some preference improvements

frontend/lib/structs/destination.dart

@@ -1,31 +1,62 @@
+import "package:flutter/material.dart";
 
 class Destination {
   final double latitude;
   final double longitude;
   final String name;
   final String description;
-  final DestinationType type;
+  // final DestinationType type;
   final Duration duration;
   final bool visited;
 
-  Destination({
+  const Destination({
     required this.latitude,
     required this.longitude,
     required this.name,
     required this.description,
-    required this.type,
+    // required this.type,
     required this.duration,
     required this.visited,
   });
+
+  factory Destination.fromJson(Map<String, dynamic> json) {
+  return switch (json) {
+    {
+      'lat': double latitude,
+      'lon': double longitude,
+      'name': String name,
+      'description': String description,
+      // 'type': String type,
+      'duration': int duration,
+      'visited': bool visited
+
+    } =>
+      Destination(
+        latitude: latitude,
+        longitude: longitude,
+        name: name,
+        description: description,
+        // type: "DestinationType.values.firstWhere((element) => element.name == type)",
+        duration: Duration(minutes: duration),
+        visited: visited
+      ),
+    _ => throw const FormatException('Failed to load destination.'),
+  };
+}
+
 }
 
 
 class DestinationType {
   final String name;
   final String description;
+  final Icon icon;
   
-  DestinationType({
+  const DestinationType({
     required this.name,
     required this.description,
+    required this.icon,
   });
 }
+
+

frontend/lib/structs/preferences.dart

@@ -0,0 +1,82 @@
+import 'package:flutter/material.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+
+class SinglePreference {
+  String name;
+  String description;
+  int value;
+  Icon icon;
+  String key;
+
+  SinglePreference({
+    required this.name,
+    required this.description,
+    required this.value,
+    required this.icon,
+    required this.key,
+  });
+}
+
+
+class UserPreferences {
+  List<SinglePreference> preferences = [
+    SinglePreference(
+      name: "Sightseeing",
+      description: "How much do you like sightseeing?",
+      value: 0,
+      icon: Icon(Icons.church),
+      key: "sightseeing",
+    ),
+    SinglePreference(
+      name: "Shopping",
+      description: "How much do you like shopping?",
+      value: 0,
+      icon: Icon(Icons.shopping_bag),
+      key: "shopping",
+    ),
+    SinglePreference(
+      name: "Foods & Drinks",
+      description: "How much do you like eating?",
+      value: 0,
+      icon: Icon(Icons.restaurant),
+      key: "eating",
+    ),
+    SinglePreference(
+      name: "Nightlife",
+      description: "How much do you like nightlife?",
+      value: 0,
+      icon: Icon(Icons.wine_bar),
+      key: "nightlife",
+    ),
+    SinglePreference(
+      name: "Nature",
+      description: "How much do you like nature?",
+      value: 0,
+      icon: Icon(Icons.landscape),
+      key: "nature",
+    ),
+    SinglePreference(
+      name: "Culture",
+      description: "How much do you like culture?",
+      value: 0,
+      icon: Icon(Icons.palette),
+      key: "culture",
+    ),
+  ];
+
+
+  void save() async {
+    SharedPreferences prefs = await SharedPreferences.getInstance();
+    for (SinglePreference pref in preferences) {
+      prefs.setInt(pref.key, pref.value);
+    }
+  }
+
+  void load() async {
+    SharedPreferences prefs = await SharedPreferences.getInstance();
+    for (SinglePreference pref in preferences) {
+      pref.value = prefs.getInt(pref.key) ?? 0;
+    }
+  }
+}

frontend/lib/structs/route.dart

@@ -0,0 +1,14 @@
+import "package:fast_network_navigation/structs/destination.dart";
+
+
+class Route {
+  final String name;
+  final Duration duration;
+  final List<Destination> destinations;
+  
+  Route({
+    required this.name,
+    required this.duration,
+    required this.destinations
+  });
+}