break up offlin areas

lib/services/offline_area_service.dart

@@ -1,17 +1,16 @@
 import 'dart:io';
 import 'dart:convert';
-import 'dart:math' as math;
 import 'package:flutter/foundation.dart';
 import 'package:latlong2/latlong.dart';
 import 'package:flutter_map/flutter_map.dart' show LatLngBounds;
 import 'package:path_provider/path_provider.dart';
 import 'offline_areas/offline_area_models.dart';
 import 'offline_areas/offline_tile_utils.dart';
-import 'offline_areas/offline_area_service_tile_fetch.dart'; // Only used for file IO during area downloads.
+import 'offline_areas/offline_area_downloader.dart';
+import 'offline_areas/world_area_manager.dart';
 import '../models/osm_camera_node.dart';
 import '../app_state.dart';
 import 'map_data_provider.dart';
-import 'map_data_submodules/cameras_from_overpass.dart';
 import 'package:flock_map_app/dev_config.dart';
 
 /// Service for managing download, storage, and retrieval of offline map areas and cameras.
@@ -39,7 +38,7 @@ class OfflineAreaService {
     if (_initialized) return;
     
     await _loadAreasFromDisk();
-    await _ensureAndAutoDownloadWorldArea();
+    await WorldAreaManager.ensureWorldArea(_areas, getOfflineAreaDir, downloadArea);
     _initialized = true;
   }
 
@@ -151,77 +150,7 @@ class OfflineAreaService {
     }
   }
 
-  Future<void> _ensureAndAutoDownloadWorldArea() async {
-    final dir = await getOfflineAreaDir();
-    final worldDir = "${dir.path}/world";
-    final LatLngBounds worldBounds = globalWorldBounds();
-    OfflineArea? world;
-    for (final a in _areas) {
-      if (a.isPermanent) { world = a; break; }
-    }
-    final Set<List<int>> expectedTiles = computeTileList(worldBounds, kWorldMinZoom, kWorldMaxZoom);
-    if (world != null) {
-      int filesFound = 0;
-      List<List<int>> missingTiles = [];
-      for (final tile in expectedTiles) {
-        final f = File('${world.directory}/tiles/${tile[0]}/${tile[1]}/${tile[2]}.png');
-        if (f.existsSync()) {
-          filesFound++;
-        } else if (missingTiles.length < 10) {
-          missingTiles.add(tile);
-        }
-      }
-      if (filesFound != expectedTiles.length) {
-        debugPrint('World area: missing ${expectedTiles.length - filesFound} tiles. First few: $missingTiles');
-      } else {
-        debugPrint('World area: all tiles accounted for.');
-      }
-      world.tilesTotal = expectedTiles.length;
-      world.tilesDownloaded = filesFound;
-      world.progress = (world.tilesTotal == 0) ? 0.0 : (filesFound / world.tilesTotal);
-      if (filesFound == world.tilesTotal) {
-        world.status = OfflineAreaStatus.complete;
-        await saveAreasToDisk();
-        return;
-      } else {
-        world.status = OfflineAreaStatus.downloading;
-        await saveAreasToDisk();
-        downloadArea(
-          id: world.id,
-          bounds: world.bounds,
-          minZoom: world.minZoom,
-          maxZoom: world.maxZoom,
-          directory: world.directory,
-          name: world.name,
-        );
-        return;
-      }
-    }
-    // If not present, create and start download
-    world = OfflineArea(
-      id: 'permanent_world',
-      name: 'World (required)',
-      bounds: worldBounds,
-      minZoom: kWorldMinZoom,
-      maxZoom: kWorldMaxZoom,
-      directory: worldDir,
-      status: OfflineAreaStatus.downloading,
-      progress: 0.0,
-      isPermanent: true,
-      tilesTotal: expectedTiles.length,
-      tilesDownloaded: 0,
-    );
-    _areas.insert(0, world);
-    await saveAreasToDisk();
-    downloadArea(
-      id: world.id,
-      bounds: world.bounds,
-      minZoom: world.minZoom,
-      maxZoom: world.maxZoom,
-      directory: world.directory,
-      name: world.name,
-    );
-  }
+
 
