/*
   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/>.
 */

#include "AP_ESC_Telem.h"
#include <AP_HAL/AP_HAL.h>
#include <GCS_MAVLink/GCS.h>
#include <AP_Logger/AP_Logger.h>

#if HAL_WITH_ESC_TELEM

#include <AP_BoardConfig/AP_BoardConfig.h>

//#define ESC_TELEM_DEBUG

extern const AP_HAL::HAL& hal;

AP_ESC_Telem::AP_ESC_Telem()
{
    if (_singleton) {
        AP_HAL::panic("Too many AP_ESC_Telem instances");
    }
    _singleton = this;
}

// return the average motor frequency in Hz for dynamic filtering
float AP_ESC_Telem::get_average_motor_frequency_hz() const
{
    float motor_freq = 0.0f;
    uint8_t valid_escs = 0;

    // average the rpm of each motor and convert to Hz
    for (uint8_t i = 0; i < ESC_TELEM_MAX_ESCS; i++) {
        float rpm;
        if (get_rpm(i, rpm)) {
            motor_freq += rpm * (1.0f / 60.0f);
            valid_escs++;
        }
    }
    if (valid_escs > 0) {
        motor_freq /= valid_escs;
    }

    return motor_freq;
}

// return all the motor frequencies in Hz for dynamic filtering
uint8_t AP_ESC_Telem::get_motor_frequencies_hz(uint8_t nfreqs, float* freqs) const
{
    uint8_t valid_escs = 0;

    // average the rpm of each motor as reported by BLHeli and convert to Hz
    for (uint8_t i = 0; i < ESC_TELEM_MAX_ESCS && i < nfreqs; i++) {
        float rpm;
        if (get_rpm(i, rpm)) {
            freqs[valid_escs++] = rpm * (1.0f / 60.0f);
        }
    }

    return MIN(valid_escs, nfreqs);
}

// return number of active ESCs present
uint8_t AP_ESC_Telem::get_num_active_escs() const {
    uint8_t nmotors = 0;
    uint32_t now = AP_HAL::millis();
    for (uint8_t i = 0; i < ESC_TELEM_MAX_ESCS; i++) {
        if (now - _telem_data[i].last_update_ms < ESC_TELEM_DATA_TIMEOUT_MS) {
            nmotors++;
        }
    }
    return nmotors;
}

// get an individual ESC's slewed rpm if available, returns true on success
bool AP_ESC_Telem::get_rpm(uint8_t esc_index, float& rpm) const
{
    const volatile AP_ESC_Telem_Backend::RpmData& rpmdata = _rpm_data[esc_index];

    if (esc_index > ESC_TELEM_MAX_ESCS || is_zero(rpmdata.update_rate_hz)) {
        return false;
    }

    const uint32_t now = AP_HAL::micros();
    if (rpmdata.last_update_us > 0 && (now >= rpmdata.last_update_us)
        && (now - rpmdata.last_update_us < ESC_RPM_DATA_TIMEOUT_US)) {
        const float slew = MIN(1.0f, (now - rpmdata.last_update_us) * rpmdata.update_rate_hz * (1.0f / 1e6f));
        rpm = (rpmdata.prev_rpm + (rpmdata.rpm - rpmdata.prev_rpm) * slew);
        return true;
    }
    return false;
}

// get an individual ESC's raw rpm if available, returns true on success
bool AP_ESC_Telem::get_raw_rpm(uint8_t esc_index, float& rpm) const
{
    const volatile AP_ESC_Telem_Backend::RpmData& rpmdata = _rpm_data[esc_index];

    const uint32_t now = AP_HAL::micros();

    if (esc_index >= ESC_TELEM_MAX_ESCS || now < rpmdata.last_update_us
        || now - rpmdata.last_update_us > ESC_RPM_DATA_TIMEOUT_US) {
        return false;
    }

    rpm = rpmdata.rpm;
    return true;
}

// get an individual ESC's temperature in centi-degrees if available, returns true on success
bool AP_ESC_Telem::get_temperature(uint8_t esc_index, int16_t& temp) const
{
    if (esc_index >= ESC_TELEM_MAX_ESCS
        || AP_HAL::millis() - _telem_data[esc_index].last_update_ms > ESC_TELEM_DATA_TIMEOUT_MS
        || !(_telem_data[esc_index].types & AP_ESC_Telem_Backend::TelemetryType::TEMPERATURE)) {
        return false;
    }
    temp = _telem_data[esc_index].temperature_cdeg;
    return true;
}

