#include <AP_HAL/AP_HAL.h>

#if CONFIG_HAL_BOARD_SUBTYPE == HAL_BOARD_SUBTYPE_LINUX_BEBOP
#include <endian.h>
#include <stdio.h>
#include <sys/time.h>
#include <poll.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/mman.h>
#include <pthread.h>
#include "RCOutput_Bebop.h"

/* BEBOP BLDC motor controller address and registers description */
#define BEBOP_BLDC_I2C_ADDR 0x08
#define BEBOP_BLDC_STARTPROP 0x40
#define BEBOP_BLDC_CLOCKWISE 1
#define BEBOP_BLDC_COUNTERCLOCKWISE 0

static const uint8_t bebop_motors_bitmask = (BEBOP_BLDC_COUNTERCLOCKWISE  <<
    (BEBOP_BLDC_MOTORS_NUM - 1 - BEBOP_BLDC_LEFT_BACK)) |
    (BEBOP_BLDC_CLOCKWISE << (BEBOP_BLDC_MOTORS_NUM - 1 - BEBOP_BLDC_RIGHT_BACK))|
    (BEBOP_BLDC_COUNTERCLOCKWISE  << (BEBOP_BLDC_MOTORS_NUM - 1 - BEBOP_BLDC_RIGHT_FRONT))|
    (BEBOP_BLDC_CLOCKWISE << (BEBOP_BLDC_MOTORS_NUM - 1 - BEBOP_BLDC_LEFT_FRONT));


#define BEBOP_BLDC_SETREFSPEED 0x02
struct bldc_ref_speed_data {
    uint8_t     cmd;
    uint16_t    rpm[BEBOP_BLDC_MOTORS_NUM];
    uint8_t     enable_security;
    uint8_t     checksum;
}__attribute__((packed));

#define BEBOP_BLDC_GETOBSDATA 0x20
struct bldc_obs_data {
    uint16_t    rpm[BEBOP_BLDC_MOTORS_NUM];
    uint16_t    batt_mv;
    uint8_t     status;
    uint8_t     error;
    uint8_t     motors_err;
    uint8_t     temp;
    uint8_t     checksum;
}__attribute__((packed));

#define BEBOP_BLDC_TOGGLE_GPIO 0x4d
#define BEBOP_BLDC_GPIO_RESET   (1 << 0)
#define BEBOP_BLDC_GPIO_RED     (1 << 1)
#define BEBOP_BLDC_GPIO_GREEN   (1 << 2)

#define BEBOP_BLDC_STOP_PROP 0x60

#define BEBOP_BLDC_CLEAR_ERROR 0x80

#define BEBOP_BLDC_PLAY_SOUND 0x82

#define BEBOP_BLDC_GET_INFO 0xA0

/* Bebop is a Quad X so the channels are :
 * 1 = Front Right
 * 2 = Back Left
 * 3 = Front Left
 * 4 = Back Right
 *
 * but the channels start at 0 so it is channel num - 1
*/
static const uint8_t bebop_bldc_motors[BEBOP_BLDC_MOTORS_NUM] = { BEBOP_BLDC_RIGHT_FRONT,
                                                                  BEBOP_BLDC_LEFT_BACK,
                                                                  BEBOP_BLDC_LEFT_FRONT,
                                                                  BEBOP_BLDC_RIGHT_BACK };

#define BEBOP_BLDC_MIN_PERIOD_US 1100
#define BEBOP_BLDC_MAX_PERIOD_US 1900
#define BEBOP_BLDC_MIN_RPM 3000
#define BEBOP_BLDC_MAX_RPM 11000

/* Priority of the thread controlling the BLDC via i2c
 * set to 14, which is the same as the UART 
 */
#define RCOUT_BEBOP_RTPRIO 14
/* Set timeout to 500ms */
#define BEBOP_BLDC_TIMEOUT_NS 500000000

enum {
    BEBOP_BLDC_STARTED,
    BEBOP_BLDC_STOPPED,
};

using namespace Linux;

static const AP_HAL::HAL& hal = AP_HAL_BOARD_DRIVER;

LinuxRCOutput_Bebop::LinuxRCOutput_Bebop():
    _i2c_sem(NULL),
    _min_pwm(BEBOP_BLDC_MIN_PERIOD_US),
    _max_pwm(BEBOP_BLDC_MAX_PERIOD_US),
    _state(BEBOP_BLDC_STOPPED)
{
    memset(_period_us, 0, sizeof(_period_us));
    memset(_request_period_us, 0, sizeof(_request_period_us));
    memset(_rpm, 0, sizeof(_rpm));
}

uint8_t LinuxRCOutput_Bebop::_checksum(uint8_t *data, unsigned int len)
{
    uint8_t checksum = data[0];
    unsigned int i;

    for (i = 1; i < len; i++)
        checksum = checksum ^ data[i];

    return checksum;
}

void LinuxRCOutput_Bebop::_start_prop()
{
    uint8_t data = BEBOP_BLDC_STARTPROP;

    if (!_i2c_sem->take(0))
        return;

    hal.i2c1->write(BEBOP_BLDC_I2C_ADDR, 1, &data);