   Future<void> downloadArea({
     required String id,
@@ -257,76 +186,26 @@ class OfflineAreaService {
     await saveAreasToDisk();
 
     try {
-      Set<List<int>> allTiles;
-      if (area.isPermanent) {
-        allTiles = computeTileList(globalWorldBounds(), kWorldMinZoom, kWorldMaxZoom);
-      } else {
-        allTiles = computeTileList(bounds, minZoom, maxZoom);
-      }
-      area.tilesTotal = allTiles.length;
-      const int maxPasses = 3;
-      int pass = 0;
-      Set<List<int>> allTilesSet = allTiles.toSet();
-      Set<List<int>> tilesToFetch = allTilesSet;
-      bool success = false;
-      int totalDone = 0;
-      while (pass < maxPasses && tilesToFetch.isNotEmpty) {
-        pass++;
-        int doneThisPass = 0;
-        debugPrint('DownloadArea: pass #$pass for area $id. Need ${tilesToFetch.length} tiles.');
-        for (final tile in tilesToFetch) {
-          if (area.status == OfflineAreaStatus.cancelled) break;
-          try {
-            final bytes = await MapDataProvider().getTile(
-              z: tile[0], x: tile[1], y: tile[2], source: MapSource.remote);
-            if (bytes.isNotEmpty) {
-              await saveTileBytes(tile[0], tile[1], tile[2], directory, bytes);
-            }
-            totalDone++;
-            doneThisPass++;
-            area.tilesDownloaded = totalDone;
-            area.progress = area.tilesTotal == 0 ? 0.0 : ((area.tilesDownloaded) / area.tilesTotal);
-          } catch (e) {
-            debugPrint("Tile download failed for z=${tile[0]}, x=${tile[1]}, y=${tile[2]}: $e");
-          }
-          if (onProgress != null) onProgress(area.progress);
-        }
-        await getAreaSizeBytes(area);
-        await saveAreasToDisk();
-        Set<List<int>> missingTiles = {};
-        for (final tile in allTilesSet) {
-          final f = File('$directory/tiles/${tile[0]}/${tile[1]}/${tile[2]}.png');
-          if (!f.existsSync()) missingTiles.add(tile);
-        }
-        if (missingTiles.isEmpty) {
-          success = true;
-          break;
-        }
-        tilesToFetch = missingTiles;
-      }
+      final success = await OfflineAreaDownloader.downloadArea(
+        area: area,
+        bounds: bounds,
+        minZoom: minZoom,
+        maxZoom: maxZoom,
+        directory: directory,
+        onProgress: onProgress,
+        saveAreasToDisk: saveAreasToDisk,
+        getAreaSizeBytes: getAreaSizeBytes,
+      );
 
-      if (!area.isPermanent) {
-        // Calculate expanded camera bounds that cover the entire tile area at minimum zoom
-        final cameraBounds = _calculateCameraBounds(bounds, minZoom);
-        final cameras = await MapDataProvider().getAllCamerasForDownload(
-          bounds: cameraBounds,
-          profiles: AppState.instance.enabledProfiles,
-        );
-        area.cameras = cameras;
-        await saveCameras(cameras, directory);
-        debugPrint('Area $id: Downloaded ${cameras.length} cameras from expanded bounds (${cameraBounds.north.toStringAsFixed(6)}, ${cameraBounds.west.toStringAsFixed(6)}) to (${cameraBounds.south.toStringAsFixed(6)}, ${cameraBounds.east.toStringAsFixed(6)})');
-      } else {
-        area.cameras = [];
-      }
       await getAreaSizeBytes(area);
 
       if (success) {
         area.status = OfflineAreaStatus.complete;
         area.progress = 1.0;
-        debugPrint('Area $id: all tiles accounted for and area marked complete.');
+        debugPrint('Area $id: download completed successfully.');
       } else {
         area.status = OfflineAreaStatus.error;
-        debugPrint('Area $id: MISSING tiles after $maxPasses passes. First 10: ${tilesToFetch.toList().take(10)}');
+        debugPrint('Area $id: download failed after maximum retry attempts.');
         if (!area.isPermanent) {
           final dirObj = Directory(area.directory);
           if (await dirObj.exists()) {
@@ -336,11 +215,11 @@ class OfflineAreaService {
         }
       }
       await saveAreasToDisk();
-      if (onComplete != null) onComplete(area.status);
+      onComplete?.call(area.status);
     } catch (e) {
       area.status = OfflineAreaStatus.error;
       await saveAreasToDisk();
-      if (onComplete != null) onComplete(area.status);
+      onComplete?.call(area.status);
     }
   }
 
