quite a few UX improvements

frontend/lib/modules/current_trip_loading_indicator.dart

@@ -140,9 +140,10 @@ class _AnimatedDotsTextState extends State<AnimatedDotsText> {
   @override
   Widget build(BuildContext context) {
     String dots = '.' * dotCount;
-    return Text(
+    return AutoSizeText(
       '${widget.baseText}$dots',
       style: widget.style,
+      maxLines: 2,
     );
   }
 }

frontend/lib/modules/current_trip_summary.dart

@@ -15,8 +15,9 @@ class CurrentTripSummary extends StatefulWidget {
 
 class _CurrentTripSummaryState extends State<CurrentTripSummary> {
   @override
-  Widget build(BuildContext context) {
+  Widget build(BuildContext context) => ListenableBuilder(
-    return Padding(
+    listenable: widget.trip,
+    builder: (context, child) => Padding(
       padding: const EdgeInsets.symmetric(vertical: 10, horizontal: 20),
       child: Row(
         mainAxisAlignment: MainAxisAlignment.spaceBetween,
@@ -25,18 +26,18 @@ class _CurrentTripSummaryState extends State<CurrentTripSummary> {
             children: [
               const Icon(Icons.flag, size: 20),
               const Padding(padding: EdgeInsets.only(right: 10)),
-              Text('Stops: ${widget.trip.landmarks.length}', style: Theme.of(context).textTheme.bodyLarge),
+              Text('${widget.trip.landmarks.length} stops', style: Theme.of(context).textTheme.bodyLarge),
             ]
           ),
           Row(
             children: [
               const Icon(Icons.hourglass_bottom_rounded, size: 20),
               const Padding(padding: EdgeInsets.only(right: 10)),
-              Text('Duration: ${widget.trip.totalTime} minutes', style: Theme.of(context).textTheme.bodyLarge),
+              Text('${widget.trip.totalTime.inHours}h ${widget.trip.totalTime.inMinutes.remainder(60)}min', style: Theme.of(context).textTheme.bodyLarge),
             ]
           ),
         ],
       )
-    );
+    )
-  }
+  );
 }

frontend/lib/modules/new_trip_map.dart

@@ -78,6 +78,7 @@ class _NewTripMapState extends State<NewTripMap> {
     widget.trip.addListener(updateTripDetails);
     Future<SharedPreferences> preferences = SharedPreferences.getInstance();
 
+
     return FutureBuilder(
       future: preferences,
       builder: (context, snapshot) {

frontend/lib/modules/onbarding_agreement_card.dart

@@ -1,3 +1,4 @@
+import 'package:anyway/structs/agreement.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_markdown/flutter_markdown.dart';
 
@@ -26,7 +27,6 @@ class OnboardingAgreementCard extends StatefulWidget {
 }
 
 class _OnboardingAgreementCardState extends State<OnboardingAgreementCard> {
-  bool agreed = false;
   @override
   Widget build(BuildContext context) {
     return Padding(
@@ -39,21 +39,42 @@ class _OnboardingAgreementCardState extends State<OnboardingAgreementCard> {
           Row(
             mainAxisAlignment: MainAxisAlignment.center,
             children: [
-              Checkbox(
+              // The checkbox of the agreement
-                value: agreed,
+              FutureBuilder(
-                onChanged: (value) {
+                future: getAgreement(),
-                  setState(() {
+                builder: (context, snapshot) {
-                    agreed = value!;
+                  bool agreed = false;
-                    widget.onAgreementChanged(value);
+                  if (snapshot.connectionState == ConnectionState.done) {
-                  });
+                    if (snapshot.hasData) {
+                      Agreement agreement = snapshot.data!;
+                      agreed = agreement.agreed;
+                    } else {
+                      agreed = false;
+                    }
+                  } else {
+                    agreed = false;
+                  }
+                  return Checkbox(
+                    value: agreed,
+                    onChanged: (value) {
+                      setState(() {
+                        widget.onAgreementChanged(value!);
+                      });
+                      saveAgreement(value!);
+                    },
+                  );
                 },
               ),
+              
+              // The text of the agreement
               Text(
                 "I agree to the ",
                 style: Theme.of(context).textTheme.bodyMedium!.copyWith(
                   color: Colors.white,
                 ),
               ),
+              
+              // The clickable text of the agreement that shows the agreement text
               GestureDetector(
                 onTap: () {
                   // show a dialog with the agreement text

frontend/lib/modules/step_between_landmarks.dart

@@ -48,7 +48,7 @@ class _StepBetweenLandmarksState extends State<StepBetweenLandmarks> {
             children: [
               const Icon(Icons.directions_walk),
               Text(
-                time == null ? "" : "About $time min",
+                time == null ? "" : "$time min",
                 style: const TextStyle(fontSize: 10)
               ),
             ],

frontend/lib/pages/new_trip_preferences.dart

@@ -1,5 +1,6 @@
 import 'package:anyway/layouts/scaffold.dart';
 import 'package:anyway/modules/new_trip_button.dart';
+import 'package:anyway/structs/landmark.dart';
 import 'package:anyway/structs/preferences.dart';
 import 'package:anyway/structs/trip.dart';
 import 'package:flutter/cupertino.dart';
@@ -20,6 +21,14 @@ class _NewTripPreferencesPageState extends State<NewTripPreferencesPage> with Sc
 
