// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-

#include "AP_Mount_SToRM32_serial.h"
#include <AP_HAL/AP_HAL.h>
#include <GCS_MAVLink/GCS_MAVLink.h>
#include <GCS_MAVLink/include/mavlink/v2.0/checksum.h>
#include <AP_HAL/utility/RingBuffer.h>

extern const AP_HAL::HAL& hal;

AP_Mount_SToRM32_serial::AP_Mount_SToRM32_serial(AP_Mount &frontend, AP_Mount::mount_state &state, uint8_t instance) :
    AP_Mount_Backend(frontend, state, instance),
    _port(NULL),
    _initialised(false),
    _last_send(0),
    _reply_length(0),
    _reply_counter(0),
    _reply_type(ReplyType_UNKNOWN)
{}

// init - performs any required initialisation for this instance
void AP_Mount_SToRM32_serial::init(const AP_SerialManager& serial_manager)
{
    _port = serial_manager.find_serial(AP_SerialManager::SerialProtocol_SToRM32, 0);
    if (_port) {
        _initialised = true;
        set_mode((enum MAV_MOUNT_MODE)_state._default_mode.get());
    }

}

// update mount position - should be called periodically
void AP_Mount_SToRM32_serial::update()
{
    // exit immediately if not initialised
    if (!_initialised) {
        return;
    }

    read_incoming(); // read the incoming messages from the gimbal

    // flag to trigger sending target angles to gimbal
    bool resend_now = false;

    // update based on mount mode
    switch(get_mode()) {
        // move mount to a "retracted" position.  To-Do: remove support and replace with a relaxed mode?
        case MAV_MOUNT_MODE_RETRACT:
            {
            const Vector3f &target = _state._retract_angles.get();
            _angle_ef_target_rad.x = ToRad(target.x);
            _angle_ef_target_rad.y = ToRad(target.y);
            _angle_ef_target_rad.z = ToRad(target.z);
            }
            break;

        // move mount to a neutral position, typically pointing forward
        case MAV_MOUNT_MODE_NEUTRAL:
            {
            const Vector3f &target = _state._neutral_angles.get();
            _angle_ef_target_rad.x = ToRad(target.x);
            _angle_ef_target_rad.y = ToRad(target.y);
            _angle_ef_target_rad.z = ToRad(target.z);
            }
            break;

        // point to the angles given by a mavlink message
        case MAV_MOUNT_MODE_MAVLINK_TARGETING:
            // do nothing because earth-frame angle targets (i.e. _angle_ef_target_rad) should have already been set by a MOUNT_CONTROL message from GCS
            break;

        // RC radio manual angle control, but with stabilization from the AHRS
        case MAV_MOUNT_MODE_RC_TARGETING:
            // update targets using pilot's rc inputs
            update_targets_from_rc();
            resend_now = true;
            break;

        // point mount to a GPS point given by the mission planner
        case MAV_MOUNT_MODE_GPS_POINT:
            if(_frontend._ahrs.get_gps().status() >= AP_GPS::GPS_OK_FIX_2D) {
                calc_angle_to_location(_state._roi_target, _angle_ef_target_rad, true, true);
                resend_now = true;
            }
            break;

        default:
            // we do not know this mode so do nothing
            break;
    }

    // resend target angles at least once per second
    resend_now = resend_now || ((AP_HAL::millis() - _last_send) > AP_MOUNT_STORM32_SERIAL_RESEND_MS);

    if ((AP_HAL::millis() - _last_send) > AP_MOUNT_STORM32_SERIAL_RESEND_MS*2) {
        _reply_type = ReplyType_UNKNOWN;
    }
    if (can_send(resend_now)) {
        if (resend_now) {
            send_target_angles(ToDeg(_angle_ef_target_rad.y), ToDeg(_angle_ef_target_rad.x), ToDeg(_angle_ef_target_rad.z));
            get_angles();
            _reply_type = ReplyType_ACK;
            _reply_counter = 0;
            _reply_length = get_reply_size(_reply_type);
        } else {
            get_angles();
            _reply_type = ReplyType_DATA;
            _reply_counter = 0;
            _reply_length = get_reply_size(_reply_type);
        }
    }
}

// has_pan_control - returns true if this mount can control it's pan (required for multicopters)
bool AP_Mount_SToRM32_serial::has_pan_control() const
{
    // we do not have yaw control
    return false;
}

// set_mode - sets mount's mode
void AP_Mount_SToRM32_serial::set_mode(enum MAV_MOUNT_MODE mode)
{
    // exit immediately if not initialised
    if (!_initialised) {
        return;
    }

