Users can report their own generated content (thanks Google Play reviewers)

This reverts commit 56c5eb33

.gitignore

@@ -74,3 +74,5 @@ lib/*private*.dart
 
 .flutter-plugins-dependencies
 
+local.properties
+.gradle

android/app/build.gradle

@@ -22,6 +22,7 @@ if (flutterVersionName == null) {
 }
 
 apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 
@@ -33,24 +34,33 @@ if (keystorePropertiesFile.exists()) {
 }
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion flutter.compileSdkVersion
 
     compileOptions {
-
-        // Required to use WebRTC
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8
-
     }
 
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+
+    sourceSets {
+        main.java.srcDirs += 'src/main/java'
+    }
+
+
     lintOptions {
         disable 'InvalidPackage'
+
+        // TODO remove this fix to use Gradle plugin 4 ASAP
+        checkReleaseBuilds false
     }
 
     defaultConfig {
         applicationId "org.communiquons.comunic"
-        minSdkVersion 21
+        minSdkVersion 23
-        targetSdkVersion 30
+        targetSdkVersion flutter.targetSdkVersion
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
@@ -76,9 +86,7 @@ android {
 
     buildTypes {
         release {
-            useProguard true
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
-
         }
     }
 
@@ -109,10 +117,11 @@ flutter {
 }
 
 dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
     implementation 'com.neovisionaries:nv-websocket-client:2.14'
-    testImplementation 'junit:junit:4.12'
+    testImplementation 'junit:junit:4.13.1'
-    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
-    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
 }
 
 apply plugin: 'com.google.gms.google-services'

android/app/src/main/AndroidManifest.xml

@@ -59,7 +59,8 @@
             android:hardwareAccelerated="true"
             android:launchMode="singleTop"
             android:theme="@style/LaunchTheme"
-            android:windowSoftInputMode="adjustResize">
+            android:windowSoftInputMode="adjustResize"
+            android:exported="true">
             <!-- This keeps the window background of the activity showing
                  until Flutter renders its first frame. It can be removed if
                  there is no splash screen (such as the default splash screen
@@ -69,12 +70,6 @@
                 android:name="io.flutter.embedding.android.NormalTheme"
                 android:resource="@style/NormalTheme" />
 
-            <!-- Specify that the launch screen should continue being displayed -->
-            <!-- until Flutter renders its first frame. -->
-            <meta-data
-                android:name="io.flutter.embedding.android.SplashScreenDrawable"
-                android:resource="@drawable/launch_background" />
-
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />

android/app/src/main/java/org/communiquons/comunic/independentnotifications/NotificationsService.java

@@ -100,7 +100,10 @@ public class NotificationsService extends Service implements Runnable {
 
         Intent notificationIntent = new Intent(this, MainActivity.class);
         PendingIntent pendingIntent = PendingIntent.getActivity(this,
-                0, notificationIntent, 0);
+                0,
+                notificationIntent,
+                android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M ? PendingIntent.FLAG_IMMUTABLE : 0);
+
         Notification notification = new NotificationCompat.Builder(this, SVC_CHANNEL_ID)
                 .setContentTitle("Comunic")
                 .setContentText(getText(R.string.independent_push_notification_notification_text))
@@ -197,12 +200,12 @@ public class NotificationsService extends Service implements Runnable {
         ws.setPingInterval(PING_INTERVAL);
         ws.addListener(new WebSocketAdapter() {
             @Override
-            public void onConnected(WebSocket websocket, Map<String, List<String>> headers) throws Exception {
+            public void onConnected(WebSocket websocket, Map<String, List<String>> headers) {
                 Log.v(TAG, "Connected to independent push notifications service!");
             }
 
             @Override
-            public void onDisconnected(WebSocket websocket, WebSocketFrame serverCloseFrame, WebSocketFrame clientCloseFrame, boolean closedByServer) throws Exception {
+            public void onDisconnected(WebSocket websocket, WebSocketFrame serverCloseFrame, WebSocketFrame clientCloseFrame, boolean closedByServer) {
                 Log.v(TAG, "Disconnected from independent push notifications websocket!");
                 synchronized (lock) {
                     lock.notify();
@@ -210,12 +213,12 @@ public class NotificationsService extends Service implements Runnable {
             }
 
             @Override
-            public void onTextFrame(WebSocket websocket, WebSocketFrame frame) throws Exception {
+            public void onTextFrame(WebSocket websocket, WebSocketFrame frame) {
                 handleTextFrame(frame);
             }
 
             @Override
-            public void onError(WebSocket websocket, WebSocketException cause) throws Exception {
+            public void onError(WebSocket websocket, WebSocketException cause) {
                 Log.e(TAG, "An error occured, closing WebSocket!");
                 cause.printStackTrace();
                 websocket.disconnect();
@@ -254,17 +257,14 @@ public class NotificationsService extends Service implements Runnable {
         }
     }
 
-    private void dropNotification(String id) throws Exception {
+    private void dropNotification(String id) {
-        new Handler(Looper.getMainLooper()).post(new Runnable() {
+        new Handler(Looper.getMainLooper()).post(() -> {
-            @Override
-            public void run() {
             NotificationManagerCompat notifManager = NotificationManagerCompat.from(NotificationsService.this);
             notifManager.cancel(id, NOTIFS_ID);
-            }
         });
     }
 
-    private void sendNotification(PushNotification n) throws Exception {
+    private void sendNotification(PushNotification n) {
         new Handler(Looper.getMainLooper()).post(() -> postNotification(n));
     }
 
@@ -273,7 +273,12 @@ public class NotificationsService extends Service implements Runnable {
         createPushNotificationChannel();
 
         Intent intent = new Intent(this, MainActivity.class);
-        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);
+        PendingIntent pendingIntent = PendingIntent.getActivity(
+                this,
+                0,
+                intent,
+                android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M ? PendingIntent.FLAG_IMMUTABLE : 0
+        );
 
         NotificationCompat.Builder builder = new NotificationCompat.Builder(this, NOTIFS_CHANNEL_ID)
                 .setSmallIcon(R.drawable.ic_notifications)

android/app/src/main/kotlin/org/communiquons/comunic/MainActivity.kt

@@ -1,6 +0,0 @@
-package org.communiquons.comunic
-
-import io.flutter.embedding.android.FlutterActivity
-
-class MainActivity: FlutterActivity() {
-}

android/build.gradle

@@ -1,21 +1,23 @@
 buildscript {
+    ext.kotlin_version = '1.5.30'
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.4'
+        classpath 'com.android.tools.build:gradle:4.1.3'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
 
         // Firebase
-        classpath 'com.google.gms:google-services:4.3.5'
+        classpath 'com.google.gms:google-services:4.3.10'
     }
 }
 
 allprojects {
     repositories {
         google()
-        jcenter()
+        mavenCentral()
     }
 }
 

android/gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.4-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.4-all.zip

assets/langs/fr.json

@@ -340,6 +340,7 @@
     "Failed to remove conversation logo!": "Erreur lors de la suppression du logo de la conversation !",
     "Failed to remove member!": "Echec de la suppression d'un membre !",
     "Failed to send a file!": "Erreur lors de l'envoi d'un fichier !",
+    "Failed to send report!": "Erreur lors de l'envoi du signalement !",
     "Failed to start recording!": "Erreur lors du lancement de l'enregistrement !",
     "Failed to toggle admin status of user!": "Echec du changement du status administrateur d'un membre !",
     "Failed to update conversation settings!": "Echec de la mise à jour des paramètres de la conversation !",
@@ -500,6 +501,7 @@
     "Please check back soon!": "Revenez plus tard finir la configuration de l'application !",
     "Please choose new account image visibility level:": "Veuillez choisir un nouveau niveau de visibilité pour votre image de compte :",
     "Please choose now the Forez group you want to join...": "Veuillez maintenant choisir le groupe #Forez que vous souhaitez rejoindre...",
+    "Please choose the reason of your report:": "Veuillez indiquer la raison de votre signalement",
     "Please click on the day you will be in the plain, so that everyone gets informed ! ;)": "Veuillez cliquer sur les jours où vous serez présent dans la plaine du Forez, que tout le monde soit au courant ;)",
     "Please enter message content: ": "Veuillez entrer le contenu du message :",
     "Please enter new message content:": "Veuillez entrer le contenu du nouveau message :",
@@ -534,6 +536,7 @@
     "Question 1": "Question 1",
     "Question 2": "Question 2",
     "Ready": "Prêt",
+    "Reason of report": "Raison du signalement",
     "Receive notifications for the conversations you follow.": "Recevoir des notifications push pour les conversations que vous suivez",
     "Record audio": "Faire un enregistrement audio",
     "Recording...": "Enregistrement...",
@@ -543,6 +546,8 @@
     "Remove": "Supprimer",
     "Remove selected image": "Supprimer l'image sélectionnée",
     "Replace image": "Remplacer l'image",
+    "Report abuse": "Signaler un abus",
+    "Report successfully saved. Thank you for your contribution!": "Le report a bien été pris en compte. Merci pour votre contribution !",
     "Request membership": "Demander de rejoindre le groupe",
     "Requested": "En attente",
     "Respond to survey": "Répondre au sondage",
@@ -642,8 +647,11 @@
     "You can search the people you know and ask them to become your friends!": "Vous pouvez rechercher vos connaissances et les demander en amis !",
     "You can search the people you know and ask them to become your friends!\\n\\nThis will help you to reach them to exchange information!": "Vous pouvez rechercher vos connaissances et les demander en amis, pour entrer facilement en contact avec elles !",
     "You can use this virtual directory.": "Vous pouvez utiliser ce répertoire virtuel.",
+    "You do not have any conversation yet!": "Vous n'avez pas encore de conversation !",
+    "You do not have any friend yet!": "Vous n'avez pas encore d'amis sur Comunic !",
     "You do not have any notification now.": "Vous n'avez pas de notification pour l'intant.",
     "You do not have any unread conversation yet...": "Vous n'avez aucune conversation non lue pour le moment...",
+    "You have already sent a report for this resource!": "Vous avez déjà soumis un signalement pour cette ressource !",
     "You must accept the Terms Of Service to continue.": "Vous devez accepter les Conditions d'utilisation pour continuer.",
     "You security questions have been successfully updated!": "Vos questions de sécurité ont été mises avec succès !",
     "You will need to restart the application to apply changes": "Vous aurez besoin de redémarrer l'application pour appliquer les changements",

build_all_comunic_releases.sh

@@ -5,7 +5,7 @@ make stable_release_split_per_abi && \
 	mv build/app/outputs/flutter-apk/app-armeabi-v7a-stable-release.apk "$DEST" && \
 	mv build/app/outputs/flutter-apk/app-arm64-v8a-stable-release.apk "$DEST" && \
 	mv build/app/outputs/flutter-apk/app-x86_64-stable-release.apk "$DEST" && \
-	mv build/app/outputs/mapping/stable/release/mapping.txt "$DEST" && \
+	mv build/app/outputs/mapping/stableRelease/mapping.txt "$DEST" && \
 	make stable_release && \
 	mv build/app/outputs/flutter-apk/app-stable-release.apk "$DEST"
 

build_all_forez.sh

@@ -5,4 +5,4 @@ make forez_release_split_per_abi && \
 	mv build/app/outputs/flutter-apk/app-armeabi-v7a-forez-release.apk "$DEST" && \
 	mv build/app/outputs/flutter-apk/app-arm64-v8a-forez-release.apk "$DEST" && \
 	mv build/app/outputs/flutter-apk/app-x86_64-forez-release.apk "$DEST" && \
-	mv build/app/outputs/mapping/forez/release/mapping.txt "$DEST"
+	mv build/app/outputs/mapping/forezRelease/mapping.txt "$DEST"

lib/enums/report_target_type.dart

@@ -0,0 +1,28 @@
+/// What kind of content that can be reported
+enum ReportTargetType {
+  Post,
+  Comment,
+  Conversation,
+  ConversationMessage,
+  User,
+  Group
+}
+
+extension ReportTargetExt on ReportTargetType {
+  String get apiId {
+    switch (this) {
+      case ReportTargetType.Post:
+        return "post";
+      case ReportTargetType.Comment:
+        return "comment";
+      case ReportTargetType.Conversation:
+        return "conversation";
+      case ReportTargetType.ConversationMessage:
+        return "conversation_message";
+      case ReportTargetType.User:
+        return "user";
+      case ReportTargetType.Group:
+        return "group";
+    }
+  }
+}

lib/forez/helpers/forez_group_helper.dart

@@ -8,7 +8,7 @@ import 'package:comunic/models/advanced_group_info.dart';
 ///
 /// @author Pierre Hubert
 
-AdvancedGroupInfo _forezGroup;
+AdvancedGroupInfo? _forezGroup;
 
 class ForezGroupHelper {
   static Future<void> setId(int groupID) async {
@@ -16,7 +16,7 @@ class ForezGroupHelper {
         .setInt(PreferencesKeyList.FOREZ_GROUP, groupID);
   }
 
-  static Future<int> getId() async {
+  static Future<int?> getId() async {
     return (await PreferencesHelper.getInstance())
         .getInt(PreferencesKeyList.FOREZ_GROUP);
   }
@@ -27,7 +27,7 @@ class ForezGroupHelper {
     _forezGroup = res.info;
   }
 
-  static AdvancedGroupInfo getGroup() => _forezGroup;
+  static AdvancedGroupInfo? getGroup() => _forezGroup;
 }
 
-AdvancedGroupInfo get forezGroup => ForezGroupHelper.getGroup();
+AdvancedGroupInfo? get forezGroup => ForezGroupHelper.getGroup();

lib/forez/init.dart

@@ -11,10 +11,10 @@ import 'package:flutter/material.dart';
 
 class ForezConfig extends Config {
   ForezConfig({
-    @required String apiServerName,
+    required String apiServerName,
-    @required String apiServerUri,
+    required String apiServerUri,
-    @required bool apiServerSecure,
+    required bool apiServerSecure,
-    @required String clientName,
+    required String clientName,
   }) : super(
           apiServerName: apiServerName,
           apiServerUri: apiServerUri,

lib/forez/main_forez_dev.dart

@@ -11,7 +11,7 @@ import 'package:comunic/models/config.dart';
 /// Fix HTTPS issue
 class MyHttpOverride extends HttpOverrides {
   @override
-  HttpClient createHttpClient(SecurityContext context) {
+  HttpClient createHttpClient(SecurityContext? context) {
     return super.createHttpClient(context)
       ..badCertificateCallback = (cert, host, port) {
         return host == "devweb.local"; // Forcefully trust local website

lib/forez/tour/forez_tour_builder.dart

@@ -29,7 +29,7 @@ List<Widget> buildTour(TourRouteState state) {
       msgTwo: tr("Let's first join a Forez group!"),
     ),
     JoinForezGroupPane(
-      key: state.pubKeys[_JOIN_GROUP_KEY_ID],
+      key: state.pubKeys[_JOIN_GROUP_KEY_ID] as GlobalKey<JoinGroupPaneBodyState>?,
       onUpdated: () => state.rebuild(),
     ),
     FirstTourPane(
@@ -51,7 +51,7 @@ List<Widget> buildTour(TourRouteState state) {
     // Forez specific features
     PresentationPane(
       icon: Icons.calendar_today,
-      title: tr("Presence in Forez"),
+      title: tr("Presence in Forez")!,
       text: tr(
           "Easily specify the days you are in Forez plain, so that everyone can know it!"),
       actionTitle: tr("Do it now!"),
@@ -62,7 +62,7 @@ List<Widget> buildTour(TourRouteState state) {
     // Chat pane
     PresentationPane(
       icon: Icons.question_answer,
-      title: tr("Conversations"),
+      title: tr("Conversations")!,
       text: tr(
           "#Forez now integrates the conversation system of Comunic, so you have access both to public and private conversations!"),
     ),

lib/forez/tour/join_group_pane.dart

@@ -16,17 +16,17 @@ import 'package:flutter/material.dart';
 
 class JoinForezGroupPane extends PresentationPane {
   JoinForezGroupPane({
-    @required Function() onUpdated,
+    required Function() onUpdated,
-    @required GlobalKey<JoinGroupPaneBodyState> key,
+    required GlobalKey<JoinGroupPaneBodyState>? key,
   }) : super(
           icon: Icons.login,
-          title: tr("Join a Forez group"),
+          title: tr("Join a Forez group")!,
           child: (c) => _JoinGroupPaneBody(
             key: key,
             onUpdated: onUpdated,
           ),
           canGoNext: key?.currentState?.canGoNext ?? false,
-          onTapNext: (c) => key.currentState.validateChoice(),
+          onTapNext: (c) => key!.currentState!.validateChoice(),
         );
 }
 
@@ -34,10 +34,9 @@ class _JoinGroupPaneBody extends StatefulWidget {
   final Function() onUpdated;
 
   const _JoinGroupPaneBody({
-    Key key,
+    Key? key,
-    @required this.onUpdated,
+    required this.onUpdated,
-  })  : assert(onUpdated != null),
+  })  : super(key: key);
-        super(key: key);
 
   @override
   JoinGroupPaneBodyState createState() => JoinGroupPaneBodyState();
@@ -46,10 +45,10 @@ class _JoinGroupPaneBody extends StatefulWidget {
 class JoinGroupPaneBodyState extends State<_JoinGroupPaneBody> {
   final _key = GlobalKey<AsyncScreenWidgetState>();
 
-  List<Group> _groups;
+  late List<Group> _groups;
-  int _currChoice;
+  int? _currChoice;
 
-  bool get canGoNext => _currChoice != null && _currChoice > 0;
+  bool get canGoNext => _currChoice != null && _currChoice! > 0;
 
   Group get _currGroup => _groups.firstWhere((e) => e.id == _currChoice);
 
@@ -65,17 +64,17 @@ class JoinGroupPaneBodyState extends State<_JoinGroupPaneBody> {
       key: _key,
       onReload: _load,
       onBuild: onBuild,
-      errorMessage: tr("Failed to load the list of Forez groups!"));
+      errorMessage: tr("Failed to load the list of Forez groups!")!);
 
   Widget onBuild() => ConstrainedBox(
         constraints: BoxConstraints(maxWidth: 300),
         child: Column(
           children: [
-            Text(tr("Please choose now the Forez group you want to join...")),
+            Text(tr("Please choose now the Forez group you want to join...")!),
           ]..addAll(_groups.map((e) => RadioListTile(
                 value: e.id,
                 groupValue: _currChoice,
-                onChanged: (v) => setState(() => _currChoice = _currChoice),
+                onChanged: (dynamic v) => setState(() => _currChoice = e.id),
                 title: Text(e.name),
                 subtitle: Text(e.membershipText),
               ))),
@@ -112,7 +111,7 @@ class JoinGroupPaneBodyState extends State<_JoinGroupPaneBody> {
         await alert(context,
             "${tr("You can not access this group yet, please wait for a member of the group to accept your request.")}\n${tr("Hopefully this will not be too long.")}\n${tr("Please check back soon!")}");
 
-        _key.currentState.refresh();
+        _key.currentState!.refresh();
 
         return false;
       }
@@ -121,8 +120,8 @@ class JoinGroupPaneBodyState extends State<_JoinGroupPaneBody> {
       return true;
     } catch (e, s) {
       logError(e, s);
-      snack(context, tr("Failed to register to group!"));
+      snack(context, tr("Failed to register to group!")!);
-      _key.currentState.refresh();
+      _key.currentState!.refresh();
       return false;
     }
   }

lib/forez/ui/routes/forez_member_profile_route.dart

@@ -14,7 +14,7 @@ import 'package:comunic/utils/conversations_utils.dart';
 import 'package:comunic/utils/intl_utils.dart';
 import 'package:comunic/utils/ui_utils.dart';
 import 'package:flutter/material.dart';
-import 'package:url_launcher/url_launcher.dart';
+import 'package:url_launcher/url_launcher_string.dart';
 
 /// Show information about a Forez member
 ///
@@ -24,10 +24,9 @@ class ForezMemberProfileRoute extends StatefulWidget {
   final int userID;
 
   const ForezMemberProfileRoute({
-    Key key,
+    Key? key,
-    @required this.userID,
+    required this.userID,
-  })  : assert(userID != null),
+  }) : super(key: key);
-        super(key: key);
 
   @override
   _ForezMemberProfileRouteState createState() =>
@@ -39,13 +38,14 @@ class _ForezMemberProfileRouteState extends State<ForezMemberProfileRoute> {
 
   final _key = GlobalKey<AsyncScreenWidgetState>();
 
-  AdvancedUserInfo _user;
+  late AdvancedUserInfo _user;
-  PresenceSet _presence;
+  late PresenceSet _presence;
 
   Future<void> _load() async {
-    _user = await ForezGroupsHelper.getMemberInfo(forezGroup.id, widget.userID);
+    _user =
+        await ForezGroupsHelper.getMemberInfo(forezGroup!.id, widget.userID);
     _presence =
-        await ForezPresenceHelper.getForUser(forezGroup.id, widget.userID);
+        await ForezPresenceHelper.getForUser(forezGroup!.id, widget.userID);
   }
 