@@ -354,7 +233,7 @@ class OfflineAreaService {
     _areas.remove(area);
     await saveAreasToDisk();
     if (area.isPermanent) {
-      _ensureAndAutoDownloadWorldArea();
+      await WorldAreaManager.ensureWorldArea(_areas, getOfflineAreaDir, downloadArea);
     }
   }
 
@@ -368,56 +247,5 @@ class OfflineAreaService {
     await saveAreasToDisk();
   }
   
-  /// Calculate expanded bounds that cover the entire tile area at minimum zoom
-  /// This ensures we fetch all cameras that could be relevant for the offline area
-  LatLngBounds _calculateCameraBounds(LatLngBounds visibleBounds, int minZoom) {
-    // Get all tiles that cover the visible bounds at minimum zoom
-    final tiles = computeTileList(visibleBounds, minZoom, minZoom);
-    if (tiles.isEmpty) return visibleBounds;
-    
-    // Find the bounding box of all these tiles
-    double minLat = 90.0, maxLat = -90.0;
-    double minLon = 180.0, maxLon = -180.0;
-    
-    for (final tile in tiles) {
-      final z = tile[0];
-      final x = tile[1]; 
-      final y = tile[2];
-      
-      // Convert tile coordinates back to lat/lng bounds
-      final tileBounds = _tileToLatLngBounds(x, y, z);
-      
-      minLat = math.min(minLat, tileBounds.south);
-      maxLat = math.max(maxLat, tileBounds.north);
-      minLon = math.min(minLon, tileBounds.west);
-      maxLon = math.max(maxLon, tileBounds.east);
-    }
-    
-    return LatLngBounds(
-      LatLng(minLat, minLon),
-      LatLng(maxLat, maxLon),
-    );
-  }
-  
-  /// Convert tile coordinates to LatLng bounds
-  LatLngBounds _tileToLatLngBounds(int x, int y, int z) {
-    final n = math.pow(2, z);
-    final lonDeg = x / n * 360.0 - 180.0;
-    final latRad = math.atan(_sinh(math.pi * (1 - 2 * y / n)));
-    final latDeg = latRad * 180.0 / math.pi;
-    
-    final lonDegNext = (x + 1) / n * 360.0 - 180.0;
-    final latRadNext = math.atan(_sinh(math.pi * (1 - 2 * (y + 1) / n)));
-    final latDegNext = latRadNext * 180.0 / math.pi;
-    
-    return LatLngBounds(
-      LatLng(latDegNext, lonDeg),      // SW corner
-      LatLng(latDeg, lonDegNext),      // NE corner  
-    );
-  }
-  
-  /// Hyperbolic sine function: sinh(x) = (e^x - e^(-x)) / 2
-  double _sinh(double x) {
-    return (math.exp(x) - math.exp(-x)) / 2;
-  }
+
 }

