feat: app biometric lock

app/src/main/java/com/bitcointxoko/gudariwallet/MainActivity.kt

@@ -31,12 +31,17 @@ import kotlinx.coroutines.flow.MutableSharedFlow
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import cafe.adriel.lyricist.ProvideStrings
+import com.bitcointxoko.gudariwallet.data.AppLockStore
 import com.bitcointxoko.gudariwallet.data.HistoricalSyncStore
+import com.bitcointxoko.gudariwallet.ui.lock.BiometricLockScreen
 import com.bitcointxoko.gudariwallet.util.NotificationConstants
 
 class MainActivity : AppCompatActivity() {
 
     private lateinit var secretStore: EncryptedSecretStore
+    private lateinit var appLockStore: AppLockStore
+
+    private val isUnlocked = mutableStateOf(false)
 
     private val vm: WalletViewModel by viewModels {
         WalletViewModelFactory(application)
@@ -84,6 +89,7 @@ class MainActivity : AppCompatActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         secretStore = EncryptedSecretStore(applicationContext)
+        appLockStore = AppLockStore(applicationContext)
         val syncStore = HistoricalSyncStore(applicationContext)
         val credentialsState = secretStore.credentials
             .stateIn(
@@ -91,6 +97,12 @@ class MainActivity : AppCompatActivity() {
                 started = SharingStarted.WhileSubscribed(5_000),
                 initialValue = null
             )
+        val appLockEnabledState = appLockStore.appLockEnabled
+            .stateIn(
+                scope = lifecycleScope,
+                started = SharingStarted.WhileSubscribed(5_000),
+                initialValue = true   // safe default: locked
+            )
 
         // Must be first — before any notification is posted
         // NotificationHelper.createChannels(applicationContext)
@@ -121,9 +133,25 @@ class MainActivity : AppCompatActivity() {
                     // ─────────────────────────────────────────────────────────────
 
                     val credentials by credentialsState.collectAsState()
+                    val appLockEnabled by appLockEnabledState.collectAsState()
                     val isOnboarded = credentials?.isOnboarded == true
 
-                    if (isOnboarded) {
+                    when {
+                        !isOnboarded -> {
+                            OnboardingScreen(
+                                secretStore = secretStore,
+                                syncStore = syncStore,
+                                appLockStore = appLockStore,
+                                onRequestNotificationPermission = { requestNotificationPermissionIfNeeded() },
+                                onComplete = {}
+                            )
+                        }
+                        appLockEnabled && !isUnlocked.value -> {
+                            BiometricLockScreen(
+                                onUnlocked = { isUnlocked.value = true }
+                            )
+                        }
+                        else -> {
                             LaunchedEffect(Unit) {
                                 WalletNotificationService.start(this@MainActivity)
                                 requestNotificationPermissionIfNeeded()
@@ -136,18 +164,17 @@ class MainActivity : AppCompatActivity() {
                                 pendingPaymentUri = pendingPaymentUri,
                                 lyricist = lyricist
                             )
-                    } else {
-                        OnboardingScreen(
-                            secretStore                     = secretStore,
-                            syncStore                       = syncStore,
-                            onRequestNotificationPermission = { requestNotificationPermissionIfNeeded() },
-                            onComplete                      = {}
-                        )
                         }
                     }
                 }
             }
         }
+    }
+
+    override fun onStop() {
+        super.onStop()
+        isUnlocked.value = false
+    }
 
     // ── NFC foreground dispatch ───────────────────────────────────────────────
 

app/src/main/java/com/bitcointxoko/gudariwallet/data/AppLockStore.kt

@@ -0,0 +1,27 @@
+package com.bitcointxoko.gudariwallet.data
+
+import android.content.Context
+import androidx.datastore.preferences.core.booleanPreferencesKey
+import androidx.datastore.preferences.core.edit
+import androidx.datastore.preferences.preferencesDataStore
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.map
+
+private val Context.appLockDataStore by preferencesDataStore(name = "app_lock_prefs")
+
+class AppLockStore(private val context: Context) {
+
+    companion object {
+        private val KEY_APP_LOCK_ENABLED = booleanPreferencesKey("app_lock_enabled")
+    }
+
+    /** Defaults to true (locked) as required. */
+    val appLockEnabled: Flow<Boolean> = context.appLockDataStore.data
+        .map { prefs -> prefs[KEY_APP_LOCK_ENABLED] ?: true }
+
+    suspend fun setAppLockEnabled(enabled: Boolean) {
+        context.appLockDataStore.edit { prefs ->
+            prefs[KEY_APP_LOCK_ENABLED] = enabled
+        }
+    }
+}

