chore(wip): upgrade dependencies, begin refactor

frontend/lib/old/structs/trip.dart

@@ -0,0 +1,142 @@
+// Represents a collection of landmarks that represent a journey
+// Different instances of a Trip can be saved and loaded by the user
+
+import 'dart:collection';
+import 'dart:convert';
+import 'dart:developer';
+
+import 'package:anyway/structs/landmark.dart';
+import 'package:flutter/foundation.dart';
+import 'package:geocoding/geocoding.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+
+class Trip with ChangeNotifier {
+  String uuid;
+  Duration totalTime;
+  LinkedList<Landmark> landmarks;
+  // could be empty as well
+  String? errorDescription;
+
+  Future<String> get cityName async {
+    List<double>? location = landmarks.firstOrNull?.location;
+    if (GeocodingPlatform.instance == null) {
+      return '$location';
+    } else if (location == null) {
+      return 'Unknown';
+    } else{
+      List<Placemark> placemarks = await placemarkFromCoordinates(location[0], location[1]);
+      return placemarks.first.locality ?? 'Unknown';
+    }
+  }
+
+  Future<int> landmarkPosition (Landmark landmark) async {
+    int i = 0;
+    for (Landmark l in landmarks) {
+      if (l.uuid == landmark.uuid) {
+        return i;
+      } else if (l.type != typeStart && l.type != typeFinish) {
+      i++;
+      }
+    }
+    return -1;
+  }
+
+
+  Trip({
+    this.uuid = 'pending',
+    this.totalTime = Duration.zero,
+    LinkedList<Landmark>? landmarks
+    // a trip can be created with no landmarks, but the list should be initialized anyway
+  }) : landmarks = landmarks ?? LinkedList<Landmark>();
+
+
+  factory Trip.fromJson(Map<String, dynamic> json) {
+    Trip trip = Trip(
+      uuid: json['uuid'],
+      totalTime: Duration(minutes: json['total_time']),
+    );
+
+    return trip;
+  }
+
+  void loadFromJson(Map<String, dynamic> json) {
+    uuid = json['uuid'];
+    totalTime = Duration(minutes: json['total_time']);
+    notifyListeners();
+  }
+
+  void addLandmark(Landmark landmark) {
+    landmarks.add(landmark);
+    notifyListeners();
+  }
+
+  void updateUUID(String newUUID) {
+    uuid = newUUID;
+    notifyListeners();
+  }
+
+  void removeLandmark (Landmark landmark) async {
+    Landmark? previous = landmark.previous;
+    Landmark? next = landmark.next;
+    landmarks.remove(landmark);
+    // removing the landmark means we need to recompute the time between the two adjoined landmarks
+    if (previous != null && next != null) {
+      // previous.next = next happens automatically since we are using a LinkedList
+      totalTime -= previous.tripTime ?? Duration.zero;
+      previous.tripTime = null;
+      // TODO
+    }
+    totalTime -= landmark.tripTime ?? Duration.zero;
+
+    notifyListeners();
+  }
+
+  void updateError(String error) {
+    errorDescription = error;
+    notifyListeners();
+  }
+
+  void notifyUpdate(){
+    notifyListeners();
+  }
+
+  factory Trip.fromPrefs(SharedPreferences prefs, String uuid) {
+    String? content = prefs.getString('trip_$uuid');
+    Map<String, dynamic> json = jsonDecode(content!);
+    Trip trip = Trip.fromJson(json);
+    String? firstUUID = json['first_landmark_uuid'];
+    log('Loading trip $uuid with first landmark $firstUUID');
+    LinkedList<Landmark> landmarks = readLandmarks(prefs, firstUUID);
+    trip.landmarks = landmarks;
+    return trip;
+  }
+
+
+  Map<String, dynamic> toJson() => {
+    'uuid': uuid,
+    'total_time': totalTime.inMinutes,
+    'first_landmark_uuid': landmarks.first.uuid
+  };
+
+
+  void toPrefs(SharedPreferences prefs){
+    Map<String, dynamic> json = toJson();
+    log('Saving trip $uuid : $json');
+    prefs.setString('trip_$uuid', jsonEncode(json));
+    for (Landmark landmark in landmarks) {
+      landmarkToPrefs(prefs, landmark, landmark.next);
+    }
+  }
+}
+
+
+// Helper
+LinkedList<Landmark> readLandmarks(SharedPreferences prefs, String? firstUUID) {
+  LinkedList<Landmark> landmarks = LinkedList<Landmark>();
+  while (firstUUID != null) {
+    var (head, nextUUID) = getLandmarkFromPrefs(prefs, firstUUID);
+    landmarks.add(head);
+    firstUUID = nextUUID;
+  }
+  return landmarks;
+}