lib/services/offline_areas/offline_area_downloader.dart

@@ -0,0 +1,191 @@
+import 'dart:io';
+import 'dart:convert';
+import 'dart:math' as math;
+import 'package:flutter/foundation.dart';
+import 'package:latlong2/latlong.dart';
+import 'package:flutter_map/flutter_map.dart' show LatLngBounds;
+
+import '../../app_state.dart';
+import '../../models/osm_camera_node.dart';
+import '../map_data_provider.dart';
+import 'offline_area_models.dart';
+import 'offline_tile_utils.dart';
+import 'package:flock_map_app/dev_config.dart';
+
+/// Handles the actual downloading process for offline areas
+class OfflineAreaDownloader {
+  static const int _maxRetryPasses = 3;
+
+  /// Download tiles and cameras for an offline area
+  static Future<bool> downloadArea({
+    required OfflineArea area,
+    required LatLngBounds bounds,
+    required int minZoom,
+    required int maxZoom,
+    required String directory,
+    void Function(double progress)? onProgress,
+    required Future<void> Function() saveAreasToDisk,
+    required Future<void> Function(OfflineArea) getAreaSizeBytes,
+  }) async {
+    // Calculate tiles to download
+    Set<List<int>> allTiles;
+    if (area.isPermanent) {
+      allTiles = computeTileList(globalWorldBounds(), kWorldMinZoom, kWorldMaxZoom);
+    } else {
+      allTiles = computeTileList(bounds, minZoom, maxZoom);
+    }
+    area.tilesTotal = allTiles.length;
+
+    // Download tiles with retry logic
+    final success = await _downloadTilesWithRetry(
+      area: area,
+      allTiles: allTiles,
+      directory: directory,
+      onProgress: onProgress,
+      saveAreasToDisk: saveAreasToDisk,
+      getAreaSizeBytes: getAreaSizeBytes,
+    );
+
+    // Download cameras for non-permanent areas
+    if (!area.isPermanent) {
+      await _downloadCameras(
+        area: area,
+        bounds: bounds,
+        minZoom: minZoom,
+        directory: directory,
+      );
+    } else {
+      area.cameras = [];
+    }
+
+    return success;
+  }
+
+  /// Download tiles with retry logic
+  static Future<bool> _downloadTilesWithRetry({
+    required OfflineArea area,
+    required Set<List<int>> allTiles,
+    required String directory,
+    void Function(double progress)? onProgress,
+    required Future<void> Function() saveAreasToDisk,
+    required Future<void> Function(OfflineArea) getAreaSizeBytes,
+  }) async {
+    int pass = 0;
+    Set<List<int>> tilesToFetch = allTiles;
+    int totalDone = 0;
+
+    while (pass < _maxRetryPasses && tilesToFetch.isNotEmpty) {
+      pass++;
+      debugPrint('DownloadArea: pass #$pass for area ${area.id}. Need ${tilesToFetch.length} tiles.');
+      
+      for (final tile in tilesToFetch) {
+        if (area.status == OfflineAreaStatus.cancelled) break;
+        
+        if (await _downloadSingleTile(tile, directory)) {
+          totalDone++;
+          area.tilesDownloaded = totalDone;
+          area.progress = area.tilesTotal == 0 ? 0.0 : (totalDone / area.tilesTotal);
+          onProgress?.call(area.progress);
+        }
+      }
+
+      await getAreaSizeBytes(area);
+      await saveAreasToDisk();
+      
+      // Check for missing tiles
+      tilesToFetch = _findMissingTiles(allTiles, directory);
+      if (tilesToFetch.isEmpty) {
+        return true; // Success!
+      }
+    }
+
+    return false; // Failed after max retries
+  }
+
+  /// Download a single tile
+  static Future<bool> _downloadSingleTile(List<int> tile, String directory) async {
+    try {
+      final bytes = await MapDataProvider().getTile(
+        z: tile[0], 
+        x: tile[1], 
+        y: tile[2], 
+        source: MapSource.remote,
+      );
+      if (bytes.isNotEmpty) {
+        await OfflineAreaDownloader.saveTileBytes(tile[0], tile[1], tile[2], directory, bytes);
+        return true;
+      }
+    } catch (e) {
+      debugPrint("Tile download failed for z=${tile[0]}, x=${tile[1]}, y=${tile[2]}: $e");
+    }
+    return false;
+  }
+
+  /// Find tiles that are missing from disk
+  static Set<List<int>> _findMissingTiles(Set<List<int>> allTiles, String directory) {
+    final missingTiles = <List<int>>{};
+    for (final tile in allTiles) {
+      final file = File('$directory/tiles/${tile[0]}/${tile[1]}/${tile[2]}.png');
+      if (!file.existsSync()) {
+        missingTiles.add(tile);
+      }
+    }
+    return missingTiles;
+  }
+
+  /// Download cameras for the area with expanded bounds
+  static Future<void> _downloadCameras({
+    required OfflineArea area,
+    required LatLngBounds bounds,
+    required int minZoom,
+    required String directory,
+  }) async {
+    // Calculate expanded camera bounds that cover the entire tile area at minimum zoom
+    final cameraBounds = _calculateCameraBounds(bounds, minZoom);
+    final cameras = await MapDataProvider().getAllCamerasForDownload(
+      bounds: cameraBounds,
+      profiles: AppState.instance.enabledProfiles,
+    );
+    area.cameras = cameras;
+    await OfflineAreaDownloader.saveCameras(cameras, directory);
+    debugPrint('Area ${area.id}: Downloaded ${cameras.length} cameras from expanded bounds');
+  }
+
+  /// Calculate expanded bounds that cover the entire tile area at minimum zoom
+  static LatLngBounds _calculateCameraBounds(LatLngBounds visibleBounds, int minZoom) {
+    final tiles = computeTileList(visibleBounds, minZoom, minZoom);
+    if (tiles.isEmpty) return visibleBounds;
+    
+    // Find the bounding box of all these tiles
+    double minLat = 90.0, maxLat = -90.0;
+    double minLon = 180.0, maxLon = -180.0;
+    
+    for (final tile in tiles) {
+      final tileBounds = tileToLatLngBounds(tile[1], tile[2], tile[0]);
+      
+      minLat = math.min(minLat, tileBounds.south);
+      maxLat = math.max(maxLat, tileBounds.north);
+      minLon = math.min(minLon, tileBounds.west);
+      maxLon = math.max(maxLon, tileBounds.east);
+    }
+    
+    return LatLngBounds(
+      LatLng(minLat, minLon),
+      LatLng(maxLat, maxLon),
+    );
+  }
+
+  /// Save tile bytes to disk
+  static Future<void> saveTileBytes(int z, int x, int y, String baseDir, List<int> bytes) async {
+    final dir = Directory('$baseDir/tiles/$z/$x');
+    await dir.create(recursive: true);
+    final file = File('${dir.path}/$y.png');
+    await file.writeAsBytes(bytes);
+  }
+
+  /// Save cameras to disk as JSON
+  static Future<void> saveCameras(List<OsmCameraNode> cams, String dir) async {
+    final file = File('$dir/cameras.json');
+    await file.writeAsString(jsonEncode(cams.map((c) => c.toJson()).toList()));
+  }
+}

