Require biometric with device lock fallback to copy nsec

app/build.gradle

@@ -73,6 +73,9 @@ dependencies {
     implementation "androidx.lifecycle:lifecycle-runtime-ktx:$lifecycle_version"
     implementation "androidx.lifecycle:lifecycle-livedata:$lifecycle_version"
 
+    // Biometrics
+    implementation "androidx.biometric:biometric-ktx:1.2.0-alpha05"
+
     // Swipe Refresh
     implementation 'com.google.accompanist:accompanist-swiperefresh:0.29.1-alpha'
 

app/src/main/java/com/vitorpamplona/amethyst/ui/MainActivity.kt

@@ -2,12 +2,12 @@ package com.vitorpamplona.amethyst.ui
 
 import android.os.Build.VERSION.SDK_INT
 import android.os.Bundle
-import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.material.MaterialTheme
 import androidx.compose.material.Surface
 import androidx.compose.ui.Modifier
+import androidx.fragment.app.FragmentActivity
 import androidx.lifecycle.viewmodel.compose.viewModel
 import coil.Coil
 import coil.ImageLoader
@@ -22,7 +22,7 @@ import com.vitorpamplona.amethyst.ui.screen.AccountScreen
 import com.vitorpamplona.amethyst.ui.screen.AccountStateViewModel
 import com.vitorpamplona.amethyst.ui.theme.AmethystTheme
 
-class MainActivity : ComponentActivity() {
+class MainActivity : FragmentActivity() {
   override fun onCreate(savedInstanceState: Bundle?) {
     super.onCreate(savedInstanceState)
 

app/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/AccountBackupDialog.kt

@@ -1,6 +1,12 @@
 package com.vitorpamplona.amethyst.ui.screen.loggedIn
 
+import android.content.Context
+import android.content.ContextWrapper
 import android.widget.Toast
+import androidx.biometric.BiometricManager
+import androidx.biometric.BiometricManager.Authenticators.BIOMETRIC_STRONG
+import androidx.biometric.BiometricManager.Authenticators.DEVICE_CREDENTIAL
+import androidx.biometric.BiometricPrompt
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Column
@@ -24,6 +30,7 @@ import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.platform.ClipboardManager
 import androidx.compose.ui.platform.LocalClipboardManager
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
@@ -31,6 +38,7 @@ import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.unit.dp
 import androidx.compose.ui.window.Dialog
 import androidx.compose.ui.window.DialogProperties
+import androidx.fragment.app.FragmentActivity
 import com.halilibo.richtext.markdown.Markdown
 import com.halilibo.richtext.ui.RichTextStyle
 import com.halilibo.richtext.ui.material.MaterialRichText
@@ -38,6 +46,7 @@ import com.halilibo.richtext.ui.resolveDefaults
 import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.model.Account
 import com.vitorpamplona.amethyst.ui.actions.CloseButton
+import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.launch
 import nostr.postr.toNsec
 
@@ -98,16 +107,7 @@ private fun NSecCopyButton(
     Button(
         modifier = Modifier.padding(horizontal = 3.dp),
         onClick = {
-            account.loggedIn.privKey?.let {
-                clipboardManager.setText(AnnotatedString(it.toNsec()))
-                scope.launch {
-                    Toast.makeText(
-                        context,
-                        context.getString(R.string.secret_key_copied_to_clipboard),
-                        Toast.LENGTH_SHORT
-                    ).show()
-                }
-            }
+            authenticatedCopyNSec(context, scope, account, clipboardManager)
         },
         shape = RoundedCornerShape(20.dp), colors = ButtonDefaults.buttonColors(
             backgroundColor = MaterialTheme.colors.primary
@@ -121,3 +121,77 @@ private fun NSecCopyButton(
         Text("Copy Secret Key", color = MaterialTheme.colors.onPrimary)
     }
 }
+
+fun Context.getFragmentActivity(): FragmentActivity? {
+    var currentContext = this
+    while (currentContext is ContextWrapper) {
+        if (currentContext is FragmentActivity) {
+            return currentContext
+        }
+        currentContext = currentContext.baseContext
+    }
+    return null
+}
+
+private fun authenticatedCopyNSec(
+    context: Context,
+    scope: CoroutineScope,
+    account: Account,
+    clipboardManager: ClipboardManager,
+) {
+    val fragmentContext = context.getFragmentActivity()!!
+    val authenticators = BIOMETRIC_STRONG or DEVICE_CREDENTIAL
+    val biometricManager = BiometricManager.from(context)
+
+    val promptInfo = BiometricPrompt.PromptInfo.Builder()
+        .setTitle(context.getString(R.string.app_name_release))
+        .setSubtitle(context.getString(R.string.copy_my_secret_key))
+        .setAllowedAuthenticators(authenticators)
+        .build()
+
+    val biometricPrompt = BiometricPrompt(
+        fragmentContext,
+        object : BiometricPrompt.AuthenticationCallback() {
+            override fun onAuthenticationFailed() {
+                super.onAuthenticationFailed()
+                scope.launch {
+                    Toast.makeText(
+                        context,
+                        context.getString(R.string.biometric_authentication_failed),
+                        Toast.LENGTH_SHORT
+                    ).show()
+                }
+            }
+
+            override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
+                super.onAuthenticationSucceeded(result)
+                copyNSec(context, scope, account, clipboardManager)
+            }
+        }
+    )
+
+    val canAuth = biometricManager.canAuthenticate(authenticators)
+    if (canAuth == BiometricManager.BIOMETRIC_SUCCESS) {
+        biometricPrompt.authenticate(promptInfo)
+    } else {
+        copyNSec(context, scope, account, clipboardManager)
+    }
+}
+
+private fun copyNSec(
+    context: Context,
+    scope: CoroutineScope,
+    account: Account,
+    clipboardManager: ClipboardManager,
+) {
+    account.loggedIn.privKey?.let {
+        clipboardManager.setText(AnnotatedString(it.toNsec()))
+        scope.launch {
+            Toast.makeText(
+                context,
+                context.getString(R.string.secret_key_copied_to_clipboard),
+                Toast.LENGTH_SHORT
+            ).show()
+        }
+    }
+}

app/src/main/res/values/strings.xml

@@ -181,4 +181,6 @@
         \n- **Do** keep a secure backup of your secret key for account recovery. We recommend using a password manager.
     </string>
     <string name="secret_key_copied_to_clipboard">Secret key (nsec) copied to clipboard</string>
+    <string name="copy_my_secret_key">Copy my secret key</string>
+    <string name="biometric_authentication_failed">Authentication failed</string>
 </resources>