feat: Add drawing functionality with line and rectangle support, including toolbar and layer integration

lib/providers/drawing_provider.dart

@@ -0,0 +1,259 @@
+import 'dart:convert';
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:latlong2/latlong.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+import '../models/map_drawing.dart';
+
+/// Drawing mode state
+enum DrawingMode {
+  none,
+  line,
+  rectangle,
+}
+
+/// Provider for managing map drawings
+class DrawingProvider with ChangeNotifier {
+  static const String _storageKey = 'map_drawings';
+
+  // Drawing state
+  DrawingMode _drawingMode = DrawingMode.none;
+  Color _selectedColor = DrawingColors.palette[0];
+
+  // Completed drawings
+  final List<MapDrawing> _drawings = [];
+
+  // In-progress drawing
+  MapDrawing? _currentDrawing;
+  List<LatLng> _currentLinePoints = [];
+  LatLng? _rectangleStartPoint;
+
+  // Getters
+  DrawingMode get drawingMode => _drawingMode;
+  Color get selectedColor => _selectedColor;
+  List<MapDrawing> get drawings => List.unmodifiable(_drawings);
+  MapDrawing? get currentDrawing => _currentDrawing;
+  List<LatLng> get currentLinePoints => List.unmodifiable(_currentLinePoints);
+  LatLng? get rectangleStartPoint => _rectangleStartPoint;
+  bool get isDrawing => _drawingMode != DrawingMode.none;
+
+  /// Initialize and load saved drawings
+  Future<void> initialize() async {
+    await _loadDrawings();
+  }
+
+  /// Set drawing mode
+  void setDrawingMode(DrawingMode mode) {
+    if (_drawingMode != mode) {
+      // Cancel any in-progress drawing when switching modes
+      _cancelCurrentDrawing();
+      _drawingMode = mode;
+      notifyListeners();
+    }
+  }
+
+  /// Set selected color
+  void setColor(Color color) {
+    _selectedColor = color;
+    notifyListeners();
+  }
+
+  /// Start drawing a line
+  void startLine(LatLng point) {
+    if (_drawingMode != DrawingMode.line) return;
+
+    _currentLinePoints = [point];
+    notifyListeners();
+  }
+
+  /// Add point to current line
+  void addLinePoint(LatLng point) {
+    if (_drawingMode != DrawingMode.line || _currentLinePoints.isEmpty) return;
+
+    _currentLinePoints.add(point);
+    notifyListeners();
+  }
+
+  /// Complete current line drawing
+  void completeLine() {
+    if (_drawingMode != DrawingMode.line || _currentLinePoints.length < 2) {
+      _cancelCurrentDrawing();
+      return;
+    }
+
+    final drawing = LineDrawing(
+      id: DateTime.now().millisecondsSinceEpoch.toString(),
+      color: _selectedColor,
+      createdAt: DateTime.now(),
+      points: List.from(_currentLinePoints),
+    );
+
+    _drawings.add(drawing);
+    _currentLinePoints = [];
+    _saveDrawings();
+    notifyListeners();
+  }
+
+  /// Start drawing a rectangle
+  void startRectangle(LatLng point) {
+    if (_drawingMode != DrawingMode.rectangle) return;
+
+    _rectangleStartPoint = point;
+    notifyListeners();
+  }
+
+  /// Update rectangle end point (for preview)
+  void updateRectangleEndPoint(LatLng endPoint) {
+    if (_drawingMode != DrawingMode.rectangle || _rectangleStartPoint == null) return;
+
+    // Create preview rectangle
+    _currentDrawing = RectangleDrawing(
+      id: 'preview',
+      color: _selectedColor,
+      createdAt: DateTime.now(),
+      topLeft: LatLng(
+        _rectangleStartPoint!.latitude > endPoint.latitude
+            ? endPoint.latitude
+            : _rectangleStartPoint!.latitude,
+        _rectangleStartPoint!.longitude < endPoint.longitude
+            ? _rectangleStartPoint!.longitude
+            : endPoint.longitude,
+      ),
+      bottomRight: LatLng(
+        _rectangleStartPoint!.latitude < endPoint.latitude
+            ? endPoint.latitude
+            : _rectangleStartPoint!.latitude,
