/*
   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/>.
 */

/*
 *       AP_MotorsHeli.cpp - ArduCopter motors library
 *       Code by RandyMackay. DIYDrones.com
 *
 */
#include <stdlib.h>
#include <AP_HAL/AP_HAL.h>
#include "AP_MotorsHeli.h"
#include <GCS_MAVLink/GCS.h>

extern const AP_HAL::HAL& hal;

const AP_Param::GroupInfo AP_MotorsHeli::var_info[] = {

    // 1 was ROL_MAX which has been replaced by CYC_MAX

    // 2 was PIT_MAX which has been replaced by CYC_MAX

    // @Param: COL_MIN
    // @DisplayName: Collective Pitch Minimum
    // @Description: Lowest possible servo position in PWM microseconds for the swashplate
    // @Range: 1000 2000
    // @Units: PWM
    // @Increment: 1
    // @User: Standard
    AP_GROUPINFO("COL_MIN", 3, AP_MotorsHeli, _collective_min, AP_MOTORS_HELI_COLLECTIVE_MIN),

    // @Param: COL_MAX
    // @DisplayName: Collective Pitch Maximum
    // @Description: Highest possible servo position in PWM microseconds for the swashplate
    // @Range: 1000 2000
    // @Units: PWM
    // @Increment: 1
    // @User: Standard
    AP_GROUPINFO("COL_MAX", 4, AP_MotorsHeli, _collective_max, AP_MOTORS_HELI_COLLECTIVE_MAX),

    // @Param: COL_MID
    // @DisplayName: Collective Pitch Mid-Point
    // @Description: Swash servo position in PWM microseconds corresponding to zero collective pitch (or zero lift for Asymmetrical blades)
    // @Range: 1000 2000
    // @Units: PWM
    // @Increment: 1
    // @User: Standard
    AP_GROUPINFO("COL_MID", 5, AP_MotorsHeli, _collective_mid, AP_MOTORS_HELI_COLLECTIVE_MID),

    // @Param: SV_MAN
    // @DisplayName: Manual Servo Mode
    // @Description: Manual servo override for swash set-up. Do not set this manually!
    // @Values: 0:Disabled,1:Passthrough,2:Max collective,3:Mid collective,4:Min collective
    // @User: Standard
    AP_GROUPINFO("SV_MAN",  6, AP_MotorsHeli, _servo_mode, SERVO_CONTROL_MODE_AUTOMATED),

    // @Param: RSC_SETPOINT
    // @DisplayName: External Motor Governor Setpoint
    // @Description: PWM in microseconds passed to the external motor governor when external governor is enabled
    // @Range: 0 1000
    // @Units: PWM
    // @Increment: 10
    // @User: Standard
    AP_GROUPINFO("RSC_SETPOINT", 7, AP_MotorsHeli, _rsc_setpoint, AP_MOTORS_HELI_RSC_SETPOINT),

    // @Param: RSC_MODE
    // @DisplayName: Rotor Speed Control Mode
    // @Description: Determines the method of rotor speed control
    // @Values: 1:Ch8 Input, 2:SetPoint, 3:Throttle Curve, 4:Governor
    // @User: Standard
    AP_GROUPINFO("RSC_MODE", 8, AP_MotorsHeli, _rsc_mode, (int8_t)ROTOR_CONTROL_MODE_SPEED_PASSTHROUGH),

    // index 9 was LAND_COL_MIN. Do not use this index in the future.