// get an individual motor's temperature in centi-degrees if available, returns true on success
bool AP_ESC_Telem::get_motor_temperature(uint8_t esc_index, int16_t& temp) const
{
    if (esc_index >= ESC_TELEM_MAX_ESCS
        || AP_HAL::millis() - _telem_data[esc_index].last_update_ms > ESC_TELEM_DATA_TIMEOUT_MS
        || !(_telem_data[esc_index].types & AP_ESC_Telem_Backend::TelemetryType::MOTOR_TEMPERATURE)) {
        return false;
    }
    temp = _telem_data[esc_index].motor_temp_cdeg;
    return true;
}

// get an individual ESC's current in Ampere if available, returns true on success
bool AP_ESC_Telem::get_current(uint8_t esc_index, float& amps) const
{
    if (esc_index >= ESC_TELEM_MAX_ESCS
        || AP_HAL::millis() - _telem_data[esc_index].last_update_ms > ESC_TELEM_DATA_TIMEOUT_MS
        || !(_telem_data[esc_index].types & AP_ESC_Telem_Backend::TelemetryType::CURRENT)) {
        return false;
    }
    amps = _telem_data[esc_index].current;
    return true;
}

// get an individual ESC's voltage in Volt if available, returns true on success
bool AP_ESC_Telem::get_voltage(uint8_t esc_index, float& volts) const
{
    if (esc_index >= ESC_TELEM_MAX_ESCS
        || AP_HAL::millis() - _telem_data[esc_index].last_update_ms > ESC_TELEM_DATA_TIMEOUT_MS
        || !(_telem_data[esc_index].types & AP_ESC_Telem_Backend::TelemetryType::VOLTAGE)) {
        return false;
    }
    volts = _telem_data[esc_index].voltage;
    return true;
}

// get an individual ESC's energy consumption in milli-Ampere.hour if available, returns true on success
bool AP_ESC_Telem::get_consumption_mah(uint8_t esc_index, float& consumption_mah) const
{
    if (esc_index >= ESC_TELEM_MAX_ESCS
        || AP_HAL::millis() - _telem_data[esc_index].last_update_ms > ESC_TELEM_DATA_TIMEOUT_MS
        || !(_telem_data[esc_index].types & AP_ESC_Telem_Backend::TelemetryType::CONSUMPTION)) {
        return false;
    }
    consumption_mah = _telem_data[esc_index].consumption_mah;
    return true;
}

// get an individual ESC's usage time in seconds if available, returns true on success
bool AP_ESC_Telem::get_usage_seconds(uint8_t esc_index, uint32_t& usage_s) const
{
    if (esc_index >= ESC_TELEM_MAX_ESCS
        || AP_HAL::millis() - _telem_data[esc_index].last_update_ms > ESC_TELEM_DATA_TIMEOUT_MS
        || !(_telem_data[esc_index].types & AP_ESC_Telem_Backend::TelemetryType::USAGE)) {
        return false;
    }
    usage_s = _telem_data[esc_index].usage_s;
    return true;
}

// send ESC telemetry messages over MAVLink
void AP_ESC_Telem::send_esc_telemetry_mavlink(uint8_t mav_chan)
{
    static_assert(ESC_TELEM_MAX_ESCS <= 12, "AP_ESC_Telem::send_esc_telemetry_mavlink() only supports up-to 12 motors");

    uint32_t now = AP_HAL::millis();
    uint32_t now_us = AP_HAL::micros();
    // loop through 3 groups of 4 ESCs
    for (uint8_t i = 0; i < 3; i++) {