    _i2c_sem->give();
    _state = BEBOP_BLDC_STARTED;
}

void LinuxRCOutput_Bebop::_set_ref_speed(uint16_t rpm[BEBOP_BLDC_MOTORS_NUM])
{
    struct bldc_ref_speed_data data;
    int i;

    data.cmd = BEBOP_BLDC_SETREFSPEED;

    for (i=0; i<BEBOP_BLDC_MOTORS_NUM; i++)
        data.rpm[i] = htobe16(rpm[i]);

    data.enable_security = 0;
    data.checksum = _checksum((uint8_t *) &data, sizeof(data) - 1);

    if (!_i2c_sem->take(0))
        return;

    hal.i2c1->write(BEBOP_BLDC_I2C_ADDR, sizeof(data), (uint8_t *)&data);

    _i2c_sem->give();
}

int LinuxRCOutput_Bebop::read_obs_data(BebopBLDC_ObsData &obs)
{
    struct bldc_obs_data data;
    int i;

    memset(&data, 0, sizeof(data));
    if (!_i2c_sem->take(0))
        return -EBUSY;

    hal.i2c1->readRegisters(BEBOP_BLDC_I2C_ADDR, BEBOP_BLDC_GETOBSDATA,
                            sizeof(data), (uint8_t *)&data);

    _i2c_sem->give();

    if (data.checksum != _checksum((uint8_t *)&data, sizeof(data) - 1))
        hal.console->printf("RCOutput_Bebop: bad checksum in obs data");

    /* fill obs class */
    for (i = 0; i < BEBOP_BLDC_MOTORS_NUM; i++) {
        /* extract 'rpm saturation bit' */
        obs.rpm_saturated[i] = (data.rpm[i] & (1 << 7)) ? 1 : 0;
        /* clear 'rpm saturation bit' */
        data.rpm[i] &= (uint16_t)(~(1 << 7));
        obs.rpm[i] = be16toh(data.rpm[i]);
        if (obs.rpm[i] == 0)
            obs.rpm_saturated[i] = 0;
    }

    obs.batt_mv = be16toh(data.batt_mv);
    obs.status = data.status;
    obs.error = data.error;
    obs.motors_err = data.motors_err;
    obs.temperature = data.temp;
    return 0;
}

void LinuxRCOutput_Bebop::_toggle_gpio(uint8_t mask)
{
    if (!_i2c_sem->take(0))
        return;

    hal.i2c1->writeRegister(BEBOP_BLDC_I2C_ADDR, BEBOP_BLDC_TOGGLE_GPIO, mask);

    _i2c_sem->give();
}

void LinuxRCOutput_Bebop::_stop_prop()
{
    uint8_t data = BEBOP_BLDC_STOP_PROP;
    _state = BEBOP_BLDC_STOPPED;

    if (!_i2c_sem->take(0))
        return;

    hal.i2c1->write(BEBOP_BLDC_I2C_ADDR, 1, &data);

    _i2c_sem->give();
}

void LinuxRCOutput_Bebop::_clear_error()
{
    uint8_t data = BEBOP_BLDC_CLEAR_ERROR;

    if (!_i2c_sem->take(0))
        return;

    hal.i2c1->write(BEBOP_BLDC_I2C_ADDR, 1, &data);

    _i2c_sem->give();
}

void LinuxRCOutput_Bebop::_play_sound(uint8_t sound)
{
    if (!_i2c_sem->take(0))
        return;

    hal.i2c1->writeRegister(BEBOP_BLDC_I2C_ADDR, BEBOP_BLDC_PLAY_SOUND, sound);

    _i2c_sem->give();
}

uint16_t LinuxRCOutput_Bebop::_period_us_to_rpm(uint16_t period_us)
{
    float period_us_fl = period_us;

    float rpm_fl = (period_us_fl - _min_pwm)/(_max_pwm - _min_pwm) *
                    (BEBOP_BLDC_MAX_RPM - BEBOP_BLDC_MIN_RPM) + BEBOP_BLDC_MIN_RPM;

    return (uint16_t)rpm_fl;
}

void LinuxRCOutput_Bebop::init(void* dummy)
{
    int ret=0;
    struct sched_param param = { .sched_priority = RCOUT_BEBOP_RTPRIO };
    pthread_attr_t attr;
    pthread_condattr_t cond_attr;

    _i2c_sem = hal.i2c1->get_semaphore();
    if (_i2c_sem == NULL) {
        hal.scheduler->panic(PSTR("RCOutput_Bebop: can't get i2c sem"));
        return; /* never reached */
    }