    // @Param: RSC_RAMP_TIME
    // @DisplayName: RSC Ramp Time
    // @Description: Time in seconds for the output to the main rotor's ESC to reach full speed
    // @Range: 0 60
    // @Units: s
    // @User: Standard
    AP_GROUPINFO("RSC_RAMP_TIME", 10, AP_MotorsHeli, _rsc_ramp_time, AP_MOTORS_HELI_RSC_RAMP_TIME),

    // @Param: RSC_RUNUP_TIME
    // @DisplayName: RSC Runup Time
    // @Description: Time in seconds for the main rotor to reach full speed.  Must be longer than RSC_RAMP_TIME
    // @Range: 0 60
    // @Units: s
    // @User: Standard
    AP_GROUPINFO("RSC_RUNUP_TIME", 11, AP_MotorsHeli, _rsc_runup_time, AP_MOTORS_HELI_RSC_RUNUP_TIME),

    // @Param: RSC_CRITICAL
    // @DisplayName: Critical Rotor Speed
    // @Description: Rotor speed below which flight is not possible
    // @Range: 0 1000
    // @Increment: 10
    // @User: Standard
    AP_GROUPINFO("RSC_CRITICAL", 12, AP_MotorsHeli, _rsc_critical, AP_MOTORS_HELI_RSC_CRITICAL),

    // @Param: RSC_IDLE
    // @DisplayName: Rotor Speed Output at Idle
    // @Description: Rotor speed output while armed but rotor control speed is not engaged
    // @Range: 0 500
    // @Increment: 10
    // @User: Standard
    AP_GROUPINFO("RSC_IDLE", 13, AP_MotorsHeli, _rsc_idle_output, AP_MOTORS_HELI_RSC_IDLE_DEFAULT),

    // index 14 was RSC_POWER_LOW. Do not use this index in the future.

    // index 15 was RSC_POWER_HIGH. Do not use this index in the future.

    // @Param: CYC_MAX
    // @DisplayName: Cyclic Pitch Angle Max
    // @Description: Maximum pitch angle of the swash plate
    // @Range: 0 18000
    // @Units: cdeg
    // @Increment: 100
    // @User: Advanced
    AP_GROUPINFO("CYC_MAX", 16, AP_MotorsHeli, _cyclic_max, AP_MOTORS_HELI_SWASH_CYCLIC_MAX),

    // @Param: SV_TEST
    // @DisplayName: Boot-up Servo Test Cycles
    // @Description: Number of cycles to run servo test on boot-up
    // @Range: 0 10
    // @Increment: 1
    // @User: Standard
    AP_GROUPINFO("SV_TEST",  17, AP_MotorsHeli, _servo_test, 0),

    // index 18 was RSC_POWER_NEGC. Do not use this index in the future.

    // @Param: RSC_SLEWRATE
    // @DisplayName: Throttle servo slew rate
    // @Description: This controls the maximum rate at which the throttle output can change, as a percentage per second. A value of 100 means the throttle can change over its full range in one second. A value of zero gives unlimited slew rate.
    // @Range: 0 500
    // @Increment: 10
    // @User: Standard
    AP_GROUPINFO("RSC_SLEWRATE", 19, AP_MotorsHeli, _rsc_slewrate, 0),

    // indices 20 to 25 was throttle curve. Do not use this index in the future.

    // @Group: RSC_CRV_
    // @Path: AP_MotorsHeli_RSC.cpp
    AP_SUBGROUPINFO(_rsc_thrcrv, "RSC_CRV_", 27, AP_MotorsHeli, RSCThrCrvParam),

    // @Group: RSC_GOV_
    // @Path: AP_MotorsHeli_RSC.cpp
    AP_SUBGROUPINFO(_rsc_gov, "RSC_GOV_", 28, AP_MotorsHeli, RSCGovParam),

    AP_GROUPEND
};

//
// public methods
//

// init
void AP_MotorsHeli::init(motor_frame_class frame_class, motor_frame_type frame_type)
{
    // remember frame class and type
    _frame_type = frame_type;
    _frame_class = frame_class;

    // set update rate
    set_update_rate(_speed_hz);

    // load boot-up servo test cycles into counter to be consumed
    _servo_test_cycle_counter = _servo_test;

    // ensure inputs are not passed through to servos on start-up
    _servo_mode = SERVO_CONTROL_MODE_AUTOMATED;

    // initialise radio passthrough for collective to middle
    _throttle_radio_passthrough = 0.5f;

