/**
 * MK & MK4due 3D Printer Firmware
 *
 * Based on Marlin, Sprinter and grbl
 * Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
 * Copyright (C) 2013 - 2016 Alberto Cotronei @MagoKimbra
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

/**
 * Copyright (c) 2013 Arduino LLC. All right reserved.
 *
 * 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
 */

#include "../../base.h"

#if HAS(SERVOS)
  #include "servo.h"

  #define usToTicks(_us)    (( clockCyclesPerMicrosecond()* _us) / 8)     // converts microseconds to tick (assumes prescale of 8)  // 12 Aug 2009
  #define ticksToUs(_ticks) (( (unsigned)_ticks * 8)/ clockCyclesPerMicrosecond() ) // converts from ticks back to microseconds

  #define TRIM_DURATION       2                               // compensation ticks to trim adjust for digitalWrite delays

  static servo_t servos[MAX_SERVOS];                          // static array of servo structures
  static volatile int8_t Channel[_Nbr_16timers ];             // counter for the servo being pulsed for each timer (or -1 if refresh interval)

  uint8_t ServoCount = 0;                                     // the total number of attached servos

  // convenience macros
  #define SERVO_INDEX_TO_TIMER(_servo_nbr) ((timer16_Sequence_t)(_servo_nbr / SERVOS_PER_TIMER)) // returns the timer controlling this servo
  #define SERVO_INDEX_TO_CHANNEL(_servo_nbr) (_servo_nbr % SERVOS_PER_TIMER)       // returns the index of the servo on this timer
  #define SERVO_INDEX(_timer,_channel)  ((_timer*SERVOS_PER_TIMER) + _channel)     // macro to access servo index by timer and channel
  #define SERVO(_timer,_channel)  (servos[SERVO_INDEX(_timer,_channel)])            // macro to access servo class by timer and channel

  #define SERVO_MIN() (MIN_PULSE_WIDTH - this->min * 4)  // minimum value in uS for this servo
  #define SERVO_MAX() (MAX_PULSE_WIDTH - this->max * 4)  // maximum value in uS for this servo

  /************ static functions common to all instances ***********************/

  static inline void handle_interrupts(timer16_Sequence_t timer, volatile uint16_t *TCNTn, volatile uint16_t* OCRnA)
  {
    if( Channel[timer] < 0 )
      *TCNTn = 0; // channel set to -1 indicated that refresh interval completed so reset the timer
    else{
      if( SERVO_INDEX(timer,Channel[timer]) < ServoCount && SERVO(timer,Channel[timer]).Pin.isActive == true )
        digitalWrite( SERVO(timer,Channel[timer]).Pin.nbr,LOW); // pulse this channel low if activated
    }

    Channel[timer]++;    // increment to the next channel
    if( SERVO_INDEX(timer,Channel[timer]) < ServoCount && Channel[timer] < SERVOS_PER_TIMER) {
      *OCRnA = *TCNTn + SERVO(timer,Channel[timer]).ticks;
      if(SERVO(timer,Channel[timer]).Pin.isActive == true)     // check if activated
        digitalWrite( SERVO(timer,Channel[timer]).Pin.nbr,HIGH); // its an active channel so pulse it high
    }
    else {
      // finished all channels so wait for the refresh period to expire before starting over
      if( ((unsigned)*TCNTn) + 4 < usToTicks(REFRESH_INTERVAL) )  // allow a few ticks to ensure the next OCR1A not missed
        *OCRnA = (unsigned int)usToTicks(REFRESH_INTERVAL);
      else
        *OCRnA = *TCNTn + 4;  // at least REFRESH_INTERVAL has elapsed
      Channel[timer] = -1; // this will get incremented at the end of the refresh period to start again at the first channel
    }
  }

  #ifndef WIRING // Wiring pre-defines signal handlers so don't define any if compiling for the Wiring platform
  // Interrupt handlers for Arduino
  #if defined(_useTimer1)
  SIGNAL (TIMER1_COMPA_vect)
  {
    handle_interrupts(_timer1, &TCNT1, &OCR1A);
  }
  #endif

