ui improvements for trips and landmarks

frontend/lib/structs/landmark.dart

@@ -3,6 +3,14 @@ import 'dart:convert';
 
 import 'package:shared_preferences/shared_preferences.dart';
 
+
+const LandmarkType museum = LandmarkType(name: 'Museum');
+const LandmarkType monument = LandmarkType(name: 'Monument');
+const LandmarkType park = LandmarkType(name: 'Park');
+const LandmarkType restaurant = LandmarkType(name: 'Restaurant');
+const LandmarkType shop = LandmarkType(name: 'Shop');
+
+
 final class Landmark extends LinkedListEntry<Landmark>{
   // A linked node of a list of Landmarks
   final String uuid;
@@ -55,11 +63,12 @@ final class Landmark extends LinkedListEntry<Landmark>{
       final imageURL = json['image_url'] as String?;
       final description = json['description'] as String?;
       var duration = Duration(minutes: json['duration'] ?? 0) as Duration?;
-      if (duration == const Duration()) {duration = null;};
+      // if (duration == const Duration()) {duration = null;};
       final visited = json['visited'] as bool?;
+      var tripTime = Duration(minutes: json['time_to_reach_next'] ?? 0) as Duration?;
       
       return Landmark(
-        uuid: uuid, name: name, location: locationFixed, type: typeFixed, isSecondary: isSecondary, imageURL: imageURL, description: description, duration: duration, visited: visited);
+        uuid: uuid, name: name, location: locationFixed, type: typeFixed, isSecondary: isSecondary, imageURL: imageURL, description: description, duration: duration, visited: visited, tripTime: tripTime);
     } else {
       throw FormatException('Invalid JSON: $json');
     }
@@ -81,7 +90,8 @@ final class Landmark extends LinkedListEntry<Landmark>{
     'image_url': imageURL,
     'description': description,
     'duration': duration?.inMinutes,
-    'visited': visited
+    'visited': visited,
+    'trip_time': tripTime?.inMinutes,
   };
 }