feat: Implement update checker and dialog for available app updates with localization support

lib/l10n/app_de.arb

@@ -2541,5 +2541,11 @@
   "yourDrawingsCount": "Ihre Zeichnungen ({count})",
   "shared": "Geteilt",
   "line": "Linie",
-  "rectangle": "Rechteck"
+  "rectangle": "Rechteck",
+
+  "updateAvailable": "Update Verfügbar",
+  "currentVersion": "Aktuell",
+  "latestVersion": "Neueste",
+  "downloadUpdate": "Herunterladen",
+  "updateLater": "Später"
 }

lib/l10n/app_en.arb

@@ -3138,5 +3138,30 @@
   "rectangle": "Rectangle",
   "@rectangle": {
     "description": "Rectangle drawing type label"
+  },
+
+  "updateAvailable": "Update Available",
+  "@updateAvailable": {
+    "description": "Title for update dialog when new version is available"
+  },
+
+  "currentVersion": "Current",
+  "@currentVersion": {
+    "description": "Label for current app version"
+  },
+
+  "latestVersion": "Latest",
+  "@latestVersion": {
+    "description": "Label for latest available app version"
+  },
+
+  "downloadUpdate": "Download",
+  "@downloadUpdate": {
+    "description": "Button to download app update"
+  },
+
+  "updateLater": "Later",
+  "@updateLater": {
+    "description": "Button to dismiss update dialog"
   }
 }

lib/l10n/app_es.arb

@@ -2536,5 +2536,11 @@
   "yourDrawingsCount": "Sus Dibujos ({count})",
   "shared": "Compartido",
   "line": "Línea",
-  "rectangle": "Rectángulo"
+  "rectangle": "Rectángulo",
+
+  "updateAvailable": "Actualización Disponible",
+  "currentVersion": "Actual",
+  "latestVersion": "Última",
+  "downloadUpdate": "Descargar",
+  "updateLater": "Más Tarde"
 }

lib/l10n/app_fr.arb

@@ -2541,5 +2541,11 @@
   "yourDrawingsCount": "Vos Dessins ({count})",
   "shared": "Partagé",
   "line": "Ligne",
-  "rectangle": "Rectangle"
+  "rectangle": "Rectangle",
+
+  "updateAvailable": "Mise à Jour Disponible",
+  "currentVersion": "Actuelle",
+  "latestVersion": "Dernière",
+  "downloadUpdate": "Télécharger",
+  "updateLater": "Plus Tard"
 }

lib/l10n/app_hr.arb

@@ -949,5 +949,11 @@
   "yourDrawingsCount": "Vaši Crteži ({count})",
   "shared": "Podijeljeno",
   "line": "Linija",
-  "rectangle": "Pravokutnik"
+  "rectangle": "Pravokutnik",
+
+  "updateAvailable": "Dostupno Ažuriranje",
+  "currentVersion": "Trenutna",
+  "latestVersion": "Najnovija",
+  "downloadUpdate": "Preuzmi",
+  "updateLater": "Kasnije"
 }

lib/l10n/app_it.arb

@@ -2541,5 +2541,11 @@
   "yourDrawingsCount": "I Tuoi Disegni ({count})",
   "shared": "Condiviso",
   "line": "Linea",
-  "rectangle": "Rettangolo"
+  "rectangle": "Rettangolo",
+
+  "updateAvailable": "Aggiornamento Disponibile",
+  "currentVersion": "Attuale",
+  "latestVersion": "Ultima",
+  "downloadUpdate": "Scarica",
+  "updateLater": "Più Tardi"
 }

lib/l10n/app_localizations.dart

@@ -3344,6 +3344,36 @@ abstract class AppLocalizations {
   /// In en, this message translates to:
   /// **'Rectangle'**
   String get rectangle;
+
+  /// Title for update dialog when new version is available
+  ///
+  /// In en, this message translates to:
+  /// **'Update Available'**
+  String get updateAvailable;
+
+  /// Label for current app version
+  ///
+  /// In en, this message translates to:
+  /// **'Current'**
+  String get currentVersion;
+
+  /// Label for latest available app version
+  ///
+  /// In en, this message translates to:
+  /// **'Latest'**
+  String get latestVersion;
+
+  /// Button to download app update
+  ///
+  /// In en, this message translates to:
+  /// **'Download'**
+  String get downloadUpdate;
+
+  /// Button to dismiss update dialog
+  ///
+  /// In en, this message translates to:
+  /// **'Later'**
+  String get updateLater;
 }
 