   @override
@@ -56,25 +56,25 @@ class _ForezMemberProfileRouteState extends State<ForezMemberProfileRoute> {
       loadingWidget: _buildLoading(),
       errorWidget: _buildError(),
       errorMessage: tr(
-          "Failed to load user information, maybe it is not a Forez member yet?"));
+          "Failed to load user information, maybe it is not a Forez member yet?")!);
 
   Widget _buildLoading() => Scaffold(
         appBar: AppBar(
-          title: Text(tr("Loading...")),
+          title: Text(tr("Loading...")!),
         ),
         body: buildCenteredProgressBar(),
       );
 
   Widget _buildError() => Scaffold(
         appBar: AppBar(
-          title: Text(tr("Error")),
+          title: Text(tr("Error")!),
         ),
         body: buildErrorCard(
             tr("Failed to load user information, maybe it is not a Forez member yet?"),
             actions: [
               MaterialButton(
-                onPressed: () => _key.currentState.refresh(),
+                onPressed: () => _key.currentState!.refresh(),
-                child: Text(tr("Try again")),
+                child: Text(tr("Try again")!),
                 textColor: Colors.white,
               )
             ]),
@@ -97,9 +97,7 @@ class _ForezMemberProfileRouteState extends State<ForezMemberProfileRoute> {
           background: Stack(
             fit: StackFit.expand,
             children: <Widget>[
-              _user.accountImageURL == null
+              CachedNetworkImage(
-                  ? Container()
-                  : CachedNetworkImage(
                 fit: BoxFit.cover,
                 imageUrl: _user.accountImageURL,
                 height: _appBarHeight,
@@ -135,7 +133,7 @@ class _ForezMemberProfileRouteState extends State<ForezMemberProfileRoute> {
             : ListTile(
                 leading: Icon(Icons.note),
                 title: TextWidget(content: DisplayedString(_user.publicNote)),
-                subtitle: Text(tr("Note")),
+                subtitle: Text(tr("Note")!),
               ),
 
         // Email address
@@ -143,9 +141,9 @@ class _ForezMemberProfileRouteState extends State<ForezMemberProfileRoute> {
             ? Container()
             : ListTile(
                 leading: Icon(Icons.email),
-                title: Text(_user.emailAddress),
+                title: Text(_user.emailAddress!),
-                subtitle: Text(tr("Email address")),
+                subtitle: Text(tr("Email address")!),
-                trailing: CopyIcon(_user.emailAddress),
+                trailing: CopyIcon(_user.emailAddress!),
               ),
 
         // Location
@@ -153,9 +151,9 @@ class _ForezMemberProfileRouteState extends State<ForezMemberProfileRoute> {
             ? Container()
             : ListTile(
                 leading: Icon(Icons.location_on),
-                title: Text(_user.location),
+                title: Text(_user.location!),
-                subtitle: Text(tr("Location")),
+                subtitle: Text(tr("Location")!),
-                trailing: CopyIcon(_user.location),
+                trailing: CopyIcon(_user.location!),
               ),
 
         // Website
@@ -164,20 +162,20 @@ class _ForezMemberProfileRouteState extends State<ForezMemberProfileRoute> {
             : ListTile(
                 leading: Icon(Icons.link),
                 title: Text(_user.personalWebsite),
-                subtitle: Text(tr("Website")),
+                subtitle: Text(tr("Website")!),
                 trailing: IconButton(
                   icon: Icon(Icons.open_in_new),
-                  onPressed: () => launch(_user.personalWebsite),
+                  onPressed: () => launchUrlString(_user.personalWebsite),
                 ),
               ),
 
         Divider(),
         ListTile(
           leading: Icon(Icons.calendar_today),
-          title: Text(tr("Presence in Forez")),
+          title: Text(tr("Presence in Forez")!),
           subtitle: Text(_presence.containsDate(DateTime.now())
-              ? tr("Present today")
+              ? tr("Present today")!
-              : tr("Absent")),
+              : tr("Absent")!),
         ),
         PresenceCalendarWidget(presenceSet: _presence),
         Divider(),

lib/forez/ui/routes/forez_route.dart

@@ -9,6 +9,7 @@ import 'package:comunic/ui/routes/main_route/page_info.dart';
 import 'package:comunic/ui/screens/conversations_list_screen.dart';
 import 'package:comunic/ui/screens/group_sections/forez_presence_section.dart';
 import 'package:comunic/ui/screens/group_sections/group_posts_section.dart';
+import 'package:comunic/ui/widgets/banner_widget.dart';
 import 'package:comunic/ui/widgets/safe_state.dart';
 import 'package:comunic/ui/widgets/status_widget.dart';
 import 'package:comunic/ui/widgets/tab_transition_widget.dart';
@@ -20,7 +21,7 @@ import 'package:flutter/material.dart';
 /// @author Pierre Hubert
 
 class ForezRoute extends StatefulWidget implements MainRoute {
-  const ForezRoute({Key key}) : super(key: key);
+  const ForezRoute({Key? key}) : super(key: key);
 
   @override
   State<StatefulWidget> createState() => _MainRouteState();
@@ -39,7 +40,7 @@ class _MainRouteState extends MainController {
 
   @override
   Widget build(BuildContext context) {
-    if (forezGroup == null) return Text(tr("Missing Forez group!"));
+    if (forezGroup == null) return Text(tr("Missing Forez group!")!);
 
     return StatusWidget(
       child: (c) => SafeArea(
@@ -66,11 +67,11 @@ class _MainRouteState extends MainController {
   @override
   void openConversation(Conversation conv, {fullScreen: false}) {
     // Forcefully open conversations in a "normal" way (do not display groups)
-    openConversationById(conv.id, fullScreen: fullScreen);
+    openConversationById(conv.id!, fullScreen: fullScreen);
   }
 
   @override
-  void openGroup(int groupID, {int conversationID}) => _unsupportedFeature();
+  void openGroup(int groupID, {int? conversationID}) => _unsupportedFeature();
 
   @override
   void openUserPage(int userID) => pushPage(PageInfo(
@@ -91,7 +92,7 @@ class _MainRouteState extends MainController {
 enum _PopupMenuItems { ACTION_SETTINGS, ACTION_SIGN_OUT }
 
 class ForezRouteBody extends StatefulWidget {
-  ForezRouteBody({Key key}) : super(key: key);
+  ForezRouteBody({Key? key}) : super(key: key);
 
   @override
   _ForezRouteBodyState createState() => _ForezRouteBodyState();
@@ -111,11 +112,16 @@ class _ForezRouteBodyState extends SafeState<ForezRouteBody> {
       length: _tabs.length,
       child: Scaffold(
         appBar: AppBar(
-          title: Text(forezGroup.name),
+          title: Text(forezGroup!.name),
           actions: <Widget>[_buildPopupMenuButton()],
           bottom: TabBar(tabs: _tabs),
         ),
-        body: TabBarView(children: _tabsPages),
+        body: Column(
+          children: [
+            BannerWidget(),
+            Expanded(child: TabBarView(children: _tabsPages)),
+          ],
+        ),
       ),
     );
   }
@@ -123,11 +129,11 @@ class _ForezRouteBodyState extends SafeState<ForezRouteBody> {
   Widget _buildPopupMenuButton() => PopupMenuButton<_PopupMenuItems>(
         itemBuilder: (c) => [
           PopupMenuItem(
-            child: Text(tr("Settings")),
+            child: Text(tr("Settings")!),
             value: _PopupMenuItems.ACTION_SETTINGS,
           ),
           PopupMenuItem(
-            child: Text(tr("Sign out")),
+            child: Text(tr("Sign out")!),
             value: _PopupMenuItems.ACTION_SIGN_OUT,
           ),
         ],
@@ -137,10 +143,10 @@ class _ForezRouteBodyState extends SafeState<ForezRouteBody> {
   void _onMenuSelection(_PopupMenuItems value) {
     switch (value) {
       case _PopupMenuItems.ACTION_SETTINGS:
-        MainController.of(context).openSettings();
+        MainController.of(context)!.openSettings();
         break;
       case _PopupMenuItems.ACTION_SIGN_OUT:
-        MainController.of(context).requestLogout();
+        MainController.of(context)!.requestLogout();
         break;
     }
   }
@@ -149,29 +155,29 @@ class _ForezRouteBodyState extends SafeState<ForezRouteBody> {
     // Posts tab
     _Tab(
       icon: Icons.auto_stories,
-      title: tr("Posts"),
+      title: tr("Posts")!,
-      widget: () => GroupPostsSection(group: forezGroup),
+      widget: () => GroupPostsSection(group: forezGroup!),
     ),
 
     // Presence tab
     _Tab(
       icon: Icons.calendar_today,
-      title: tr("Presence"),
+      title: tr("Presence")!,
-      widget: () => ForezPresenceSection(groupID: forezGroup.id),
+      widget: () => ForezPresenceSection(groupID: forezGroup!.id),
     ),
 
     // Conversations tab
     _Tab(
       icon: Icons.question_answer,
-      title: tr("Conversations"),
+      title: tr("Conversations")!,
       widget: () => ConversationsListScreen(),
-      isUnread: (c) => StatusWidgetState.of(c).unreadConversations > 0,
+      isUnread: (c) => StatusWidgetState.of(c)!.unreadConversations! > 0,
     ),
 
     // Directory tab
     _Tab(
       icon: Icons.import_contacts,
-      title: tr("Directory"),
+      title: tr("Directory")!,
       widget: () => ForezDirectoryScreen(),
     ),
   ];
@@ -197,14 +203,12 @@ class _Tab {
   final IconData icon;
   final String title;
   final Widget Function() widget;
-  final bool Function(BuildContext) isUnread;
+  final bool Function(BuildContext)? isUnread;
 
   const _Tab({
-    @required this.icon,
+    required this.icon,
-    @required this.title,
+    required this.title,
-    @required this.widget,
+    required this.widget,
     this.isUnread,
-  })  : assert(icon != null),
+  });
-        assert(title != null),
-        assert(widget != null);
 }

lib/forez/ui/routes/search_users.dart

@@ -7,18 +7,18 @@ import 'package:flutter/material.dart';
 ///
 /// @author Pierre Hubert
 
-Future<User> searchUser(BuildContext context, UsersList users) async {
+Future<User?> searchUser(BuildContext context, UsersList users) async {
-  return await showSearch<User>(
+  return await showSearch<User?>(
       context: context, delegate: _SearchDelegate(users));
 }
 
-class _SearchDelegate extends SearchDelegate<User> {
+class _SearchDelegate extends SearchDelegate<User?> {
   final UsersList _usersList;
 
-  _SearchDelegate(this._usersList) : assert(_usersList != null);
+  _SearchDelegate(this._usersList);
 
   @override
-  List<Widget> buildActions(BuildContext context) => null;
+  List<Widget>? buildActions(BuildContext context) => null;
 
   @override
   Widget buildLeading(BuildContext context) => IconButton(
@@ -28,7 +28,7 @@ class _SearchDelegate extends SearchDelegate<User> {
 
   @override
   Widget buildSuggestions(BuildContext context) {
-    final list = _usersList
+    final List<User> list = _usersList
         .where((element) =>
             element.fullName.toLowerCase().contains(query.toLowerCase()))
         .toList();

lib/forez/ui/screens/forez_directory_screen.dart

@@ -35,11 +35,11 @@ class ForezDirectoryScreen extends StatefulWidget {
 class _ForezDirectoryScreenState extends State<ForezDirectoryScreen> {
   final _key = GlobalKey<AsyncScreenWidgetState>();
 
-  UsersList _users;
+  late UsersList _users;
-  GroupMembersList _members;
+  late GroupMembersList _members;
 
   Future<void> _load() async {
-    _members = await GroupsHelper.getMembersList(forezGroup.id);
+    _members = await GroupsHelper.getMembersList(forezGroup!.id);
     _users = await UsersHelper().getListWithThrow(_members.usersID);
   }
 
@@ -49,7 +49,7 @@ class _ForezDirectoryScreenState extends State<ForezDirectoryScreen> {
           AsyncScreenWidget(
             onReload: _load,
             onBuild: onBuild,
-            errorMessage: tr("Failed to load members list!"),
+            errorMessage: tr("Failed to load members list!")!,
             key: _key,
           ),
           Positioned(
@@ -88,13 +88,13 @@ class _ForezDirectoryScreenState extends State<ForezDirectoryScreen> {
                   "Do you really want to cancel the invitation sent to %u%?",
                   args: {"u": user.fullName}))) return;
 
-          await GroupsHelper.cancelInvitation(forezGroup.id, user.id);
+          await GroupsHelper.cancelInvitation(forezGroup!.id, user.id);
-          _key.currentState.refresh();
+          _key.currentState!.refresh();
           break;
 
         case _PopupMenuActions.ACCEPT_REQUEST:
-          await GroupsHelper.respondRequest(forezGroup.id, user.id, true);
+          await GroupsHelper.respondRequest(forezGroup!.id, user.id, true);
-          _key.currentState.refresh();
+          _key.currentState!.refresh();
           break;
 
         case _PopupMenuActions.REJECT_REQUEST:
@@ -104,13 +104,13 @@ class _ForezDirectoryScreenState extends State<ForezDirectoryScreen> {
                   "Do you really want to reject the request of %u% to join the Forez group?",
                   args: {"u": user.fullName}))) return;
 
-          await GroupsHelper.respondRequest(forezGroup.id, user.id, false);
+          await GroupsHelper.respondRequest(forezGroup!.id, user.id, false);
-          _key.currentState.refresh();
+          _key.currentState!.refresh();
           break;
       }
     } catch (e, s) {
       logError(e, s);
-      snack(context, tr("Error while processing action!"));
+      snack(context, tr("Error while processing action!")!);
     }
   }
 
@@ -125,7 +125,7 @@ class _ForezDirectoryScreenState extends State<ForezDirectoryScreen> {
   }
 
   void _openUserProfile(User user) =>
-      MainController.of(context).openUserPage(user.id);
+      MainController.of(context)!.openUserPage(user.id);
 }
 
 class _ForezMemberTile extends StatelessWidget {
@@ -135,11 +135,11 @@ class _ForezMemberTile extends StatelessWidget {
   final Function(User) onTap;
 
   const _ForezMemberTile({
-    Key key,
+    Key? key,
-    @required this.user,
+    required this.user,
-    @required this.member,
+    required this.member,
-    @required this.selectedAction,
+    required this.selectedAction,
-    @required this.onTap,
+    required this.onTap,
   }) : super(key: key);
 
   @override
@@ -147,7 +147,7 @@ class _ForezMemberTile extends StatelessWidget {
         leading: AccountImageWidget(user: user),
         title: Text(user.fullName),
         subtitle: Text(member.membershipText),
-        trailing: !member.isAtLeastMember && forezGroup.isAtLeastModerator
+        trailing: !member.isAtLeastMember && forezGroup!.isAtLeastModerator
             ? (member.isInvited
                 ? _buildInvitedButton()
                 : _buildRequestedButton())
@@ -155,7 +155,7 @@ class _ForezMemberTile extends StatelessWidget {
         onTap: member.isAtLeastMember ? () => onTap(user) : null,
       );
 
-  Widget _buildConversationButton() => user.id == userID()
+  Widget? _buildConversationButton() => user.id == userID()
       ? null
       : IconButton(
           icon: Icon(Icons.message),
@@ -201,18 +201,13 @@ class _MembershipButton extends StatelessWidget {
   final IconData icon;
 
   const _MembershipButton({
-    Key key,
+    Key? key,
-    @required this.user,
+    required this.user,
-    @required this.action,
+    required this.action,
-    @required this.onTap,
+    required this.onTap,
-    @required this.color,
+    required this.color,
-    @required this.icon,
+    required this.icon,
-  })  : assert(user != null),
+  }) : super(key: key);
-        assert(action != null),
-        assert(onTap != null),
-        assert(color != null),
-        assert(icon != null),
-        super(key: key);
 
   @override
   Widget build(BuildContext context) => ElevatedButton(

lib/generated_plugin_registrant.dart

@@ -2,26 +2,33 @@
 // Generated file. Do not edit.
 //
 
+// ignore_for_file: directives_ordering
 // ignore_for_file: lines_longer_than_80_chars
+// ignore_for_file: depend_on_referenced_packages
 
-import 'package:connectivity_for_web/connectivity_for_web.dart';
+import 'package:connectivity_plus_web/connectivity_plus_web.dart';
-import 'package:file_picker/src/file_picker_web.dart';
+import 'package:file_picker/_internal/file_picker_web.dart';
 import 'package:firebase_core_web/firebase_core_web.dart';
 import 'package:firebase_messaging_web/firebase_messaging_web.dart';
-import 'package:flutter_web_plugins/flutter_web_plugins.dart';
+import 'package:image_cropper_for_web/image_cropper_for_web.dart';
 import 'package:image_picker_for_web/image_picker_for_web.dart';
+import 'package:package_info_plus_web/package_info_plus_web.dart';
 import 'package:shared_preferences_web/shared_preferences_web.dart';
 import 'package:url_launcher_web/url_launcher_web.dart';
 import 'package:video_player_web/video_player_web.dart';
 import 'package:wakelock_web/wakelock_web.dart';
 
+import 'package:flutter_web_plugins/flutter_web_plugins.dart';
+
 // ignore: public_member_api_docs
 void registerPlugins(Registrar registrar) {
-  ConnectivityPlugin.registerWith(registrar);
+  ConnectivityPlusPlugin.registerWith(registrar);
   FilePickerWeb.registerWith(registrar);
   FirebaseCoreWeb.registerWith(registrar);
   FirebaseMessagingWeb.registerWith(registrar);
+  ImageCropperPlugin.registerWith(registrar);
   ImagePickerPlugin.registerWith(registrar);
+  PackageInfoPlugin.registerWith(registrar);
   SharedPreferencesPlugin.registerWith(registrar);
   UrlLauncherPlugin.registerWith(registrar);
   VideoPlayerPlugin.registerWith(registrar);

lib/helpers/account_helper.dart

@@ -26,7 +26,7 @@ enum CreateAccountResult {
 
 class AccountHelper {
   // Current user ID
-  static int _currentUserID = -1;
+  static int? _currentUserID = -1;
 
   /// Checkout whether current user is signed in or not
   ///
@@ -67,7 +67,7 @@ class AccountHelper {
     }
 
     // Save current user ID
-    final preferences = await PreferencesHelper.getInstance();
+    final preferences = await (PreferencesHelper.getInstance());
     await preferences.setInt(PreferencesKeyList.USER_ID, userID);
     _currentUserID = userID;
 
@@ -130,14 +130,14 @@ class AccountHelper {
           .getObject()["exists"];
 
   /// Get current user email address
-  static Future<String> getCurrentAccountEmailAddress() async =>
+  static Future<String?> getCurrentAccountEmailAddress() async =>
       (await APIRequest.withLogin("account/mail")
           .execWithThrowGetObject())["mail"];
 
   /// Check out whether security questions have been set for an account or not
   ///
   /// Throws in case of failure
-  static Future<bool> hasSecurityQuestions(String email) async =>
+  static Future<bool?> hasSecurityQuestions(String email) async =>
       (await APIRequest.withoutLogin("account/has_security_questions")
               .addString("email", email)
               .execWithThrow())
@@ -146,7 +146,7 @@ class AccountHelper {
   /// Get the security questions of the user
   ///
   /// Throws in case of failure
-  static Future<List<String>> getSecurityQuestions(String email) async =>
+  static Future<List<String>?> getSecurityQuestions(String? email) async =>
       ((await APIRequest.withoutLogin("account/get_security_questions")
                   .addString("email", email)
                   .execWithThrow())
@@ -158,8 +158,8 @@ class AccountHelper {
   /// Throws an [Exception] in case of failure
   ///
   /// Returns a password reset token in case of success
-  static Future<String> checkAnswers(
+  static Future<String?> checkAnswers(
-          String email, List<String> answers) async =>
+          String? email, List<String> answers) async =>
       (await APIRequest.withoutLogin("account/check_security_answers")
               .addString("email", email)
               .addString("answers",
@@ -195,7 +195,7 @@ class AccountHelper {
           .execWithThrow();
 
   /// Get current user ID from the server
-  Future<int> _downloadCurrentUserID() async {
+  Future<int?> _downloadCurrentUserID() async {
     final response = await APIRequest.withLogin("account/id").exec();
 
     if (response.code != 200) return null;
@@ -210,10 +210,10 @@ class AccountHelper {
   }
 
   /// Check if current user ID is loaded or not
-  static bool get isUserIDLoaded => _currentUserID > 0;
+  static bool get isUserIDLoaded => _currentUserID! > 0;
 
   /// Get the ID of the currently signed in user
-  static int getCurrentUserID() {
+  static int? getCurrentUserID() {
     if (_currentUserID == -1) throw "Current user ID has not been loaded yet!";
     return _currentUserID;
   }

lib/helpers/api_helper.dart

@@ -41,13 +41,13 @@ class APIHelper {
       else
         url = Uri.https(config().apiServerName, path);
 
-      final data = FormData.fromMap(request.args);
+      final data = FormData.fromMap(request.args!);
 
       // Process files (if required)
       if (multipart) {
         // Process filesystem files
         for (final key in request.files.keys) {
-          var v = request.files[key];
+          var v = request.files[key]!;
           data.files.add(MapEntry(
               key,
               await MultipartFile.fromFile(v.path,
@@ -56,11 +56,11 @@ class APIHelper {
 