   @override
   Widget build(BuildContext context) {
+    // Ensure that the trip is "empty" save for the start landmark
+    // This is necessary because users can swipe back to this page even after the trip has been created
+    if (widget.trip.landmarks.length > 1) {
+      Landmark start = widget.trip.landmarks.first;
+      widget.trip.landmarks.clear();
+      widget.trip.addLandmark(start);
+    }
+
     return mainScaffold(
       context,
       child: Scaffold(

frontend/lib/pages/no_trips_page.dart

@@ -0,0 +1,50 @@
+import 'package:anyway/pages/new_trip_location.dart';
+import 'package:flutter/material.dart';
+
+import 'package:anyway/layouts/scaffold.dart';
+class NoTripsPage extends StatefulWidget {
+  const NoTripsPage({super.key});
+
+  @override
+  State<NoTripsPage> createState() => _NoTripsPageState();
+}
+
+class _NoTripsPageState extends State<NoTripsPage> with ScaffoldLayout {
+  @override
+  Widget build(BuildContext context) => mainScaffold(
+    context,
+    child: Scaffold(
+      body: Center(
+        child: Column(
+          mainAxisAlignment: MainAxisAlignment.center,
+          children: [
+            Text(
+              "No trips yet",
+              style: Theme.of(context).textTheme.headlineMedium,
+            ),
+            Text(
+              "You can start a new trip by clicking the button below",
+              style: Theme.of(context).textTheme.bodyMedium,
+            ),
+          ],
+        ),
+      ),
+      floatingActionButton: FloatingActionButton.extended(
+        onPressed: () {
+          Navigator.of(context).push(
+            MaterialPageRoute(
+              builder: (context) => const NewTripPage()
+            )
+          );
+        },
+        label: const Row(
+          children: [
+            Text("Start planning!"),
+            Padding(padding: EdgeInsets.only(right: 8.0)),
+            Icon(Icons.map_outlined)
+          ],
+        )
+      )
+    )
+  );
+}

frontend/lib/pages/onboarding.dart

@@ -4,6 +4,7 @@ import 'package:anyway/constants.dart';
 import 'package:anyway/modules/onbarding_agreement_card.dart';
 import 'package:anyway/modules/onboarding_card.dart';
 import 'package:anyway/pages/new_trip_location.dart';
+import 'package:anyway/structs/agreement.dart';
 import 'package:flutter/material.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
@@ -121,11 +122,7 @@ class _OnboardingPageState extends State<OnboardingPage> {
         );
       } else {
         // only allow the user to proceed if they have agreed to the terms and conditions
-        Future<bool> hasAgreed = SharedPreferences.getInstance().then(
+        Future<bool> hasAgreed = getAgreement().then((agreement) => agreement.agreed);
-          (SharedPreferences prefs) {
-            return prefs.getBool('TC_agree') ?? false;
-          }
-        );
 
         return FutureBuilder(
           future: hasAgreed,
@@ -157,8 +154,7 @@ class _OnboardingPageState extends State<OnboardingPage> {
   );
 
   void onAgreementChanged(bool value) async {
-    SharedPreferences prefs = await SharedPreferences.getInstance();
+    saveAgreement(value);
-    await prefs.setBool('TC_agree', value);
     // Update the state of the OnboardingPage
     setState(() {});
   }

frontend/lib/structs/agreement.dart

@@ -0,0 +1,17 @@
+import 'package:shared_preferences/shared_preferences.dart';
+
+final class Agreement{
+  bool agreed;
+
+  Agreement({required this.agreed});
+}
+
+void saveAgreement(bool agreed) async {
+  SharedPreferences prefs = await SharedPreferences.getInstance();
+  prefs.setBool('agreed_to_terms_and_conditions', agreed);
+}
+
+Future<Agreement> getAgreement() async {
+  SharedPreferences prefs = await SharedPreferences.getInstance();
+  return Agreement(agreed: prefs.getBool('agreed_to_terms_and_conditions') ?? false);
+}

frontend/lib/structs/trip.dart

@@ -12,7 +12,7 @@ import 'package:shared_preferences/shared_preferences.dart';
 
 class Trip with ChangeNotifier {
   String uuid;
-  int totalTime;
+  Duration totalTime;
   LinkedList<Landmark> landmarks;
   // could be empty as well
   String? errorDescription;
@@ -44,7 +44,7 @@ class Trip with ChangeNotifier {
 
