/*
* Copyright (C) 2012 The Paparazzi Team
*
* This file is part of paparazzi.
*
* paparazzi 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 2, or (at your option)
* any later version.
*
* paparazzi 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 paparazzi; see the file COPYING. If not, write to
* the Free Software Foundation, 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/

/**
* @file firmwares/rotorcraft/autopilot_arming_yaw.h
*
* Arm the motors by with max yaw stick.
*
*/

#ifndef AUTOPILOT_ARMING_YAW_H
#define AUTOPILOT_ARMING_YAW_H

#include "autopilot_rc_helpers.h"

/** Delay until motors are armed/disarmed.
* In number of rc frames recieved.
* So 40 is usually ~1s.
*/
#ifndef MOTOR_ARMING_DELAY
#define MOTOR_ARMING_DELAY 40
#endif

/// Motors ON check state machine states
enum arming_state {
  STATUS_MOTORS_OFF,
  STATUS_M_OFF_STICK_PUSHED,
  STATUS_START_MOTORS,
  STATUS_MOTORS_ON,
  STATUS_M_ON_STICK_PUSHED,
  STATUS_STOP_MOTORS
};

uint32_t autopilot_motors_on_counter;
enum arming_state autopilot_check_motor_status;


static inline void autopilot_arming_init(void) {
  autopilot_motors_on_counter = 0;
  autopilot_check_motor_status = STATUS_MOTORS_OFF;
}


/** Update the status of the check_motors state machine.
*/
static inline void autopilot_arming_set(bool_t motors_on) {
  if (motors_on)
    autopilot_check_motor_status = STATUS_MOTORS_ON;
  else
    autopilot_check_motor_status = STATUS_MOTORS_OFF;
}

/**
* State machine to check if motors should be turned ON or OFF.
* The motors start/stop when pushing the yaw stick without throttle until #MOTOR_ARMING_DELAY is reached.
* An intermediate state prevents oscillating between ON and OFF while keeping the stick pushed.
* The stick must return to a neutral position before starting/stoping again.
*/
static inline void autopilot_arming_check_motors_on( void ) {
  /* only allow switching motor if not in FAILSAFE or KILL mode */
  if (autopilot_mode > AP_MODE_KILL) {

    switch(autopilot_check_motor_status) {
    case STATUS_MOTORS_OFF:
      autopilot_motors_on = FALSE;
      autopilot_motors_on_counter = 0;
      if (THROTTLE_STICK_DOWN() && YAW_STICK_PUSHED_NEAGTIVE()) // stick pushed
        autopilot_check_motor_status = STATUS_M_OFF_STICK_PUSHED;
      break;
    case STATUS_M_OFF_STICK_PUSHED:
      autopilot_motors_on = FALSE;
      autopilot_motors_on_counter++;
      if (autopilot_motors_on_counter >= MOTOR_ARMING_DELAY)
        autopilot_check_motor_status = STATUS_START_MOTORS;
      else if (!(THROTTLE_STICK_DOWN() && YAW_STICK_PUSHED_NEGATIVE())) // stick released too soon
        autopilot_check_motor_status = STATUS_MOTORS_OFF;
      break;
    case STATUS_START_MOTORS:
      autopilot_motors_on = TRUE;
      autopilot_motors_on_counter = MOTOR_ARMING_DELAY;
      if (!(THROTTLE_STICK_DOWN() && YAW_STICK_PUSHED_NEGATIVE())) // wait until stick released
        autopilot_check_motor_status = STATUS_MOTORS_ON;
      break;
    case STATUS_MOTORS_ON:
      autopilot_motors_on = TRUE;
      autopilot_motors_on_counter = MOTOR_ARMING_DELAY;
      if (THROTTLE_STICK_DOWN() && YAW_STICK_PUSHED_POSITIVE()) // stick pushed
        autopilot_check_motor_status = STATUS_M_ON_STICK_PUSHED;
      break;
    case STATUS_M_ON_STICK_PUSHED:
      autopilot_motors_on = TRUE;
      autopilot_motors_on_counter--;
      if (autopilot_motors_on_counter == 0)
        autopilot_check_motor_status = STATUS_STOP_MOTORS;
      else if (!(THROTTLE_STICK_DOWN() && YAW_STICK_PUSHED_POSITIVE())) // stick released too soon
        autopilot_check_motor_status = STATUS_MOTORS_ON;
      break;
    case STATUS_STOP_MOTORS:
      autopilot_motors_on = FALSE;
      autopilot_motors_on_counter = 0;
      if (!(THROTTLE_STICK_DOWN() && YAW_STICK_PUSHED_POSITIVE())) // wait until stick released
        autopilot_check_motor_status = STATUS_MOTORS_OFF;
      break;
    default:
      break;
    };
  }
}

#endif /* AUTOPILOT_ARMING_YAW_H */