         // Process in-memory files
         for (final key in request.bytesFiles.keys) {
-          var v = request.bytesFiles[key];
+          var v = request.bytesFiles[key]!;
           data.files.add(MapEntry(
               key,
               MultipartFile.fromBytes(
-                v.bytes,
+                v.bytes!,
                 filename: v.filename.split("/").last,
                 contentType: v.type,
               )));
@@ -85,9 +85,9 @@ class APIHelper {
         EventsHelper.emit(InvalidLoginTokensEvent());
 
       if (response.statusCode != HttpStatus.ok)
-        return APIResponse(response.statusCode, response.data);
+        return APIResponse(response.statusCode!, response.data);
 
-      return APIResponse(response.statusCode, response.data);
+      return APIResponse(response.statusCode!, response.data);
     } catch (e, stack) {
       print(e.toString());
       print("Could not execute a request!");

lib/helpers/calls_helper.dart

@@ -39,12 +39,12 @@ class CallsHelper {
             .cast<CallMember>());
 
   /// Request an offer to access another peer's stream
-  static Future<void> requestOffer(int callID, int peerID) async =>
+  static Future<void> requestOffer(int callID, int? peerID) async =>
       await ws("calls/request_offer", {"callID": callID, "peerID": peerID});
 
   /// Send a Session Description message to the server
   static Future<void> sendSessionDescription(
-          int callID, int peerID, RTCSessionDescription sdp) async =>
+          int callID, int? peerID, RTCSessionDescription sdp) async =>
       await ws("calls/signal", {
         "callID": callID,
         "peerID": peerID,
@@ -54,7 +54,7 @@ class CallsHelper {
 
   /// Send an IceCandidate
   static Future<void> sendIceCandidate(
-          int callID, int peerID, RTCIceCandidate candidate) async =>
+          int callID, int? peerID, RTCIceCandidate candidate) async =>
       await ws("calls/signal", {
         "callID": callID,
         "peerID": peerID,

lib/helpers/comments_helper.dart

@@ -27,7 +27,7 @@ class CommentsHelper {
   }
 
   /// Get a single comment from the server, specified by its [id]
-  Future<Comment> getSingle(int id) async {
+  Future<Comment?> getSingle(int id) async {
     final response = await APIRequest(
         uri: "comments/get_single",
         needLogin: true,
@@ -39,7 +39,7 @@ class CommentsHelper {
   }
 
   /// Update comment content
-  Future<bool> updateContent(int id, String newContent) async {
+  Future<bool> updateContent(int id, String? newContent) async {
     return (await APIRequest(uri: "comments/edit", needLogin: true, args: {
       "commentID": id.toString(),
       "content": newContent,

lib/helpers/conversations_helper.dart

@@ -21,7 +21,6 @@ import 'package:comunic/utils/account_utils.dart';
 import 'package:comunic/utils/color_utils.dart';
 import 'package:comunic/utils/dart_color.dart';
 import 'package:dio/dio.dart';
-import 'package:meta/meta.dart';
 
 /// Conversation helper
 ///
@@ -39,7 +38,7 @@ class ConversationsHelper {
   /// Throws in case of failure
   static Future<int> createConversation(NewConversation settings) async {
     final response = await APIRequest.withLogin("conversations/create", args: {
-      "name": settings.name ?? "",
+      "name": settings.name,
       "follow": settings.follow ? "true" : "false",
       "users": settings.members.join(","),
       "color": colorToHex(settings.color)
@@ -53,7 +52,7 @@ class ConversationsHelper {
   /// Add a member to a conversation.
   ///
   /// Throws in case of failure
-  static Future<void> addMember(int convID, int userID) async =>
+  static Future<void> addMember(int? convID, int? userID) async =>
       await APIRequest.withLogin("conversations/addMember")
           .addInt("convID", convID)
           .addInt("userID", userID)
@@ -62,7 +61,7 @@ class ConversationsHelper {
   /// Remove a member from a conversation.
   ///
   /// Throws in case of failure
-  static Future<void> removeMember(int convID, int userID) async =>
+  static Future<void> removeMember(int? convID, int? userID) async =>
       await APIRequest.withLogin("conversations/removeMember")
           .addInt("convID", convID)
           .addInt("userID", userID)
@@ -90,8 +89,8 @@ class ConversationsHelper {
     // Update conversation settings
     if (settings.isComplete)
       request
-          .addString("name", settings.name ?? "")
+          .addString("name", settings.name)
-          .addBool("canEveryoneAddMembers", settings.canEveryoneAddMembers)
+          .addBool("canEveryoneAddMembers", settings.canEveryoneAddMembers!)
           .addString("color", colorToHex(settings.color));
 
     await request.execWithThrow();
@@ -104,7 +103,7 @@ class ConversationsHelper {
   /// Set a new conversation logo
   ///
   /// Throws in case of failure
-  static Future<void> changeImage(int convID, BytesFile file) async =>
+  static Future<void> changeImage(int? convID, BytesFile file) async =>
       await APIRequest.withLogin("conversations/change_image")
           .addInt("convID", convID)
           .addBytesFile("file", file)
@@ -113,13 +112,13 @@ class ConversationsHelper {
   /// Remove conversation logo
   ///
   /// Throws in case of failure
-  static Future<void> removeLogo(int convID) async =>
+  static Future<void> removeLogo(int? convID) async =>
       await APIRequest.withLogin("conversations/delete_image")
           .addInt("convID", convID)
           .execWithThrow();
 
   /// Delete a conversation specified by its [id]
-  Future<void> deleteConversation(int id) async =>
+  Future<void> deleteConversation(int? id) async =>
       await APIRequest.withLogin("conversations/delete")
           .addInt("conversationID", id)
           .execWithThrow();
@@ -132,7 +131,7 @@ class ConversationsHelper {
         await APIRequest.withLogin("conversations/getList").execWithThrow();
 
     ConversationsList list = ConversationsList();
-    response.getArray().forEach((f) => list.add(apiToConversation(f)));
+    response.getArray()!.forEach((f) => list.add(apiToConversation(f)));
 
     // Update the database
     await ConversationsSerializationHelper().setList(list);
@@ -148,7 +147,7 @@ class ConversationsHelper {
   }
 
   /// Get information about a single conversation specified by its [id]
-  Future<Conversation> _downloadSingle(int id) async {
+  Future<Conversation> _downloadSingle(int? id) async {
     final response = await APIRequest(
         uri: "conversations/get_single",
         needLogin: true,
@@ -167,7 +166,7 @@ class ConversationsHelper {
   /// case of failure
   ///
   /// Return value of this method is never null.
-  Future<Conversation> getSingle(int id, {bool force = false}) async {
+  Future<Conversation> getSingle(int? id, {bool force = false}) async {
     if (force ||
         !await ConversationsSerializationHelper().any((c) => c.id == id))
       return await _downloadSingle(id);
@@ -178,19 +177,19 @@ class ConversationsHelper {
   /// Get the name of a [conversation]. This requires information
   /// about the users of this conversation
   static String getConversationName(
-      Conversation conversation, UsersList users) {
+      Conversation conversation, UsersList? users) {
-    if (conversation.hasName) return conversation.name;
+    if (conversation.hasName) return conversation.name!;
 
     String name = "";
     int count = 0;
-    for (int i = 0; i < 3 && i < conversation.members.length; i++)
+    for (int i = 0; i < 3 && i < conversation.members!.length; i++)
-      if (conversation.members[i].userID != userID()) {
+      if (conversation.members![i].userID != userID()) {
         name += (count > 0 ? ", " : "") +
-            users.getUser(conversation.members[i].userID).fullName;
+            users!.getUser(conversation.members![i].userID).fullName;
         count++;
       }
 
-    if (conversation.members.length > 3) name += ", ...";
+    if (conversation.members!.length > 3) name += ", ...";
 
     return name;
   }
@@ -200,7 +199,7 @@ class ConversationsHelper {
   /// true
   ///
   /// Throws an exception in case of failure
-  Future<int> getPrivate(int userID, {bool allowCreate = true}) async {
+  Future<int> getPrivate(int? userID, {bool allowCreate = true}) async {
     final response = await APIRequest(
       uri: "conversations/getPrivate",
       needLogin: true,
@@ -222,7 +221,7 @@ class ConversationsHelper {
   /// Throws an exception in case of failure
   static Future<String> getConversationNameAsync(
       Conversation conversation) async {
-    if (conversation.hasName) return conversation.name;
+    if (conversation.hasName) return conversation.name!;
 
     //Get information about the members of the conversation
     final members = await UsersHelper().getList(conversation.membersID);
@@ -273,7 +272,7 @@ class ConversationsHelper {
 
     // Parse the response of the server
     ConversationMessagesList list = ConversationMessagesList();
-    response.getArray().forEach((f) {
+    response.getArray()!.forEach((f) {
       list.add(
         apiToConversationMessage(f),
       );
@@ -294,7 +293,7 @@ class ConversationsHelper {
   /// Throws an exception in case of failure
   Future<ConversationMessagesList> _downloadNewMessagesSingle(
       int conversationID,
-      {int lastMessageID = 0}) async {
+      {int? lastMessageID = 0}) async {
     // Execute the request on the server
     final response = await APIRequest(
         uri: "conversations/refresh_single",
@@ -311,8 +310,8 @@ class ConversationsHelper {
   ///
   /// Throws in case of failure
   Future<ConversationMessagesList> getOlderMessages({
-    @required int conversationID,
+    required int conversationID,
-    @required int oldestMessagesID,
+    required int? oldestMessagesID,
     int limit = 15,
   }) async {
     // Perform the request online
@@ -334,8 +333,8 @@ class ConversationsHelper {
   ///
   /// Throws in case of failure
   Future<ConversationMessagesList> getNewMessages(
-      {@required int conversationID,
+      {required int conversationID,
-      int lastMessageID = 0,
+      int? lastMessageID = 0,
       bool online = true}) async {
     if (online)
       return await _downloadNewMessagesSingle(conversationID,
@@ -348,8 +347,8 @@ class ConversationsHelper {
   /// Send a new message to the server
   Future<SendMessageResult> sendMessage(
     NewConversationMessage message, {
-    ProgressCallback sendProgress,
+    ProgressCallback? sendProgress,
-    CancelToken cancelToken,
+    CancelToken? cancelToken,
   }) async {
     final request = APIRequest.withLogin("conversations/sendMessage")
         .addInt("conversationID", message.conversationID)
@@ -388,7 +387,7 @@ class ConversationsHelper {
       await ConversationsMessagesSerializationHelper(msg.convID).remove(msg);
 
   /// Update a message content
-  Future<bool> updateMessage(int id, String newContent) async {
+  Future<bool> updateMessage(int? id, String newContent) async {
     final response = await APIRequest(
         uri: "conversations/updateMessage",
         needLogin: true,
@@ -400,7 +399,7 @@ class ConversationsHelper {
   }
 
   /// Delete permanently a message specified by its [id]
-  Future<bool> deleteMessage(int id) async {
+  Future<bool> deleteMessage(int? id) async {
     // Delete the message online
     final response = await APIRequest(
         uri: "conversations/deleteMessage",
@@ -418,7 +417,7 @@ class ConversationsHelper {
   static Future<UnreadConversationsList> getListUnread() async {
     final list = (await APIRequest.withLogin("conversations/get_list_unread")
             .execWithThrow())
-        .getArray();
+        .getArray()!;
 
     return UnreadConversationsList()
       ..addAll(list.map((f) => UnreadConversation(
@@ -431,7 +430,7 @@ class ConversationsHelper {
   /// conversation through WebSocket
   Future<void> registerConversationEvents(int id) async {
     if (_registeredConversations.containsKey(id))
-      _registeredConversations[id]++;
+      _registeredConversations.update(id, (value) => value + 1);
     else {
       _registeredConversations[id] = 1;
       await ws("\$main/register_conv", {"convID": id});
@@ -442,16 +441,16 @@ class ConversationsHelper {
   Future<void> unregisterConversationEvents(int id) async {
     if (!_registeredConversations.containsKey(id)) return;
 
-    _registeredConversations[id]--;
+    _registeredConversations.update(id, (value) => value - 1);
 
-    if (_registeredConversations[id] <= 0) {
+    if (_registeredConversations[id]! <= 0) {
       _registeredConversations.remove(id);
       await ws("\$main/unregister_conv", {"convID": id});
     }
   }
 
   /// Send a notification to inform that the user is writing a message
-  static Future<void> sendWritingEvent(int convID) async =>
+  static Future<void> sendWritingEvent(int? convID) async =>
       await ws("conversations/is_writing", {"convID": convID});
 
   /// Turn an API response into a ConversationMessage object

lib/helpers/database/database_helper.dart

@@ -9,11 +9,11 @@ import 'package:sqflite/sqflite.dart';
 /// @author Pierre HUBERT
 
 abstract class DatabaseHelper {
-  static Database _db;
+  static Database? _db;
 
   /// Open the database
   static Future<void> open() async {
-    if (_db != null && _db.isOpen) return;
+    if (_db != null && _db!.isOpen) return;
 
     var databasePath = await getDatabasesPath();
     _db = await openDatabase(
@@ -24,7 +24,7 @@ abstract class DatabaseHelper {
   }
 
   /// Get a database instance
-  static Future<Database> get() async {
+  static Future<Database?> get() async {
     await open();
     return _db;
   }

lib/helpers/database/model_database_helper.dart

@@ -18,12 +18,12 @@ abstract class ModelDatabaseHelper<T extends CacheModel> {
 
   /// Insert an entry in the database
   Future<void> _insertDB(T el) async {
-    await (await DatabaseHelper.get()).insert(tableName(), el.toMap());
+    await (await DatabaseHelper.get())!.insert(tableName(), el.toMap());
   }
 
   /// Update an element in the database
   Future<void> _updateDB(T el) async {
-    await (await DatabaseHelper.get()).update(
+    await (await DatabaseHelper.get())!.update(
       tableName(),
       el.toMap(),
       where: "${BaseTableContract.C_ID} = ?",
@@ -34,14 +34,14 @@ abstract class ModelDatabaseHelper<T extends CacheModel> {
   /// Get an element from the database with a specified [id]
   ///
   /// Returns null if none found
-  Future<T> get(int id) async {
+  Future<T?> get(int id) async {
-    List<Map> maps = await (await DatabaseHelper.get()).query(
+    List<Map> maps = await (await DatabaseHelper.get())!.query(
       tableName(),
       where: '${BaseTableContract.C_ID} = ?',
       whereArgs: [id],
     );
 
-    if (maps.length > 0) return initializeFromMap(maps[0]);
+    if (maps.length > 0) return initializeFromMap(maps[0] as Map<String, dynamic>);
 
     return null;
   }
@@ -50,7 +50,7 @@ abstract class ModelDatabaseHelper<T extends CacheModel> {
   ///
   /// Return true if at least one entry was deleted / false else
   Future<bool> delete(int id) async {
-    return await (await DatabaseHelper.get()).delete(
+    return await (await DatabaseHelper.get())!.delete(
       tableName(),
       where: '${BaseTableContract.C_ID} = ?',
       whereArgs: [id],
@@ -59,22 +59,22 @@ abstract class ModelDatabaseHelper<T extends CacheModel> {
 
   /// Get all the entries from the table
   Future<List<T>> getAll() async {
-    List<Map> maps = await (await DatabaseHelper.get()).query(tableName());
+    List<Map> maps = await (await DatabaseHelper.get())!.query(tableName());
-    return maps.map((f) => initializeFromMap(f)).toList();
+    return maps.map((f) => initializeFromMap(f as Map<String, dynamic>)).toList();
   }
 
   /// Get some entries from the table based on some conditions
   Future<List<T>> getMultiple(
-      {bool distinct,
+      {bool? distinct,
-      List<String> columns,
+      List<String>? columns,
-      String where,
+      String? where,
-      List<dynamic> whereArgs,
+      List<dynamic>? whereArgs,
-      String groupBy,
+      String? groupBy,
-      String having,
+      String? having,
-      String orderBy,
+      String? orderBy,
-      int limit,
+      int? limit,
-      int offset}) async {
+      int? offset}) async {
-    List<Map> maps = await (await DatabaseHelper.get()).query(
+    List<Map> maps = await (await DatabaseHelper.get())!.query(
       tableName(),
       distinct: distinct,
       columns: columns,
@@ -86,12 +86,12 @@ abstract class ModelDatabaseHelper<T extends CacheModel> {
       limit: limit,
       offset: offset,
     );
-    return maps.map((f) => initializeFromMap(f)).toList();
+    return maps.map((f) => initializeFromMap(f as Map<String, dynamic>)).toList();
   }
 
   /// Empty the table
   Future<void> clearTable() async {
-    await (await DatabaseHelper.get()).execute("DELETE FROM ${tableName()}");
+    await (await DatabaseHelper.get())!.execute("DELETE FROM ${tableName()}");
   }
 
   /// Check out whether an element specified with its [id] is present

lib/helpers/events_helper.dart

@@ -17,14 +17,14 @@ class WSClosedEvent {}
 
 /// New number of notifications
 class NewNumberNotifsEvent {
-  final int newNum;
+  final int? newNum;
 
   NewNumberNotifsEvent(this.newNum);
 }
 
 /// New number of unread conversations
 class NewNumberUnreadConversations {
-  final int newNum;
+  final int? newNum;
 
   NewNumberUnreadConversations(this.newNum);
 }
@@ -45,15 +45,15 @@ class UpdatedCommentEvent {
 
 /// Deleted comment
 class DeletedCommentEvent {
-  final int commentID;
+  final int? commentID;
 
   DeletedCommentEvent(this.commentID);
 }
 
 /// Writing message in conversation event
 class WritingMessageInConversationEvent {
-  final int convID;
+  final int? convID;
-  final int userID;
+  final int? userID;
 
   WritingMessageInConversationEvent(this.convID, this.userID);
 }
@@ -81,31 +81,31 @@ class DeletedConversationMessageEvent {
 
 /// Remove user from conversation
 class RemovedUserFromConversationEvent {
-  final int convID;
+  final int? convID;
-  final int userID;
+  final int? userID;
 
   RemovedUserFromConversationEvent(this.convID, this.userID);
 }
 
 /// Deleted conversation
 class DeletedConversationEvent {
-  final int convID;
+  final int? convID;
 
   DeletedConversationEvent(this.convID);
 }
 
 /// User joined call event
 class UserJoinedCallEvent {
-  final int callID;
+  final int? callID;
-  final int userID;
+  final int? userID;
 
   UserJoinedCallEvent(this.callID, this.userID);
 }
 
 /// User left call event
 class UserLeftCallEvent {
-  final int callID;
+  final int? callID;
-  final int userID;
+  final int? userID;
 
   UserLeftCallEvent(this.callID, this.userID);
 }
@@ -114,38 +114,36 @@ class UserLeftCallEvent {
 class NewCallSignalEvent {
   final int callID;
   final int peerID;
-  final RTCSessionDescription sessionDescription;
+  final RTCSessionDescription? sessionDescription;
-  final RTCIceCandidate candidate;
+  final RTCIceCandidate? candidate;
 
   const NewCallSignalEvent({
-    this.callID,
+    required this.callID,
-    this.peerID,
+    required this.peerID,
     this.sessionDescription,
     this.candidate,
-  })  : assert(callID != null),
+  }) : assert(sessionDescription != null || candidate != null);
-        assert(peerID != null),
-        assert(sessionDescription != null || candidate != null);
 }
 
 /// Call peer ready event
 class CallPeerReadyEvent {
-  final int callID;
+  final int? callID;
-  final int peerID;
+  final int? peerID;
 
   CallPeerReadyEvent(this.callID, this.peerID);
 }
 
 /// Call peer interrupted streaming event
 class CallPeerInterruptedStreamingEvent {
-  final int callID;
+  final int? callID;
-  final int peerID;
+  final int? peerID;
 
   CallPeerInterruptedStreamingEvent(this.callID, this.peerID);
 }
 
 /// Call closed event
 class CallClosedEvent {
-  final int callID;
+  final int? callID;
 
   CallClosedEvent(this.callID);
 }

lib/helpers/firebase_messaging_helper.dart

@@ -20,7 +20,7 @@ class FirebaseMessagingHelper {
   }
 
   /// Get a Firebase access token
-  static Future<String> getToken() async {
+  static Future<String?> getToken() async {
     return await FirebaseMessaging.instance.getToken();
   }
 }

lib/helpers/forez_groups_helper.dart

@@ -11,7 +11,7 @@ import 'package:comunic/models/group.dart';
 class ForezGroupsHelper {
   static Future<List<Group>> getForezGroups() async {
     return (await APIRequest.withLogin("forez/get_groups").execWithThrow())
-        .getArray()
+        .getArray()!
         .cast<Map<String, dynamic>>()
         .map(GroupsHelper.getGroupFromAPI)
         .toList();
@@ -21,10 +21,10 @@ class ForezGroupsHelper {
   ///
   /// This methods throws an exception in case of failure
   static Future<AdvancedUserInfo> getMemberInfo(int groupID, int userID) async {
-    final response = await APIRequest.withLogin("forez/get_member_info")
+    final response = await (APIRequest.withLogin("forez/get_member_info")
         .addInt("group", groupID)
         .addInt("user", userID)
-        .execWithThrowGetObject();
+        .execWithThrowGetObject());
 
     return UsersHelper.apiToAdvancedUserInfo(response);
   }

lib/helpers/forez_presence_helper.dart

@@ -6,8 +6,8 @@ import 'package:comunic/models/forez_presence.dart';
 ///
 /// @author Pierre Hubert
 
