1 files changed, 78 insertions, 0 deletions
diff --git a/app/src/main/java/dev/msfjarvis/aps/util/auth/BiometricAuthenticator.kt b/app/src/main/java/dev/msfjarvis/aps/util/auth/BiometricAuthenticator.kt
new file mode 100644
index 00000000..4b987ebe
--- /dev/null
+++ b/app/src/main/java/dev/msfjarvis/aps/util/auth/BiometricAuthenticator.kt
@@ -0,0 +1,78 @@
+/*
+ * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved.
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+package dev.msfjarvis.aps.util.auth
+
+import android.app.KeyguardManager
+import androidx.annotation.StringRes
+import androidx.biometric.BiometricManager
+import androidx.biometric.BiometricManager.Authenticators
+import androidx.biometric.BiometricPrompt
+import androidx.core.content.ContextCompat
+import androidx.core.content.getSystemService
+import androidx.fragment.app.FragmentActivity
+import com.github.ajalt.timberkt.Timber.tag
+import com.github.ajalt.timberkt.d
+import dev.msfjarvis.aps.R
+
+object BiometricAuthenticator {
+
+    private const val TAG = "BiometricAuthenticator"
+    private const val validAuthenticators = Authenticators.DEVICE_CREDENTIAL or Authenticators.BIOMETRIC_WEAK
+
+    sealed class Result {
+        data class Success(val cryptoObject: BiometricPrompt.CryptoObject?) : Result()
+        data class Failure(val code: Int?, val message: CharSequence) : Result()
+        object HardwareUnavailableOrDisabled : Result()
+        object Cancelled : Result()
+    }
+
+    fun canAuthenticate(activity: FragmentActivity): Boolean {
+        return BiometricManager.from(activity).canAuthenticate(validAuthenticators) == BiometricManager.BIOMETRIC_SUCCESS
+    }
+
+    fun authenticate(
+        activity: FragmentActivity,
+        @StringRes dialogTitleRes: Int = R.string.biometric_prompt_title,
+        callback: (Result) -> Unit
+    ) {
+        val authCallback = object : BiometricPrompt.AuthenticationCallback() {
+            override fun onAuthenticationError(errorCode: Int, errString: CharSequence) {
+                super.onAuthenticationError(errorCode, errString)
+                tag(TAG).d { "BiometricAuthentication error: errorCode=$errorCode, msg=$errString" }
+                callback(when (errorCode) {
+                    BiometricPrompt.ERROR_CANCELED, BiometricPrompt.ERROR_USER_CANCELED,
+                    BiometricPrompt.ERROR_NEGATIVE_BUTTON -> {
+                        Result.Cancelled
+                    }
+                    BiometricPrompt.ERROR_HW_NOT_PRESENT, BiometricPrompt.ERROR_HW_UNAVAILABLE,
+                    BiometricPrompt.ERROR_NO_BIOMETRICS, BiometricPrompt.ERROR_NO_DEVICE_CREDENTIAL -> {
+                        Result.HardwareUnavailableOrDisabled
+                    }
+                    else -> Result.Failure(errorCode, activity.getString(R.string.biometric_auth_error_reason, errString))
+                })
+            }
+
+            override fun onAuthenticationFailed() {
+                super.onAuthenticationFailed()
+                callback(Result.Failure(null, activity.getString(R.string.biometric_auth_error)))
+            }
+
+            override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
+                super.onAuthenticationSucceeded(result)
+                callback(Result.Success(result.cryptoObject))
+            }
+        }
+        val deviceHasKeyguard = activity.getSystemService<KeyguardManager>()?.isDeviceSecure == true
+        if (canAuthenticate(activity) || deviceHasKeyguard) {
+            val promptInfo = BiometricPrompt.PromptInfo.Builder()
+                .setTitle(activity.getString(dialogTitleRes))
+                .setAllowedAuthenticators(validAuthenticators)
+                .build()
+            BiometricPrompt(activity, ContextCompat.getMainExecutor(activity.applicationContext), authCallback).authenticate(promptInfo)
+        } else {
+            callback(Result.HardwareUnavailableOrDisabled)
+        }
+    }
+}