lib/services/offline_areas/offline_area_service_tile_fetch.dart

@@ -1,19 +0,0 @@
-import 'dart:io';
-import 'dart:convert';
-import '../../models/osm_camera_node.dart';
-
-/// Disk IO utilities for offline area file management ONLY. No network requests should occur here.
-
-/// Save-to-disk for a tile that has already been fetched elsewhere.
-Future<void> saveTileBytes(int z, int x, int y, String baseDir, List<int> bytes) async {
-  final dir = Directory('$baseDir/tiles/$z/$x');
-  await dir.create(recursive: true);
-  final file = File('${dir.path}/$y.png');
-  await file.writeAsBytes(bytes);
-}
-
-/// Save-to-disk for cameras.json; called only by OfflineAreaService during area download
-Future<void> saveCameras(List<OsmCameraNode> cams, String dir) async {
-  final file = File('$dir/cameras.json');
-  await file.writeAsString(jsonEncode(cams.map((c) => c.toJson()).toList()));
-}

lib/services/offline_areas/offline_tile_utils.dart

@@ -56,6 +56,32 @@ List<int> latLonToTile(double lat, double lon, int zoom) {
   return [xtile, ytile];
 }
 
+/// Convert tile coordinates back to LatLng bounds
+LatLngBounds tileToLatLngBounds(int x, int y, int z) {
+  final n = pow(2, z);
+  
+  // Calculate bounds for this tile
+  final lonWest = x / n * 360.0 - 180.0;
+  final lonEast = (x + 1) / n * 360.0 - 180.0;
+  
+  // For latitude, we need to invert the mercator projection
+  final latNorthRad = atan(sinh(pi * (1 - 2 * y / n)));
+  final latSouthRad = atan(sinh(pi * (1 - 2 * (y + 1) / n)));
+  
+  final latNorth = latNorthRad * 180.0 / pi;
+  final latSouth = latSouthRad * 180.0 / pi;
+  
+  return LatLngBounds(
+    LatLng(latSouth, lonWest),   // SW corner
+    LatLng(latNorth, lonEast),   // NE corner
+  );
+}
+
+/// Hyperbolic sine function: sinh(x) = (e^x - e^(-x)) / 2
+double sinh(double x) {
+  return (exp(x) - exp(-x)) / 2;
+}
+
 LatLngBounds globalWorldBounds() {
   // Use slightly shrunken bounds to avoid tile index overflow at extreme coordinates
   return LatLngBounds(LatLng(-85.0, -179.9), LatLng(85.0, 179.9));