-int _cachedGroup;
+int? _cachedGroup;
-PresenceSet _cache;
+PresenceSet? _cache;
 
 class ForezPresenceHelper {
   /// Refresh presence cache
@@ -40,16 +40,16 @@ class ForezPresenceHelper {
   /// Get the presences of a given user
   ///
   /// Throws in case of failure
-  static Future<PresenceSet> getForUser(int groupID, int userID) async {
+  static Future<PresenceSet> getForUser(int groupID, int? userID) async {
     await _checkCache(groupID);
 
-    return _cache.getForUser(userID);
+    return _cache!.getForUser(userID);
   }
 
   /// Get all the available presences
   ///
   /// Throws in case of failure
-  static Future<PresenceSet> getAll(int groupID) async {
+  static Future<PresenceSet?> getAll(int groupID) async {
     await _checkCache(groupID);
     return _cache;
   }

lib/helpers/friends_helper.dart

@@ -3,7 +3,6 @@ import 'package:comunic/lists/friends_list.dart';
 import 'package:comunic/models/api_request.dart';
 import 'package:comunic/models/friend.dart';
 import 'package:comunic/models/friend_status.dart';
-import 'package:meta/meta.dart';
 
 /// Friends helper
 ///
@@ -16,7 +15,7 @@ class FriendsHelper {
   ///
   /// Returns the list of friends in case of success, or null if an error
   /// occurred
-  Future<FriendsList> _downloadList() async {
+  Future<FriendsList?> _downloadList() async {
     final response = await APIRequest(
       uri: "friends/getList",
       needLogin: true,
@@ -30,7 +29,7 @@ class FriendsHelper {
     // Parse and return the list of friends
     FriendsList list = FriendsList()
       ..addAll(response
-          .getArray()
+          .getArray()!
           .cast<Map<String, dynamic>>()
           .map(apiToFriend)
           .toList());
@@ -54,7 +53,7 @@ class FriendsHelper {
   }
 
   /// Get the list, either from an online or an offline source
-  Future<FriendsList> getList({@required bool online}) async {
+  Future<FriendsList?> getList({required bool online}) async {
     if (online)
       return await _downloadList();
     else
@@ -132,7 +131,7 @@ class FriendsHelper {
     if (response.code != 200)
       throw new Exception("Could not get the list of friends of this user!");
 
-    return Set<int>.from(response.getArray());
+    return Set<int>.from(response.getArray()!);
   }
 
   /// Send a friendship request to a specified user

lib/helpers/groups_helper.dart

@@ -49,15 +49,15 @@ enum GetAdvancedInfoStatus { SUCCESS, ACCESS_DENIED }
 
 class GetAdvancedInfoResult {
   final GetAdvancedInfoStatus status;
-  final AdvancedGroupInfo info;
+  final AdvancedGroupInfo? info;
 
-  GetAdvancedInfoResult(this.status, this.info) : assert(status != null);
+  GetAdvancedInfoResult(this.status, this.info);
 }
 
 /// Groups helper
 class GroupsHelper {
   /// Download a list of groups information from the server
-  Future<GroupsList> _downloadList(Set<int> groups) async {
+  Future<GroupsList?> _downloadList(Set<int?> groups) async {
     final response = await APIRequest(
       uri: "groups/get_multiple_info",
       needLogin: true,
@@ -77,7 +77,7 @@ class GroupsHelper {
 
   /// Get a list of groups from the server. In case of error, this method throws
   /// an exception
-  Future<GroupsList> getListOrThrow(Set<int> groups,
+  Future<GroupsList> getListOrThrow(Set<int?> groups,
       {bool force = false}) async {
     final list = await getList(groups, force: force);
 
@@ -87,11 +87,11 @@ class GroupsHelper {
   }
 
   /// Get a list of groups from the server
-  Future<GroupsList> getList(Set<int> groups, {bool force = false}) async {
+  Future<GroupsList?> getList(Set<int?> groups, {bool force = false}) async {
     final list = GroupsList();
 
     // Check which groups information to download
-    final toDownload = Set<int>();
+    final toDownload = Set<int?>();
     groups.forEach((groupID) {
       if (!force && _groupsListCache.containsKey(groupID))
         list[groupID] = _groupsListCache[groupID];
@@ -122,10 +122,10 @@ class GroupsHelper {
   }
 
   /// Get the list of groups of a user
-  Future<Set<int>> getListUser() async =>
+  Future<Set<int?>> getListUser() async =>
       (await APIRequest(uri: "groups/get_my_list", needLogin: true).exec())
           .assertOk()
-          .getArray()
+          .getArray()!
           .map((f) => cast<int>(f))
           .toSet();
 
@@ -142,7 +142,7 @@ class GroupsHelper {
 
   /// Perform a simple membership request
   static Future<bool> _simpleMembershipRequest(int groupID, String uri,
-          {Map<String, String> args}) async =>
+          {Map<String, String>? args}) async =>
       (await (APIRequest.withLogin(uri)
                 ..addInt("id", groupID)
                 ..addArgs(args == null ? Map() : args))
@@ -176,7 +176,7 @@ class GroupsHelper {
           .isOK;
 
   /// Get advanced information about the user
-  Future<GetAdvancedInfoResult> getAdvancedInfo(int groupID) async {
+  Future<GetAdvancedInfoResult> getAdvancedInfo(int? groupID) async {
     // Get advanced information about the user
     final result =
         await (APIRequest(uri: "groups/get_advanced_info", needLogin: true)
@@ -202,7 +202,7 @@ class GroupsHelper {
   /// change in the future
   ///
   /// Throws in case of error
-  Future<AdvancedGroupInfo> getSettings(int groupID) async {
+  Future<AdvancedGroupInfo?> getSettings(int groupID) async {
     final groupInfo = await getAdvancedInfo(groupID);
 
     if (groupInfo.status != GetAdvancedInfoStatus.SUCCESS)
@@ -239,7 +239,7 @@ class GroupsHelper {
             "posts_level",
             invertMap(
                 _APIGroupsPostsCreationLevelsMap)[settings.postCreationLevel])
-        .addBool("is_members_list_public", settings.isMembersListPublic)
+        .addBool("is_members_list_public", settings.isMembersListPublic!)
         .addString("description", settings.description)
         .addString("url", settings.url)
         .execWithThrow();
@@ -248,7 +248,7 @@ class GroupsHelper {
   /// Upload a new logo
   ///
   /// Throws in case of failure
-  static Future<void> uploadNewLogo(int groupID, Uint8List bytes) async =>
+  static Future<void> uploadNewLogo(int groupID, Uint8List? bytes) async =>
       await APIRequest(uri: "groups/upload_logo", needLogin: true)
           .addInt("id", groupID)
           .addBytesFile("logo", BytesFile("logo.png", bytes))
@@ -279,7 +279,7 @@ class GroupsHelper {
         ..addAll((await APIRequest(uri: "groups/get_members", needLogin: true)
                 .addInt("id", groupID)
                 .execWithThrow())
-            .getArray()
+            .getArray()!
             .map((f) => _apiToGroupMembership(f))
             .toList());
 
@@ -295,7 +295,7 @@ class GroupsHelper {
   /// Cancel a group membership invitation
   ///
   /// Throws an exception in case of failure
-  static Future<void> cancelInvitation(int groupID, int userID) async =>
+  static Future<void> cancelInvitation(int groupID, int? userID) async =>
       await APIRequest.withLogin("groups/cancel_invitation")
           .addInt("groupID", groupID)
           .addInt("userID", userID)
@@ -305,7 +305,7 @@ class GroupsHelper {
   ///
   /// Throws an exception in case of failure
   static Future<void> respondRequest(
-          int groupID, int userID, bool accept) async =>
+          int groupID, int? userID, bool accept) async =>
       await APIRequest.withLogin("groups/respond_request")
           .addInt("groupID", groupID)
           .addInt("userID", userID)
@@ -351,7 +351,7 @@ class GroupsHelper {
   ///
   /// Throws in case of failure
   static Future<void> setConversationVisibility(
-          int convID, GroupMembershipLevel newLevel) async =>
+          int? convID, GroupMembershipLevel? newLevel) async =>
       await APIRequest.withLogin("groups/set_conversation_visibility")
           .addInt("conv_id", convID)
           .addString(
@@ -364,7 +364,7 @@ class GroupsHelper {
   /// Delete a group's conversation
   ///
   /// Throws in case of failure
-  static Future<void> deleteConversation(int convID) async =>
+  static Future<void> deleteConversation(int? convID) async =>
       await APIRequest.withLogin("groups/delete_conversation")
           .addInt("conv_id", convID)
           .execWithThrow();
@@ -376,11 +376,11 @@ class GroupsHelper {
         name: map["name"],
         iconURL: map["icon_url"],
         numberMembers: map["number_members"],
-        membershipLevel: APIGroupsMembershipLevelsMap[map["membership"]],
+        membershipLevel: APIGroupsMembershipLevelsMap[map["membership"]]!,
-        visibilityLevel: _APIGroupsVisibilityLevelsMap[map["visibility"]],
+        visibilityLevel: _APIGroupsVisibilityLevelsMap[map["visibility"]]!,
         registrationLevel:
-            _APIGroupsRegistrationLevelsMap[map["registration_level"]],
+            _APIGroupsRegistrationLevelsMap[map["registration_level"]]!,
-        postCreationLevel: _APIGroupsPostsCreationLevelsMap[map["posts_level"]],
+        postCreationLevel: _APIGroupsPostsCreationLevelsMap[map["posts_level"]]!,
         virtualDirectory: nullToEmpty(map["virtual_directory"]),
         following: map["following"]);
   }
@@ -392,11 +392,11 @@ class GroupsHelper {
         name: map["name"],
         iconURL: map["icon_url"],
         numberMembers: map["number_members"],
-        membershipLevel: APIGroupsMembershipLevelsMap[map["membership"]],
+        membershipLevel: APIGroupsMembershipLevelsMap[map["membership"]]!,
-        visibilityLevel: _APIGroupsVisibilityLevelsMap[map["visibility"]],
+        visibilityLevel: _APIGroupsVisibilityLevelsMap[map["visibility"]]!,
         registrationLevel:
-            _APIGroupsRegistrationLevelsMap[map["registration_level"]],
+            _APIGroupsRegistrationLevelsMap[map["registration_level"]]!,
-        postCreationLevel: _APIGroupsPostsCreationLevelsMap[map["posts_level"]],
+        postCreationLevel: _APIGroupsPostsCreationLevelsMap[map["posts_level"]]!,
         isMembersListPublic: map["is_members_list_public"],
         virtualDirectory: nullToEmpty(map["virtual_directory"]),
         following: map["following"],
@@ -418,6 +418,6 @@ class GroupsHelper {
         userID: row["user_id"],
         groupID: row["group_id"],
         timeCreate: row["time_create"],
-        level: APIGroupsMembershipLevelsMap[row["level"]],
+        level: APIGroupsMembershipLevelsMap[row["level"]]!,
       );
 }

lib/helpers/independent_push_notifications_helper.dart

@@ -29,7 +29,7 @@ class IndependentPushNotificationsHelper {
   }
 
   /// Configure independent push notification services with a pull URL
-  static Future<void> configure(String wsURL) async {
+  static Future<void> configure(String? wsURL) async {
     await platform.invokeMethod("configure", wsURL);
   }
 

lib/helpers/likes_helper.dart

@@ -1,6 +1,5 @@
 import 'package:comunic/enums/likes_type.dart';
 import 'package:comunic/helpers/websocket_helper.dart';
-import 'package:meta/meta.dart';
 
 /// Likes helper
 ///
@@ -16,9 +15,9 @@ const LikesAPIMap = {
 class LikesHelper {
   /// Update liking status of an element
   Future<void> setLiking({
-    @required LikesType type,
+    required LikesType type,
-    @required bool like,
+    required bool like,
-    @required int id,
+    required int id,
   }) async {
     return (await ws("likes/update", {
       "type": LikesAPIMap[type],

lib/helpers/notifications_helper.dart

@@ -75,15 +75,15 @@ class NotificationsHelper {
     // Parse the list of notifications
     return NotificationsList()
       ..addAll(response
-          .getArray()
+          .getArray()!
           .map((f) => Notification(
               id: f["id"],
               timeCreate: f["time_create"],
               seen: f["seen"],
               fromUser: f["from_user_id"],
               onElemId: f["on_elem_id"],
-              onElemType: _NotificationElementTypeAPImapping[f["on_elem_type"]],
+              onElemType: _NotificationElementTypeAPImapping[f["on_elem_type"]]!,
-              type: _NotificationsTypeAPImapping[f["type"]],
+              type: _NotificationsTypeAPImapping[f["type"]]!,
               fromContainerId: f["from_container_id"],
               fromContainerType: f["from_container_type"] == ""
                   ? null

lib/helpers/posts_helper.dart

@@ -55,7 +55,7 @@ class PostsHelper {
 
   /// Get the list of latest posts. Return the list of posts or null in case of
   /// failure
-  Future<PostsList> getLatest({int from = 0}) async {
+  Future<PostsList?> getLatest({int from = 0}) async {
     final response =
         await APIRequest(uri: "posts/get_latest", needLogin: true, args: {
       "include_groups": true.toString(),
@@ -66,7 +66,8 @@ class PostsHelper {
 
     try {
       // Parse & return the list of posts
-      return PostsList()..addAll(response.getArray().map((f) => _apiToPost(f)));
+      return PostsList()
+        ..addAll(response.getArray()!.map((f) => _apiToPost(f)));
     } catch (e) {
       print(e.toString());
       return null;
@@ -74,7 +75,7 @@ class PostsHelper {
   }
 
   /// Get the list of posts of a user
-  Future<PostsList> getUserPosts(int userID, {int from = 0}) async {
+  Future<PostsList?> getUserPosts(int? userID, {int from = 0}) async {
     final response = await (APIRequest(uri: "posts/get_user", needLogin: true)
           ..addInt("userID", userID)
           ..addInt("startFrom", from == 0 ? 0 : from - 1))
@@ -84,7 +85,8 @@ class PostsHelper {
 
     try {
       // Parse & return the list of posts
-      return PostsList()..addAll(response.getArray().map((f) => _apiToPost(f)));
+      return PostsList()
+        ..addAll(response.getArray()!.map((f) => _apiToPost(f)));
     } catch (e) {
       print(e.toString());
       return null;
@@ -92,7 +94,7 @@ class PostsHelper {
   }
 
   /// Get the list of posts of a group
-  Future<PostsList> getGroupPosts(int groupID, {int from = 0}) async {
+  Future<PostsList?> getGroupPosts(int groupID, {int from = 0}) async {
     final response = await (APIRequest(uri: "posts/get_group", needLogin: true)
           ..addInt("groupID", groupID)
           ..addInt("startFrom", from == 0 ? 0 : from - 1))
@@ -102,7 +104,8 @@ class PostsHelper {
 
     try {
       // Parse & return the list of posts
-      return PostsList()..addAll(response.getArray().map((f) => _apiToPost(f)));
+      return PostsList()
+        ..addAll(response.getArray()!.map((f) => _apiToPost(f)));
     } catch (e) {
       print(e.toString());
       return null;
@@ -158,13 +161,14 @@ class PostsHelper {
 
       case PostKind.COUNTDOWN:
         request.addInt(
-            "time-end", (post.timeEnd.millisecondsSinceEpoch / 1000).floor());
+            "time-end", (post.timeEnd!.millisecondsSinceEpoch / 1000).floor());
         break;
 
       case PostKind.SURVEY:
-        request.addString("question", post.survey.question);
+        request.addString("question", post.survey!.question);
-        request.addString("answers", post.survey.answers.join("<>"));
+        request.addString("answers", post.survey!.answers.join("<>"));
-        request.addBool("allowNewAnswers", post.survey.allowNewChoicesCreation);
+        request.addBool(
+            "allowNewAnswers", post.survey!.allowNewChoicesCreation);
         break;
 
       case PostKind.YOUTUBE:
@@ -173,7 +177,6 @@ class PostsHelper {
 
       default:
         throw Exception("Unsupported post type :" + post.kind.toString());
-        break;
     }
 
     final response = await request.execWithFiles();
@@ -221,7 +224,7 @@ class PostsHelper {
   /// Register to a post events
   Future<void> registerPostEvents(int id) async {
     if (_registeredPosts.containsKey(id))
-      _registeredPosts[id]++;
+      _registeredPosts.update(id, (v) => v + 1);
     else {
       _registeredPosts[id] = 1;
       await ws("\$main/register_post", {"postID": id});
@@ -232,9 +235,9 @@ class PostsHelper {
   Future<void> unregisterPostEvents(int id) async {
     if (!_registeredPosts.containsKey(id)) return;
 
-    _registeredPosts[id]--;
+    _registeredPosts.update(id, (v) => v - 1);
 
-    if (_registeredPosts[id] <= 0) {
+    if (_registeredPosts[id]! <= 0) {
       _registeredPosts.remove(id);
       await ws("\$main/unregister_post", {"postID": id});
     }
@@ -242,14 +245,14 @@ class PostsHelper {
 
   /// Turn an API entry into a [Post] object
   Post _apiToPost(Map<String, dynamic> map) {
-    final postKind = _APIPostsKindsMap[map["kind"]];
+    final postKind = _APIPostsKindsMap[map["kind"]]!;
 
     // Parse comments
-    CommentsList comments;
+    CommentsList? comments;
     if (map["comments"] != null) {
       comments = CommentsList();
       map["comments"]
-          .forEach((v) => comments.add(CommentsHelper.apiToComment(v)));
+          .forEach((v) => comments!.add(CommentsHelper.apiToComment(v)));
     }
 
     final survey = postKind == PostKind.SURVEY
@@ -263,7 +266,7 @@ class PostsHelper {
         groupID: map["group_id"],
         timeSent: map["post_time"],
         content: DisplayedString(map["content"]),
-        visibilityLevel: _APIPostsVisibilityLevelMap[map["visibility_level"]],
+        visibilityLevel: _APIPostsVisibilityLevelMap[map["visibility_level"]]!,
         kind: postKind,
         fileSize: map["file_size"],
         fileType: map["file_type"],
@@ -276,7 +279,7 @@ class PostsHelper {
         linkImage: map["link_image"],
         likes: map["likes"],
         userLike: map["userlike"],
-        access: _APIUserAccessMap[map["user_access"]],
+        access: _APIUserAccessMap[map["user_access"]]!,
         comments: comments,
         survey: survey);
   }

lib/helpers/preferences_helper.dart

@@ -30,7 +30,7 @@ const _PreferenceKeysName = {
 };
 
 class PreferencesHelper {
-  static PreferencesHelper _instance;
+  static PreferencesHelper? _instance;
 
   static Future<PreferencesHelper> getInstance() async {
     if (_instance == null) {
@@ -38,10 +38,10 @@ class PreferencesHelper {
       await _init();
     }
 
-    return _instance;
+    return _instance!;
   }
 
-  static SharedPreferences _sharedPreferences;
+  static late SharedPreferences _sharedPreferences;
 
   PreferencesHelper._();
 
@@ -50,7 +50,7 @@ class PreferencesHelper {
   }
 
   /// Set new login tokens
-  Future<void> setLoginToken(String token) async {
+  Future<void> setLoginToken(String? token) async {
     if (token != null)
       await setString(PreferencesKeyList.LOGIN_TOKEN, token);
     else
@@ -58,7 +58,7 @@ class PreferencesHelper {
   }
 
   /// Get current [LoginTokens]. Returns null if none or in case of failure
-  String getLoginToken() {
+  String? getLoginToken() {
     try {
       final string = getString(PreferencesKeyList.LOGIN_TOKEN);
       return string;
@@ -69,35 +69,35 @@ class PreferencesHelper {
   }
 
   bool containsKey(PreferencesKeyList key) {
-    return _sharedPreferences.containsKey(_PreferenceKeysName[key]);
+    return _sharedPreferences.containsKey(_PreferenceKeysName[key]!);
   }
 
   Future<bool> removeKey(PreferencesKeyList key) async {
-    return await _sharedPreferences.remove(_PreferenceKeysName[key]);
+    return await _sharedPreferences.remove(_PreferenceKeysName[key]!);
   }
 
   Future<bool> setString(PreferencesKeyList key, String value) async {
-    return await _sharedPreferences.setString(_PreferenceKeysName[key], value);
+    return await _sharedPreferences.setString(_PreferenceKeysName[key]!, value);
   }
 
-  String getString(PreferencesKeyList key) {
+  String? getString(PreferencesKeyList key) {
-    return _sharedPreferences.getString(_PreferenceKeysName[key]);
+    return _sharedPreferences.getString(_PreferenceKeysName[key]!);
   }
 
   Future<bool> setBool(PreferencesKeyList key, bool value) async {
-    return await _sharedPreferences.setBool(_PreferenceKeysName[key], value);
+    return await _sharedPreferences.setBool(_PreferenceKeysName[key]!, value);
   }
 