    // record the mode change
    _state._mode = mode;
}

// status_msg - called to allow mounts to send their status to GCS using the MOUNT_STATUS message
void AP_Mount_SToRM32_serial::status_msg(mavlink_channel_t chan)
{
    // return target angles as gimbal's actual attitude.
    mavlink_msg_mount_status_send(chan, 0, 0, _current_angle.y, _current_angle.x, _current_angle.z);
}

bool AP_Mount_SToRM32_serial::can_send(bool with_control) {
    uint16_t required_tx = 1;
    if (with_control) {
        required_tx += sizeof(AP_Mount_SToRM32_serial::cmd_set_angles_struct);
    }
    return (_reply_type == ReplyType_UNKNOWN) && (_port->txspace() >= required_tx);
}


// send_target_angles
void AP_Mount_SToRM32_serial::send_target_angles(float pitch_deg, float roll_deg, float yaw_deg)
{

    static cmd_set_angles_struct cmd_set_angles_data = {
        0xFA,
        0x0E,
        0x11,
        0, // pitch
        0, // roll
        0, // yaw
        0, // flags
        0, // type
        0, // crc
    };

    // exit immediately if not initialised
    if (!_initialised) {
        return;
    }

    if ((size_t)_port->txspace() < sizeof(cmd_set_angles_data)) {
        return;
    }

    // reverse pitch and yaw control
    pitch_deg = -pitch_deg;
    yaw_deg = -yaw_deg;

    // send CMD_SETANGLE
    cmd_set_angles_data.pitch = pitch_deg;
    cmd_set_angles_data.roll = roll_deg;
    cmd_set_angles_data.yaw = yaw_deg;

    uint8_t* buf = (uint8_t*)&cmd_set_angles_data;

    cmd_set_angles_data.crc = crc_calculate(&buf[1], sizeof(cmd_set_angles_data)-3);

    for (uint8_t i = 0;  i != sizeof(cmd_set_angles_data) ; i++) {
        _port->write(buf[i]);
    }

    // store time of send
    _last_send = AP_HAL::millis();
}

void AP_Mount_SToRM32_serial::get_angles() {
    // exit immediately if not initialised
    if (!_initialised) {
        return;
    }

    if (_port->txspace() < 1) {
        return;
    }

    _port->write('d');
};


uint8_t AP_Mount_SToRM32_serial::get_reply_size(ReplyType reply_type) {
    switch (reply_type) {
        case ReplyType_DATA:
            return sizeof(SToRM32_reply_data_struct);
            break;
        case ReplyType_ACK:
            return sizeof(SToRM32_reply_ack_struct);
            break;
        default:
            return 0;
    }
}


void AP_Mount_SToRM32_serial::read_incoming() {
    uint8_t data;
    int16_t numc;

    numc = _port->available();

    if (numc < 0 ){
        return;
    }

    for (int16_t i = 0; i < numc; i++) {        // Process bytes received
        data = _port->read();
        if (_reply_type == ReplyType_UNKNOWN) {
            continue;
        }

        _buffer.bytes[_reply_counter++] = data;
        if (_reply_counter == _reply_length) {
            parse_reply();

            switch (_reply_type) {
                case ReplyType_ACK:
                    _reply_type = ReplyType_DATA;
                    _reply_length = get_reply_size(_reply_type);
                    _reply_counter = 0;
                    break;
                case ReplyType_DATA:
                    _reply_type = ReplyType_UNKNOWN;
                    _reply_length = get_reply_size(_reply_type);
                    _reply_counter = 0;
                    break;
                default:
                    _reply_length = get_reply_size(_reply_type);
                    _reply_counter = 0;
                    break;
            }
        }
    }
}

void AP_Mount_SToRM32_serial::parse_reply() {
    uint16_t crc;
    bool crc_ok;

    switch (_reply_type) {
        case ReplyType_DATA:
            crc = crc_calculate(_buffer.bytes, sizeof(_buffer.data)-3);
            crc_ok = crc == _buffer.data.crc;
            if (!crc_ok) {
                break;
            }

            _current_angle.x = _buffer.data.imu1_roll;
            _current_angle.y = _buffer.data.imu1_pitch;
            _current_angle.z = _buffer.data.imu1_yaw;
            break;
        case ReplyType_ACK:
            crc = crc_calculate(&_buffer.bytes[1], sizeof(SToRM32_reply_ack_struct)-3);
            crc_ok = crc == _buffer.ack.crc;
            break;
        default:
            break;
    }
}
