feat: auto-activate biometrics prompt when mobile regains focus (#1891)

packages/mobile/src/Lib/Interface.ts

@@ -13,7 +13,7 @@ import {
   TransferPayload,
   UuidString,
 } from '@standardnotes/snjs'
-import { Alert, Linking, PermissionsAndroid, Platform, StatusBar } from 'react-native'
+import { Alert, AppState, AppStateStatus, Linking, PermissionsAndroid, Platform, StatusBar } from 'react-native'
 import FileViewer from 'react-native-file-viewer'
 import FingerprintScanner from 'react-native-fingerprint-scanner'
 import FlagSecure from 'react-native-flag-secure-android'
@@ -610,4 +610,8 @@ export class MobileDevice implements MobileDeviceInterface {
   isUrlComponentUrl(url: string): boolean {
     return Array.from(this.componentUrls.values()).includes(url)
   }
+
+  async getAppState(): Promise<AppStateStatus> {
+    return AppState.currentState
+  }
 }

packages/services/src/Domain/Device/MobileDeviceInterface.ts

@@ -20,4 +20,5 @@ export interface MobileDeviceInterface extends DeviceInterface {
   addComponentUrl(componentUuid: string, componentUrl: string): void
   removeComponentUrl(componentUuid: string): void
   isUrlComponentUrl(url: string): boolean
+  getAppState(): Promise<'active' | 'background' | 'inactive' | 'unknown' | 'extension'>
 }

packages/web/src/javascripts/Application/Application.ts

@@ -35,7 +35,7 @@ import {
   ThemeManager,
   WebAlertService,
 } from '@standardnotes/ui-services'
-import { MobileWebReceiver } from '../NativeMobileWeb/MobileWebReceiver'
+import { MobileWebReceiver, NativeMobileEventListener } from '../NativeMobileWeb/MobileWebReceiver'
 import { AndroidBackHandler } from '@/NativeMobileWeb/AndroidBackHandler'
 import { PrefDefaults } from '@/Constants/PrefDefaults'
 import { setViewportHeightWithFallback } from '@/setViewportHeightWithFallback'
@@ -330,4 +330,12 @@ export class WebApplication extends SNApplication implements WebApplicationInter
   openPurchaseFlow(): void {
     this.getViewControllerManager().purchaseFlowController.openPurchaseFlow()
   }
+
+  addNativeMobileEventListener = (listener: NativeMobileEventListener) => {
+    if (!this.mobileWebReceiver) {
+      return
+    }
+
+    return this.mobileWebReceiver.addReactListener(listener)
+  }
 }

packages/web/src/javascripts/Components/ChallengeModal/ChallengePrompt.tsx

@@ -1,5 +1,10 @@
-import { ChallengePrompt, ChallengeValidation, ProtectionSessionDurations } from '@standardnotes/snjs'
-import { FunctionComponent, useEffect, useRef } from 'react'
+import {
+  ChallengePrompt,
+  ChallengeValidation,
+  ProtectionSessionDurations,
+  ReactNativeToWebEvent,
+} from '@standardnotes/snjs'
+import { FunctionComponent, useCallback, useEffect, useRef } from 'react'
 import DecoratedInput from '@/Components/Input/DecoratedInput'
 import DecoratedPasswordInput from '@/Components/Input/DecoratedPasswordInput'
 import { ChallengeModalValues } from './ChallengeModalValues'
@@ -27,6 +32,40 @@ const ChallengeModalPrompt: FunctionComponent<Props> = ({
   const inputRef = useRef<HTMLInputElement>(null)
   const biometricsButtonRef = useRef<HTMLButtonElement>(null)
 
+  const activatePrompt = useCallback(async () => {
+    if (prompt.validation === ChallengeValidation.Biometric) {
+      if (application.isNativeMobileWeb()) {
+        const appState = await application.mobileDevice().getAppState()
+
+        if (appState !== 'active') {
+          return
+        }
+      }
+
+      biometricsButtonRef.current?.click()
+    } else {
+      inputRef.current?.focus()
+    }
+  }, [application, prompt.validation])
+
+  useEffect(() => {
+    if (!application.isNativeMobileWeb()) {
+      return
+    }
+
+    const disposeListener = application.addNativeMobileEventListener((event: ReactNativeToWebEvent) => {
+      if (event === ReactNativeToWebEvent.GainingFocus) {
+        void activatePrompt()
+      }
+    })
+
+    return () => {
+      if (disposeListener) {
+        disposeListener()
+      }
+    }
+  }, [activatePrompt, application])
+
   useEffect(() => {
     const isNotFirstPrompt = index !== 0
 
@@ -34,12 +73,8 @@ const ChallengeModalPrompt: FunctionComponent<Props> = ({
       return
     }
 
-    if (prompt.validation === ChallengeValidation.Biometric) {
-      biometricsButtonRef.current?.click()
-    } else {
-      inputRef.current?.focus()
-    }
-  }, [index, prompt.validation])
+    void activatePrompt()
+  }, [activatePrompt, index])
 
   useEffect(() => {
     if (isInvalid) {

packages/web/src/javascripts/NativeMobileWeb/MobileWebReceiver.ts

@@ -1,6 +1,10 @@
 import { ReactNativeToWebEvent, WebApplicationInterface } from '@standardnotes/snjs'
 
+export type NativeMobileEventListener = (event: ReactNativeToWebEvent) => void
+
 export class MobileWebReceiver {
+  private listeners: Set<NativeMobileEventListener> = new Set()
+
   constructor(private application: WebApplicationInterface) {
     this.listenForNativeMobileEvents()
   }
@@ -39,6 +43,14 @@ export class MobileWebReceiver {
     }
   }
 
+  addReactListener = (listener: NativeMobileEventListener) => {
+    this.listeners.add(listener)
+
+    return () => {
+      this.listeners.delete(listener)
+    }
+  }
+
   handleNativeEvent(event: ReactNativeToWebEvent) {
     switch (event) {
       case ReactNativeToWebEvent.EnteringBackground:
@@ -60,5 +72,7 @@ export class MobileWebReceiver {
       default:
         break
     }
+
+    this.listeners.forEach((listener) => listener(event))
   }
 }