   Future<bool> setInt(PreferencesKeyList key, int value) async {
-    return await _sharedPreferences.setInt(_PreferenceKeysName[key], value);
+    return await _sharedPreferences.setInt(_PreferenceKeysName[key]!, value);
   }
 
-  int getInt(PreferencesKeyList key) {
+  int? getInt(PreferencesKeyList key) {
-    return _sharedPreferences.getInt(_PreferenceKeysName[key]);
+    return _sharedPreferences.getInt(_PreferenceKeysName[key]!);
   }
 
   bool getBool(PreferencesKeyList key, {bool alternative = false}) {
-    final v = _sharedPreferences.getBool(_PreferenceKeysName[key]);
+    final v = _sharedPreferences.getBool(_PreferenceKeysName[key]!);
     return v == null ? alternative : v;
   }
 
@@ -115,7 +115,7 @@ class PreferencesHelper {
   }
 }
 
-PreferencesHelper preferences() {
+PreferencesHelper? preferences() {
   if (PreferencesHelper._instance == null)
     throw Exception("Try to get preference before their initialization!");
 

lib/helpers/push_notifications_helper.dart

@@ -21,14 +21,14 @@ const _PushNotificationsAPIMap = {
 
 class PushNotificationsHelper {
   /// Get cached status of push notifications
-  static Future<PushNotificationsStatus> getLocalStatus() async {
+  static Future<PushNotificationsStatus?> getLocalStatus() async {
     final pref = await PreferencesHelper.getInstance();
 
     if (!pref.containsKey(PreferencesKeyList.PUSH_NOTIFICATIONS_STATUS))
       return PushNotificationsStatus.UNDEFINED;
 
     return _PushNotificationsAPIMap[
-        pref.getString(PreferencesKeyList.PUSH_NOTIFICATIONS_STATUS)];
+        pref.getString(PreferencesKeyList.PUSH_NOTIFICATIONS_STATUS)!];
   }
 
   /// Refresh local status with information from server
@@ -62,8 +62,8 @@ class PushNotificationsHelper {
 
   /// Configure push notifications
   static Future<void> configure(
-      BuildContext context, PushNotificationsStatus newStatus) async {
+      BuildContext context, PushNotificationsStatus? newStatus) async {
-    String firebaseToken = "";
+    String? firebaseToken = "";
     switch (newStatus) {
       case PushNotificationsStatus.DISABLED:
         break;
@@ -90,8 +90,8 @@ class PushNotificationsHelper {
 
   /// Set new push notification status on the server
   static Future<void> setNewStatus(
-    PushNotificationsStatus newStatus, {
+    PushNotificationsStatus? newStatus, {
-    String firebaseToken = "",
+    String? firebaseToken = "",
   }) async =>
       await APIRequest.withLogin("push_notifications/configure")
           .addString(
@@ -104,6 +104,6 @@ class PushNotificationsHelper {
 
   /// Is true if possible if push notifications are configurable
   static bool get arePushNotificationsAvailable =>
-      srvConfig.notificationsPolicy.hasFirebase ||
+      srvConfig!.notificationsPolicy.hasFirebase ||
-      (isAndroid && srvConfig.notificationsPolicy.hasIndependent);
+      (isAndroid && srvConfig!.notificationsPolicy.hasIndependent);
 }

lib/helpers/report_helper.dart

@@ -0,0 +1,38 @@
+import 'package:comunic/enums/report_target_type.dart';
+import 'package:comunic/models/api_request.dart';
+import 'package:comunic/models/report_target.dart';
+import 'package:comunic/models/server_config.dart';
+
+/// Reports Helper
+///
+/// @author Pierre Hubert
+
+enum ReportResult {
+  Success,
+  ErrorAlreadyReported,
+  Error,
+}
+
+class ReportHelper {
+  /// Send a new report to the server
+  static Future<ReportResult> sendReport({
+    required ReportCause cause,
+    required ReportTarget target,
+    required String comment,
+  }) async {
+    final response = await APIRequest.withLogin("reports/create", args: {
+      "cause": cause.id,
+      "target_type": target.type.apiId,
+      "target_id": target.id.toString(),
+      "comment": comment
+    }).exec();
+
+    if (response.isOK) return ReportResult.Success;
+
+    print("Failed to send report: ${response.content}");
+
+    if (response.code == 409) return ReportResult.ErrorAlreadyReported;
+
+    return ReportResult.Error;
+  }
+}

lib/helpers/search_helper.dart

@@ -13,7 +13,7 @@ class SearchHelper {
   /// Search for user. This method returns information about the target users
   ///
   /// Returns information about the target users or null if an error occurred
-  Future<UsersList> searchUser(String query) async {
+  Future<UsersList?> searchUser(String query) async {
     // Execute the query on the server
     final response = await APIRequest(
         uri: "user/search", needLogin: true, args: {"query": query}).exec();
@@ -21,7 +21,7 @@ class SearchHelper {
     if (response.code != 200) return null;
 
     return await UsersHelper()
-        .getUsersInfo(response.getArray().map((f) => cast<int>(f)).toList());
+        .getUsersInfo(response.getArray()!.map((f) => cast<int>(f)).toList());
   }
 
   /// Perform a global search
@@ -31,7 +31,7 @@ class SearchHelper {
 
     result.assertOk();
 
-    return SearchResultsList()..addAll(result.getArray().map((f) {
+    return SearchResultsList()..addAll(result.getArray()!.map((f) {
       switch (f["kind"]) {
         case "user":
           return SearchResult(id: f["id"], kind: SearchResultKind.USER);

lib/helpers/serialization/base_serialization_helper.dart

@@ -17,7 +17,7 @@ abstract class SerializableElement<T> extends Comparable<T> {
 
 abstract class BaseSerializationHelper<T extends SerializableElement> {
   /// List cache
-  List<T> _cache;
+  List<T>? _cache;
 
   /// The name of the type of data to serialise
   String get type;
@@ -48,12 +48,15 @@ abstract class BaseSerializationHelper<T extends SerializableElement> {
     try {
       final file = await _getFilePath();
 
-      if (!await file.exists()) return _cache = [];
+      if (!await file.exists()) {
+        _cache = [];
+        return;
+      }
 
       final List<dynamic> json = jsonDecode(await file.readAsString());
       _cache = json.cast<Map<String, dynamic>>().map(parse).toList();
 
-      _cache.sort();
+      _cache!.sort();
     } catch (e, s) {
       logError(e, s);
       print("Failed to read serialized data!");
@@ -67,8 +70,10 @@ abstract class BaseSerializationHelper<T extends SerializableElement> {
 
     try {
       final file = await _getFilePath();
-      await file.writeAsString(jsonEncode(
+      await file.writeAsString(jsonEncode(_cache!
-          _cache.map((e) => e.toJson()).toList().cast<Map<String, dynamic>>()));
+          .map((e) => e.toJson())
+          .toList()
+          .cast<Map<String, dynamic>>()));
     } catch (e, s) {
       print("Failed to write file!");
       logError(e, s);
@@ -78,7 +83,7 @@ abstract class BaseSerializationHelper<T extends SerializableElement> {
   /// Get the current list of elements
   Future<List<T>> getList() async {
     await _loadCache();
-    return List.from(_cache);
+    return List.from(_cache!);
   }
 
   /// Set a new list of conversations
@@ -90,23 +95,23 @@ abstract class BaseSerializationHelper<T extends SerializableElement> {
   /// Insert new element
   Future<void> insert(T el) async {
     await _loadCache();
-    _cache.add(el);
+    _cache!.add(el);
-    _cache.sort();
+    _cache!.sort();
     await _saveCache();
   }
 
   /// Insert new element
   Future<void> insertMany(List<T> els) async {
     await _loadCache();
-    _cache.addAll(els);
+    _cache!.addAll(els);
-    _cache.sort();
+    _cache!.sort();
     await _saveCache();
   }
 
   /// Check if any entry in the last match the predicate
   Future<bool> any(bool isContained(T t)) async {
     await _loadCache();
-    return _cache.any((element) => isContained(element));
+    return _cache!.any((element) => isContained(element));
   }
 
   Future<bool> has(T el) => any((t) => t == el);
@@ -114,7 +119,7 @@ abstract class BaseSerializationHelper<T extends SerializableElement> {
   /// Check if any entry in the last match the predicate
   Future<T> first(bool filter(T t)) async {
     await _loadCache();
-    return _cache.firstWhere((element) => filter(element));
+    return _cache!.firstWhere((element) => filter(element));
   }
 
   /// Replace an element with another one
@@ -122,10 +127,10 @@ abstract class BaseSerializationHelper<T extends SerializableElement> {
     await _loadCache();
 
     // Insert or replace the element
-    _cache = _cache.where((element) => !isToReplace(element)).toList();
+    _cache = _cache!.where((element) => !isToReplace(element)).toList();
-    _cache.add(newEl);
+    _cache!.add(newEl);
 
-    _cache.sort();
+    _cache!.sort();
     await _saveCache();
   }
 
@@ -133,8 +138,8 @@ abstract class BaseSerializationHelper<T extends SerializableElement> {
   Future<void> insertOrReplaceElements(List<T> list) async {
     await _loadCache();
 
-    _cache.removeWhere((element) => list.any((newEl) => element == newEl));
+    _cache!.removeWhere((element) => list.any((newEl) => element == newEl));
-    _cache.addAll(list);
+    _cache!.addAll(list);
 
     await _saveCache();
   }
@@ -142,7 +147,7 @@ abstract class BaseSerializationHelper<T extends SerializableElement> {
   /// Remove elements
   Future<void> removeElement(bool isToRemove(T t)) async {
     await _loadCache();
-    _cache.removeWhere((element) => isToRemove(element));
+    _cache!.removeWhere((element) => isToRemove(element));
     await _saveCache();
   }
 

lib/helpers/serialization/conversation_message_serialization_helper.dart

@@ -8,23 +8,22 @@ import 'package:comunic/models/conversation_message.dart';
 ///
 /// @author Pierre Hubert
 
-HashMap<int, ConversationsMessagesSerializationHelper> _instances;
+HashMap<int?, ConversationsMessagesSerializationHelper>? _instances;
 
 class ConversationsMessagesSerializationHelper
     extends BaseSerializationHelper<ConversationMessage> {
   final int convID;
 
   ConversationsMessagesSerializationHelper._(int convID)
-      : convID = convID,
+      : convID = convID;
-        assert(convID != null);
 
-  factory ConversationsMessagesSerializationHelper(int convID) {
+  factory ConversationsMessagesSerializationHelper(int? convID) {
     if (_instances == null) _instances = HashMap();
 
-    if (!_instances.containsKey(convID))
+    if (!_instances!.containsKey(convID))
-      _instances[convID] = ConversationsMessagesSerializationHelper._(convID);
+      _instances![convID] = ConversationsMessagesSerializationHelper._(convID!);
 
-    return _instances[convID];
+    return _instances![convID]!;
   }
 
   @override

lib/helpers/serialization/conversations_serialization_helper.dart

@@ -28,5 +28,5 @@ class ConversationsSerializationHelper
       ConversationsList()..addAll(await super.getList());
 
   /// Get a conversation
-  Future<Conversation> get(int id) => first((t) => t.id == id);
+  Future<Conversation> get(int? id) => first((t) => t.id == id);
 }

lib/helpers/serialization/user_list_serialization_helper.dart

@@ -5,7 +5,7 @@ import 'package:comunic/models/user.dart';
 ///
 /// @author Pierre Hubert
 
-UsersListSerialisationHelper _singleton;
+UsersListSerialisationHelper? _singleton;
 
 class UsersListSerialisationHelper extends BaseSerializationHelper<User> {
   UsersListSerialisationHelper._();
@@ -13,7 +13,7 @@ class UsersListSerialisationHelper extends BaseSerializationHelper<User> {
   factory UsersListSerialisationHelper() {
     if (_singleton == null) _singleton = UsersListSerialisationHelper._();
 
-    return _singleton;
+    return _singleton!;
   }
 
   @override
@@ -23,6 +23,6 @@ class UsersListSerialisationHelper extends BaseSerializationHelper<User> {
   User parse(Map<String, dynamic> m) => User.fromJson(m);
 
   /// Remove a user by its ID
-  Future<void> removeUserByID(int userID) =>
+  Future<void> removeUserByID(int? userID) =>
       removeElement((t) => t.id == userID);
 }

lib/helpers/server_config_helper.dart

@@ -7,7 +7,7 @@ import 'package:version/version.dart';
 /// @author Pierre Hubert
 
 class ServerConfigurationHelper {
-  static ServerConfig _config;
+  static ServerConfig? _config;
 
   /// Make sure the configuration has been correctly loaded
   static Future<void> ensureLoaded() async {
@@ -17,11 +17,13 @@ class ServerConfigurationHelper {
         (await APIRequest.withoutLogin("server/config").execWithThrow())
             .getObject();
 
+    final banner = response["banner"];
     final pushNotificationsPolicy = response["push_notifications"];
     final passwordPolicy = response["password_policy"];
     final dataConservationPolicy = response["data_conservation_policy"];
     final conversationsPolicy = response["conversations_policy"];
     final accountInformationPolicy = response["account_info_policy"];
+    final reportPolicy = response["report_policy"];
 
     _config = ServerConfig(
         minSupportedMobileVersion:
@@ -31,6 +33,15 @@ class ServerConfigurationHelper {
         contactEmail: response["contact_email"],
         playStoreURL: response["play_store_url"],
         androidDirectDownloadURL: response["android_direct_download_url"],
+        banner: banner == null
+            ? null
+            : Banner(
+                enabled: banner["enabled"],
+                expire: banner["expire"],
+                nature: BannerNatureExt.fromStr(banner["nature"]),
+                message: Map<String, dynamic>.from(banner["message"])
+                    .map((key, value) => MapEntry(key, value.toString())),
+                link: banner["link"]),
         notificationsPolicy: NotificationsPolicy(
           hasFirebase: pushNotificationsPolicy["has_firebase"],
           hasIndependent: pushNotificationsPolicy["has_independent"],
@@ -70,7 +81,8 @@ class ServerConfigurationHelper {
           writingEventInterval: conversationsPolicy["writing_event_interval"],
           writingEventLifetime: conversationsPolicy["writing_event_lifetime"],
           maxMessageImageWidth: conversationsPolicy["max_message_image_width"],
-        maxMessageImageHeight: conversationsPolicy["max_message_image_height"],
+          maxMessageImageHeight:
+              conversationsPolicy["max_message_image_height"],
           maxThumbnailWidth: conversationsPolicy["max_thumbnail_width"],
           maxThumbnailHeight: conversationsPolicy["max_thumbnail_height"],
           maxLogoWidth: conversationsPolicy["max_logo_width"],
@@ -83,11 +95,22 @@ class ServerConfigurationHelper {
           maxLastNameLength: accountInformationPolicy["max_last_name_length"],
           maxLocationLength: accountInformationPolicy["max_location_length"],
         ),
-    );
+        reportPolicy: reportPolicy == null
+            ? null
+            : ReportPolicy(
+                causes: List.from(reportPolicy["causes"]
+                    .map((cause) => ReportCause(
+                        id: cause["id"],
+                        label: new Map<String, String>.from(cause["label"])))
+                    .toList()),
+                maxCommentLength: reportPolicy["max_comment_length"],
+                canUserReportHisOwnContent:
+                    reportPolicy["can_user_report_his_own_content"],
+              ));
   }
 
   /// Get current server configuration, throwing if it is not loaded yet
-  static ServerConfig get config {
+  static ServerConfig? get config {
     if (_config == null)
       throw Exception(
           "Trying to access server configuration but it is not loaded yet!");
@@ -97,4 +120,6 @@ class ServerConfigurationHelper {
 }
 
 /// Shortcut for server configuration
-ServerConfig get srvConfig => ServerConfigurationHelper.config;
+ServerConfig? get srvConfig => ServerConfigurationHelper.config;
+
+bool get showBanner => srvConfig!.banner != null && srvConfig!.banner!.visible;

lib/helpers/settings_helper.dart

@@ -94,7 +94,7 @@ class SettingsHelper {
         hasImage: response["has_image"],
         imageURL: response["image_url"],
         visibility:
-            _APIAccountImageVisibilityAPILevels[response["visibility"]]);
+            _APIAccountImageVisibilityAPILevels[response["visibility"]]!);
   }
 
   /// Upload a new account image
@@ -143,7 +143,7 @@ class SettingsHelper {
   /// Delete a custom emoji
   ///
   /// Throws in case of failure
-  static Future<void> deleteCustomEmoji(int emojiID) async =>
+  static Future<void> deleteCustomEmoji(int? emojiID) async =>
       (await APIRequest(uri: "settings/delete_custom_emoji", needLogin: true)
               .addInt("emojiID", emojiID)
               .exec())
@@ -223,7 +223,7 @@ class SettingsHelper {
   ///
   /// Throws in case of failure
   static Future<void> setDataConservationPolicy(
-      String password, DataConservationPolicySettings newSettings) async {
+      String? password, DataConservationPolicySettings newSettings) async {
     await APIRequest(
             uri: "settings/set_data_conservation_policy", needLogin: true)
         .addString("password", password)

lib/helpers/survey_helper.dart

@@ -1,7 +1,6 @@
 import 'package:comunic/models/api_request.dart';
 import 'package:comunic/models/survey.dart';
 import 'package:comunic/models/survey_choice.dart';
-import 'package:meta/meta.dart';
 
 /// Survey helper
 ///
@@ -26,9 +25,7 @@ class SurveyHelper {
 
   /// Send the response of a user to a survey
   Future<bool> respondToSurvey(
-      {@required Survey survey, @required SurveyChoice choice}) async {
+      {required Survey survey, required SurveyChoice choice}) async {
-    assert(survey != null);
-    assert(choice != null);
 
     return (await APIRequest(
       uri: "surveys/send_response",

lib/helpers/users_helper.dart

@@ -23,7 +23,7 @@ enum GetUserAdvancedInformationErrorCause {
 class GetUserAdvancedUserError extends Error {
   final GetUserAdvancedInformationErrorCause cause;
 
-  GetUserAdvancedUserError(this.cause) : assert(cause != null);
+  GetUserAdvancedUserError(this.cause);
 }
 
 class UsersHelper {
@@ -31,7 +31,7 @@ class UsersHelper {
   ///
   /// Return the list of users information in case of success, null in case of
   /// failure
-  Future<UsersList> _downloadInfo(List<int> users) async {
+  Future<UsersList?> _downloadInfo(List<int?> users) async {
     // Execute the request
     final response = await APIRequest(
         uri: "user/getInfoMultiple",
@@ -69,7 +69,7 @@ class UsersHelper {
 
   /// Get users information from a given [Set]. Throws an exception in case
   /// of failure
-  Future<UsersList> getListWithThrow(Set<int> users,
+  Future<UsersList> getListWithThrow(Set<int?> users,
       {bool forceDownload = false}) async {
     final list =
         await getUsersInfo(users.toList(), forceDownload: forceDownload);
@@ -82,16 +82,16 @@ class UsersHelper {
   }
 
   /// Get information about a single user. Throws in case of failure
-  Future<User> getSingleWithThrow(int user,
+  Future<User> getSingleWithThrow(int? user,
       {bool forceDownload = false}) async {
-    return (await getListWithThrow(Set<int>()..add(user),
+    return (await getListWithThrow(Set<int?>()..add(user),
         forceDownload: forceDownload))[0];
   }
 
   /// Get users information from a given [Set]
   ///
   /// Throws in case of failure
-  Future<UsersList> getList(Set<int> users,
+  Future<UsersList> getList(Set<int?> users,
       {bool forceDownload = false}) async {
     final list = await getUsersInfo(users.toList());
 
@@ -104,13 +104,13 @@ class UsersHelper {
   ///
   /// If [forceDownload] is set to true, the data will always be retrieved from
   /// the server, otherwise cached data will be used if available
-  Future<UsersList> getUsersInfo(List<int> users,
+  Future<UsersList?> getUsersInfo(List<int?> users,
       {bool forceDownload = false}) async {
-    List<int> toDownload = [];
+    List<int?> toDownload = [];
     UsersList list = UsersList();
 
     // Check cache
-    for (int userID in users) {
+    for (int? userID in users) {
       if (!forceDownload &&
           await UsersListSerialisationHelper().any((u) => u.id == userID))
         list.add(

lib/helpers/version_helper.dart

@@ -1,5 +1,5 @@
 import 'package:comunic/utils/flutter_utils.dart';
-import 'package:package_info/package_info.dart';
+import 'package:package_info_plus/package_info_plus.dart';
 import 'package:version/version.dart';
 
 /// Application version helper
@@ -7,15 +7,15 @@ import 'package:version/version.dart';
 /// @author Pierre Hubert
 
 class VersionHelper {
-  static PackageInfo _info;
+  static PackageInfo? _info;
 
   static Future<void> ensureLoaded() async {
     if (!isWeb) _info = await PackageInfo.fromPlatform();
   }
 
   /// Get current version information
-  static PackageInfo get info => _info;
+  static PackageInfo? get info => _info;
 
