feat: MeshCore SAR - Flutter BLE mesh radio companion app

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/models/location_trail.dart

@@ -0,0 +1,106 @@
+import 'package:latlong2/latlong.dart';
+
+/// Represents a single point in a location trail
+class TrailPoint {
+  final LatLng position;
+  final DateTime timestamp;
+  final double? accuracy;
+  final double? speed;
+
+  TrailPoint({
+    required this.position,
+    required this.timestamp,
+    this.accuracy,
+    this.speed,
+  });
+
+  Map<String, dynamic> toJson() => {
+        'lat': position.latitude,
+        'lon': position.longitude,
+        'timestamp': timestamp.toIso8601String(),
+        'accuracy': accuracy,
+        'speed': speed,
+      };
+
+  factory TrailPoint.fromJson(Map<String, dynamic> json) {
+    return TrailPoint(
+      position: LatLng(json['lat'] as double, json['lon'] as double),
+      timestamp: DateTime.parse(json['timestamp'] as String),
+      accuracy: json['accuracy'] as double?,
+      speed: json['speed'] as double?,
+    );
+  }
+}
+
+/// Represents a location trail (breadcrumb trail) on the map
+class LocationTrail {
+  final String id;
+  final List<TrailPoint> points;
+  final DateTime startTime;
+  DateTime? endTime;
+  bool isActive;
+
+  LocationTrail({
+    required this.id,
+    List<TrailPoint>? points,
+    DateTime? startTime,
+    this.endTime,
+    this.isActive = true,
+  })  : points = points ?? [],
+        startTime = startTime ?? DateTime.now();
+
+  /// Add a new point to the trail
+  void addPoint(TrailPoint point) {
+    points.add(point);
+  }
+
+  /// Get total distance traveled in meters
+  double get totalDistance {
+    if (points.length < 2) return 0;
+
+    final distance = Distance();
+    double total = 0;
+
+    for (int i = 0; i < points.length - 1; i++) {
+      total += distance.as(
+        LengthUnit.Meter,
+        points[i].position,
+        points[i + 1].position,
+      );
+    }
+
+    return total;
+  }
+
+  /// Get duration of the trail
+  Duration get duration {
+    if (points.isEmpty) return Duration.zero;
+    final end = endTime ?? DateTime.now();
+    return end.difference(startTime);
+  }
+
+  /// Get list of LatLng points for rendering
+  List<LatLng> get latLngPoints => points.map((p) => p.position).toList();
+
+  Map<String, dynamic> toJson() => {
+        'id': id,
+        'points': points.map((p) => p.toJson()).toList(),
+        'startTime': startTime.toIso8601String(),
+        'endTime': endTime?.toIso8601String(),
+        'isActive': isActive,
+      };
+
+  factory LocationTrail.fromJson(Map<String, dynamic> json) {
+    return LocationTrail(
+      id: json['id'] as String,
+      points: (json['points'] as List)
+          .map((p) => TrailPoint.fromJson(p as Map<String, dynamic>))
+          .toList(),
+      startTime: DateTime.parse(json['startTime'] as String),
+      endTime: json['endTime'] != null
+          ? DateTime.parse(json['endTime'] as String)
+          : null,
+      isActive: json['isActive'] as bool? ?? true,
+    );
+  }
+}