 class _AppLocalizationsDelegate

lib/l10n/app_localizations_de.dart

@@ -1869,4 +1869,19 @@ class AppLocalizationsDe extends AppLocalizations {
 
   @override
   String get rectangle => 'Rechteck';
+
+  @override
+  String get updateAvailable => 'Update Verfügbar';
+
+  @override
+  String get currentVersion => 'Aktuell';
+
+  @override
+  String get latestVersion => 'Neueste';
+
+  @override
+  String get downloadUpdate => 'Herunterladen';
+
+  @override
+  String get updateLater => 'Später';
 }

lib/l10n/app_localizations_en.dart

@@ -1849,4 +1849,19 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get rectangle => 'Rectangle';
+
+  @override
+  String get updateAvailable => 'Update Available';
+
+  @override
+  String get currentVersion => 'Current';
+
+  @override
+  String get latestVersion => 'Latest';
+
+  @override
+  String get downloadUpdate => 'Download';
+
+  @override
+  String get updateLater => 'Later';
 }

lib/l10n/app_localizations_es.dart

@@ -1871,4 +1871,19 @@ class AppLocalizationsEs extends AppLocalizations {
 
   @override
   String get rectangle => 'Rectángulo';
+
+  @override
+  String get updateAvailable => 'Actualización Disponible';
+
+  @override
+  String get currentVersion => 'Actual';
+
+  @override
+  String get latestVersion => 'Última';
+
+  @override
+  String get downloadUpdate => 'Descargar';
+
+  @override
+  String get updateLater => 'Más Tarde';
 }

lib/l10n/app_localizations_fr.dart

@@ -1877,4 +1877,19 @@ class AppLocalizationsFr extends AppLocalizations {
 
   @override
   String get rectangle => 'Rectangle';
+
+  @override
+  String get updateAvailable => 'Mise à Jour Disponible';
+
+  @override
+  String get currentVersion => 'Actuelle';
+
+  @override
+  String get latestVersion => 'Dernière';
+
+  @override
+  String get downloadUpdate => 'Télécharger';
+
+  @override
+  String get updateLater => 'Plus Tard';
 }

lib/l10n/app_localizations_hr.dart

@@ -1859,4 +1859,19 @@ class AppLocalizationsHr extends AppLocalizations {
 
   @override
   String get rectangle => 'Pravokutnik';
+
+  @override
+  String get updateAvailable => 'Dostupno Ažuriranje';
+
+  @override
+  String get currentVersion => 'Trenutna';
+
+  @override
+  String get latestVersion => 'Najnovija';
+
+  @override
+  String get downloadUpdate => 'Preuzmi';
+
+  @override
+  String get updateLater => 'Kasnije';
 }

lib/l10n/app_localizations_it.dart

@@ -1868,4 +1868,19 @@ class AppLocalizationsIt extends AppLocalizations {
 
   @override
   String get rectangle => 'Rettangolo';
+
+  @override
+  String get updateAvailable => 'Aggiornamento Disponibile';
+
+  @override
+  String get currentVersion => 'Attuale';
+
+  @override
+  String get latestVersion => 'Ultima';
+
+  @override
+  String get downloadUpdate => 'Scarica';
+
+  @override
+  String get updateLater => 'Più Tardi';
 }

lib/l10n/app_localizations_sl.dart

@@ -1860,4 +1860,19 @@ class AppLocalizationsSl extends AppLocalizations {
 
   @override
   String get rectangle => 'Pravokotnik';
+
+  @override
+  String get updateAvailable => 'Na Voljo Posodobitev';
+
+  @override
+  String get currentVersion => 'Trenutna';
+
+  @override
+  String get latestVersion => 'Najnovejša';
+
+  @override
+  String get downloadUpdate => 'Prenesi';
+
+  @override
+  String get updateLater => 'Kasneje';
 }