   /// Get current application version, in parsed format
-  static Version get version => Version.parse(info.version);
+  static Version get version => Version.parse(info!.version);
 }

lib/helpers/virtual_directory_helper.dart

@@ -1,5 +1,4 @@
 import 'package:comunic/models/api_request.dart';
-import 'package:flutter/material.dart';
 
 /// Virtual directory helper
 ///
@@ -9,12 +8,12 @@ enum VirtualDirectoryType { USER, GROUP, NONE }
 
 class VirtualDirectoryResult {
   final VirtualDirectoryType type;
-  final int id;
+  final int? id;
 
   const VirtualDirectoryResult({
-    @required this.type,
+    required this.type,
     this.id,
-  }) : assert(type != null);
+  });
 }
 
 class VirtualDirectoryHelper {
@@ -43,7 +42,6 @@ class VirtualDirectoryHelper {
           default:
             throw Exception("Unsupported virtual directory kind: $kind");
         }
-        break;
 
       default:
         throw new Exception("Could not get virtual directory!");

lib/helpers/webapp_helper.dart

@@ -15,7 +15,7 @@ class WebAppHelper {
   static Future<MembershipList> getMemberships() async {
     final response =
         (await APIRequest.withLogin("webApp/getMemberships").execWithThrow())
-            .getArray();
+            .getArray()!;
 
     return MembershipList()
       ..addAll(response
@@ -26,7 +26,7 @@ class WebAppHelper {
   }
 
   /// Turn an API entry into a membership entry
-  static Membership _apiToMembership(Map<String, dynamic> entry) {
+  static Membership? _apiToMembership(Map<String, dynamic> entry) {
     switch (entry["type"]) {
       case "conversation":
         return Membership.conversation(

lib/helpers/websocket_helper.dart

@@ -15,7 +15,7 @@ import 'package:web_socket_channel/web_socket_channel.dart';
 /// @author Pierre Hubert
 
 class WebSocketHelper {
-  static WebSocketChannel _ws;
+  static WebSocketChannel? _ws;
 
   static int _counter = 0;
 
@@ -23,11 +23,11 @@ class WebSocketHelper {
 
   /// Check out whether we are currently connected to WebSocket or not
   static bool isConnected() {
-    return _ws != null && _ws.closeCode == null;
+    return _ws != null && _ws!.closeCode == null;
   }
 
   /// Get WebSocket access token
-  static Future<String> _getWsToken() async =>
+  static Future<String?> _getWsToken() async =>
       (await APIRequest(uri: "ws/token", needLogin: true).exec())
           .assertOk()
           .getObject()["token"];
@@ -47,7 +47,7 @@ class WebSocketHelper {
     // Connect
     _ws = WebSocketChannel.connect(wsURI);
 
-    _ws.stream.listen(
+    _ws!.stream.listen(
       // When we got data
       (data) {
         print("WS New data: $data");
@@ -75,7 +75,7 @@ class WebSocketHelper {
 
   /// Close current WebSocket (if any)
   static close() {
-    if (isConnected()) _ws.sink.close();
+    if (isConnected()) _ws!.sink.close();
   }
 
   /// Send a new message
@@ -93,7 +93,7 @@ class WebSocketHelper {
 
     print("WS Send message: $msg");
 
-    _ws.sink.add(msg);
+    _ws!.sink.add(msg);
 
     _requests[id] = completer;
     return completer.future;
@@ -240,11 +240,11 @@ class WebSocketHelper {
 
     // Handles errors
     if (msg.title != "success") {
-      completer.completeError(Exception("Could not process request!"));
+      completer!.completeError(Exception("Could not process request!"));
       return;
     }
 
-    completer.complete(msg.data);
+    completer!.complete(msg.data);
   }
 }
 

lib/lists/abstract_list.dart

@@ -16,4 +16,7 @@ class AbstractList<E> extends ListBase<E> {
 
   @override
   void operator []=(int index, E value) => _list[index] = value;
+
+  @override
+  void add(E element) => _list.add(element);
 }

lib/lists/base_set.dart

@@ -11,7 +11,7 @@ class BaseSet<T> extends SetBase<T> {
   bool add(T value) => _set.add(value);
 
   @override
-  bool contains(Object element) => _set.contains(element);
+  bool contains(Object? element) => _set.contains(element);
 
   @override
   Iterator<T> get iterator => _set.iterator;
@@ -20,10 +20,10 @@ class BaseSet<T> extends SetBase<T> {
   int get length => _set.length;
 
   @override
-  T lookup(Object element) => _set.lookup(element);
+  T? lookup(Object? element) => _set.lookup(element);
 
   @override
-  bool remove(Object value) => _set.remove(value);
+  bool remove(Object? value) => _set.remove(value);
 
   @override
   Set<T> toSet() => _set.toSet();

lib/lists/call_members_list.dart

@@ -10,10 +10,10 @@ class CallMembersList extends AbstractList<CallMember> {
   Set<int> get usersID => this.map((f) => f.userID).toSet();
 
   /// Remove a specific member from this list
-  void removeUser(int userID) => this.removeWhere((f) => f.userID == userID);
+  void removeUser(int? userID) => this.removeWhere((f) => f.userID == userID);
 
   /// Get the connection of a specific user
-  CallMember getUser(int userID) => this.firstWhere((f) => f.userID == userID);
+  CallMember getUser(int? userID) => this.firstWhere((f) => f.userID == userID);
 
   /// Extract ready peers from this list
   CallMembersList get readyPeers =>

lib/lists/comments_list.dart

@@ -1,5 +1,4 @@
-import 'dart:collection';
+import 'package:comunic/lists/abstract_list.dart';
-
 import 'package:comunic/models/comment.dart';
 
 /// Comments list
@@ -8,19 +7,7 @@ import 'package:comunic/models/comment.dart';
 ///
 /// @author Pierre HUBERT
 
-class CommentsList extends ListBase<Comment> {
+class CommentsList extends AbstractList<Comment> {
-  List<Comment> _list = [];
-
-  int get length => _list.length;
-
-  set length(int l) => _list.length = l;
-
-  @override
-  Comment operator [](int index) => _list[index];
-
-  @override
-  void operator []=(int index, Comment value) => _list[index] = value;
-
   /// Get the list of users in this comments, as a set
   Set<int> get usersID => map((f) => f.userID).toSet();
 }

lib/lists/conversation_messages_list.dart

@@ -1,31 +1,14 @@
-import 'dart:collection';
+import 'package:comunic/lists/abstract_list.dart';
-
 import 'package:comunic/models/conversation_message.dart';
 
 /// Conversations messages list
 ///
 /// @author Pierre HUBERT
 
-class ConversationMessagesList extends ListBase<ConversationMessage> {
+class ConversationMessagesList extends AbstractList<ConversationMessage> {
-  final List<ConversationMessage> _list = [];
-
-  set length(int v) => _list.length = v;
-
-  int get length => _list.length;
-
-  @override
-  ConversationMessage operator [](int index) {
-    return _list[index];
-  }
-
-  @override
-  void operator []=(int index, ConversationMessage value) {
-    _list[index] = value;
-  }
-
   /// Get the list of the users ID who own a message in this list
-  Set<int> getUsersID() {
+  Set<int?> getUsersID() {
-    final Set<int> users = Set();
+    final Set<int?> users = Set();
 
     for (ConversationMessage message in this) users.addAll(message.usersID);
 
@@ -33,18 +16,18 @@ class ConversationMessagesList extends ListBase<ConversationMessage> {
   }
 
   /// Get the ID of the last message present in this list
-  int get lastMessageID {
+  int? get lastMessageID {
-    int lastMessageID = 0;
+    int? lastMessageID = 0;
     for (ConversationMessage message in this)
-      if (message.id > lastMessageID) lastMessageID = message.id;
+      if (message.id! > lastMessageID!) lastMessageID = message.id;
     return lastMessageID;
   }
 
   /// Get the ID of the first message present in this list
-  int get firstMessageID {
+  int? get firstMessageID {
-    int firstMessageID = this[0].id;
+    int? firstMessageID = this[0].id;
     for (ConversationMessage message in this)
-      if (message.id < firstMessageID) firstMessageID = message.id;
+      if (message.id! < firstMessageID!) firstMessageID = message.id;
     return firstMessageID;
   }
 
@@ -55,5 +38,5 @@ class ConversationMessagesList extends ListBase<ConversationMessage> {
   }
 
   /// Remove a message from this list
-  void removeMsg(int id) => removeWhere((f) => f.id == id);
+  void removeMsg(int? id) => removeWhere((f) => f.id == id);
 }

lib/lists/conversations_list.dart

@@ -22,12 +22,15 @@ class ConversationsList extends ListBase<Conversation> {
   /// Get the entire lists of users ID in this list
   Set<int> get allUsersID {
     final Set<int> list = Set();
-    forEach((c) => c.members.forEach((member) => list.add(member.userID)));
+    forEach((c) => c.members!.forEach((member) => list.add(member.userID)));
     return list;
   }
 
   /// Get the entire lists of groups ID in this list
-  Set<int> get allGroupsID => where((element) => element.isGroupConversation)
+  Set<int?> get allGroupsID => where((element) => element.isGroupConversation)
       .map((e) => e.groupID)
       .toSet();
+
+  @override
+  void add(Conversation element) => _list.add(element);
 }

lib/lists/custom_emojies_list.dart

@@ -7,8 +7,7 @@ import 'package:comunic/models/custom_emoji.dart';
 
 class CustomEmojiesList extends AbstractList<CustomEmoji> {
   /// Check if an emoji, identified by its shortcut, is present in this list
-  bool hasShortcut(String shortcut) =>
+  bool hasShortcut(String shortcut) => any((f) => f.shortcut == shortcut);
-      firstWhere((f) => f.shortcut == shortcut, orElse: () => null) != null;
 
   /// Serialize this list
   List<Map<String, dynamic>> toSerializableList() =>

lib/lists/forez_presences_set.dart

@@ -7,7 +7,7 @@ import 'package:comunic/models/forez_presence.dart';
 
 class PresenceSet extends BaseSet<Presence> {
   /// Get the presence of a specific user
-  PresenceSet getForUser(int userID) =>
+  PresenceSet getForUser(int? userID) =>
       PresenceSet()..addAll(where((element) => element.userID == userID));
 
   bool containsDate(DateTime dt) => any(
@@ -24,11 +24,11 @@ class PresenceSet extends BaseSet<Presence> {
             element.day == dt.day,
       );
 
-  void toggleDate(DateTime dt, int userID) {
+  void toggleDate(DateTime dt, int? userID) {
     if (containsDate(dt))
       removeDate(dt);
     else
-      add(Presence.fromDateTime(dt, userID));
+      add(Presence.fromDateTime(dt, userID!));
   }
 
   int countAtDate(DateTime dt) => where(

lib/lists/friends_list.dart

@@ -1,24 +1,11 @@
-import 'dart:collection';
+import 'package:comunic/lists/abstract_list.dart';
-
 import 'package:comunic/models/friend.dart';
 
 /// List of friends of the user
 ///
 /// @author Pierre HUBERT
 
-class FriendsList extends ListBase<Friend> {
+class FriendsList extends AbstractList<Friend> {
-  List<Friend> _list = [];
-
-  int get length => _list.length;
-
-  set length(int length) => _list.length = length;
-
-  @override
-  Friend operator [](int index) => _list[index];
-
-  @override
-  void operator []=(int index, Friend value) => _list[index] = value;
-
   /// Get the ID of all the friends of the current user
   List<int> get usersId => map((f) => f.id).toList();
 }

lib/lists/groups_list.dart

@@ -6,23 +6,23 @@ import 'package:comunic/models/group.dart';
 ///
 /// @author Pierre HUBERT
 
-class GroupsList extends MapBase<int, Group> {
+class GroupsList extends MapBase<int?, Group> {
-  final Map<int, Group> _groups = Map();
+  final Map<int?, Group?> _groups = Map();
 
   @override
-  Group operator [](Object key) => _groups[key];
+  Group? operator [](Object? key) => _groups[key];
 
   @override
-  void operator []=(int key, Group value) => _groups[key] = value;
+  void operator []=(int? key, Group? value) => _groups[key] = value;
 
   @override
   void clear() => _groups.clear();
 
   @override
-  Iterable<int> get keys => _groups.keys;
+  Iterable<int?> get keys => _groups.keys;
 
   @override
-  Group remove(Object key) => _groups.remove(key);
+  Group? remove(Object? key) => _groups.remove(key);
 
-  Group getGroup(int id) => this[id];
+  Group? getGroup(int? id) => this[id];
 }

lib/lists/memberships_list.dart

@@ -5,20 +5,20 @@ import 'package:comunic/models/membership.dart';
 ///
 /// @author Pierre Hubert
 
-class MembershipList extends AbstractList<Membership> {
+class MembershipList extends AbstractList<Membership?> {
   /// Get the IDs of all the users included in some way in this list
-  Set<int> get usersId {
+  Set<int?> get usersId {
-    final s = Set<int>();
+    final s = Set<int?>();
 
     forEach((m) {
-      switch (m.type) {
+      switch (m!.type) {
         case MembershipType.FRIEND:
-          s.add(m.friend.id);
+          s.add(m.friend!.id);
           break;
         case MembershipType.GROUP:
           break;
         case MembershipType.CONVERSATION:
-          s.addAll(m.conversation.membersID);
+          s.addAll(m.conversation!.membersID);
           break;
       }
     });
@@ -27,16 +27,16 @@ class MembershipList extends AbstractList<Membership> {
   }
 
   /// Get the ID of the groups included in this list
-  Set<int> get groupsId => where((f) => f.type == MembershipType.GROUP)
+  Set<int?> get groupsId => where((f) => f!.type == MembershipType.GROUP)
-      .map((f) => f.groupID)
+      .map((f) => f!.groupID)
       .toSet();
 
   /// Remove a friend membership from the list
   void removeFriend(int friendID) => remove(firstWhere(
-      (f) => f.type == MembershipType.FRIEND && f.friend.id == friendID));
+      (f) => f!.type == MembershipType.FRIEND && f.friend!.id == friendID));
 
   /// Get the list of conversations of a group
-  Set<Membership> getGroupConversations(int groupID) => where((element) =>
+  Set<Membership?> getGroupConversations(int groupID) => where((element) =>
-      element.type == MembershipType.CONVERSATION &&
+      element!.type == MembershipType.CONVERSATION &&
-      element.conversation.groupID == groupID).toSet();
+      element.conversation!.groupID == groupID).toSet();
 }

lib/lists/notifications_list.dart

@@ -8,8 +8,8 @@ import 'package:comunic/models/notification.dart';
 class NotificationsList extends AbstractList<Notification> {
   /// Get the ID of all the users related to the notifications
   /// included in the list
-  Set<int> get usersIds {
+  Set<int?> get usersIds {
-    final list = Set<int>();
+    final list = Set<int?>();
 
     forEach((n) {
       list.add(n.fromUser);
@@ -28,8 +28,8 @@ class NotificationsList extends AbstractList<Notification> {
 
   /// Get the ID of all the groups related to the notifications
   /// included in the list
-  Set<int> get groupsIds {
+  Set<int?> get groupsIds {
-    final list = Set<int>();
+    final list = Set<int?>();
 
     forEach((n) {
       if (n.onElemType == NotificationElementType.GROUP_PAGE)

lib/lists/posts_list.dart

@@ -1,5 +1,4 @@
-import 'dart:collection';
+import 'package:comunic/lists/abstract_list.dart';
-
 import 'package:comunic/models/post.dart';
 
 /// Posts List
@@ -8,37 +7,25 @@ import 'package:comunic/models/post.dart';
 ///
 /// @author Pierre HUBERT
 
-class PostsList extends ListBase<Post> {
+class PostsList extends AbstractList<Post> {
-  List<Post> _list = [];
-
-  int get length => _list.length;
-
-  set length(int l) => _list.length = l;
-
-  @override
-  Post operator [](int index) => _list[index];
-
-  @override
-  void operator []=(int index, Post value) => _list[index] = value;
-
   // Get the list of users ID in this set
-  Set<int> get usersID {
+  Set<int?> get usersID {
-    Set<int> set = Set();
+    Set<int?> set = Set();
 
     forEach((p) {
       set.add(p.userID);
 
-      if (p.userPageID != null && p.userPageID > 0) set.add(p.userPageID);
+      if (p.userPageID != null && p.userPageID! > 0) set.add(p.userPageID);
 
-      if (p.comments != null) set.addAll(p.comments.usersID);
+      if (p.comments != null) set.addAll(p.comments!.usersID);
     });
 
     return set;
   }
 
   /// Get the list of groups in this list of posts
-  Set<int> get groupsID {
+  Set<int?> get groupsID {
-    Set<int> set = Set();
+    Set<int?> set = Set();
 
     forEach((p) {
       if (p.isGroupPost) set.add(p.groupID);
@@ -49,8 +36,7 @@ class PostsList extends ListBase<Post> {
 
   /// Get the ID of the oldest post of this list. Returns 0 if the list is empty
   int get oldestID {
-    if(isEmpty)
+    if (isEmpty) return 0;
-      return 0;
 
     return this.elementAt(length - 1).id;
   }

lib/lists/unread_conversations_list.dart

@@ -7,8 +7,8 @@ import 'package:comunic/models/unread_conversation.dart';
 
 class UnreadConversationsList extends AbstractList<UnreadConversation> {
   /// Get the ID of the users included in this list
-  Set<int> get usersID {
+  Set<int?> get usersID {
-    final set = Set<int>();
+    final set = Set<int?>();
     forEach((element) {
       set.addAll(element.conv.membersID);
       set.addAll(element.message.usersID);
@@ -17,8 +17,8 @@ class UnreadConversationsList extends AbstractList<UnreadConversation> {
   }
 
   /// Get the ID of the groups references ind this list
-  Set<int> get groupsID {
+  Set<int?> get groupsID {
-    final set = Set<int>();
+    final set = Set<int?>();
     forEach((element) {
       if (element.conv.isGroupConversation) set.add(element.conv.groupID);
     });

lib/lists/users_list.dart

@@ -24,7 +24,7 @@ class UsersList extends ListBase<User> {
   }
 
   /// Find a user with a specific ID
-  User getUser(int userID) {
+  User getUser(int? userID) {
     for (int i = 0; i < this.length; i++)
       if (this[i].id == userID) return this[i];
 
@@ -32,8 +32,11 @@ class UsersList extends ListBase<User> {
   }
 
   /// Check if the user is included in this list or not
-  bool hasUser(int userID) => any((f) => f.id == userID);
+  bool hasUser(int? userID) => any((f) => f.id == userID);
 
   /// Get the list of users ID present in this list
-  List<int> get usersID => List.generate(length, (i) => this[i].id);
+  List<int?> get usersID => List.generate(length, (i) => this[i].id);
+
+  @override
+  void add(User element) => _list.add(element);
 }

lib/main.dart

@@ -7,8 +7,9 @@ import 'package:comunic/models/config.dart';
 import 'package:comunic/ui/widgets/init_widget.dart';
 import 'package:comunic/utils/flutter_utils.dart';
 import 'package:comunic/utils/intl_utils.dart';
-import 'package:connectivity/connectivity.dart';
+import 'package:connectivity_plus/connectivity_plus.dart';
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 
 /// Main file of the application
 ///
@@ -43,10 +44,9 @@ class ComunicApplication extends StatefulWidget {
   final PreferencesHelper preferences;
 
   const ComunicApplication({
-    Key key,
+    Key? key,
-    @required this.preferences,
+    required this.preferences,
-  })  : assert(preferences != null),
+  })  : super(key: key);
-        super(key: key);
 
   @override
   ComunicApplicationState createState() => ComunicApplicationState();
@@ -68,7 +68,8 @@ class ComunicApplicationState extends State<ComunicApplication> {
               primaryColor: config().primaryColor,
               primaryColorDark: config().primaryColorDark,
               appBarTheme: AppBarTheme(
-                brightness: Brightness.dark,
+                backgroundColor: config().primaryColor,
+                systemOverlayStyle: SystemUiOverlayStyle.light,
               )),
       showPerformanceOverlay: prefs.showPerformancesOverlay,
     );

lib/main_dev.dart

@@ -11,7 +11,7 @@ import 'package:comunic/utils/flutter_utils.dart';
 /// Fix HTTPS issue
 class MyHttpOverride extends HttpOverrides {
   @override
-  HttpClient createHttpClient(SecurityContext context) {
+  HttpClient createHttpClient(SecurityContext? context) {
     return super.createHttpClient(context)
       ..badCertificateCallback = (cert, host, port) {
         return host == "devweb.local"; // Forcefully trust local website

lib/models/account_image_settings.dart

@@ -1,5 +1,3 @@
-import 'package:flutter/widgets.dart';
-
 /// Account image settings
 ///
 /// @author Pierre Hubert
@@ -12,10 +10,8 @@ class AccountImageSettings {
   final AccountImageVisibilityLevels visibility;
 
   const AccountImageSettings({
-    @required this.hasImage,
+    required this.hasImage,
-    @required this.imageURL,
+    required this.imageURL,
-    @required this.visibility,
+    required this.visibility,
-  })  : assert(hasImage != null),
+  });
-        assert(imageURL != null),
-        assert(visibility != null);
 }

lib/models/advanced_group_info.dart

@@ -1,7 +1,6 @@
 import 'package:comunic/enums/likes_type.dart';
 import 'package:comunic/models/conversation.dart';
 import 'package:comunic/models/like_element.dart';
-import 'package:flutter/material.dart';
 
 import 'group.dart';
 