lib/services/offline_areas/world_area_manager.dart

@@ -0,0 +1,111 @@
+import 'dart:io';
+import 'package:flutter/foundation.dart';
+import 'package:flutter_map/flutter_map.dart' show LatLngBounds;
+import 'package:path_provider/path_provider.dart';
+
+import 'offline_area_models.dart';
+import 'offline_tile_utils.dart';
+import 'package:flock_map_app/dev_config.dart';
+
+/// Manages the world area (permanent offline area for base map)
+class WorldAreaManager {
+  static const String _worldAreaId = 'world';
+  static const String _worldAreaName = 'World Base Map';
+
+  /// Ensure world area exists and check if download is needed
+  static Future<OfflineArea> ensureWorldArea(
+    List<OfflineArea> areas,
+    Future<Directory> Function() getOfflineAreaDir,
+    Future<void> Function({
+      required String id,
+      required LatLngBounds bounds,
+      required int minZoom,
+      required int maxZoom,
+      required String directory,
+      String? name,
+    }) downloadArea,
+  ) async {
+    // Find existing world area
+    OfflineArea? world;
+    for (final area in areas) {
+      if (area.isPermanent) {
+        world = area;
+        break;
+      }
+    }
+
+    // Create world area if it doesn't exist
+    if (world == null) {
+      final appDocDir = await getOfflineAreaDir();
+      final dir = "${appDocDir.path}/$_worldAreaId";
+      world = OfflineArea(
+        id: _worldAreaId,
+        name: _worldAreaName,
+        bounds: globalWorldBounds(),
+        minZoom: kWorldMinZoom,
+        maxZoom: kWorldMaxZoom,
+        directory: dir,
+        status: OfflineAreaStatus.downloading,
+        isPermanent: true,
+      );
+      areas.insert(0, world);
+    }
+
+    // Check world area status and start download if needed
+    await _checkAndStartWorldDownload(world, downloadArea);
+    return world;
+  }
+
+  /// Check world area download status and start if needed
+  static Future<void> _checkAndStartWorldDownload(
+    OfflineArea world,
+    Future<void> Function({
+      required String id,
+      required LatLngBounds bounds,
+      required int minZoom,
+      required int maxZoom,
+      required String directory,
+      String? name,
+    }) downloadArea,
+  ) async {
+    if (world.status == OfflineAreaStatus.complete) return;
+
+    // Count existing tiles
+    final expectedTiles = computeTileList(
+      globalWorldBounds(), 
+      kWorldMinZoom, 
+      kWorldMaxZoom,
+    );
+    
+    int filesFound = 0;
+    for (final tile in expectedTiles) {
+      final file = File('${world.directory}/tiles/${tile[0]}/${tile[1]}/${tile[2]}.png');
+      if (file.existsSync()) {
+        filesFound++;
+      }
+    }
+
+    // Update world area stats
+    world.tilesTotal = expectedTiles.length;
+    world.tilesDownloaded = filesFound;
+    world.progress = (world.tilesTotal == 0) ? 0.0 : (filesFound / world.tilesTotal);
+    
+    if (filesFound == world.tilesTotal) {
+      world.status = OfflineAreaStatus.complete;
+      debugPrint('WorldAreaManager: World area download already complete.');
+    } else {
+      world.status = OfflineAreaStatus.downloading;
+      debugPrint('WorldAreaManager: Starting world area download. ${world.tilesDownloaded}/${world.tilesTotal} tiles found.');
+      
+      // Start download (fire and forget)
+      downloadArea(
+        id: world.id,
+        bounds: world.bounds,
+        minZoom: world.minZoom,
+        maxZoom: world.maxZoom,
+        directory: world.directory,
+        name: world.name,
+      );
+    }
+  }
+}