    // initialise Servo/PWM ranges and endpoints
    if (!init_outputs()) {
        // don't set initialised_ok
        return;
    }

    // calculate all scalars
    calculate_scalars();

    // record successful initialisation if what we setup was the desired frame_class
    _flags.initialised_ok = (frame_class == MOTOR_FRAME_HELI);

    // set flag to true so targets are initialized once aircraft is armed for first time
    _heliflags.init_targets_on_arming = true;

}

// set frame class (i.e. quad, hexa, heli) and type (i.e. x, plus)
void AP_MotorsHeli::set_frame_class_and_type(motor_frame_class frame_class, motor_frame_type frame_type)
{
    _flags.initialised_ok = (frame_class == MOTOR_FRAME_HELI);
}

// output_min - sets servos to neutral point with motors stopped
void AP_MotorsHeli::output_min()
{
    // move swash to mid
    move_actuators(0.0f,0.0f,0.5f,0.0f);

    update_motor_control(ROTOR_CONTROL_STOP);

    // override limits flags
    limit.roll_pitch = true;
    limit.yaw = true;
    limit.throttle_lower = true;
    limit.throttle_upper = false;
}

// output - sends commands to the servos
void AP_MotorsHeli::output()
{
    // update throttle filter
    update_throttle_filter();

    // run spool logic
    output_logic();

    if (_flags.armed) {
        calculate_armed_scalars();
        if (!_flags.interlock) {
            output_armed_zero_throttle();
        } else {
            output_armed_stabilizing();
        }
    } else {
        output_disarmed();
    }
    
    output_to_motors();

};

// sends commands to the motors
void AP_MotorsHeli::output_armed_stabilizing()
{
    // if manual override active after arming, deactivate it and reinitialize servos
    if (_servo_mode != SERVO_CONTROL_MODE_AUTOMATED) {
        reset_flight_controls();
    }

    move_actuators(_roll_in, _pitch_in, get_throttle(), _yaw_in);
}

// output_armed_zero_throttle - sends commands to the motors
void AP_MotorsHeli::output_armed_zero_throttle()
{
    // if manual override active after arming, deactivate it and reinitialize servos
    if (_servo_mode != SERVO_CONTROL_MODE_AUTOMATED) {
        reset_flight_controls();
    }

    move_actuators(_roll_in, _pitch_in, get_throttle(), _yaw_in);
}

// output_disarmed - sends commands to the motors
void AP_MotorsHeli::output_disarmed()
{
    if (_servo_test_cycle_counter > 0){
        // perform boot-up servo test cycle if enabled
        servo_test();
    } else {
        // manual override (i.e. when setting up swash)
        switch (_servo_mode) {
            case SERVO_CONTROL_MODE_MANUAL_PASSTHROUGH:
                // pass pilot commands straight through to swash
                _roll_in = _roll_radio_passthrough;
                _pitch_in = _pitch_radio_passthrough;
                _throttle_filter.reset(_throttle_radio_passthrough);
                _yaw_in = _yaw_radio_passthrough;
                break;
            case SERVO_CONTROL_MODE_MANUAL_CENTER:
                // fixate mid collective
                _roll_in = 0.0f;
                _pitch_in = 0.0f;
                _throttle_filter.reset(_collective_mid_pct);
                _yaw_in = 0.0f;
                break;
            case SERVO_CONTROL_MODE_MANUAL_MAX:
                // fixate max collective
                _roll_in = 0.0f;
                _pitch_in = 0.0f;
                _throttle_filter.reset(1.0f);
                if (_frame_class == MOTOR_FRAME_HELI_DUAL ||
                    _frame_class == MOTOR_FRAME_HELI_QUAD) {
                    _yaw_in = 0;
                } else {
                    _yaw_in = 1;
                }
                break;
            case SERVO_CONTROL_MODE_MANUAL_MIN:
                // fixate min collective
                _roll_in = 0.0f;
                _pitch_in = 0.0f;
                _throttle_filter.reset(0.0f);
                if (_frame_class == MOTOR_FRAME_HELI_DUAL ||
                    _frame_class == MOTOR_FRAME_HELI_QUAD) {
                    _yaw_in = 0;
                } else {
                    _yaw_in = -1;
                }
                break;
            case SERVO_CONTROL_MODE_MANUAL_OSCILLATE:
                // use servo_test function from child classes
                servo_test();
                break;
            default:
                // no manual override
                break;
        }
    }