@@ -10,36 +9,35 @@ import 'group.dart';
 /// @author Pierre Hubert
 
 class AdvancedGroupInfo extends Group implements LikeElement {
-  bool isMembersListPublic;
+  bool? isMembersListPublic;
-  final int timeCreate;
+  final int? timeCreate;
   String description;
   String url;
   int likes;
   bool userLike;
-  List<Conversation> conversations;
+  List<Conversation>? conversations;
   bool isForezGroup;
 
   AdvancedGroupInfo({
-    @required int id,
+    required int id,
-    @required String name,
+    required String name,
-    @required String iconURL,
+    required String iconURL,
-    @required int numberMembers,
+    required int numberMembers,
-    @required GroupMembershipLevel membershipLevel,
+    required GroupMembershipLevel membershipLevel,
-    @required GroupVisibilityLevel visibilityLevel,
+    required GroupVisibilityLevel visibilityLevel,
-    @required GroupRegistrationLevel registrationLevel,
+    required GroupRegistrationLevel registrationLevel,
-    @required GroupPostCreationLevel postCreationLevel,
+    required GroupPostCreationLevel postCreationLevel,
-    @required String virtualDirectory,
+    required String virtualDirectory,
-    @required bool following,
+    required bool following,
-    @required this.isMembersListPublic,
+    required this.isMembersListPublic,
-    @required this.timeCreate,
+    required this.timeCreate,
-    @required this.description,
+    required this.description,
-    @required this.url,
+    required this.url,
-    @required this.likes,
+    required this.likes,
-    @required this.userLike,
+    required this.userLike,
-    @required this.conversations,
+    required this.conversations,
-    @required this.isForezGroup,
+    required this.isForezGroup,
-  })  : assert(isForezGroup != null),
+  }) : super(
-        super(
             id: id,
             name: name,
             iconURL: iconURL,
@@ -54,8 +52,7 @@ class AdvancedGroupInfo extends Group implements LikeElement {
   @override
   LikesType likeType = LikesType.GROUP;
 
-  get hasURL => url != null && url.isNotEmpty && url != "null";
+  get hasURL => url.isNotEmpty && url != "null";
 
-  get hasDescription =>
+  get hasDescription => description.isNotEmpty && description != "null";
-      description != null && description.isNotEmpty && description != "null";
 }

lib/models/advanced_user_info.dart

@@ -3,51 +3,42 @@ import 'package:comunic/enums/user_page_visibility.dart';
 import 'package:comunic/lists/custom_emojies_list.dart';
 import 'package:comunic/models/like_element.dart';
 import 'package:comunic/models/user.dart';
-import 'package:meta/meta.dart';
 
 /// Advanced user information
 ///
 /// @author Pierre HUBERT
 
 class AdvancedUserInfo extends User implements LikeElement {
-  final String emailAddress;
+  final String? emailAddress;
   final String publicNote;
   final bool canPostTexts;
   final bool isFriendsListPublic;
   final int numberFriends;
   final int accountCreationTime;
   final String personalWebsite;
-  final String location;
+  final String? location;
   bool userLike;
   int likes;
 
   AdvancedUserInfo({
-    @required int id,
+    required int id,
-    @required String firstName,
+    required String firstName,
-    @required String lastName,
+    required String lastName,
-    @required UserPageVisibility pageVisibility,
+    required UserPageVisibility pageVisibility,
-    @required String virtualDirectory,
+    required String? virtualDirectory,
-    @required String accountImageURL,
+    required String accountImageURL,
-    @required CustomEmojiesList customEmojies,
+    required CustomEmojiesList customEmojies,
-    @required this.emailAddress,
+    required this.emailAddress,
-    @required this.publicNote,
+    required this.publicNote,
-    @required this.canPostTexts,
+    required this.canPostTexts,
-    @required this.isFriendsListPublic,
+    required this.isFriendsListPublic,
-    @required this.numberFriends,
+    required this.numberFriends,
-    @required this.accountCreationTime,
+    required this.accountCreationTime,
-    @required this.personalWebsite,
+    required this.personalWebsite,
-    @required this.location,
+    required this.location,
-    @required this.userLike,
+    required this.userLike,
-    @required this.likes,
+    required this.likes,
-  })  : assert(publicNote != null),
+  }) : super(
-        assert(canPostTexts != null),
-        assert(isFriendsListPublic != null),
-        assert(numberFriends != null),
-        assert(accountCreationTime != null),
-        assert(personalWebsite != null),
-        assert(userLike != null),
-        assert(likes != null),
-        super(
             id: id,
             firstName: firstName,
             lastName: lastName,
@@ -60,9 +51,9 @@ class AdvancedUserInfo extends User implements LikeElement {
 
   bool get hasPersonalWebsite => personalWebsite.isNotEmpty;
 
-  bool get hasEmailAddress => emailAddress != null && emailAddress.isNotEmpty;
+  bool get hasEmailAddress => emailAddress != null && emailAddress!.isNotEmpty;
 
-  bool get hasLocation => location != null && location.isNotEmpty;
+  bool get hasLocation => location != null && location!.isNotEmpty;
 
   @override
   LikesType get likeType => LikesType.USER;

lib/models/api_request.dart

@@ -4,7 +4,6 @@ import 'package:comunic/helpers/api_helper.dart';
 import 'package:comunic/models/api_response.dart';
 import 'package:dio/dio.dart';
 import 'package:http_parser/http_parser.dart';
-import 'package:meta/meta.dart';
 
 /// API Request model
 ///
@@ -14,8 +13,8 @@ import 'package:meta/meta.dart';
 
 class BytesFile {
   final String filename;
-  final List<int> bytes;
+  final List<int>? bytes;
-  final MediaType type;
+  final MediaType? type;
 
   const BytesFile(
     this.filename,
@@ -27,42 +26,36 @@ class BytesFile {
 class APIRequest {
   final String uri;
   final bool needLogin;
-  ProgressCallback progressCallback;
+  ProgressCallback? progressCallback;
-  CancelToken cancelToken;
+  CancelToken? cancelToken;
-  Map<String, String> args;
+  Map<String, String?>? args;
   Map<String, File> files = Map();
-  Map<String, BytesFile> bytesFiles = Map();
+  Map<String, BytesFile?> bytesFiles = Map();
 
-  APIRequest({@required this.uri, this.needLogin = false, this.args})
+  APIRequest({required this.uri, this.needLogin = false, this.args}) {
-      : assert(uri != null),
-        assert(needLogin != null) {
     if (this.args == null) this.args = Map();
   }
 
-  APIRequest.withLogin(this.uri, {this.args})
+  APIRequest.withLogin(this.uri, {this.args}) : needLogin = true {
-      : needLogin = true,
-        assert(uri != null) {
     if (args == null) this.args = Map();
   }
 
-  APIRequest.withoutLogin(this.uri, {this.args})
+  APIRequest.withoutLogin(this.uri, {this.args}) : needLogin = false {
-      : needLogin = false,
-        assert(uri != null) {
     if (args == null) this.args = Map();
   }
 
-  APIRequest addString(String name, String value) {
+  APIRequest addString(String name, String? value) {
-    args[name] = value;
+    args![name] = value;
     return this;
   }
 
-  APIRequest addInt(String name, int value) {
+  APIRequest addInt(String name, int? value) {
-    args[name] = value.toString();
+    args![name] = value.toString();
     return this;
   }
 
   APIRequest addBool(String name, bool value) {
-    args[name] = value ? "true" : "false";
+    args![name] = value ? "true" : "false";
     return this;
   }
 
@@ -71,12 +64,12 @@ class APIRequest {
     return this;
   }
 
-  APIRequest addBytesFile(String name, BytesFile file) {
+  APIRequest addBytesFile(String name, BytesFile? file) {
     this.bytesFiles[name] = file;
     return this;
   }
 
-  void addArgs(Map<String, String> newArgs) => args.addAll(newArgs);
+  void addArgs(Map<String, String> newArgs) => args!.addAll(newArgs);
 
   /// Execute the request
   Future<APIResponse> exec() async => APIHelper().exec(this);

lib/models/api_response.dart

@@ -6,13 +6,13 @@ import 'dart:convert';
 
 class APIResponse {
   final int code;
-  final String content;
+  final String? content;
 
-  const APIResponse(this.code, this.content) : assert(code != null);
+  const APIResponse(this.code, this.content);
 
-  List<dynamic> getArray() => jsonDecode(this.content);
+  List<dynamic>? getArray() => jsonDecode(this.content!);
 
-  Map<String, dynamic> getObject() => jsonDecode(this.content);
+  Map<String, dynamic> getObject() => jsonDecode(this.content!);
 
   /// Check if the request is successful or not
   bool get isOK => code == 200;

lib/models/application_preferences.dart

@@ -1,4 +1,4 @@
-import 'package:flutter/cupertino.dart';
+
 
 /// Application settings
 ///
@@ -10,10 +10,8 @@ class ApplicationPreferences {
   bool showPerformancesOverlay;
 
   ApplicationPreferences({
-    @required this.enableDarkMode,
+    required this.enableDarkMode,
-    @required this.forceMobileMode,
+    required this.forceMobileMode,
-    @required this.showPerformancesOverlay,
+    required this.showPerformancesOverlay,
-  })  : assert(enableDarkMode != null),
+  }) ;
-        assert(forceMobileMode != null),
-        assert(showPerformancesOverlay != null);
 }

lib/models/authentication_details.dart

@@ -1,4 +1,4 @@
-import 'package:meta/meta.dart';
+
 
 /// Authentication details
 ///
@@ -8,7 +8,5 @@ class AuthenticationDetails {
   final String email;
   final String password;
 
-  const AuthenticationDetails({@required this.email, @required this.password})
+  const AuthenticationDetails({required this.email, required this.password});
-      : assert(email != null),
-        assert(password != null);
 }

lib/models/cache_model.dart

@@ -1,5 +1,4 @@
 import 'package:comunic/helpers/database/database_contract.dart';
-import 'package:meta/meta.dart';
 
 /// Cache base model
 ///
@@ -8,7 +7,7 @@ import 'package:meta/meta.dart';
 abstract class CacheModel {
   final int id;
 
-  const CacheModel({@required this.id}) : assert(id != null);
+  const CacheModel({required this.id});
 
   /// Initialize a CacheModel from a map
   CacheModel.fromMap(Map<String, dynamic> map)

lib/models/call_config.dart

@@ -1,5 +1,3 @@
-import 'package:flutter/material.dart';
-
 /// Call configuration
 ///
 /// @author Pierre Hubert
@@ -8,8 +6,8 @@ class CallConfig {
   final List<String> iceServers;
 
   const CallConfig({
-    @required this.iceServers,
+    required this.iceServers,
-  }) : assert(iceServers != null);
+  });
 
   /// Turn this call configuration into the right for the WebRTC plugin
   Map<String, dynamic> get pluginConfig => {

lib/models/call_member.dart

@@ -1,4 +1,3 @@
-import 'package:flutter/material.dart';
 import 'package:flutter_webrtc/flutter_webrtc.dart';
 
 /// Single call member information
@@ -10,14 +9,13 @@ enum MemberStatus { JOINED, READY }
 class CallMember {
   final int userID;
   MemberStatus status;
-  MediaStream stream;
+  MediaStream? stream;
 
   CallMember({
-    @required this.userID,
+    required this.userID,
     this.status = MemberStatus.JOINED,
-  })  : assert(userID != null),
+  });
-        assert(status != null);
 
   bool get hasVideoStream =>
-      stream != null && stream.getVideoTracks().length > 0;
+      stream != null && stream!.getVideoTracks().length > 0;
 }

lib/models/comment.dart

@@ -2,7 +2,6 @@ import 'package:comunic/enums/likes_type.dart';
 import 'package:comunic/models/displayed_content.dart';
 import 'package:comunic/models/like_element.dart';
 import 'package:comunic/utils/account_utils.dart' as account;
-import 'package:meta/meta.dart';
 
 /// Comments
 ///
@@ -16,29 +15,22 @@ class Comment implements LikeElement {
   final int postID;
   final int timeSent;
   DisplayedString content;
-  final String imageURL;
+  final String? imageURL;
   int likes;
   bool userLike;
 
   Comment({
-    @required this.id,
+    required this.id,
-    @required this.userID,
+    required this.userID,
-    @required this.postID,
+    required this.postID,
-    @required this.timeSent,
+    required this.timeSent,
-    @required this.content,
+    required this.content,
-    @required this.imageURL,
+    required this.imageURL,
-    @required this.likes,
+    required this.likes,
-    @required this.userLike,
+    required this.userLike,
-  })  : assert(id != null),
+  });
-        assert(userID != null),
-        assert(postID != null),
-        assert(timeSent != null),
-        assert(content != null),
-        assert(likes != null),
-        assert(userLike != null);
 
-  bool get hasContent =>
+  bool get hasContent => !content.isNull && content.length > 0;
-      content != null && !content.isNull && content.length > 0;
 
   bool get hasImage => imageURL != null;
 

lib/models/config.dart

@@ -1,8 +1,5 @@
-import 'dart:ui';
-
 import 'package:comunic/ui/routes/tour_route.dart';
 import 'package:flutter/material.dart';
-import 'package:meta/meta.dart';
 
 /// Application configuration model
 ///
@@ -19,27 +16,27 @@ class Config {
 
   // Theme customization
   final Color splashBackgroundColor;
-  final Color primaryColor;
+  final Color? primaryColor;
-  final Color primaryColorDark;
+  final Color? primaryColorDark;
   final String appName;
-  final String appQuickDescription;
+  final String? appQuickDescription;
-  final Color unreadConversationColor;
+  final Color? unreadConversationColor;
-  final Color defaultConversationColor;
+  final Color? defaultConversationColor;
 
   // Entries for the welcome tour
-  final TourEntriesBuilder toursEntriesBuilder;
+  final TourEntriesBuilder? toursEntriesBuilder;
 
   // Custom initialization
-  final Future<void> Function() additionalLoading;
+  final Future<void> Function()? additionalLoading;
 
   // Custom main application route
-  final Widget Function(BuildContext, GlobalKey) mainRouteBuilder;
+  final Widget Function(BuildContext, GlobalKey)? mainRouteBuilder;
 
   const Config({
-    @required this.apiServerName,
+    required this.apiServerName,
-    @required this.apiServerUri,
+    required this.apiServerUri,
-    @required this.apiServerSecure,
+    required this.apiServerSecure,
-    @required this.clientName,
+    required this.clientName,
     this.splashBackgroundColor = defaultColor,
     this.primaryColor,
     this.primaryColorDark,
@@ -50,17 +47,12 @@ class Config {
     this.toursEntriesBuilder,
     this.additionalLoading,
     this.mainRouteBuilder,
-  })  : assert(apiServerName != null),
+  });
-        assert(apiServerUri != null),
-        assert(apiServerSecure != null),
-        assert(clientName != null),
-        assert(splashBackgroundColor != null),
-        assert(appName != null);
 
   /// Get and set static configuration
-  static Config _config;
+  static Config? _config;
 
-  static Config get() {
+  static Config? get() {
     return _config;
   }
 
@@ -71,5 +63,5 @@ class Config {
 
 /// Get the current configuration of the application
 Config config() {
-  return Config.get();
+  return Config.get()!;
 }

lib/models/conversation.dart

@@ -1,8 +1,8 @@
+import 'package:collection/collection.dart' show IterableExtension;
 import 'package:comunic/helpers/serialization/base_serialization_helper.dart';
 import 'package:comunic/models/conversation_member.dart';
 import 'package:comunic/utils/account_utils.dart';
 import 'package:flutter/material.dart';
-import 'package:meta/meta.dart';
 
 import 'group.dart';
 
@@ -13,44 +13,38 @@ import 'group.dart';
 enum CallCapabilities { NONE, AUDIO, VIDEO }
 
 class Conversation extends SerializableElement<Conversation> {
-  final int id;
+  final int? id;
-  final int lastActivity;
+  final int? lastActivity;
-  final String name;
+  final String? name;
-  final Color color;
+  final Color? color;
-  final String logoURL;
+  final String? logoURL;
-  final int groupID;
+  final int? groupID;
-  final GroupMembershipLevel groupMinMembershipLevel;
+  final GroupMembershipLevel? groupMinMembershipLevel;
-  final List<ConversationMember> members;
+  final List<ConversationMember>? members;
-  final bool canEveryoneAddMembers;
+  final bool? canEveryoneAddMembers;
   final CallCapabilities callCapabilities;
   final bool isHavingCall;
 
   Conversation({
-    @required this.id,
+    /*required*/ required int this.id,
-    @required this.lastActivity,
+    /*required*/ required int this.lastActivity,
-    @required this.name,
+    required this.name,
-    @required this.color,
+    required this.color,
-    @required this.logoURL,
+    required this.logoURL,
-    @required this.groupID,
+    required this.groupID,
-    @required this.groupMinMembershipLevel,
+    required this.groupMinMembershipLevel,
-    @required this.members,
+    /*required*/ required List<ConversationMember> this.members,
-    @required this.canEveryoneAddMembers,
+    /*required*/ required bool this.canEveryoneAddMembers,
     this.callCapabilities = CallCapabilities.NONE,
     this.isHavingCall = false,
-  })  : assert(id != null),
+  }) : assert((groupID == null) == (groupMinMembershipLevel == null));
-        assert(lastActivity != null),
-        assert(members != null),
-        assert(canEveryoneAddMembers != null),
-        assert((groupID == null) == (groupMinMembershipLevel == null)),
-        assert(callCapabilities != null),
-        assert(isHavingCall != null);
 
   /// Check out whether a conversation has a fixed name or not
   bool get hasName => this.name != null;
 
   /// Get current user membership
   ConversationMember get membership =>
-      members.firstWhere((m) => m.userID == userID());
+      members!.firstWhere((m) => m.userID == userID());
 
   /// Check out whether current user of the application is an admin
   bool get isAdmin => membership.isAdmin;
@@ -62,17 +56,17 @@ class Conversation extends SerializableElement<Conversation> {
   bool get following => membership.following;
 
   /// Get the list of members in the conversation
-  Set<int> get membersID => members.map((e) => e.userID).toSet();
+  Set<int?> get membersID => members!.map((e) => e.userID).toSet();
 
   /// Get the list of admins in the conversation
-  Set<int> get adminsID =>
+  Set<int?> get adminsID =>
-      members.where((e) => e.isAdmin).map((e) => e.userID).toSet();
+      members!.where((e) => e.isAdmin).map((e) => e.userID).toSet();
 
   /// Get the list of the OTHER members of the conversation (all except current user)
-  Set<int> get otherMembersID => membersID..remove(userID());
+  Set<int?> get otherMembersID => membersID..remove(userID());
 
   /// Check if the last message has been seen or not
-  bool get sawLastMessage => lastActivity <= membership.lastAccessTime;
+  bool get sawLastMessage => lastActivity! <= membership.lastAccessTime;
 
   /// Check out whether a conversation is managed or not
   bool get isManaged => isGroupConversation;
@@ -87,9 +81,8 @@ class Conversation extends SerializableElement<Conversation> {
         color = map["color"] == null ? null : Color(map["color"]),
         logoURL = map["logoURL"],
         groupID = map["groupID"],
-        groupMinMembershipLevel = GroupMembershipLevel.values.firstWhere(
+        groupMinMembershipLevel = GroupMembershipLevel.values.firstWhereOrNull(
-            (element) => element.toString() == map["groupMinMembershipLevel"],
+            (element) => element.toString() == map["groupMinMembershipLevel"]),
-            orElse: () => null),
         lastActivity = map["lastActivity"],
         members = map["members"]
             .map((el) => ConversationMember.fromJSON(el))
@@ -110,13 +103,13 @@ class Conversation extends SerializableElement<Conversation> {
       "groupID": groupID,
       "groupMinMembershipLevel": groupMinMembershipLevel?.toString(),
       "lastActivity": lastActivity,
-      "members": members.map((e) => e.toJson()).toList(),
+      "members": members!.map((e) => e.toJson()).toList(),
       "canEveryoneAddMembers": canEveryoneAddMembers,
     };
   }
 
   @override
   int compareTo(Conversation other) {
-    return other.lastActivity.compareTo(this.lastActivity);
+    return other.lastActivity!.compareTo(this.lastActivity!);
   }
 }

lib/models/conversation_member.dart

@@ -1,5 +1,3 @@
-import 'package:flutter/widgets.dart';
-
 /// Conversation member
 ///
 /// @author Pierre Hubert
@@ -12,16 +10,12 @@ class ConversationMember {
   final bool isAdmin;
 
   const ConversationMember({
-    @required this.userID,
+    required this.userID,
-    @required this.lastMessageSeen,
+    required this.lastMessageSeen,
-    @required this.lastAccessTime,
+    required this.lastAccessTime,
-    @required this.following,
+    required this.following,
-    @required this.isAdmin,
+    required this.isAdmin,
-  })  : assert(userID != null),
+  });
-        assert(lastMessageSeen != null),
-        assert(lastAccessTime != null),
-        assert(following != null),
-        assert(isAdmin != null);
 
