120 lines
3.9 KiB
Dart
120 lines
3.9 KiB
Dart
import 'dart:io';
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import 'package:get/get.dart';
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import 'package:intaleq_maps/intaleq_maps.dart';
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import 'dart:math' as math;
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import '../main.dart';
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import '../print.dart';
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class OfflineMapService {
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static final OfflineMapService instance = OfflineMapService._();
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OfflineMapService._();
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final _offlineRegionName = "UserRegion";
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bool _isDownloading = false;
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LatLng? _lastDownloadedCenter;
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/// Calculate bounding box for a given center and radius in km
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LatLngBounds _calculateBounds(LatLng center, double radiusKm) {
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const double earthRadius = 6371.0;
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// Latitude degrees per km
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double latDelta = (radiusKm / earthRadius) * (180 / math.pi);
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// Longitude degrees per km at given latitude
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double lngDelta = (radiusKm / earthRadius) *
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(180 / math.pi) /
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math.cos(center.latitude * math.pi / 180);
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return LatLngBounds(
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southwest:
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LatLng(center.latitude - latDelta, center.longitude - lngDelta),
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northeast:
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LatLng(center.latitude + latDelta, center.longitude + lngDelta),
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);
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}
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/// Downloads a specified radius around a coordinate
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Future<void> downloadRegion(LatLng center,
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{double radiusKm = 10.0,
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double minZoom = 6.0,
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double maxZoom = 15.0}) async {
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if (_isDownloading) return;
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// Avoid re-downloading if the user hasn't moved significantly (e.g. > 5km)
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if (_lastDownloadedCenter != null) {
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double distance = _calculateDistance(center, _lastDownloadedCenter!);
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if (distance < 5.0) return; // skip if close to previously downloaded
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}
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_isDownloading = true;
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try {
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final bounds = _calculateBounds(center, radiusKm);
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// Select style based on current theme
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final String styleStr =
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Get.isDarkMode ? "assets/style_dark.json" : "assets/style.json";
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// iOS native crash guard: MLNTilePyramidOfflineRegion does not support relative asset URLs.
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// We skip native offline registration on iOS if using local assets to ensure stability.
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if (Platform.isIOS && !styleStr.startsWith('http')) {
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Log.print(
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"ℹ️ Skipping native offline registration on iOS for asset-based style to prevent crash.");
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return;
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}
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final regionDefinition = OfflineRegionDefinition(
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bounds: bounds,
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mapStyleUrl: styleStr,
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minZoom: minZoom,
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maxZoom: maxZoom,
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);
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// We'll update the last downloaded center immediately
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_lastDownloadedCenter = center;
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// MapLibre standard API for offline downloads
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await downloadOfflineRegion(regionDefinition, metadata: {
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'name': '$_offlineRegionName-${center.latitude}-${center.longitude}',
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'downloadDate': DateTime.now().toIso8601String(),
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});
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// Reassurance log for the user
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Log.print("📍 Map Ready: Service is utilizing local tile cache.");
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Log.print(
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"✅ Offline Map Cached for Region: $center (radius: ${radiusKm}km, style: $styleStr)");
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} catch (e) {
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Log.print("⚠️ Offline Map Download Failed: $e");
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} finally {
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_isDownloading = false;
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}
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}
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/// Helper to calculate distance in km
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double _calculateDistance(LatLng p1, LatLng p2) {
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var p = 0.017453292519943295;
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var c = math.cos;
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var a = 0.5 -
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c((p2.latitude - p1.latitude) * p) / 2 +
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c(p1.latitude * p) *
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c(p2.latitude * p) *
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(1 - c((p2.longitude - p1.longitude) * p)) /
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2;
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return 12742 * math.asin(math.sqrt(a));
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}
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/// Clears all offline map regions and tiles from local storage
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Future<void> clearCache() async {
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try {
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Log.print("♻️ Purging MapLibre Offline Cache...");
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final List<OfflineRegion> regions = await getListOfRegions();
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for (var region in regions) {
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await deleteOfflineRegion(region.id);
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}
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Log.print("✅ Map cache cleared successfully. ${regions.length} regions removed.");
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} catch (e) {
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Log.print("⚠️ Failed to clear map cache: $e");
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}
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}
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}
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