    /* Initialize thread, cond, and mutex */
    ret = pthread_mutex_init(&_mutex, NULL);
    if (ret != 0) {
        perror("RCout_Bebop: failed to init mutex\n");
        return;
    }

    pthread_mutex_lock(&_mutex);

    pthread_condattr_init(&cond_attr);
    pthread_condattr_setclock(&cond_attr, CLOCK_MONOTONIC);
    ret = pthread_cond_init(&_cond, &cond_attr);
    pthread_condattr_destroy(&cond_attr);
    if (ret != 0) {
        perror("RCout_Bebop: failed to init cond\n");
        goto exit;
    }

    ret = pthread_attr_init(&attr);
    if (ret != 0) {
        perror("RCOut_Bebop: failed to init attr\n");
        goto exit;
    }
    pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
    pthread_attr_setschedpolicy(&attr, SCHED_FIFO);
    pthread_attr_setschedparam(&attr, &param);
    ret = pthread_create(&_thread, &attr, _control_thread, this);
    if (ret != 0) {
        perror("RCOut_Bebop: failed to create thread\n");
        goto exit;
    }

    _clear_error();

    /* Set an initial dummy frequency */
    _frequency = 50;

exit:
    pthread_mutex_unlock(&_mutex);
    return;
}

void LinuxRCOutput_Bebop::set_freq(uint32_t chmask, uint16_t freq_hz)
{
    _frequency = freq_hz;
}

uint16_t LinuxRCOutput_Bebop::get_freq(uint8_t ch)
{
    return _frequency;
}

void LinuxRCOutput_Bebop::enable_ch(uint8_t ch)
{
}

void LinuxRCOutput_Bebop::disable_ch(uint8_t ch)
{
    _stop_prop();
}

void LinuxRCOutput_Bebop::write(uint8_t ch, uint16_t period_us)
{
    if (ch >= BEBOP_BLDC_MOTORS_NUM)
        return;

    _request_period_us[ch] = period_us;

    if (!_corking)
        push();
}

void LinuxRCOutput_Bebop::cork()
{
    _corking = true;
}

void LinuxRCOutput_Bebop::push()
{
    _corking = false;
    pthread_mutex_lock(&_mutex);
    memcpy(_period_us, _request_period_us, sizeof(_period_us));
    pthread_cond_signal(&_cond);
    pthread_mutex_unlock(&_mutex);
    memset(_request_period_us, 0 ,sizeof(_request_period_us));
}

uint16_t LinuxRCOutput_Bebop::read(uint8_t ch)
{
    if (ch < BEBOP_BLDC_MOTORS_NUM) {
        return _period_us[ch];
    } else {
        return 0;
    }
}

void LinuxRCOutput_Bebop::read(uint16_t* period_us, uint8_t len)
{
    for (int i = 0; i < len; i++)
        period_us[i] = read(0 + i);
}

void LinuxRCOutput_Bebop::set_esc_scaling(uint16_t min_pwm, uint16_t max_pwm)
{
    _min_pwm = min_pwm;
    _max_pwm = max_pwm;
}

/* Separate thread to handle the Bebop motors controller */
void* LinuxRCOutput_Bebop::_control_thread(void *arg) {
    LinuxRCOutput_Bebop* rcout = (LinuxRCOutput_Bebop *) arg;

    rcout->_run_rcout();
    return NULL;
}

void LinuxRCOutput_Bebop::_run_rcout()
{
    uint16_t current_period_us[BEBOP_BLDC_MOTORS_NUM];
    uint8_t i;
    int ret;
    struct timespec ts;

    memset(current_period_us, 0, sizeof(current_period_us));

    while (true) {
        pthread_mutex_lock(&_mutex);
        ret = clock_gettime(CLOCK_MONOTONIC, &ts);
        if (ret != 0)
            hal.console->println_P("RCOutput_Bebop: bad checksum in obs data");

        if (ts.tv_nsec > (1000000000 - BEBOP_BLDC_TIMEOUT_NS))
        {
            ts.tv_sec += 1;
            ts.tv_nsec = ts.tv_nsec + BEBOP_BLDC_TIMEOUT_NS - 1000000000;
        } else {
            ts.tv_nsec += BEBOP_BLDC_TIMEOUT_NS;
        }

        ret = 0;
        while ((memcmp(_period_us, current_period_us, sizeof(_period_us)) == 0) && (ret == 0))
            ret = pthread_cond_timedwait(&_cond, &_mutex, &ts);

        memcpy(current_period_us, _period_us, sizeof(_period_us));
        pthread_mutex_unlock(&_mutex);

        /* start propellers if the speed of the 4 motors is >= min speed
         * min speed set to min_pwm + 50*/
        for (i = 0; i < BEBOP_BLDC_MOTORS_NUM; i++) {
            if (current_period_us[i] <= _min_pwm + 50)
                break;
            _rpm[bebop_bldc_motors[i]] = _period_us_to_rpm(current_period_us[i]);
        }

        if (i < BEBOP_BLDC_MOTORS_NUM) {
            /* one motor pwm value is at minimum (or under)
             * if the motors are started, stop them*/
            if (_state == BEBOP_BLDC_STARTED) {
                _stop_prop();
                _clear_error();
            }
        } else {
            /* all the motor pwm values are higher than minimum
             * if the bldc is stopped, start it*/
            if (_state == BEBOP_BLDC_STOPPED)
                _start_prop();
        }
        _set_ref_speed(_rpm);
    }
}
#endif