split into frontend and backend

frontend/lib/modules/overview.dart

@@ -0,0 +1,153 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_map/flutter_map.dart';
+import 'package:sliding_up_panel/sliding_up_panel.dart';
+import 'package:latlong2/latlong.dart';
+import 'package:geocoding/geocoding.dart';
+import 'package:geocode/geocode.dart';
+import 'dart:async';
+
+import 'package:fast_network_navigation/modules/navigation.dart';
+
+class MapPage extends StatefulWidget {
+  @override
+  _MapPageState createState() => _MapPageState();
+}
+class Debounce {
+  Duration delay;
+  Timer? _timer;
+
+  Debounce(
+    this.delay,
+  );
+
+  call(void Function() callback) {
+    _timer?.cancel();
+    _timer = Timer(delay, callback);
+  }
+
+  dispose() {
+    _timer?.cancel();
+  }
+}
+
+
+class _MapPageState extends State<MapPage> {
+  GeoCode geoCode = GeoCode();
+  final mapController = MapController();
+  String _currentCityName = "...";
+  final Debounce _debounce = Debounce(Duration(seconds: 3));
+
+  void _setCurrentCityName() async {
+    if (mapController.camera.zoom < 9) {
+      return; // Don't bother if the view is too wide
+    }
+    var currentCoordinates = mapController.camera.center;
+    String? city;
+    
+    try{
+      List<Placemark> placemarks = await placemarkFromCoordinates(currentCoordinates.latitude, currentCoordinates.longitude);
+      city = placemarks[0].locality.toString();
+    } catch (e) {
+      debugPrint("Error: $e");
+      try {
+        Address address = await geoCode.reverseGeocoding(latitude: currentCoordinates.latitude, longitude: currentCoordinates.longitude);
+        
+        if (address.city == null || address.city.toString().contains("Throttled!")){
+          throw Exception("Probably rate limited");
+        }
+        city = address.city.toString();
+      } catch (e) {
+        debugPrint("Error: $e");
+
+      }
+    }
+    if (city != null) {
+      setState(() {
+        _currentCityName = city!;
+      });
+    } else {
+      _debounce(() async {_setCurrentCityName();});
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final ThemeData theme = Theme.of(context);
+    return SlidingUpPanel(
+        renderPanelSheet: false,
+        panel: _floatingPanel(theme),
+        collapsed: _floatingCollapsed(theme),
+        body: FlutterMap(
+          mapController: mapController,
+          options: MapOptions(
+            initialZoom: 11,
+            initialCenter: LatLng(51.509364, -0.128928),
+            onMapReady: () {
+                mapController.mapEventStream.listen((evt) {_debounce(() async {_setCurrentCityName();});});
+                // And any other `MapController` dependent non-movement methods
+            },
+
+          ),
+          children: [
+            openStreetMapTileLayer,
+          ],
+        ),
+    );
+  }
+
+  Widget _floatingCollapsed(ThemeData theme){
+    return Container(
+      decoration: BoxDecoration(
+        color: theme.canvasColor,
+        borderRadius: BorderRadius.only(topLeft: Radius.circular(24.0), topRight: Radius.circular(24.0)),
+      ),
+      
+      child: Greeting(theme)
+    );
+  }
+
+  Widget _floatingPanel(ThemeData theme){
+    return Container(
+      decoration: BoxDecoration(
+        color: Colors.white,
+        borderRadius: BorderRadius.all(Radius.circular(24.0)),
+        boxShadow: [
+          BoxShadow(
+            blurRadius: 20.0,
+            color: theme.shadowColor,
+          ),
+        ]
+      ),
+      child: Center(
+        child: Padding(
+        padding: EdgeInsets.all(8.0),
+        child: SingleChildScrollView(
+          child: Column(
+            children: <Widget>[
+              Greeting(theme),
+              Text("Got a lot to do today! Here is a rundown:"),
+              ...loadDestinations(),
+            ],
+          ),
+        ),
+      ),
+    ),
+    );
+  }
+
+  Widget Greeting (ThemeData theme) {
+    return Center(
+        child: Text(
+            "Explore ${_currentCityName}",
+          style: TextStyle(color: theme.primaryColor, fontSize: 24.0, fontWeight: FontWeight.bold),
+        ),
+      );
+  }
+}
+
+TileLayer get openStreetMapTileLayer => TileLayer(
+  urlTemplate: 'https://tile.openstreetmap.org/{z}/{x}/{y}.png',
+  userAgentPackageName: 'flutter_map',
+);
+
+// Add a pin to the map