  #if defined(_useTimer3)
  SIGNAL (TIMER3_COMPA_vect)
  {
    handle_interrupts(_timer3, &TCNT3, &OCR3A);
  }
  #endif

  #if defined(_useTimer4)
  SIGNAL (TIMER4_COMPA_vect)
  {
    handle_interrupts(_timer4, &TCNT4, &OCR4A);
  }
  #endif

  #if defined(_useTimer5)
  SIGNAL (TIMER5_COMPA_vect)
  {
    handle_interrupts(_timer5, &TCNT5, &OCR5A);
  }
  #endif

  #elif defined WIRING
  // Interrupt handlers for Wiring
  #if defined(_useTimer1)
  void Timer1Service()
  {
    handle_interrupts(_timer1, &TCNT1, &OCR1A);
  }
  #endif
  #if defined(_useTimer3)
  void Timer3Service()
  {
    handle_interrupts(_timer3, &TCNT3, &OCR3A);
  }
  #endif
  #endif


  static void initISR(timer16_Sequence_t timer)
  {
  #if defined (_useTimer1)
    if(timer == _timer1) {
      TCCR1A = 0;             // normal counting mode
      TCCR1B = _BV(CS11);     // set prescaler of 8
      TCNT1 = 0;              // clear the timer count
  #if defined(__AVR_ATmega8__)|| defined(__AVR_ATmega128__)
      TIFR |= _BV(OCF1A);      // clear any pending interrupts;
      TIMSK |=  _BV(OCIE1A) ;  // enable the output compare interrupt
  #else
      // here if not ATmega8 or ATmega128
      TIFR1 |= _BV(OCF1A);     // clear any pending interrupts;
      TIMSK1 |=  _BV(OCIE1A) ; // enable the output compare interrupt
  #endif
  #if defined(WIRING)
      timerAttach(TIMER1OUTCOMPAREA_INT, Timer1Service);
  #endif
    }
  #endif

  #if defined (_useTimer3)
    if(timer == _timer3) {
      TCCR3A = 0;             // normal counting mode
      TCCR3B = _BV(CS31);     // set prescaler of 8
      TCNT3 = 0;              // clear the timer count
  #if defined(__AVR_ATmega128__)
      TIFR |= _BV(OCF3A);     // clear any pending interrupts;
    ETIMSK |= _BV(OCIE3A);  // enable the output compare interrupt
  #else
      TIFR3 = _BV(OCF3A);     // clear any pending interrupts;
      TIMSK3 =  _BV(OCIE3A) ; // enable the output compare interrupt
  #endif
  #if defined(WIRING)
      timerAttach(TIMER3OUTCOMPAREA_INT, Timer3Service);  // for Wiring platform only
  #endif
    }
  #endif

  #if defined (_useTimer4)
    if(timer == _timer4) {
      TCCR4A = 0;             // normal counting mode
      TCCR4B = _BV(CS41);     // set prescaler of 8
      TCNT4 = 0;              // clear the timer count
      TIFR4 = _BV(OCF4A);     // clear any pending interrupts;
      TIMSK4 =  _BV(OCIE4A) ; // enable the output compare interrupt
    }
  #endif

  #if defined (_useTimer5)
    if(timer == _timer5) {
      TCCR5A = 0;             // normal counting mode
      TCCR5B = _BV(CS51);     // set prescaler of 8
      TCNT5 = 0;              // clear the timer count
      TIFR5 = _BV(OCF5A);     // clear any pending interrupts;
      TIMSK5 =  _BV(OCIE5A) ; // enable the output compare interrupt
    }
  #endif
  }

  static void finISR(timer16_Sequence_t timer)
  {
      //disable use of the given timer
  #if defined WIRING   // Wiring
    if(timer == _timer1) {
      #if defined(__AVR_ATmega1281__)||defined(__AVR_ATmega2561__)
      TIMSK1 &=  ~_BV(OCIE1A) ;  // disable timer 1 output compare interrupt
      #else
      TIMSK &=  ~_BV(OCIE1A) ;  // disable timer 1 output compare interrupt
      #endif
      timerDetach(TIMER1OUTCOMPAREA_INT);
    }
    else if(timer == _timer3) {
      #if defined(__AVR_ATmega1281__)||defined(__AVR_ATmega2561__)
      TIMSK3 &= ~_BV(OCIE3A);    // disable the timer3 output compare A interrupt
      #else
      ETIMSK &= ~_BV(OCIE3A);    // disable the timer3 output compare A interrupt
      #endif
      timerDetach(TIMER3OUTCOMPAREA_INT);
    }
  #else
      //For arduino - in future: call here to a currently undefined function to reset the timer
  #endif
  }