lib/l10n/app_sl.arb

@@ -949,5 +949,11 @@
   "yourDrawingsCount": "Vaše Risbe ({count})",
   "shared": "Deljeno",
   "line": "Črta",
-  "rectangle": "Pravokotnik"
+  "rectangle": "Pravokotnik",
+
+  "updateAvailable": "Na Voljo Posodobitev",
+  "currentVersion": "Trenutna",
+  "latestVersion": "Najnovejša",
+  "downloadUpdate": "Prenesi",
+  "updateLater": "Kasneje"
 }

lib/main.dart

@@ -1,3 +1,4 @@
+import 'dart:io' show Platform;
 import 'package:flutter/material.dart';
 import 'package:flutter_localizations/flutter_localizations.dart';
 import 'package:provider/provider.dart';
@@ -13,6 +14,8 @@ import 'providers/app_provider.dart';
 import 'services/tile_cache_service.dart';
 import 'services/notification_service.dart';
 import 'services/locale_preferences.dart';
+import 'services/update_checker_service.dart';
+import 'widgets/update_dialog.dart';
 import 'screens/home_screen.dart';
 import 'theme/app_theme.dart';
 import 'l10n/app_localizations.dart';
@@ -49,6 +52,10 @@ class _MeshCoreSarAppState extends State<MeshCoreSarApp> {
     // Check if we need to request location permissions
     await _checkLocationPermissions();
 
+    // Check for app updates (Android only) - runs in background
+    // Shows dialog if update is available
+    _checkForUpdates();
+
     setState(() {
       _isInitialized = true;
     });
@@ -95,6 +102,37 @@ class _MeshCoreSarAppState extends State<MeshCoreSarApp> {
     });
   }
 
+  /// Check for app updates on Android only
+  /// Shows dialog if update is available
+  Future<void> _checkForUpdates() async {
+    // Only check for updates on Android
+    if (!Platform.isAndroid) {
+      debugPrint('[UpdateChecker] Skipping update check (not Android)');
+      return;
+    }
+
+    try {
+      debugPrint('[UpdateChecker] Starting update check...');
+      final updateInfo = await UpdateCheckerService().checkForUpdate();
+
+      if (!updateInfo.isAvailable) {
+        debugPrint('[UpdateChecker] No update available');
+        return;
+      }
+
+      debugPrint('[UpdateChecker] Update available! Showing dialog...');
+
+      // Wait for widget tree to be built before showing dialog
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        if (mounted) {
+          UpdateDialog.show(context, updateInfo);
+        }
+      });
+    } catch (e) {
+      debugPrint('[UpdateChecker] Error checking for updates: $e');
+    }
+  }
+
   @override
   Widget build(BuildContext context) {
     if (!_isInitialized) {

lib/models/update_info.dart

@@ -0,0 +1,52 @@
+/// Information about an available app update
+class UpdateInfo {
+  final bool isAvailable;
+  final String currentCommitHash;
+  final String? latestCommitHash;
+  final String? downloadUrl;
+  final String? buildId;
+  final String? timestamp;
+
+  const UpdateInfo({
+    required this.isAvailable,
+    required this.currentCommitHash,
+    this.latestCommitHash,
+    this.downloadUrl,
+    this.buildId,
+    this.timestamp,
+  });
+
+  /// Factory constructor for when no update is available
+  factory UpdateInfo.noUpdate(String currentCommitHash) {
+    return UpdateInfo(
+      isAvailable: false,
+      currentCommitHash: currentCommitHash,
+    );
+  }
+
+  /// Factory constructor for when an update is available
+  factory UpdateInfo.available({
+    required String currentCommitHash,
+    required String latestCommitHash,
+    required String downloadUrl,
+    String? buildId,
+    String? timestamp,
+  }) {
+    return UpdateInfo(
+      isAvailable: true,
+      currentCommitHash: currentCommitHash,
+      latestCommitHash: latestCommitHash,
+      downloadUrl: downloadUrl,
+      buildId: buildId,
+      timestamp: timestamp,
+    );
+  }
+
+  @override
+  String toString() {
+    return 'UpdateInfo(isAvailable: $isAvailable, '
+        'current: $currentCommitHash, '
+        'latest: $latestCommitHash, '
+        'downloadUrl: $downloadUrl)';
+  }
+}

