/*
 * M5Timer.h
 *
 * M5Timer - A timer library for Arduino.
 * Author: mromani@ottotecnica.com
 * Copyright (c) 2010 OTTOTECNICA Italy
 *
 * This library is free software; you can redistribute it
 * and/or modify it under the terms of the GNU Lesser
 * General Public License as published by the Free Software
 * Foundation; either version 2.1 of the License, or (at
 * your option) any later version.
 *
 * This library is distributed in the hope that it will
 * be useful, but WITHOUT ANY WARRANTY; without even the
 * implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 *
 * You should have received a copy of the GNU Lesser
 * General Public License along with this library; if not,
 * write to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 *
 */


#ifndef M5Timer_H
  #define M5Timer_H

  #include <functional>
  #include <Arduino.h>

  typedef std::function<void(void)> timer_callback;

  class M5Timer {
    public:
      // maximum number of timers
      const static int MAX_TIMERS = 10;

      // setTimer() constants
      const static int RUN_FOREVER = 0;
      const static int RUN_ONCE = 1;

      // constructor
      M5Timer();

      // this function must be called inside loop()
      void run();

      // call function f every d milliseconds
      int setInterval(long d, timer_callback f);

      // call function f once after d milliseconds
      int setTimeout(long d, timer_callback f);

      // call function f every d milliseconds for n times
      int setTimer(long d, timer_callback f, int n);

      // destroy the specified timer
      void deleteTimer(int numTimer);

      // restart the specified timer
      void restartTimer(int numTimer);

      // returns true if the specified timer is enabled
      boolean isEnabled(int numTimer);

      // enables the specified timer
      void enable(int numTimer);

      // disables the specified timer
      void disable(int numTimer);

      // enables the specified timer if it's currently disabled,
      // and vice-versa
      void toggle(int numTimer);

      // returns the number of used timers
      int getNumTimers();

      // returns the number of available timers
      int getNumAvailableTimers() { return MAX_TIMERS - numTimers; };

    private:
      // deferred call constants
      const static int DEFCALL_DONTRUN = 0;   // don't call the callback function
      const static int DEFCALL_RUNONLY = 1;   // call the callback function but don't delete the timer
      const static int DEFCALL_RUNANDDEL = 2;  // call the callback function and delete the timer

      // find the first available slot
      int findFirstFreeSlot();

      // value returned by the millis() function
      // in the previous run() call
      unsigned long prev_millis[MAX_TIMERS];

      // pointers to the callback functions
      timer_callback callbacks[MAX_TIMERS];

      // delay values
      long delays[MAX_TIMERS];

      // number of runs to be executed for each timer
      int maxNumRuns[MAX_TIMERS];

      // number of executed runs for each timer
      int numRuns[MAX_TIMERS];

      // which timers are enabled
      boolean enabled[MAX_TIMERS];

      // deferred function call (sort of) - N.B.: this array is only used in run()
      int toBeCalled[MAX_TIMERS];

      // actual number of timers in use
      int numTimers;
  };

#endif
