From 188e76c68cf61c58a0f796b7b4343281f1251eff Mon Sep 17 00:00:00 2001
From: Heiko Rothe <me@heikorothe.com>
Date: Sun, 1 Nov 2020 22:34:37 +0100
Subject: [PATCH] feat(bluetooth-low-energy): share discovered apps with
 cluster

---
 .../bluetooth-low-energy.service.spec.ts      | 37 +++++++++++++++++
 .../bluetooth-low-energy.service.ts           | 40 ++++++++++++++++---
 2 files changed, 72 insertions(+), 5 deletions(-)

diff --git a/src/integrations/bluetooth-low-energy/bluetooth-low-energy.service.spec.ts b/src/integrations/bluetooth-low-energy/bluetooth-low-energy.service.spec.ts
index 55b9950..c68ba53 100644
--- a/src/integrations/bluetooth-low-energy/bluetooth-low-energy.service.spec.ts
+++ b/src/integrations/bluetooth-low-energy/bluetooth-low-energy.service.spec.ts
@@ -19,6 +19,7 @@ import { Peripheral } from '@abandonware/noble';
 import { ConfigService } from '../../config/config.service';
 import { Test, TestingModule } from '@nestjs/testing';
 import {
+  APP_DISCOVERY_CHANNEL,
   BluetoothLowEnergyService,
   NEW_DISTANCE_CHANNEL,
 } from './bluetooth-low-energy.service';
@@ -152,6 +153,14 @@ describe('BluetoothLowEnergyService', () => {
       expect.any(Function)
     );
     expect(clusterService.subscribe).toHaveBeenCalledWith(NEW_DISTANCE_CHANNEL);
+
+    expect(clusterService.on).toHaveBeenCalledWith(
+      APP_DISCOVERY_CHANNEL,
+      expect.any(Function)
+    );
+    expect(clusterService.subscribe).toHaveBeenCalledWith(
+      APP_DISCOVERY_CHANNEL
+    );
   });
 
   it('should detect iBeacons based on their manufacturer data', () => {
@@ -951,6 +960,34 @@ describe('BluetoothLowEnergyService', () => {
       expect(discoverSpy).toHaveBeenCalledTimes(1);
     });
 
+    it('should publish discovered companion app IDs to the cluster', async () => {
+      jest
+        .spyOn(service, 'handleNewDistance')
+        .mockImplementation(() => undefined);
+      jest.spyOn(service, 'isWhitelistEnabled').mockReturnValue(true);
+      jest.spyOn(service, 'isOnWhitelist').mockReturnValue(true);
+      jest.spyOn(service, 'discoverCompanionAppId').mockResolvedValue('app-id');
+
+      await service.handleDiscovery({
+        id: 'abcd1234',
+        rssi: -50,
+        connectable: true,
+        advertisement: {
+          localName: 'Test Beacon',
+          txPowerLevel: -72,
+          manufacturerData: APPLE_MANUFACTURER_DATA,
+        },
+      } as Peripheral);
+
+      expect(clusterService.publish).toHaveBeenCalledWith(
+        APP_DISCOVERY_CHANNEL,
+        {
+          tagId: 'abcd1234',
+          appId: 'app-id',
+        }
+      );
+    });
+
     it('should temporarily blacklist devices that time out from discovery attempts', async () => {
       jest.useFakeTimers('modern');
       jest
diff --git a/src/integrations/bluetooth-low-energy/bluetooth-low-energy.service.ts b/src/integrations/bluetooth-low-energy/bluetooth-low-energy.service.ts
index 1ce9424..780188a 100644
--- a/src/integrations/bluetooth-low-energy/bluetooth-low-energy.service.ts
+++ b/src/integrations/bluetooth-low-energy/bluetooth-low-energy.service.ts
@@ -26,8 +26,11 @@ import { BluetoothLowEnergyPresenceSensor } from './bluetooth-low-energy-presenc
 import { BluetoothService } from '../bluetooth/bluetooth.service';
 
 export const NEW_DISTANCE_CHANNEL = 'bluetooth-low-energy.new-distance';
+export const APP_DISCOVERY_CHANNEL = 'bluetooth-low-energy.app-discovery';
 const APPLE_ADVERTISEMENT_ID = Buffer.from([0x4c, 0x00, 0x10]);
 
+type AppDiscoveryEvent = { tagId: string; appId: string };
+
 @Injectable() // parameters determined experimentally
 export class BluetoothLowEnergyService
   extends KalmanFilterable(Object, 0.8, 15)
@@ -74,6 +77,12 @@ export class BluetoothLowEnergyService
       this.handleNewDistance.bind(this)
     );
     this.clusterService.subscribe(NEW_DISTANCE_CHANNEL);
+
+    this.clusterService.on(
+      APP_DISCOVERY_CHANNEL,
+      this.handleAppDiscovery.bind(this)
+    );
+    this.clusterService.subscribe(APP_DISCOVERY_CHANNEL);
   }
 
   /**
@@ -410,13 +419,19 @@ export class BluetoothLowEnergyService
         try {
           this.logger.log(`Attempting app discovery for tag ${tag.id}`);
           const appId = await this.discoverCompanionAppId(tag);
-          this.companionAppTags.set(tag.id, appId);
 
           if (appId) {
             this.logger.log(
               `Discovered companion app with ID ${appId} for tag ${tag.id}`
             );
           }
+
+          const event = {
+            tagId: tag.id,
+            appId: appId,
+          } as AppDiscoveryEvent;
+          this.clusterService.publish(APP_DISCOVERY_CHANNEL, event);
+          this.handleAppDiscovery(event);
         } catch (e) {
           if (e.message === 'timed out') {
             this.logger.debug(
@@ -436,13 +451,28 @@ export class BluetoothLowEnergyService
           this.companionAppTags.delete(tag.id);
         }
       }
+    }
 
-      const appId = this.companionAppTags.get(tag.id);
-      if (appId != null) {
-        tag.id = appId;
-      }
+    const appId = this.companionAppTags.get(tag.id);
+    if (appId != null) {
+      tag.id = appId;
     }
 
     return tag;
   }
+
+  /**
+   * Adds discovered app information to the local cache.
+   * Does not override already existing values to null.
+   *
+   * @param event - Discovered information
+   */
+  protected handleAppDiscovery(event: AppDiscoveryEvent): void {
+    const oldId = this.companionAppTags.get(event.tagId);
+
+    if (!(oldId != null && event.appId == null)) {
+      this.companionAppTags.set(event.tagId, event.appId);
+      this.companionAppBlacklist.delete(event.tagId);
+    }
+  }
 }