+        _rectangleStartPoint!.longitude > endPoint.longitude
+            ? _rectangleStartPoint!.longitude
+            : endPoint.longitude,
+      ),
+    );
+    notifyListeners();
+  }
+
+  /// Complete current rectangle drawing
+  void completeRectangle(LatLng endPoint) {
+    if (_drawingMode != DrawingMode.rectangle || _rectangleStartPoint == null) {
+      _cancelCurrentDrawing();
+      return;
+    }
+
+    // Calculate top-left and bottom-right corners
+    final topLeft = LatLng(
+      _rectangleStartPoint!.latitude > endPoint.latitude
+          ? endPoint.latitude
+          : _rectangleStartPoint!.latitude,
+      _rectangleStartPoint!.longitude < endPoint.longitude
+          ? _rectangleStartPoint!.longitude
+          : endPoint.longitude,
+    );
+
+    final bottomRight = LatLng(
+      _rectangleStartPoint!.latitude < endPoint.latitude
+          ? endPoint.latitude
+          : _rectangleStartPoint!.latitude,
+      _rectangleStartPoint!.longitude > endPoint.longitude
+          ? _rectangleStartPoint!.longitude
+          : endPoint.longitude,
+    );
+
+    final drawing = RectangleDrawing(
+      id: DateTime.now().millisecondsSinceEpoch.toString(),
+      color: _selectedColor,
+      createdAt: DateTime.now(),
+      topLeft: topLeft,
+      bottomRight: bottomRight,
+    );
+
+    _drawings.add(drawing);
+    _rectangleStartPoint = null;
+    _currentDrawing = null;
+    _saveDrawings();
+    notifyListeners();
+  }
+
+  /// Cancel current drawing in progress
+  void _cancelCurrentDrawing() {
+    _currentLinePoints = [];
+    _rectangleStartPoint = null;
+    _currentDrawing = null;
+  }
+
+  /// Clear current drawing (public method)
+  void cancelCurrentDrawing() {
+    _cancelCurrentDrawing();
+    notifyListeners();
+  }
+
+  /// Remove a specific drawing
+  void removeDrawing(String id) {
+    _drawings.removeWhere((d) => d.id == id);
+    _saveDrawings();
+    notifyListeners();
+  }
+
+  /// Clear all drawings
+  void clearAllDrawings() {
+    _drawings.clear();
+    _cancelCurrentDrawing();
+    _saveDrawings();
+    notifyListeners();
+  }
+
+  /// Exit drawing mode
+  void exitDrawingMode() {
+    _cancelCurrentDrawing();
+    _drawingMode = DrawingMode.none;
+    notifyListeners();
+  }
+
+  /// Save drawings to persistent storage
+  Future<void> _saveDrawings() async {
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final jsonList = _drawings.map((d) => d.toJson()).toList();
+      final jsonString = jsonEncode(jsonList);
+      await prefs.setString(_storageKey, jsonString);
+    } catch (e) {
+      debugPrint('Error saving drawings: $e');
+    }
+  }
+
+  /// Load drawings from persistent storage
+  Future<void> _loadDrawings() async {
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final jsonString = prefs.getString(_storageKey);
+      if (jsonString == null) return;
+
+      final jsonList = jsonDecode(jsonString) as List<dynamic>;
+      _drawings.clear();
+
+      for (final json in jsonList) {
+        final drawing = MapDrawing.fromJson(json as Map<String, dynamic>);
+        if (drawing != null) {
+          _drawings.add(drawing);
+        }
+      }
+
+      notifyListeners();
+    } catch (e) {
+      debugPrint('Error loading drawings: $e');
+    }
+  }
+
+  /// Get the current preview drawing for rendering
+  MapDrawing? getPreviewDrawing() {
+    if (_drawingMode == DrawingMode.line && _currentLinePoints.length >= 2) {
+      return LineDrawing(
+        id: 'preview',
+        color: _selectedColor,
+        createdAt: DateTime.now(),
+        points: _currentLinePoints,
+      );
+    } else if (_drawingMode == DrawingMode.rectangle && _currentDrawing != null) {
+      return _currentDrawing;
+    }
+    return null;
+  }
+}