feat: Add biometric authentication check

app/src/main/java/app/myzel394/alibi/db/AppSettings.kt

@@ -553,16 +553,8 @@ data class NotificationSettings(
 
 @Serializable
 class AppLockSettings {
+    // If the object is present, biometric authentication is enabled.
+    // To disable biometric authentication, set the instance to null.
     val isEnabled
         get() = true
-
-    companion object {
-        fun getDefaultInstance(): AppLockSettings = AppLockSettings()
-
-        fun isSupported(context: Context): Boolean {
-            val biometricManager = BiometricManager.from(context)
-            when (biometricManager.canAuthenticate(Authenticators.BIOMETRIC_STRONG or Authenticators.DEVICE_CREDENTIAL)) {
-
-            }
-    }
 }

app/src/main/java/app/myzel394/alibi/helpers/AppLockHelper.kt

@@ -0,0 +1,64 @@
+package app.myzel394.alibi.helpers
+
+import android.content.Context
+import androidx.biometric.BiometricManager
+import androidx.core.content.ContextCompat
+import androidx.biometric.BiometricPrompt
+import androidx.fragment.app.FragmentActivity
+import kotlinx.coroutines.CompletableDeferred
+
+class AppLockHelper {
+    enum class SupportType {
+        AVAILABLE,
+        UNAVAILABLE,
+        NONE_ENROLLED,
+    }
+
+    companion object {
+        fun isSupported(context: Context): SupportType {
+            val biometricManager = BiometricManager.from(context)
+            when (biometricManager.canAuthenticate(BiometricManager.Authenticators.BIOMETRIC_STRONG or BiometricManager.Authenticators.DEVICE_CREDENTIAL)) {
+                BiometricManager.BIOMETRIC_SUCCESS -> return SupportType.AVAILABLE
+                BiometricManager.BIOMETRIC_ERROR_NONE_ENROLLED -> return SupportType.NONE_ENROLLED
+
+                else -> return SupportType.UNAVAILABLE
+            }
+        }
+
+        fun authenticate(
+            context: Context,
+            title: String,
+            subtitle: String
+        ): CompletableDeferred<Unit> {
+            val deferred = CompletableDeferred<Unit>()
+
+            val mainExecutor = ContextCompat.getMainExecutor(context)
+            val biometricPrompt = BiometricPrompt(
+                context as FragmentActivity,
+                object : BiometricPrompt.AuthenticationCallback() {
+                    override fun onAuthenticationError(errorCode: Int, errString: CharSequence) {
+                        deferred.completeExceptionally(Exception(errString.toString()))
+                    }
+
+                    override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
+                        deferred.complete(Unit)
+                    }
+
+                    override fun onAuthenticationFailed() {
+                        deferred.completeExceptionally(Exception("Authentication failed"))
+                    }
+                }
+            )
+
+            val promptInfo = BiometricPrompt.PromptInfo.Builder()
+                .setTitle(title)
+                .setSubtitle(subtitle)
+                .setAllowedAuthenticators(BiometricManager.Authenticators.BIOMETRIC_STRONG or BiometricManager.Authenticators.DEVICE_CREDENTIAL)
+                .build()
+
+            biometricPrompt.authenticate(promptInfo)
+
+            return deferred
+        }
+    }
+}

app/src/main/java/app/myzel394/alibi/ui/Navigation.kt

@@ -45,6 +45,7 @@ import app.myzel394.alibi.ui.screens.CustomRecordingNotificationsScreen
 import app.myzel394.alibi.ui.screens.SettingsScreen
 import app.myzel394.alibi.ui.screens.WelcomeScreen
 import app.myzel394.alibi.ui.utils.CameraInfo
+import app.myzel394.alibi.helpers.AppLockHelper
 
 const val SCALE_IN = 1.25f
 
@@ -73,34 +74,7 @@ fun Navigation(
 
     LaunchedEffect(Unit) {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
-            val executor = ContextCompat.getMainExecutor(context)
+            AppLockHelper.authenticate(context, "Title", "Subtitle")
-            val promptInfo = BiometricPrompt.Builder(context)
-                .setTitle("Biometric login for my app")
-                .setSubtitle("Log in using your biometric credential")
-                .setAllowedAuthenticators(
-                    BIOMETRIC_STRONG or DEVICE_CREDENTIAL
-                )
-                .build()
-
-            // Prompt appears when user clicks "Log in".
-            // Consider integrating with the keystore to unlock cryptographic operations,
-            // if needed by your app.
-            promptInfo.authenticate(
-                CancellationSignal(),
-                executor,
-                object : BiometricPrompt.AuthenticationCallback() {
-                    override fun onAuthenticationError(errorCode: Int, errString: CharSequence) {
-                        super.onAuthenticationError(errorCode, errString)
-                    }
-
-                    override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
-                        super.onAuthenticationSucceeded(result)
-                    }
-
-                    override fun onAuthenticationFailed() {
-                        super.onAuthenticationFailed()
-                    }
-                })
         }
     }