lib/services/build_info_service.dart

@@ -0,0 +1,54 @@
+import 'dart:io' show Platform;
+import 'package:flutter/services.dart';
+import 'package:flutter/foundation.dart';
+
+/// Service for accessing build information from native platform code
+/// Currently supports Android only - returns "unknown" for other platforms
+class BuildInfoService {
+  static final BuildInfoService _instance = BuildInfoService._internal();
+  factory BuildInfoService() => _instance;
+  BuildInfoService._internal();
+
+  static const MethodChannel _channel = MethodChannel('com.meshcore.sar/build_info');
+
+  String? _cachedCommitHash;
+
+  /// Get the commit hash that was embedded during build time
+  /// Returns "unknown" if:
+  /// - Not running on Android
+  /// - Platform channel call fails
+  /// - Build was not configured with COMMIT_HASH
+  Future<String> getCommitHash() async {
+    // Return cached value if available
+    if (_cachedCommitHash != null) {
+      return _cachedCommitHash!;
+    }
+
+    // Only Android has the platform channel implementation
+    if (!Platform.isAndroid) {
+      debugPrint('[BuildInfoService] Not on Android platform, returning "unknown"');
+      _cachedCommitHash = 'unknown';
+      return _cachedCommitHash!;
+    }
+
+    try {
+      final String commitHash = await _channel.invokeMethod('getCommitHash');
+      _cachedCommitHash = commitHash;
+      debugPrint('[BuildInfoService] Commit hash: $commitHash');
+      return commitHash;
+    } on PlatformException catch (e) {
+      debugPrint('[BuildInfoService] Failed to get commit hash: ${e.message}');
+      _cachedCommitHash = 'unknown';
+      return _cachedCommitHash!;
+    } catch (e) {
+      debugPrint('[BuildInfoService] Unexpected error getting commit hash: $e');
+      _cachedCommitHash = 'unknown';
+      return _cachedCommitHash!;
+    }
+  }
+
+  /// Clear cached commit hash (useful for testing)
+  void clearCache() {
+    _cachedCommitHash = null;
+  }
+}