app/src/main/java/com/bitcointxoko/gudariwallet/ui/lock/BiometricLockScreen.kt

@@ -0,0 +1,107 @@
+package com.bitcointxoko.gudariwallet.ui.lock
+
+import androidx.biometric.BiometricManager
+import androidx.biometric.BiometricPrompt
+import androidx.compose.foundation.layout.*
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Fingerprint
+import androidx.compose.material3.*
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+import androidx.core.content.ContextCompat
+import androidx.fragment.app.FragmentActivity
+
+@Composable
+fun BiometricLockScreen(onUnlocked: () -> Unit) {
+    val context = LocalContext.current
+    val activity = context as FragmentActivity
+
+    LaunchedEffect(Unit) {
+        showBiometricPrompt(activity, onUnlocked)
+    }
+
+    Scaffold { innerPadding ->
+        Box(
+            modifier = Modifier
+                .fillMaxSize()
+                .padding(innerPadding),
+            contentAlignment = Alignment.Center
+        ) {
+            Column(
+                horizontalAlignment = Alignment.CenterHorizontally,
+                verticalArrangement = Arrangement.Center,
+                modifier = Modifier.padding(horizontal = 32.dp)
+            ) {
+                Icon(
+                    imageVector = Icons.Filled.Fingerprint,
+                    contentDescription = null,
+                    modifier = Modifier.size(64.dp),
+                    tint = MaterialTheme.colorScheme.primary
+                )
+
+                Spacer(Modifier.height(24.dp))
+
+                Text(
+                    text = "Gudari Wallet",
+                    style = MaterialTheme.typography.displaySmall,
+                    color = MaterialTheme.colorScheme.onBackground,
+                    textAlign = TextAlign.Center
+                )
+
+                Spacer(Modifier.height(8.dp))
+
+                Text(
+                    text = "Authenticate to continue",
+                    style = MaterialTheme.typography.bodyMedium,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    textAlign = TextAlign.Center
+                )
+
+                Spacer(Modifier.height(32.dp))
+
+                FilledTonalButton(
+                    onClick = { showBiometricPrompt(activity, onUnlocked) }
+                ) {
+                    Icon(
+                        imageVector = Icons.Filled.Fingerprint,
+                        contentDescription = null,
+                        modifier = Modifier.size(ButtonDefaults.IconSize)
+                    )
+                    Spacer(Modifier.width(ButtonDefaults.IconSpacing))
+                    Text("Unlock")
+                }
+            }
+        }
+    }
+}
+
+private fun showBiometricPrompt(
+    activity: FragmentActivity,
+    onUnlocked: () -> Unit
+) {
+    val executor = ContextCompat.getMainExecutor(activity)
+
+    val callback = object : BiometricPrompt.AuthenticationCallback() {
+        override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult) {
+            onUnlocked()
+        }
+    }
+
+    val prompt = BiometricPrompt(activity, executor, callback)
+
+    val promptInfo = BiometricPrompt.PromptInfo.Builder()
+        .setTitle("Unlock Gudari Wallet")
+        .setSubtitle("Authenticate to access your wallet")
+        .setAllowedAuthenticators(
+            BiometricManager.Authenticators.BIOMETRIC_STRONG
+                    or BiometricManager.Authenticators.DEVICE_CREDENTIAL
+        )
+        .build()
+
+    prompt.authenticate(promptInfo)
+}

app/src/main/java/com/bitcointxoko/gudariwallet/ui/onboarding/BiometricLockPage.kt

