Improvements to drawing mode

lib/helpers/draw_style.dart

@@ -35,6 +35,7 @@ class DrawingStyle {
 
 const kTypeStyles = <String, DrawingStyle>{
   "scribble": DrawingStyle(color: Colors.white, thin: true),
+  "eraser": DrawingStyle(color: Colors.black54),
   "road": DrawingStyle(color: Colors.white70),
   "track": DrawingStyle(color: Colors.white70, dashed: true),
   "footway": DrawingStyle(color: Colors.red),
@@ -52,6 +53,8 @@ final kTypeStylesReversed =
     kTypeStyles.map((key, value) => MapEntry(value, key));
 
 const kUnknownStyle = DrawingStyle(color: Colors.grey);
+const kToolEraser = "eraser";
+const kToolScribble = "scribble";
 
 const kStyleIcons = <String, IconData>{
   "eraser": Icons.cleaning_services,

lib/helpers/geometry.dart

@@ -1,3 +1,5 @@
+import 'dart:math' show sqrt, pow;
+
 import 'package:every_door/helpers/equirectangular.dart';
 import 'package:latlong2/latlong.dart' show LatLng;
 import 'package:flutter_map/flutter_map.dart' show LatLngBounds;
@@ -191,15 +193,19 @@ class MultiPolygon implements Polygon {
 }
 
 class LineString extends Geometry {
-  final List<LatLng> _nodes;
+  final List<LatLng> nodes;
+  LatLngBounds? _cachedBounds;
 
-  LineString(Iterable<LatLng> nodes) : _nodes = List.of(nodes) {
-    if (_nodes.length < 2)
+  LineString(Iterable<LatLng> nodes) : nodes = List.of(nodes, growable: false) {
+    if (this.nodes.length < 2)
       throw GeometryException('A path must have at least two nodes.');
   }
 
   @override
-  LatLngBounds get bounds => LatLngBounds.fromPoints(_nodes);
+  LatLngBounds get bounds {
+    _cachedBounds ??= LatLngBounds.fromPoints(nodes);
+    return _cachedBounds!;
+  }
 
   @override
   // TODO: proper center on the line
@@ -208,12 +214,67 @@ class LineString extends Geometry {
   double getLengthInMeters() {
     double length = 0.0;
     final distance = DistanceEquirectangular();
-    for (int i = 1; i < _nodes.length; i++) {
-      length += distance(_nodes[i - 1], _nodes[i]);
+    for (int i = 1; i < nodes.length; i++) {
+      length += distance(nodes[i - 1], nodes[i]);
     }
     return length;
   }
 
+  LatLng closestPoint(LatLng point) {
+    num minDist = double.infinity;
+    LatLng point = nodes[0];
+
+    for (int i = 1; i < nodes.length; i++) {
+      final x = point.longitude;
+      final y = point.latitude;
+      final x1 = nodes[i - 1].longitude;
+      final y1 = nodes[i - 1].latitude;
+      final x2 = nodes[i].longitude;
+      final y2 = nodes[i].latitude;
+      final dx = x2 - x1;
+      final dy = y2 - y1;
+
+      final dot = (x - x1) * dx + (y - y1) * dy;
+      final len = dx * dx + dy * dy;
+      double t = -1;
+      if (len > 0.0) t = dot / len;
+
+      double ix;
+      double iy;
+      if (t <= 0)
+        (ix, iy) = (x1, y1);
+      else if (t >= 1)
+        (ix, iy) = (x2, y2);
+      else
+        (ix, iy) = (x1 + t * dx, y1 + t * dy);
+
+      final d = pow(x - ix, 2) + pow(y - iy, 2);
+      if (d < minDist) {
+        minDist = d;
+        point = LatLng(iy, ix);
+      }
+    }
+
+    return point;
+  }
+
+  double distanceToPoint(LatLng point, {bool inMeters = true}) {
+    // I am lazy hence this is a StackOverflow-inspired code.
+    final closest = closestPoint(point);
+    if (inMeters) {
+      final distance = DistanceEquirectangular();
+      return distance(point, closest);
+    } else {
+      return sqrt(pow(point.longitude - closest.longitude, 2) +
+          pow(point.latitude - closest.latitude, 2));
+    }
+  }
+
+  bool intersects(LineString other) {
+    if (!bounds.isOverlapping(other.bounds)) return false;
+    return true; // TODO
+  }
+
   @override
-  String toString() => 'LineString($_nodes)';
+  String toString() => 'LineString($nodes)';
 }

lib/models/note.dart

@@ -1,5 +1,6 @@
 import 'package:every_door/constants.dart';
 import 'package:every_door/helpers/draw_style.dart';
+import 'package:every_door/helpers/geometry.dart';
 import 'package:latlong2/latlong.dart' show LatLng;
 import 'package:proximity_hash/geohash.dart';
 import 'dart:convert' show json;
@@ -218,18 +219,18 @@ class OsmNote extends BaseNote {
 
 class MapDrawing extends BaseNote {
   static const dbType = 3;
-  final List<LatLng> coordinates;
+  final LineString path;
   final String? author;
   final String pathType;
 