lib/services/update_checker_service.dart

@@ -0,0 +1,135 @@
+import 'dart:convert';
+import 'package:flutter/foundation.dart';
+import 'package:http/http.dart' as http;
+import '../models/update_info.dart';
+import 'build_info_service.dart';
+
+/// Service for checking if a new app version is available
+/// Compares current build's commit hash with latest manifest from server
+class UpdateCheckerService {
+  static final UpdateCheckerService _instance = UpdateCheckerService._internal();
+  factory UpdateCheckerService() => _instance;
+  UpdateCheckerService._internal();
+
+  final BuildInfoService _buildInfoService = BuildInfoService();
+
+  // Manifest URL for the latest unstable build
+  static const String _manifestUrl = 'https://meshcore-sar.dz0ny.dev/unstable/latest/manifest.json';
+
+  /// Check if an update is available
+  /// Returns UpdateInfo with availability status and download URL if available
+  Future<UpdateInfo> checkForUpdate() async {
+    try {
+      // Get current build's commit hash
+      final currentCommitHash = await _buildInfoService.getCommitHash();
+
+      // Skip check for dev builds (local development)
+      if (currentCommitHash == 'dev' || currentCommitHash == 'unknown') {
+        debugPrint('[UpdateChecker] Skipping update check for dev/unknown build');
+        return UpdateInfo.noUpdate(currentCommitHash);
+      }
+
+      debugPrint('[UpdateChecker] Current commit hash: $currentCommitHash');
+      debugPrint('[UpdateChecker] Fetching latest manifest from: $_manifestUrl');
+
+      // Fetch manifest from server
+      final response = await http.get(
+        Uri.parse(_manifestUrl),
+        headers: {'Accept': 'application/json'},
+      ).timeout(
+        const Duration(seconds: 10),
+        onTimeout: () {
+          debugPrint('[UpdateChecker] Manifest fetch timed out');
+          throw Exception('Manifest fetch timed out');
+        },
+      );
+
+      if (response.statusCode != 200) {
+        debugPrint('[UpdateChecker] Failed to fetch manifest: ${response.statusCode}');
+        return UpdateInfo.noUpdate(currentCommitHash);
+      }
+
+      // Parse manifest JSON
+      final Map<String, dynamic> manifest = json.decode(response.body);
+      final latestCommitHash = manifest['commit'] as String?;
+      final commitShort = manifest['commit_short'] as String?;
+      final buildId = manifest['build_id'] as String?;
+      final timestamp = manifest['timestamp'] as String?;
+      final artifacts = manifest['artifacts'] as List<dynamic>?;
+
+      if (latestCommitHash == null || commitShort == null) {
+        debugPrint('[UpdateChecker] Invalid manifest: missing commit information');
+        return UpdateInfo.noUpdate(currentCommitHash);
+      }
+
+      debugPrint('[UpdateChecker] Latest commit hash: $latestCommitHash');
+      debugPrint('[UpdateChecker] Latest commit short: $commitShort');
+
+      // Compare commit hashes
+      // Current hash might be full SHA or short (7 chars)
+      // Latest from manifest is full SHA
+      final isUpdateAvailable = !_compareCommitHashes(currentCommitHash, latestCommitHash);
+
+      if (!isUpdateAvailable) {
+        debugPrint('[UpdateChecker] No update available (same commit)');
+        return UpdateInfo.noUpdate(currentCommitHash);
+      }
+
+      // Find Android APK in artifacts
+      final String? apkUrl = _findAndroidApkUrl(artifacts);
+
+      if (apkUrl == null) {
+        debugPrint('[UpdateChecker] Update available but no APK found in artifacts');
+        return UpdateInfo.noUpdate(currentCommitHash);
+      }
+
+      debugPrint('[UpdateChecker] Update available! APK URL: $apkUrl');
+
+      return UpdateInfo.available(
+        currentCommitHash: currentCommitHash,
+        latestCommitHash: commitShort,
+        downloadUrl: apkUrl,
+        buildId: buildId,
+        timestamp: timestamp,
+      );
+    } catch (e) {
+      debugPrint('[UpdateChecker] Error checking for update: $e');
+      // Return no update on error to avoid disrupting app startup
+      final currentCommitHash = await _buildInfoService.getCommitHash();
+      return UpdateInfo.noUpdate(currentCommitHash);
+    }
+  }
+
+  /// Compare two commit hashes (handles both full SHA and short format)
+  bool _compareCommitHashes(String current, String latest) {
+    // Normalize to lowercase for comparison
+    final currentLower = current.toLowerCase();
+    final latestLower = latest.toLowerCase();
+
+    // Direct match
+    if (currentLower == latestLower) return true;
+
+    // Check if current is short form of latest
+    if (latestLower.startsWith(currentLower)) return true;
+
+    // Check if latest is short form of current
+    if (currentLower.startsWith(latestLower)) return true;
+
+    return false;
+  }
+
+  /// Find Android APK URL in artifacts list
+  String? _findAndroidApkUrl(List<dynamic>? artifacts) {
+    if (artifacts == null || artifacts.isEmpty) return null;
+
+    // Look for .apk file in artifacts
+    for (final artifact in artifacts) {
+      if (artifact is String && artifact.toLowerCase().endsWith('.apk')) {
+        // Construct full URL
+        return 'https://meshcore-sar.dz0ny.dev/unstable/latest/$artifact';
+      }
+    }
+
+    return null;
+  }
+}