@@ -0,0 +1,82 @@
+package com.bitcointxoko.gudariwallet.ui.onboarding
+
+import androidx.compose.foundation.layout.*
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.Fingerprint
+import androidx.compose.material3.*
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.unit.dp
+
+@Composable
+fun BiometricLockPage(
+    appLockEnabled: Boolean,
+    onAppLockChanged: (Boolean) -> Unit
+) {
+    Column(
+        modifier = Modifier
+            .fillMaxSize()
+            .padding(horizontal = 32.dp),
+        verticalArrangement = Arrangement.Center,
+        horizontalAlignment = Alignment.CenterHorizontally
+    ) {
+        Icon(
+            imageVector = Icons.Filled.Fingerprint,
+            contentDescription = null,
+            modifier = Modifier.size(72.dp),
+            tint = MaterialTheme.colorScheme.primary
+        )
+
+        Spacer(Modifier.height(24.dp))
+
+        Text(
+            text = "App Lock",
+            style = MaterialTheme.typography.headlineMedium,
+            textAlign = TextAlign.Center
+        )
+
+        Spacer(Modifier.height(12.dp))
+
+        Text(
+            text = "Require biometric authentication (fingerprint, face, or PIN) every time you open Gudari Wallet.",
+            style = MaterialTheme.typography.bodyMedium,
+            textAlign = TextAlign.Center,
+            color = MaterialTheme.colorScheme.onSurfaceVariant
+        )
+
+        Spacer(Modifier.height(32.dp))
+
+        Card(
+            modifier = Modifier.fillMaxWidth(),
+            colors = CardDefaults.cardColors(
+                containerColor = MaterialTheme.colorScheme.surfaceVariant
+            )
+        ) {
+            Row(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .padding(horizontal = 16.dp, vertical = 12.dp),
+                verticalAlignment = Alignment.CenterVertically,
+                horizontalArrangement = Arrangement.SpaceBetween
+            ) {
+                Column(modifier = Modifier.weight(1f)) {
+                    Text(
+                        text = "Lock app on open",
+                        style = MaterialTheme.typography.bodyLarge
+                    )
+                    Text(
+                        text = if (appLockEnabled) "Enabled (recommended)" else "Disabled",
+                        style = MaterialTheme.typography.bodySmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant
+                    )
+                }
+                Switch(
+                    checked = appLockEnabled,
+                    onCheckedChange = onAppLockChanged
+                )
+            }
+        }
+    }
+}

app/src/main/java/com/bitcointxoko/gudariwallet/ui/onboarding/OnboardingScreen.kt

@@ -14,6 +14,7 @@ import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.bitcointxoko.gudariwallet.LocalAppStrings
+import com.bitcointxoko.gudariwallet.data.AppLockStore
 import com.bitcointxoko.gudariwallet.data.HistoricalSyncStore
 import com.bitcointxoko.gudariwallet.security.SecretStore
 import kotlinx.coroutines.launch
@@ -25,13 +26,15 @@ private const val PAGE_INVOICE       = 2
 private const val PAGE_ADMIN         = 3
 private const val PAGE_NOTIFICATIONS = 4
 private const val PAGE_BATTERY       = 5
-private const val PAGE_SYNC          = 6
+private const val PAGE_BIOMETRIC     = 6
-private const val PAGE_COUNT         = 7
+private const val PAGE_SYNC          = 7
+private const val PAGE_COUNT         = 8
 
 @Composable
 fun OnboardingScreen(
     secretStore                    : SecretStore,
     syncStore                      : HistoricalSyncStore,
+    appLockStore                   : AppLockStore,
     onRequestNotificationPermission: () -> Unit,
     onComplete                     : () -> Unit
 ) {
@@ -44,7 +47,7 @@ fun OnboardingScreen(
     var adminKey     by remember { mutableStateOf("") }
     var adminVisible by remember { mutableStateOf(false) }
     var error        by remember { mutableStateOf<String?>(null) }
-    // var credentialsSaved by remember { mutableStateOf(false) }
+    var appLockEnabled by remember { mutableStateOf(true) }
 
     // ── Sync state ────────────────────────────────────────────────────────────
     val vm: OnboardingViewModel = viewModel(
@@ -119,6 +122,10 @@ fun OnboardingScreen(
                         onRequestNotificationPermission = onRequestNotificationPermission
                     )
                     PAGE_BATTERY       -> BatteryPage(strings)
+                    PAGE_BIOMETRIC -> BiometricLockPage(
+                        appLockEnabled = appLockEnabled,
+                        onAppLockChanged = { appLockEnabled = it }
+                    )
                     PAGE_SYNC          -> SyncHistoryPage(
                         workInfo      = syncWorkInfo,
                         isAlreadyDone = syncAlreadyDone,
@@ -185,6 +192,9 @@ fun OnboardingScreen(
                                     Timber.d("ONBOARDING saving adminKey (len=${adminKey.length}): $adminKey")
                                     secretStore.saveAdminKey(adminKey)
                                 }
+                                PAGE_BIOMETRIC -> {
+                                    scope.launch { appLockStore.setAppLockEnabled(appLockEnabled) }
+                                }
                                 else -> Unit
                             }
                             pagerState.animateScrollToPage(pagerState.currentPage + 1)