    // ensure swash servo endpoints haven't been moved
    init_outputs();

    // continuously recalculate scalars to allow setup
    calculate_scalars();

    // helicopters always run stabilizing flight controls
    move_actuators(_roll_in, _pitch_in, get_throttle(), _yaw_in);
}

// run spool logic
void AP_MotorsHeli::output_logic()
{
    // force desired and current spool mode if disarmed and armed with interlock enabled
    if (_flags.armed) {
        if (!_flags.interlock) {
            _spool_desired = DesiredSpoolState::GROUND_IDLE;
        } else {
            _heliflags.init_targets_on_arming = false;
        }
    } else {
        _heliflags.init_targets_on_arming = true;
        _spool_desired = DesiredSpoolState::SHUT_DOWN;
        _spool_state = SpoolState::SHUT_DOWN;
    }

    switch (_spool_state) {
        case SpoolState::SHUT_DOWN:
            // Motors should be stationary.
            // Servos set to their trim values or in a test condition.

            // make sure the motors are spooling in the correct direction
            if (_spool_desired != DesiredSpoolState::SHUT_DOWN) {
                _spool_state = SpoolState::GROUND_IDLE;
                break;
            }

            break;

        case SpoolState::GROUND_IDLE: {
            // Motors should be stationary or at ground idle.
            // Servos should be moving to correct the current attitude.
            if (_spool_desired == DesiredSpoolState::SHUT_DOWN){
                _spool_state = SpoolState::SHUT_DOWN;
            } else if(_spool_desired == DesiredSpoolState::THROTTLE_UNLIMITED) {
                _spool_state = SpoolState::SPOOLING_UP;
            } else {    // _spool_desired == GROUND_IDLE

            }

            break;
        }
        case SpoolState::SPOOLING_UP:
            // Maximum throttle should move from minimum to maximum.
            // Servos should exhibit normal flight behavior.

            // make sure the motors are spooling in the correct direction
            if (_spool_desired != DesiredSpoolState::THROTTLE_UNLIMITED ){
                _spool_state = SpoolState::SPOOLING_DOWN;
                break;
            }

            if (_heliflags.rotor_runup_complete){
                _spool_state = SpoolState::THROTTLE_UNLIMITED;
            }
            break;

        case SpoolState::THROTTLE_UNLIMITED:
            // Throttle should exhibit normal flight behavior.
            // Servos should exhibit normal flight behavior.

            // make sure the motors are spooling in the correct direction
            if (_spool_desired != DesiredSpoolState::THROTTLE_UNLIMITED) {
                _spool_state = SpoolState::SPOOLING_DOWN;
                break;
            }


            break;

        case SpoolState::SPOOLING_DOWN:
            // Maximum throttle should move from maximum to minimum.
            // Servos should exhibit normal flight behavior.

            // make sure the motors are spooling in the correct direction
            if (_spool_desired == DesiredSpoolState::THROTTLE_UNLIMITED) {
                _spool_state = SpoolState::SPOOLING_UP;
                break;
            }
            if (!rotor_speed_above_critical()){
                _spool_state = SpoolState::GROUND_IDLE;
            }
            break;
    }
}