   Trip({
     this.uuid = 'pending',
-    this.totalTime = 0,
+    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>();
@@ -53,7 +53,7 @@ class Trip with ChangeNotifier {
   factory Trip.fromJson(Map<String, dynamic> json) {
     Trip trip = Trip(
       uuid: json['uuid'],
-      totalTime: json['total_time'],
+      totalTime: Duration(minutes: json['total_time']),
     );
 
     return trip;
@@ -61,7 +61,7 @@ class Trip with ChangeNotifier {
 
   void loadFromJson(Map<String, dynamic> json) {
     uuid = json['uuid'];
-    totalTime = json['total_time'];
+    totalTime = Duration(minutes: json['total_time']);
     notifyListeners();
   }
 
@@ -82,9 +82,12 @@ class Trip with ChangeNotifier {
     // 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
+      this.totalTime -= previous.tripTime ?? Duration.zero;
       previous.tripTime = null;
       // TODO
     }
+    this.totalTime -= landmark.tripTime ?? Duration.zero;
+
     notifyListeners();
   }
 
@@ -111,7 +114,7 @@ class Trip with ChangeNotifier {
 
   Map<String, dynamic> toJson() => {
     'uuid': uuid,
-    'total_time': totalTime,
+    'total_time': totalTime.inMinutes,
     'first_landmark_uuid': landmarks.first.uuid
   };
 

frontend/lib/utils/get_first_page.dart

@@ -1,44 +1,50 @@
 import 'package:anyway/main.dart';
+import 'package:anyway/pages/no_trips_page.dart';
+import 'package:anyway/structs/agreement.dart';
 import 'package:flutter/material.dart';
 
 import 'package:anyway/structs/trip.dart';
-import 'package:anyway/utils/load_trips.dart';
 import 'package:anyway/pages/current_trip.dart';
 import 'package:anyway/pages/onboarding.dart';
 
 
 Widget getFirstPage() {
-  SavedTrips trips = savedTrips;
+  // check if the user has already seen the onboarding and agreed to the terms of service
-  trips.loadTrips();
+  return FutureBuilder(
-
+    future: getAgreement(),
-  return ListenableBuilder(
+    builder: (context, snapshot) {
-    listenable: trips,
+      if (snapshot.connectionState == ConnectionState.done) {
-    builder: (BuildContext context, Widget? child) {
+        if (snapshot.hasData) {
-      List<Trip> items = trips.trips;
+          Agreement agrement = snapshot.data!;
-      if (items.isNotEmpty) {
+          if (agrement.agreed) {
-        return TripPage(trip: items[0]);
+            return FutureBuilder(
+              future: savedTrips.loadTrips(),
+              builder: (context, snapshot) {
+                if (snapshot.connectionState == ConnectionState.done) {
+                  if (snapshot.hasData) {
+                    List<Trip> trips = snapshot.data!;
+                    if (trips.length > 0) {
+                      return TripPage(trip: trips[0]);
+                    } else {
+                      return NoTripsPage();
+                    }
+                  } else {
+                    return Center(child: CircularProgressIndicator());
+                  }
+                } else {
+                  return Center(child: CircularProgressIndicator());
+                }
+              },
+            );
+          } else {
+            return OnboardingPage();
+          }
+        } else {
+          return OnboardingPage();
+        }
       } else {
-        return const OnboardingPage();
+        return OnboardingPage();
       }
-    }
+    },
   );
-  // Future<List<Trip>> trips = loadTrips();
-  // // test if there are any active trips
-  // // if there are, return the trip list
-  // // if there are not, return the onboarding page
-  // return FutureBuilder(
-  //   future: trips,
-  //   builder: (context, snapshot) {
-  //     if (snapshot.hasData) {
-  //       List<Trip> availableTrips = snapshot.data!;
-  //       if (availableTrips.isNotEmpty) {
-  //         return TripPage(trip: availableTrips[0]);
-  //       } else {
-  //         return OnboardingPage();
-  //       }
-  //     } else {
-  //       return CircularProgressIndicator();
-  //     }
-  //   }
-  // );
 }

frontend/lib/utils/load_trips.dart

@@ -8,7 +8,7 @@ class SavedTrips extends ChangeNotifier {
 
   List<Trip> get trips => _trips;
 
-  void loadTrips() async {
+  Future<List<Trip>> loadTrips() async {
     SharedPreferences prefs = await SharedPreferences.getInstance();
 
     List<Trip> trips = [];
@@ -21,6 +21,7 @@ class SavedTrips extends ChangeNotifier {
     }
     _trips = trips;
     notifyListeners();
+    return trips;
   }
 
   void addTrip(Trip trip) async {