  static boolean isTimerActive(timer16_Sequence_t timer)
  {
    // returns true if any servo is active on this timer
    for(uint8_t channel=0; channel < SERVOS_PER_TIMER; channel++) {
      if(SERVO(timer,channel).Pin.isActive == true)
        return true;
    }
    return false;
  }

  /****************** end of static functions ******************************/

  Servo::Servo() {
    if (ServoCount < MAX_SERVOS) {
      this->servoIndex = ServoCount++;                    // assign a servo index to this instance
      servos[this->servoIndex].ticks = usToTicks(DEFAULT_PULSE_WIDTH);   // store default values
    }
    else {
      this->servoIndex = INVALID_SERVO;  // too many servos
    }
  }

  uint8_t Servo::attach(int pin) {
    return this->attach(pin, MIN_PULSE_WIDTH, MAX_PULSE_WIDTH);
  }

  uint8_t Servo::attach(int pin, int min, int max) {

    if (this->servoIndex >= MAX_SERVOS) return -1;

    if (pin > 0) servos[this->servoIndex].Pin.nbr = pin;
    pinMode(servos[this->servoIndex].Pin.nbr, OUTPUT); // set servo pin to output

    // todo min/max check: abs(min - MIN_PULSE_WIDTH) /4 < 128
    this->min = (MIN_PULSE_WIDTH - min) / 4; //resolution of min/max is 4 uS
    this->max = (MAX_PULSE_WIDTH - max) / 4;

    // initialize the timer if it has not already been initialized
    timer16_Sequence_t timer = SERVO_INDEX_TO_TIMER(servoIndex);
    if (!isTimerActive(timer)) initISR(timer);
    servos[this->servoIndex].Pin.isActive = true;  // this must be set after the check for isTimerActive

    return this->servoIndex;
  }

  void Servo::detach() {
    servos[this->servoIndex].Pin.isActive = false;
    timer16_Sequence_t timer = SERVO_INDEX_TO_TIMER(servoIndex);
    if (!isTimerActive(timer)) finISR(timer);
  }

  void Servo::write(int value) {
    if (value < MIN_PULSE_WIDTH) { // treat values less than 544 as angles in degrees (valid values in microseconds are handled as microseconds)
      value = map(constrain(value, 0, 180), 0, 180, SERVO_MIN(), SERVO_MAX());
    }
    this->writeMicroseconds(value);
  }

  void Servo::writeMicroseconds(int value) {
    // calculate and store the values for the given channel
    byte channel = this->servoIndex;
    if (channel < MAX_SERVOS) {  // ensure channel is valid
      // ensure pulse width is valid
      value = constrain(value, SERVO_MIN(), SERVO_MAX()) - TRIM_DURATION;
      value = usToTicks(value);  // convert to ticks after compensating for interrupt overhead

      CRITICAL_SECTION_START;
      servos[channel].ticks = value;
      CRITICAL_SECTION_END;
    }
  }

  // return the value as degrees
  int Servo::read() { return map(this->readMicroseconds() + 1, SERVO_MIN(), SERVO_MAX(), 0, 180); }

  int Servo::readMicroseconds() {
    return (this->servoIndex == INVALID_SERVO) ? 0 : ticksToUs(servos[this->servoIndex].ticks) + TRIM_DURATION;
  }

  bool Servo::attached() { return servos[this->servoIndex].Pin.isActive; }

  void Servo::move(int value) {
    if (this->attach(0) >= 0) {
      this->write(value);
      #if ENABLED(DEACTIVATE_SERVOS_AFTER_MOVE)
        delay(SERVO_DEACTIVATION_DELAY);
        this->detach();
      #endif
    }
  }

#endif
