Authors: Trogu Antonio Davide
*/
module dguihub.timer;

import dguihub.core.interfaces.idisposable;
import dguihub.core.winapi;
import dguihub.core.events.event;
import dguihub.core.events.eventargs;
import dguihub.core.exception;

final class Timer : IDisposable {
   private alias Timer[uint] timerMap;

   public Event!(Timer, EventArgs) tick;

   private static timerMap _timers;
   private uint _timerId = 0;
   private uint _time = 0;

   public ~this() {
      this.dispose();
   }

   extern (Windows) private static void timerProc(HWND hwnd, uint msg, uint idEvent, uint t) {
      if (idEvent in _timers) {
         _timers[idEvent].onTick(EventArgs.empty);
      } else {
         throwException!(Win32Exception)("Unknown Timer: '%08X'", idEvent);
      }
   }

   public void dispose() {
      if (this._timerId) {
         if (!KillTimer(null, this._timerId)) {
            throwException!(Win32Exception)("Cannot Dispose Timer");
         }

         _timers.remove(this._timerId);
         this._timerId = 0;
      }
   }

   @property public uint time() {
      return this._time;
   }

   @property public void time(uint t) {
      this._time = t >= 0 ? t : t * (-1); //Take the absolute value.
   }

   public void start() {
      if (!this._timerId) {
         this._timerId = SetTimer(null, 0, this._time, cast(TIMERPROC) /*FIXME may throw*/ &Timer
               .timerProc);

         if (!this._timerId) {
            throwException!(Win32Exception)("Cannot Start Timer");
         }

         this._timers[this._timerId] = this;
      }
   }

   public void stop() {
      this.dispose();
   }

   private void onTick(EventArgs e) {
      this.tick(this, e);
   }
}