        // return if no space in output buffer to send mavlink messages
        if (!HAVE_PAYLOAD_SPACE((mavlink_channel_t)mav_chan, ESC_TELEMETRY_1_TO_4)) {
            return;
        }
#define ESC_DATA_STALE(idx) \
        (now - _telem_data[idx].last_update_ms > ESC_TELEM_DATA_TIMEOUT_MS \
            && now_us - _rpm_data[idx].last_update_us > ESC_RPM_DATA_TIMEOUT_US)

        // skip this group of ESCs if no data to send
        if (ESC_DATA_STALE(i * 4) && ESC_DATA_STALE(i * 4 + 1) && ESC_DATA_STALE(i * 4 + 2) && ESC_DATA_STALE(i * 4 + 3)) {
            continue;
        }

        // arrays to hold output
        uint8_t temperature[4] {};
        uint16_t voltage[4] {};
        uint16_t current[4] {};
        uint16_t current_tot[4] {};
        uint16_t rpm[4] {};
        uint16_t count[4] {};

        // fill in output arrays
        for (uint8_t j = 0; j < 4; j++) {
            const uint8_t esc_id = i * 4 + j;
            temperature[j] = _telem_data[esc_id].temperature_cdeg / 100;
            voltage[j] = constrain_float(_telem_data[esc_id].voltage * 100.0f, 0, UINT16_MAX);
            current[j] = constrain_float(_telem_data[esc_id].current * 100.0f, 0, UINT16_MAX);
            current_tot[j] = constrain_float(_telem_data[esc_id].consumption_mah, 0, UINT16_MAX);
            float rpmf = 0.0f;
            if (get_rpm(esc_id, rpmf)) {
                rpm[j] = constrain_float(rpmf, 0, UINT16_MAX);
            } else {
                rpm[j] = 0;
            }
            count[j] = _telem_data[esc_id].count;
        }

        // send messages
        switch (i) {
            case 0:
                mavlink_msg_esc_telemetry_1_to_4_send((mavlink_channel_t)mav_chan, temperature, voltage, current, current_tot, rpm, count);
                break;
            case 1:
                mavlink_msg_esc_telemetry_5_to_8_send((mavlink_channel_t)mav_chan, temperature, voltage, current, current_tot, rpm, count);
                break;
            case 2:
                mavlink_msg_esc_telemetry_9_to_12_send((mavlink_channel_t)mav_chan, temperature, voltage, current, current_tot, rpm, count);
                break;
            default:
                break;
        }
    }
}

// record an update to the telemetry data together with timestamp
// this should be called by backends when new telemetry values are available
void AP_ESC_Telem::update_telem_data(const uint8_t esc_index, const AP_ESC_Telem_Backend::TelemetryData& new_data, const uint16_t data_mask)
{
    // rpm and telemetry data are not protected by a semaphore even though updated from different threads
    // all data is per-ESC and only written from the update thread and read by the user thread
    // each element is a primitive type and the timestamp is only updated at the end, thus a caller
    // can only get slightly more up-to-date information that perhaps they were expecting or might
    // read data that has just gone stale - both of these are safe and avoid the overhead of locking

    if (esc_index > ESC_TELEM_MAX_ESCS) {
        return;
    }

    if (data_mask & AP_ESC_Telem_Backend::TelemetryType::TEMPERATURE) {
        _telem_data[esc_index].temperature_cdeg = new_data.temperature_cdeg;
    }
    if (data_mask & AP_ESC_Telem_Backend::TelemetryType::MOTOR_TEMPERATURE) {
        _telem_data[esc_index].motor_temp_cdeg = new_data.motor_temp_cdeg;
    }
    if (data_mask & AP_ESC_Telem_Backend::TelemetryType::VOLTAGE) {
        _telem_data[esc_index].voltage = new_data.voltage;
    }
    if (data_mask & AP_ESC_Telem_Backend::TelemetryType::CURRENT) {
        _telem_data[esc_index].current = new_data.current;
    }
    if (data_mask & AP_ESC_Telem_Backend::TelemetryType::CONSUMPTION) {
        _telem_data[esc_index].consumption_mah = new_data.consumption_mah;
    }
    if (data_mask & AP_ESC_Telem_Backend::TelemetryType::USAGE) {
        _telem_data[esc_index].usage_s = new_data.usage_s;
    }