lib/widgets/update_dialog.dart

@@ -0,0 +1,180 @@
+import 'package:flutter/material.dart';
+import 'package:url_launcher/url_launcher.dart';
+import '../models/update_info.dart';
+import '../l10n/app_localizations.dart';
+
+/// Dialog widget that displays when a new app version is available
+/// Shows current vs latest commit hash and provides download button
+class UpdateDialog extends StatelessWidget {
+  final UpdateInfo updateInfo;
+
+  const UpdateDialog({
+    super.key,
+    required this.updateInfo,
+  });
+
+  /// Show the update dialog
+  static Future<void> show(BuildContext context, UpdateInfo updateInfo) {
+    return showDialog(
+      context: context,
+      barrierDismissible: true,
+      builder: (context) => UpdateDialog(updateInfo: updateInfo),
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final loc = AppLocalizations.of(context)!;
+
+    return AlertDialog(
+      icon: const Icon(
+        Icons.system_update,
+        size: 48,
+        color: Colors.blue,
+      ),
+      title: Text(loc.updateAvailable),
+      content: Column(
+        mainAxisSize: MainAxisSize.min,
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          // Current version
+          _buildInfoRow(
+            context,
+            label: loc.currentVersion,
+            value: updateInfo.currentCommitHash,
+          ),
+          const SizedBox(height: 12),
+
+          // Latest version
+          _buildInfoRow(
+            context,
+            label: loc.latestVersion,
+            value: updateInfo.latestCommitHash ?? 'unknown',
+          ),
+
+          // Optional: Build timestamp
+          if (updateInfo.timestamp != null) ...[
+            const SizedBox(height: 12),
+            _buildInfoRow(
+              context,
+              label: 'Build Time',
+              value: _formatTimestamp(updateInfo.timestamp!),
+            ),
+          ],
+        ],
+      ),
+      actions: [
+        // Later button
+        TextButton(
+          onPressed: () => Navigator.of(context).pop(),
+          child: Text(loc.updateLater),
+        ),
+
+        // Download button
+        FilledButton.icon(
+          onPressed: () => _launchDownloadUrl(context),
+          icon: const Icon(Icons.download),
+          label: Text(loc.downloadUpdate),
+        ),
+      ],
+    );
+  }
+
+  /// Build a labeled info row
+  Widget _buildInfoRow(BuildContext context, {required String label, required String value}) {
+    return Row(
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: [
+        SizedBox(
+          width: 100,
+          child: Text(
+            '$label:',
+            style: Theme.of(context).textTheme.bodyMedium?.copyWith(
+                  fontWeight: FontWeight.bold,
+                  color: Colors.grey[700],
+                ),
+          ),
+        ),
+        Expanded(
+          child: SelectableText(
+            value,
+            style: Theme.of(context).textTheme.bodyMedium?.copyWith(
+                  fontFamily: 'monospace',
+                  color: Colors.black87,
+                ),
+          ),
+        ),
+      ],
+    );
+  }
+
+  /// Format timestamp from YYYYMMDD-HHMMSS to readable format
+  String _formatTimestamp(String timestamp) {
+    try {
+      // Parse YYYYMMDD-HHMMSS format
+      if (timestamp.length >= 15) {
+        final year = timestamp.substring(0, 4);
+        final month = timestamp.substring(4, 6);
+        final day = timestamp.substring(6, 8);
+        final hour = timestamp.substring(9, 11);
+        final minute = timestamp.substring(11, 13);
+        return '$year-$month-$day $hour:$minute UTC';
+      }
+      return timestamp;
+    } catch (e) {
+      return timestamp;
+    }
+  }
+
+  /// Launch download URL in browser
+  Future<void> _launchDownloadUrl(BuildContext context) async {
+    if (updateInfo.downloadUrl == null) {
+      if (context.mounted) {
+        ScaffoldMessenger.of(context).showSnackBar(
+          const SnackBar(
+            content: Text('Download URL not available'),
+            backgroundColor: Colors.red,
+          ),
+        );
+      }
+      return;
+    }
+
+    try {
+      final url = Uri.parse(updateInfo.downloadUrl!);
+      final canLaunch = await canLaunchUrl(url);
+
+      if (!canLaunch) {
+        if (context.mounted) {
+          ScaffoldMessenger.of(context).showSnackBar(
+            const SnackBar(
+              content: Text('Cannot open download URL'),
+              backgroundColor: Colors.red,
+            ),
+          );
+        }
+        return;
+      }
+
+      await launchUrl(
+        url,
+        mode: LaunchMode.externalApplication,
+      );
+
+      // Close dialog after launching download
+      if (context.mounted) {
+        Navigator.of(context).pop();
+      }
+    } catch (e) {
+      debugPrint('[UpdateDialog] Error launching download URL: $e');
+      if (context.mounted) {
+        ScaffoldMessenger.of(context).showSnackBar(
+          SnackBar(
+            content: Text('Error opening download: $e'),
+            backgroundColor: Colors.red,
+          ),
+        );
+      }
+    }
+  }
+}