// parameter_check - check if helicopter specific parameters are sensible
bool AP_MotorsHeli::parameter_check(bool display_msg) const
{
    // returns false if _rsc_setpoint is not higher than _rsc_critical as this would not allow rotor_runup_complete to ever return true
    if (_rsc_critical >= _rsc_setpoint) {
        if (display_msg) {
            gcs().send_text(MAV_SEVERITY_CRITICAL, "PreArm: H_RSC_CRITICAL too large");
        }
        return false;
    }

    // returns false if RSC Mode is not set to a valid control mode
    if (_rsc_mode <= (int8_t)ROTOR_CONTROL_MODE_DISABLED || _rsc_mode > (int8_t)ROTOR_CONTROL_MODE_CLOSED_LOOP_POWER_OUTPUT) {
        if (display_msg) {
            gcs().send_text(MAV_SEVERITY_CRITICAL, "PreArm: H_RSC_MODE invalid");
        }
        return false;
    }

    // returns false if RSC Runup Time is less than Ramp time as this could cause undesired behaviour of rotor speed estimate
    if (_rsc_runup_time <= _rsc_ramp_time){
        if (display_msg) {
            gcs().send_text(MAV_SEVERITY_CRITICAL, "PreArm: H_RUNUP_TIME too small");
        }
        return false;
    }

    // returns false if idle output is higher than critical rotor speed as this could block runup_complete from going false
    if ( _rsc_idle_output >=  _rsc_critical){
        if (display_msg) {
            gcs().send_text(MAV_SEVERITY_CRITICAL, "PreArm: H_RSC_IDLE too large");
        }
        return false;
    }

    // all other cases parameters are OK
    return true;
}

// reset_swash_servo
void AP_MotorsHeli::reset_swash_servo(SRV_Channel::Aux_servo_function_t function)
{
    // outputs are defined on a -500 to 500 range for swash servos
    SRV_Channels::set_range(function, 1000);

    // swash servos always use full endpoints as restricting them would lead to scaling errors
    SRV_Channels::set_output_min_max(function, 1000, 2000);
}

// update the throttle input filter
void AP_MotorsHeli::update_throttle_filter()
{
    _throttle_filter.apply(_throttle_in, 1.0f/_loop_rate);

    // constrain filtered throttle
    if (_throttle_filter.get() < 0.0f) {
        _throttle_filter.reset(0.0f);
    }
    if (_throttle_filter.get() > 1.0f) {
        _throttle_filter.reset(1.0f);
    }
}

// reset_flight_controls - resets all controls and scalars to flight status
void AP_MotorsHeli::reset_flight_controls()
{
    _servo_mode = SERVO_CONTROL_MODE_AUTOMATED;
    init_outputs();
    calculate_scalars();
}

// convert input in -1 to +1 range to pwm output for swashplate servo.
// The value 0 corresponds to the trim value of the servo. Swashplate
// servo travel range is fixed to 1000 pwm and therefore the input is
// multiplied by 500 to get PWM output.
void AP_MotorsHeli::rc_write_swash(uint8_t chan, float swash_in)
{
    uint16_t pwm = (uint16_t)(1500 + 500 * swash_in);
    SRV_Channel::Aux_servo_function_t function = SRV_Channels::get_motor_function(chan);
    SRV_Channels::set_output_pwm_trimmed(function, pwm);
}

// enable_parameters - enables the rsc parameters for the rsc mode
void AP_MotorsHeli::enable_rsc_parameters(void)
{
    if (_rsc_mode == (int8_t)ROTOR_CONTROL_MODE_OPEN_LOOP_POWER_OUTPUT || _rsc_mode == (int8_t)ROTOR_CONTROL_MODE_CLOSED_LOOP_POWER_OUTPUT) {
        _rsc_thrcrv.set_thrcrv_enable(1);
    } else {
        _rsc_thrcrv.set_thrcrv_enable(0);
    }
    if (_rsc_mode == (int8_t)ROTOR_CONTROL_MODE_CLOSED_LOOP_POWER_OUTPUT) {
        _rsc_gov.set_gov_enable(1);
    } else {
        _rsc_gov.set_gov_enable(0);
    }
}