    _telem_data[esc_index].count++;
    _telem_data[esc_index].types |= data_mask;
    _telem_data[esc_index].last_update_ms = AP_HAL::millis();
}

// record an update to the RPM together with timestamp, this allows the notch values to be slewed
// this should be called by backends when new telemetry values are available
void AP_ESC_Telem::update_rpm(const uint8_t esc_index, const uint16_t new_rpm, const float error_rate)
{
    if (esc_index > ESC_TELEM_MAX_ESCS) {
        return;
    }
    const uint32_t now = AP_HAL::micros();
    volatile AP_ESC_Telem_Backend::RpmData& rpmdata = _rpm_data[esc_index];

    rpmdata.prev_rpm = rpmdata.rpm;
    rpmdata.rpm = new_rpm;
    if (now > rpmdata.last_update_us) { // cope with wrapping
        rpmdata.update_rate_hz = 1.0e6f / (now - rpmdata.last_update_us);
    }
    rpmdata.last_update_us = now;
    rpmdata.error_rate = error_rate;

#ifdef ESC_TELEM_DEBUG
    hal.console->printf("RPM: rate=%.1fhz, rpm=%d)\n", rpmdata.update_rate_hz, new_rpm);
#endif
}

// log ESC telemetry at 10Hz
void AP_ESC_Telem::update()
{
    AP_Logger *logger = AP_Logger::get_singleton();

    // Push received telemtry data into the logging system
    if (logger && logger->logging_enabled()) {

        for (uint8_t i = 0; i < ESC_TELEM_MAX_ESCS; i++) {
            if (_telem_data[i].last_update_ms != _last_telem_log_ms[i]
                || _rpm_data[i].last_update_us != _last_rpm_log_us[i]) {

                float rpm = 0.0f;
                get_rpm(i, rpm);

                // Write ESC status messages
                //   id starts from 0
                //   rpm is eRPM (rpm * 100)
                //   voltage is in Volt
                //   current is in Ampere
                //   esc_temp is in centi-degrees Celsius
                //   current_tot is in mili-Ampere hours
                //   motor_temp is in centi-degrees Celsius
                //   error_rate is in percentage
                const struct log_Esc pkt{
                    LOG_PACKET_HEADER_INIT(uint8_t(LOG_ESC_MSG)),
                    time_us     : AP_HAL::micros64(),
                    instance    : i,
                    rpm         : (int32_t) rpm * 100,
                    voltage     : _telem_data[i].voltage,
                    current     : _telem_data[i].current,
                    esc_temp    : _telem_data[i].temperature_cdeg,
                    current_tot : _telem_data[i].consumption_mah,
                    motor_temp  : _telem_data[i].motor_temp_cdeg,
                    error_rate  : _rpm_data[i].error_rate
                };
                AP::logger().WriteBlock(&pkt, sizeof(pkt));
                _last_telem_log_ms[i] = _telem_data[i].last_update_ms;
                _last_rpm_log_us[i] = _rpm_data[i].last_update_us;
            }
        }
    }
}

AP_ESC_Telem *AP_ESC_Telem::_singleton = nullptr;

/*
 * Get the AP_ESC_Telem singleton
 */
AP_ESC_Telem *AP_ESC_Telem::get_singleton()
{
    return AP_ESC_Telem::_singleton;
}

namespace AP {

AP_ESC_Telem &esc_telem()
{
    return *AP_ESC_Telem::get_singleton();
}

};

#endif