From 40cd8ce1c25da335a286b4f24dfcb0b9c252952d Mon Sep 17 00:00:00 2001
From: Jeremy Klein <jeremydk@gmail.com>
Date: Fri, 12 Feb 2021 15:13:22 -0800
Subject: [PATCH] Peloton Direct Polling support (#43)

Co-authored-by: Matt Stevens <matt@vodlogic.com>
---
 src/app/app.js       |  2 +-
 src/bikes/peloton.js | 44 ++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/src/app/app.js b/src/app/app.js
index 010982c1..6cfa0bef 100644
--- a/src/app/app.js
+++ b/src/app/app.js
@@ -4,9 +4,9 @@ import bleno from '@abandonware/bleno';
 
 import {once} from 'events';
 
-import {createBikeClient, getBikeTypes} from '../bikes';
 import {GymnasticonServer} from '../servers/ble';
 import {AntServer} from '../servers/ant';
+import {createBikeClient, getBikeTypes} from '../bikes';
 import {Simulation} from './simulation';
 import {Timer} from '../util/timer';
 import {Logger} from '../util/logger';
diff --git a/src/bikes/peloton.js b/src/bikes/peloton.js
index 5b96d14d..38da884c 100644
--- a/src/bikes/peloton.js
+++ b/src/bikes/peloton.js
@@ -5,7 +5,20 @@ import util from 'util';
 const SerialPort = require('serialport')
 const Delimiter = require('@serialport/parser-delimiter')
 
+/**
+ * Cadence and Power are both direct values returned by the bike.
+ * Resistance, on the otherhand, is a raw value returned from the bike to the
+ * Tablet, and doesn't necessarily add value for our use case. However, we are
+ * choosing to poll for it to allow for a usecase where Gymnasticon provides
+ * the polling, with the bike Tx split to the Tablet as well.
+ */
+const MEASUREMENTS_HEX_ENUM = {
+  CADENCE: Buffer.from("f6f54136", 'hex'),
+  POWER: Buffer.from("f6f54439", 'hex'),
+  RESISTANCE: Buffer.from("f6f54a3f", 'hex')
+}
 const PACKET_DELIMITER = Buffer.from('f6', 'hex');
+const POLL_RATE = 100;
 const STATS_TIMEOUT = 1.0;
 
 const debuglog = util.debuglog('gymnasticon:bikes:peloton');
@@ -23,6 +36,7 @@ export class PelotonBikeClient extends EventEmitter {
     this.onStatsUpdate = this.onStatsUpdate.bind(this);
     this.onSerialMessage = this.onSerialMessage.bind(this);
     this.onSerialClose = this.onSerialClose.bind(this);
+    this.pollMetric = this.pollMetric.bind(this);
 
     // initial stats
     this.power = 0;
@@ -31,6 +45,10 @@ export class PelotonBikeClient extends EventEmitter {
     // reset stats to 0 when the user leaves the ride screen or turns the bike off
     this.statsTimeout = new Timer(STATS_TIMEOUT, {repeats: false});
     this.statsTimeout.on('timeout', this.onStatsTimeout.bind(this));
+
+    // Let's collect interval handles for cancellation
+    this.intervalHandles = new Map();
+    this.nextMetric = 0;
   }
 
   async connect() {
@@ -47,6 +65,9 @@ export class PelotonBikeClient extends EventEmitter {
     this._parser.on('data', this.onSerialMessage);
 
     this.state = 'connected';
+
+    // Begin sending polling requests to the Peloton bike
+    this.intervalHandles['poll'] = setInterval(this.pollMetric, POLL_RATE, this._port);
     tracelog("Serial Connected");
   }
 
@@ -69,16 +90,18 @@ export class PelotonBikeClient extends EventEmitter {
   onSerialMessage(data) {
     tracelog("RECV: ", data);
     switch(data[1]) {
-      case 65:
+      case 65: // Cadence
         this.cadence = decodePeloton(data, data[2], false);
         this.onStatsUpdate();
         this.statsTimeout.reset();
         return;
-      case 68:
+      case 68: // Power
         this.power = decodePeloton(data, data[2], true);
         this.onStatsUpdate();
         this.statsTimeout.reset();
         return;
+      case 74: // Resistance
+        return; // While we can parse this, we don't do anything with it.
       default:
         debuglog("Unrecognized Message Type: ", data[1]);
         return;
@@ -87,6 +110,7 @@ export class PelotonBikeClient extends EventEmitter {
 
   onSerialClose() {
     this.emit('disconnect', {address: this.address});
+    clearInterval(this.intervalHandles['poll']);
     tracelog("Serial Closed");
   }
 
@@ -96,6 +120,22 @@ export class PelotonBikeClient extends EventEmitter {
     tracelog("StatsTimeout exceeded");
     this.onStatsUpdate();
   }
+
+  pollMetric(port) {
+    let metric = Object.keys(MEASUREMENTS_HEX_ENUM)[this.nextMetric];
+
+    port.write(MEASUREMENTS_HEX_ENUM[metric], function(err) {
+      if (err) { throw new Error(`Error requesting ${metric}: ${err.message}`); }
+    })
+    port.drain();
+
+    if (this.nextMetric === Object.keys(MEASUREMENTS_HEX_ENUM).length -1) {
+      this.nextMetric = 0;
+    } else {
+      this.nextMetric++;
+    }
+  }
+
 }
 
 export function decodePeloton(bufferArray, byteLength, isPower) {