   MapDrawing({
     super.id,
-    required this.coordinates,
+    required this.path,
     required this.pathType,
     this.author,
     super.created,
     super.deleting,
-  }) : super(type: dbType, location: coordinates[coordinates.length >> 1]);
+  }) : super(type: dbType, location: path.nodes[path.nodes.length >> 1]);
 
   DrawingStyle get style => kTypeStyles[pathType] ?? kUnknownStyle;
 
@@ -244,7 +245,7 @@ class MapDrawing extends BaseNote {
       id: data['id'],
       pathType: data['path_type'],
       author: data['author'],
-      coordinates: coords,
+      path: LineString(coords),
       created: DateTime.fromMillisecondsSinceEpoch(data['created']),
       deleting: data['is_deleting'] == 1,
     );
@@ -256,8 +257,7 @@ class MapDrawing extends BaseNote {
       ...super.toJson(),
       'path_type': pathType,
       'author': author,
-      'coords':
-          coordinates.map((c) => '${c.latitude};${c.longitude}').join('|'),
+      'coords': path.nodes.map((c) => '${c.latitude};${c.longitude}').join('|'),
     };
   }
 

lib/providers/notes.dart

@@ -3,6 +3,7 @@ import 'dart:ui';
 import 'package:every_door/constants.dart';
 import 'package:every_door/helpers/circle_bounds.dart';
 import 'package:every_door/helpers/draw_style.dart';
+import 'package:every_door/helpers/geometry.dart';
 import 'package:every_door/helpers/osm_api_converters.dart';
 import 'package:every_door/models/note.dart';
 import 'package:every_door/providers/api_status.dart';
@@ -25,13 +26,14 @@ final notesProvider = ChangeNotifierProvider((ref) => NotesProvider(ref));
 final ownScribblesProvider =
     StateNotifierProvider<OwnScribblesController, bool>(
         (_) => OwnScribblesController());
+final currentPaintToolProvider = StateProvider<String>((_) => kToolScribble);
 
 class NotesProvider extends ChangeNotifier {
   static final _logger = Logger('NotesProvider');
 
   final Ref _ref;
   int length = 0;
-  List<(bool deleted, BaseNote note)> _undoStack = [];
+  final List<(bool deleted, MapDrawing note)> _undoStack = [];
   int _undoStackLast = 0;
 
   bool get haveChanges => length > 0;
@@ -191,7 +193,7 @@ class NotesProvider extends ChangeNotifier {
         notes.add(MapDrawing(
           id: noteData['id'],
           author: noteData['username'],
-          coordinates: points.map((ll) => LatLng(ll[1], ll[0])).toList(),
+          path: LineString(points.map((ll) => LatLng(ll[1], ll[0]))),
           pathType: noteData['style'],
         ));
       } else if (noteData.containsKey('location')) {
@@ -251,7 +253,7 @@ class NotesProvider extends ChangeNotifier {
             'color': _colorToHex(note.style.color),
             'dashed': note.style.dashed,
             'thin': note.style.stroke < DrawingStyle.kDefaultStroke,
-            'points': note.coordinates
+            'points': note.path.nodes
                 .map((ll) => [ll.longitude, ll.latitude])
                 .toList(),
           });
@@ -427,6 +429,9 @@ class NotesProvider extends ChangeNotifier {
   Future<void> deleteNote(BaseNote note,
       {bool notify = true, bool addUndo = true}) async {
     final database = await _ref.read(databaseProvider).database;
+    // TODO: NOOOOO THIS DELETES FROM DATABASE
+    // TODO: Set deletion flag and do this properly. Also rethink the undo stack.
+    // TODO: Undo stack should group deletions.
     await database.delete(
       BaseNote.kTableName,
       where: 'id = ?',
@@ -440,7 +445,7 @@ class NotesProvider extends ChangeNotifier {
   bool get redoIsEmpty => _undoStackLast >= _undoStack.length;
 
   _addToUndoStack(BaseNote note, bool deleted) {
-    if (note is OsmNote) return;
+    if (note is !MapDrawing) return;
     // Add it to undo stack, discarding the top if needed.
     if (_undoStackLast < _undoStack.length)
       _undoStack.removeRange(_undoStackLast, _undoStack.length);

lib/screens/editor/map_chooser.dart

@@ -162,7 +162,7 @@ class _MapChooserPageState extends ConsumerState<MapChooserPage> {
             polylines: [
               for (final drawing in nearestNotes.whereType<MapDrawing>())
                 Polyline(
-                  points: drawing.coordinates,
+                  points: drawing.path.nodes,
                   color: drawing.style.color,
                   strokeWidth: drawing.style.stroke / 3,
                   isDotted: drawing.style.dashed,

lib/screens/editor/note.dart

@@ -197,6 +197,16 @@ class _NoteEditorPaneState extends ConsumerState<NoteEditorPane> {
                     message = value.trim();
                   },
                 ),
+                if (widget.note == null)
+                  SwitchListTile(
+                    value: isOsmNote,
+                    title: Text('Publish to OSM'),
+                    onChanged: (value) {
+                      setState(() {
+                        isOsmNote = !isOsmNote;
+                      });
+                    },
+                  ),
                 Row(
                   children: [
                     if (widget.note != null)