Add GPX export functionality and related UI components

lib/utils/gpx_export.dart

@@ -0,0 +1,165 @@
+import 'package:flutter/foundation.dart';
+import 'package:gpx/gpx.dart';
+import 'package:meshcore_open/connector/meshcore_connector.dart';
+import 'package:meshcore_open/connector/meshcore_protocol.dart';
+import 'package:path_provider/path_provider.dart';
+import 'dart:io';
+
+import 'package:share_plus/share_plus.dart';
+
+class ContactExport {
+  final String name;
+  final double lat;
+  final double lon;
+  final String desc;
+  final double? ele;
+
+  ContactExport({
+    required this.name,
+    required this.lat,
+    required this.lon,
+    required this.desc,
+    this.ele,
+  });
+}
+
+const int GpxExportFailed = -1;
+const int GpxExportSuccess = 1;
+const int GpxExportNoContacts = 2;
+const int GpxExportCancelled = 3;
+const int GpxExportNotAvailable = 4;
+
+class GpxExport {
+  MeshCoreConnector _connector;
+  List<ContactExport> _contacts = [];
+
+  GpxExport(this._connector);
+
+  void _addContact(String name, double lat, double lon, String desc, [double? ele]) {
+    _contacts.add(ContactExport(
+      name: name.trim(),
+      lat: lat,
+      lon: lon,
+      desc: desc.trim(),
+      ele: ele,
+    ));
+  }
+
+  void addRepeaters() {
+    final contacts = _connector.contacts;
+    final repeaters = contacts.where((c) => c.type == advTypeRepeater || c.type == advTypeRoom).toList();
+    for (var repeater in repeaters) {
+      if (repeater.latitude == null || repeater.longitude == null) {
+        continue;
+      }
+      _addContact(
+        repeater.name,
+        repeater.latitude ?? 0.0,
+        repeater.longitude ?? 0.0,
+        "Type: ${repeater.typeLabel}\nPublic Key: ${repeater.publicKeyHex}",
+      );
+    }
+  }
+
+  void addContacts() {
+    final contacts = _connector.contacts;
+    final repeaters = contacts.where((c) => c.type == advTypeChat).toList();
+    for (var repeater in repeaters) {
+      if (repeater.latitude == null || repeater.longitude == null) {
+        continue;
+      }
+      _addContact(
+        repeater.name,
+        repeater.latitude ?? 0.0,
+        repeater.longitude ?? 0.0,
+        "Type: ${repeater.typeLabel}\nPublic Key: ${repeater.publicKeyHex}",
+      );
+    }
+  }
+
+  void addAll() {
+    final contacts = _connector.contacts;
+     for (var repeater in contacts.toList()) {
+      if (repeater.latitude == null || repeater.longitude == null) {
+        continue;
+      }
+      _addContact(
+        repeater.name,
+        repeater.latitude ?? 0.0,
+        repeater.longitude ?? 0.0,
+        "Type: ${repeater.typeLabel}\nPublic Key: ${repeater.publicKeyHex}",
+      );
+    }
+  }
+
+  Future<int> exportGPX() async {
+    if (_contacts.isEmpty) {
+      debugPrint("No repeaters to export – nothing to share.");
+      return GpxExportNoContacts;
+    }
+
+    try {
+      // 1. Build GPX content (your existing logic – unchanged here)
+      final gpx = Gpx()
+        ..version = '1.1'
+        ..creator = 'meshcore-open Repeater Exporter'
+        ..metadata = Metadata(
+            name: 'Meshcore Repeaters',
+            desc: 'Repeater & room locations exported from meshcore-open',
+            time: DateTime.now().toUtc(),
+          );
+
+      gpx.wpts = _contacts.map((c) => Wpt(
+            lat: c.lat,
+            lon: c.lon,
+            ele: c.ele,
+            name: c.name,
+            desc: c.desc,
+          )).toList();
+
+      final xml = GpxWriter().asString(gpx, pretty: true);
+
+      // 2. Save to file
+      final dir = await getApplicationDocumentsDirectory();
+      final timestamp = DateTime.now().toUtc().toIso8601String()
+          .replaceAll(':', '-')
+          .replaceAll('.', '-')
+          .split('T')
+          .join('_');
+      final path = '${dir.path}/meshcore_repeaters_$timestamp.gpx';
+
+      final file = File(path);
+      await file.writeAsString(xml);
+
+      // 3. Modern share call (2025+ style)
+      final result = await SharePlus.instance.share(
+        ShareParams(
+          text: 'Repeater locations exported from meshcore-open app as GPX file.',
+          subject: 'Meshcore Repeaters GPX Export',
+          files: [XFile(path)],
+          // Optional: sharePositionOrigin: ... (if you want iPad popover positioning)
+        ),
+      );
+
+      // 4. Handle result
+      switch (result.status) {
+        case ShareResultStatus.success:
+          debugPrint('Share successful – user completed the action.');
+          return GpxExportSuccess;
+        case ShareResultStatus.dismissed:
+          debugPrint('Share sheet was dismissed / cancelled by user.');
+          return GpxExportCancelled;
+        case ShareResultStatus.unavailable:
+          debugPrint('Sharing is not available on this platform / context.');
+          return GpxExportNotAvailable;
+      }
+
+      // Optional cleanup (uncomment if you don't want to keep the file)
+      // await file.delete();
+    } catch (e, stack) {
+      debugPrint('Export or share failed: $e\n$stack');
+      // → here you could show a SnackBar / AlertDialog in real UI code
+    }
+    return GpxExportFailed;
+  }
+}