bluez-dbus/src/ftms-service.js

import { BaseInterface } from "./base";
import { BaseService, BaseCharacteritic, BaseApplication } from "./bluez-gatt";

export class FTMSService extends BaseService {
  UUID = "00001826-0000-1000-8000-00805f9b34fb";
  Primary = true;

  constructor(bus, path) {
    super(bus, path);
    this.addCharacteristic(new FTMSFeature(bus, this.path + "/char0", this));
    this.addCharacteristic(new IndoorBikeData(bus, this.path + "/char1", this));
    this.addCharacteristic(
      new FTMSControlPoint(bus, this.path + "/char2", this)
    );
  }
}

class FTMSFeature extends BaseCharacteritic {
  constructor(bus, path, service) {
    super(bus, path, service, "00002acc-0000-1000-8000-00805f9b34fb", ["read"]);
  }

  read() {
    console.log("read FTMS Feature");
    // 32bits features + 32bits target supported
    // 0x0a 0x44 = feature: cadence (1), inclinaison (3), hr (10), power (14)
    // 0x0a 0x20 = target: inclinaison (1), power (3), simulation parameters (13)
    return [0x0a, 0x44, 0x00, 0x00, 0x0a, 0x20, 0x00, 0x00];
  }
}

class FTMSControlPoint extends BaseCharacteritic {
  wind = 0;
  grade = 0;
  crr = 0;
  cw = 0;

  constructor(bus, path, service) {
    super(bus, path, service, "00002ad9-0000-1000-8000-00805f9b34fb", [
      "write",
      "indicate",
    ]);
  }

  write(value, options) {
    console.log("FTMS Write Control Point");
    console.log(value);
    const arraybuf = value.buffer.slice(
      value.byteOffset,
      value.byteOffset + value.byteLength
    );
    const view = new DataView(arraybuf);

    if (value[0] === 0x00) {
      // take control
      this.notify([0x80, 0x00, 0x01]);
    } else if (value[0] === 0x01) {
      // reset machine
      this.notify([0x80, 0x01, 0x01]);
    } else if (value[0] === 0x07) {
      // start/resume
      this.notify([0x80, 0x07, 0x01]);
    } else if (value[0] === 0x11) {
      // set simulations param (wind, grade, etc)
      const wind = view.getInt16(1, true);
      const grade = view.getInt16(3, true);
      const crr = view.getUint8(5);
      const cw = view.getUint8(6);

      this.wind = wind * 0.001;
      this.grade = grade * 0.01;
      this.crr = crr * 0.001;
      this.cw = cw * 0.01;

      console.log(wind * 0.001);
      console.log(grade * 0.01);
      console.log(crr * 0.0001);
      console.log(cw * 0.01);

      this.notify([0x80, 0x11, 0x01]);
    } else {
      console.log("FTMS Control point op code " + value[0] + "not supported");
    }
  }

  startNotify() {
    console.log("FTMS Start Notify CP");
  }

  stopNotify() {
    console.log("FTMS Stop Notify CP");
  }
}

class IndoorBikeData extends BaseCharacteritic {
  constructor(bus, path, service) {
    super(bus, path, service, "00002ad2-0000-1000-8000-00805f9b34fb", [
      "notify",
    ]);
  }

  startNotify() {
    if (this.Notifying) {
      return;
    }

    this.Notifying = true;

    this.interval = setInterval(() => {
      console.log("FTMS Notif Indoor Bike");
      // 0x44 0x02 = fields included: cadence (2), power (6), hr (9)
      // 0x00 0x00 = average speed, always included
      // cadence is *2 (resolution 0.5 s^-1)
      this.notify([
        0x44,
        0x02,
        0x00,
        0x00,
        Math.round(160 + Math.random() * 10),
        0x00,
        Math.round(160 + Math.random() * 40),
        0x00,
        Math.round(120 + Math.random() * 10),
      ]);
    }, 1000);
  }

  stopNotify() {
    if (!this.Notifying) {
      return;
    }

    this.Notifying = false;

    clearInterval(this.interval);
  }
}