   Map<String, dynamic> toJson() => {
         'userID': userID,

lib/models/conversation_message.dart

@@ -4,7 +4,6 @@ import 'package:comunic/models/displayed_content.dart';
 import 'package:comunic/utils/account_utils.dart' as account;
 import 'package:comunic/utils/intl_utils.dart';
 import 'package:flutter/material.dart';
-import 'package:meta/meta.dart';
 
 /// Single conversation message
 ///
@@ -31,27 +30,24 @@ const _ConversationFileMimeTypeMapping = {
 };
 
 class ConversationMessageFile {
-  final String url;
+  final String? url;
-  final int size;
+  final int? size;
-  final String name;
+  final String? name;
-  final String thumbnail;
+  final String? thumbnail;
-  final String type;
+  final String? type;
 
   const ConversationMessageFile({
-    @required this.url,
+    required String this.url,
-    @required this.size,
+    required int this.size,
-    @required this.name,
+    required String this.name,
-    @required this.thumbnail,
+    required this.thumbnail,
-    @required this.type,
+    required String this.type,
-  })  : assert(url != null),
+  });
-        assert(size != null),
-        assert(name != null),
-        assert(type != null);
 
   /// Get the type of file
-  ConversationMessageFileType get fileType {
+  ConversationMessageFileType? get fileType {
     if (type != null && _ConversationFileMimeTypeMapping.containsKey(type))
-      return _ConversationFileMimeTypeMapping[type];
+      return _ConversationFileMimeTypeMapping[type!];
     else
       return ConversationMessageFileType.OTHER;
   }
@@ -103,21 +99,20 @@ enum ConversationServerMessageType {
 
 class ConversationServerMessage {
   final ConversationServerMessageType type;
-  final int userID;
+  final int? userID;
-  final int userWhoAdded;
+  final int? userWhoAdded;
-  final int userAdded;
+  final int? userAdded;
-  final int userWhoRemoved;
+  final int? userWhoRemoved;
-  final int userRemoved;
+  final int? userRemoved;
 
   const ConversationServerMessage({
-    @required this.type,
+    required this.type,
-    @required this.userID,
+    required this.userID,
-    @required this.userWhoAdded,
+    required this.userWhoAdded,
-    @required this.userAdded,
+    required this.userAdded,
-    @required this.userWhoRemoved,
+    required this.userWhoRemoved,
-    @required this.userRemoved,
+    required this.userRemoved,
-  })  : assert(type != null),
+  })  : assert(userID != null ||
-        assert(userID != null ||
             (type != ConversationServerMessageType.USER_CREATED_CONVERSATION &&
                 type != ConversationServerMessageType.USER_LEFT_CONV)),
         assert((userWhoAdded != null && userAdded != null) ||
@@ -125,47 +120,47 @@ class ConversationServerMessage {
         assert((userWhoRemoved != null && userRemoved != null) ||
             type != ConversationServerMessageType.USER_REMOVED_ANOTHER_USER);
 
-  Set<int> get usersID {
+  Set<int?> get usersID {
     switch (type) {
       case ConversationServerMessageType.USER_CREATED_CONVERSATION:
       case ConversationServerMessageType.USER_LEFT_CONV:
         return Set()..add(userID);
 
       case ConversationServerMessageType.USER_ADDED_ANOTHER_USER:
-        return Set()..add(userWhoAdded)..add(userAdded);
+        return Set()
+          ..add(userWhoAdded)
+          ..add(userAdded);
 
       case ConversationServerMessageType.USER_REMOVED_ANOTHER_USER:
-        return Set()..add(userWhoRemoved)..add(userRemoved);
+        return Set()
+          ..add(userWhoRemoved)
+          ..add(userRemoved);
+    }
   }
 
-    throw Exception("Unsupported server message type!");
+  String? getText(UsersList? list) {
-  }
-
-  String getText(UsersList list) {
     switch (type) {
       case ConversationServerMessageType.USER_CREATED_CONVERSATION:
         return tr("%1% created the conversation",
-            args: {"1": list.getUser(userID).fullName});
+            args: {"1": list!.getUser(userID).fullName});
 
       case ConversationServerMessageType.USER_ADDED_ANOTHER_USER:
         return tr("%1% added %2% to the conversation", args: {
-          "1": list.getUser(userWhoAdded).fullName,
+          "1": list!.getUser(userWhoAdded).fullName,
           "2": list.getUser(userAdded).fullName,
         });
 
       case ConversationServerMessageType.USER_LEFT_CONV:
         return tr("%1% left the conversation", args: {
-          "1": list.getUser(userID).fullName,
+          "1": list!.getUser(userID).fullName,
         });
 
       case ConversationServerMessageType.USER_REMOVED_ANOTHER_USER:
         return tr("%1% removed %2% from the conversation", args: {
-          "1": list.getUser(userWhoRemoved).fullName,
+          "1": list!.getUser(userWhoRemoved).fullName,
           "2": list.getUser(userRemoved).fullName,
         });
     }
-
-    throw Exception("Unsupported message type!");
   }
 
   Map<String, dynamic> toJson() => {
@@ -188,29 +183,26 @@ class ConversationServerMessage {
 }
 
 class ConversationMessage extends SerializableElement<ConversationMessage> {
-  final int id;
+  final int? id;
-  final int convID;
+  final int? convID;
-  final int userID;
+  final int? userID;
-  final int timeSent;
+  final int? timeSent;
   final DisplayedString message;
-  final ConversationMessageFile file;
+  final ConversationMessageFile? file;
-  final ConversationServerMessage serverMessage;
+  final ConversationServerMessage? serverMessage;
 
   ConversationMessage({
-    @required this.id,
+    required int this.id,
-    @required this.convID,
+    required int this.convID,
-    @required this.userID,
+    required this.userID,
-    @required this.timeSent,
+    required int this.timeSent,
-    @required this.message,
+    required this.message,
-    @required this.file,
+    required this.file,
-    @required this.serverMessage,
+    required this.serverMessage,
-  })  : assert(id != null),
+  })  : assert(userID != null || serverMessage != null),
-        assert(convID != null),
+        assert(!message.isNull || file != null || serverMessage != null);
-        assert(userID != null || serverMessage != null),
-        assert(timeSent != null),
-        assert(message != null || file != null || serverMessage != null);
 
-  DateTime get date => DateTime.fromMillisecondsSinceEpoch(timeSent * 1000);
+  DateTime get date => DateTime.fromMillisecondsSinceEpoch(timeSent! * 1000);
 
   bool get hasMessage => !message.isNull && message.length > 0;
 
@@ -221,16 +213,16 @@ class ConversationMessage extends SerializableElement<ConversationMessage> {
   bool get isServerMessage => serverMessage != null;
 
   /// Get the list of the ID of the users implied in this message
-  Set<int> get usersID {
+  Set<int?> get usersID {
     if (userID != null) return Set()..add(userID);
 
-    if (serverMessage != null) return serverMessage.usersID;
+    if (serverMessage != null) return serverMessage!.usersID;
     return Set();
   }
 
   @override
   int compareTo(ConversationMessage other) {
-    return id.compareTo(other.id);
+    return id!.compareTo(other.id!);
   }
 
   Map<String, dynamic> toJson() {

lib/models/count_unread_notifications.dart

@@ -3,12 +3,11 @@
 /// @author Pierre Hubert
 
 class CountUnreadNotifications {
-  int notifications;
+  int? notifications;
-  int conversations;
+  int? conversations;
 
   CountUnreadNotifications({
-    this.notifications,
+    required int this.notifications,
-    this.conversations,
+    required int this.conversations,
-  })  : assert(notifications != null),
+  });
-        assert(conversations != null);
 }

lib/models/custom_emoji.dart

@@ -1,24 +1,19 @@
-import 'package:flutter/material.dart';
-
 /// Single custom emoji information
 ///
 /// @author Pierre Hubert
 
 class CustomEmoji {
-  final int id;
+  final int? id;
-  final int userID;
+  final int? userID;
-  final String shortcut;
+  final String? shortcut;
-  final String url;
+  final String? url;
 
   const CustomEmoji({
-    @required this.id,
+    required int this.id,
-    @required this.userID,
+    required int this.userID,
-    @required this.shortcut,
+    required String this.shortcut,
-    @required this.url,
+    required String this.url,
-  })  : assert(id != null),
+  });
-        assert(userID != null),
-        assert(shortcut != null),
-        assert(url != null);
 
   Map<String, dynamic> toMap() => {
         "id": id,

lib/models/data_conservation_policy_settings.dart

@@ -3,12 +3,12 @@
 /// @author Pierre Hubert
 
 class DataConservationPolicySettings {
-  int inactiveAccountLifeTime;
+  int? inactiveAccountLifeTime;
-  int notificationLifetime;
+  int? notificationLifetime;
-  int commentsLifetime;
+  int? commentsLifetime;
-  int postsLifetime;
+  int? postsLifetime;
-  int conversationMessagesLifetime;
+  int? conversationMessagesLifetime;
-  int likesLifetime;
+  int? likesLifetime;
 
   DataConservationPolicySettings({
     this.inactiveAccountLifeTime,

lib/models/displayed_content.dart

@@ -5,32 +5,32 @@ import 'package:comunic/utils/ui_utils.dart';
 /// @author Pierre Hubert
 
 class DisplayedString {
-  String _string;
+  String? _string;
-  String _parseCache;
+  String? _parseCache;
 
   DisplayedString(this._string);
 
-  int get length => _string.length;
+  int get length => _string!.length;
 
-  bool get isEmpty => _string.isEmpty;
+  bool get isEmpty => _string!.isEmpty;
 
   bool get isNull => _string == null;
 
-  String get content => _string;
+  String? get content => _string;
 
-  set content(String content) {
+  set content(String? content) {
     _string = content;
     _parseCache = null;
   }
 
   @override
   String toString() {
-    return _string;
+    return _string!;
   }
 
-  String get parsedString {
+  String? get parsedString {
     if (_parseCache == null) {
-      _parseCache = parseEmojies(this._string);
+      _parseCache = parseEmojies(this._string!);
     }
 
     return _parseCache;

lib/models/forez_presence.dart

@@ -1,5 +1,3 @@
-import 'package:flutter/material.dart';
-
 /// Single presence information
 ///
 /// @author Pierre Hubert
@@ -11,19 +9,14 @@ class Presence {
   final int day;
 
   const Presence({
-    @required this.userID,
+    required this.userID,
-    @required this.year,
+    required this.year,
-    @required this.month,
+    required this.month,
-    @required this.day,
+    required this.day,
-  })  : assert(userID != null),
+  });
-        assert(year != null),
-        assert(month != null),
-        assert(day != null);
 
   Presence.fromDateTime(DateTime dt, this.userID)
-      : assert(dt != null),
+      : year = dt.year,
-        year = dt.year,
         month = dt.month,
-        day = dt.day,
+        day = dt.day;
-        assert(userID != null);
 }

lib/models/friend.dart

@@ -1,7 +1,6 @@
 import 'package:comunic/helpers/database/database_contract.dart';
 import 'package:comunic/models/cache_model.dart';
 import 'package:comunic/utils/date_utils.dart';
-import 'package:meta/meta.dart';
 
 /// Single user Friend information
 ///
@@ -9,28 +8,23 @@ import 'package:meta/meta.dart';
 
 class Friend extends CacheModel implements Comparable<Friend> {
   bool accepted;
-  final int lastActive;
+  final int? lastActive;
   final bool following;
   final bool canPostTexts;
 
   Friend({
-    @required int id,
+    required int id,
-    @required this.accepted,
+    required this.accepted,
-    @required this.lastActive,
+    required int this.lastActive,
-    @required this.following,
+    required this.following,
-    @required this.canPostTexts,
+    required this.canPostTexts,
-  })  : assert(id != null),
+  }) : super(id: id);
-        assert(accepted != null),
-        assert(lastActive != null),
-        assert(following != null),
-        assert(canPostTexts != null),
-        super(id: id);
 
   /// Check out whether friend is connected or not
-  bool get isConnected => time() - 30 < lastActive;
+  bool get isConnected => time() - 30 < lastActive!;
 
   @override
-  int compareTo(Friend other) => other.lastActive.compareTo(lastActive);
+  int compareTo(Friend other) => other.lastActive!.compareTo(lastActive!);
 
   @override
   Map<String, dynamic> toMap() => {
@@ -42,8 +36,7 @@ class Friend extends CacheModel implements Comparable<Friend> {
       };
 
   Friend.fromMap(Map<String, dynamic> map)
-      : assert(map != null),
+      : accepted = map[FriendsListTableContract.C_ACCEPTED] == 1,
-        accepted = map[FriendsListTableContract.C_ACCEPTED] == 1,
         lastActive = map[FriendsListTableContract.C_LAST_ACTIVE],
         following = map[FriendsListTableContract.C_FOLLOWING] == 1,
         canPostTexts = map[FriendsListTableContract.C_CAN_POST_TEXTS] == 1,

lib/models/friend_status.dart

@@ -1,5 +1,3 @@
-import 'package:meta/meta.dart';
-
 /// Simple friendship status
 ///
 /// @author Pierre HUBERT
@@ -12,16 +10,12 @@ class FriendStatus {
   final bool following;
 
   const FriendStatus({
-    @required this.userID,
+    required this.userID,
-    @required this.areFriend,
+    required this.areFriend,
-    @required this.sentRequest,
+    required this.sentRequest,
-    @required this.receivedRequest,
+    required this.receivedRequest,
-    @required this.following,
+    required this.following,
-  })  : assert(userID != null),
+  });
-        assert(areFriend != null),
-        assert(sentRequest != null),
-        assert(receivedRequest != null),
-        assert(following != null);
 
   bool get noRequestExchanged => !areFriend && !sentRequest && !receivedRequest;
 }

lib/models/general_settings.dart

@@ -1,5 +1,4 @@
 import 'package:comunic/enums/user_page_visibility.dart';
-import 'package:flutter/material.dart';
 
 /// General settings
 ///
@@ -18,32 +17,21 @@ class GeneralSettings {
   String virtualDirectory;
   String personalWebsite;
   String publicNote;
-  String location;
+  String? location;
 
   GeneralSettings({
-    @required this.email,
+    required this.email,
-    @required this.firstName,
+    required this.firstName,
-    @required this.lastName,
+    required this.lastName,
-    @required this.pageVisibility,
+    required this.pageVisibility,
-    @required this.allowComments,
+    required this.allowComments,
-    @required this.allowPostsFromFriends,
+    required this.allowPostsFromFriends,
-    @required this.allowComunicEmails,
+    required this.allowComunicEmails,
-    @required this.publicFriendsList,
+    required this.publicFriendsList,
-    @required this.publicEmail,
+    required this.publicEmail,
-    @required this.virtualDirectory,
+    required this.virtualDirectory,
-    @required this.personalWebsite,
+    required this.personalWebsite,
-    @required this.publicNote,
+    required this.publicNote,
-    @required this.location,
+    required this.location,
-  })  : assert(email != null),
+  });
-        assert(firstName != null),
-        assert(lastName != null),
-        assert(pageVisibility != null),
-        assert(allowComments != null),
-        assert(allowPostsFromFriends != null),
-        assert(allowComunicEmails != null),
-        assert(publicFriendsList != null),
-        assert(publicEmail != null),
-        assert(virtualDirectory != null),
-        assert(personalWebsite != null),
-        assert(publicNote != null);
 }

lib/models/group.dart

@@ -1,5 +1,4 @@
 import 'package:comunic/utils/intl_utils.dart';
-import 'package:meta/meta.dart';
 
 /// Group information
 ///
@@ -17,19 +16,18 @@ enum GroupMembershipLevel {
 String membershipToText(GroupMembershipLevel level) {
   switch (level) {
     case GroupMembershipLevel.ADMINISTRATOR:
-      return tr("Administrator");
+      return tr("Administrator")!;
     case GroupMembershipLevel.MODERATOR:
-      return tr("Moderator");
+      return tr("Moderator")!;
     case GroupMembershipLevel.MEMBER:
-      return tr("Member");
+      return tr("Member")!;
     case GroupMembershipLevel.INVITED:
-      return tr("Invited");
+      return tr("Invited")!;
     case GroupMembershipLevel.PENDING:
-      return tr("Requested");
+      return tr("Requested")!;
     case GroupMembershipLevel.VISITOR:
-      return tr("Visitor");
+      return tr("Visitor")!;
   }
-  throw new Exception("Unreachable statement!");
 }
 
 enum GroupVisibilityLevel { OPEN, PRIVATE, SECRETE }
@@ -51,25 +49,17 @@ class Group implements Comparable<Group> {
   bool following;
 
   Group({
-    @required this.id,
+    required this.id,
-    @required this.name,
+    required this.name,
-    @required this.iconURL,
+    required this.iconURL,
-    @required this.numberMembers,
+    required this.numberMembers,
-    @required this.membershipLevel,
+    required this.membershipLevel,
-    @required this.visibilityLevel,
+    required this.visibilityLevel,
-    @required this.registrationLevel,
+    required this.registrationLevel,
-    @required this.postCreationLevel,
+    required this.postCreationLevel,
-    @required this.virtualDirectory,
+    required this.virtualDirectory,
-    @required this.following,
+    required this.following,
-  })  : assert(id != null),
+  });
-        assert(name != null),
-        assert(iconURL != null),
-        assert(numberMembers != null),
-        assert(membershipLevel != null),
-        assert(visibilityLevel != null),
-        assert(registrationLevel != null),
-        assert(postCreationLevel != null),
-        assert(following != null);
 
   get displayName => this.name;
 

lib/models/group_membership.dart

@@ -1,5 +1,4 @@
 import 'package:comunic/models/group.dart';
-import 'package:flutter/material.dart';
 
 /// Group membership information
 ///
@@ -12,14 +11,11 @@ class GroupMembership {
   final GroupMembershipLevel level;
 
   const GroupMembership({
-    @required this.userID,
+    required this.userID,
-    @required this.groupID,
+    required this.groupID,
-    @required this.timeCreate,
+    required this.timeCreate,
-    @required this.level,
+    required this.level,
-  })  : assert(userID != null),
+  });
-        assert(groupID != null),
-        assert(timeCreate != null),
-        assert(level != null);
 
   String get membershipText => membershipToText(level);
 

lib/models/like_element.dart

@@ -9,6 +9,6 @@ abstract class LikeElement {
 
   int get id;
 
-  bool userLike;
+  late bool userLike;
-  int likes;
+  late int likes;
 }

lib/models/membership.dart

@@ -1,6 +1,5 @@
 import 'package:comunic/models/conversation.dart';
 import 'package:comunic/models/friend.dart';
-import 'package:flutter/material.dart';
 
 /// Membership information
 ///
@@ -10,40 +9,37 @@ enum MembershipType { FRIEND, GROUP, CONVERSATION }
 
 class Membership {
   final MembershipType type;
-  final Conversation conversation;
+  final Conversation? conversation;
-  final Friend friend;
+  final Friend? friend;
-  final int groupID;
+  final int? groupID;
-  final int groupLastActive;
+  final int? groupLastActive;
 
-  Membership.conversation(this.conversation)
+  Membership.conversation(Conversation this.conversation)
       : type = MembershipType.CONVERSATION,
         friend = null,
         groupID = null,
-        groupLastActive = null,
+        groupLastActive = null;
-        assert(conversation != null);
 
-  Membership.friend(this.friend)
+  Membership.friend(Friend this.friend)
       : type = MembershipType.FRIEND,
         conversation = null,
         groupID = null,
-        groupLastActive = null,
+        groupLastActive = null;
-        assert(friend != null);
 
-  Membership.group({@required this.groupID, @required this.groupLastActive})
+  Membership.group(
+      {required int this.groupID, required int this.groupLastActive})
       : type = MembershipType.GROUP,
         conversation = null,
-        friend = null,
+        friend = null;
-        assert(groupID != null),
-        assert(groupLastActive != null);
 
-  int get lastActive {
+  int? get lastActive {
     switch (type) {
       case MembershipType.FRIEND:
-        return friend.lastActive;
+        return friend!.lastActive;
       case MembershipType.GROUP:
         return groupLastActive;
       case MembershipType.CONVERSATION:
-        return conversation.lastActivity;
+        return conversation!.lastActivity;
       default:
         throw Exception("Unreachable statment!");
     }

lib/models/new_account.dart

@@ -1,5 +1,3 @@
-import 'package:flutter/widgets.dart';
-
 /// New account information container
 ///
 /// @author Pierre HUBERT
@@ -11,12 +9,9 @@ class NewAccount {
   final String password;
 
   NewAccount({
-    @required this.firstName,
+    required this.firstName,
-    @required this.lastName,
+    required this.lastName,
-    @required this.email,
+    required this.email,
-    @required this.password,
+    required this.password,
-  })  : assert(firstName != null),
+  });
-        assert(lastName != null),
-        assert(email != null),
-        assert(password != null);
 }

lib/models/new_comment.dart

@@ -1,5 +1,3 @@
-import 'package:meta/meta.dart';
-
 import 'api_request.dart';
 
 /// New comment information
@@ -9,15 +7,15 @@ import 'api_request.dart';
 class NewComment {
   final int postID;
   final String content;
-  final BytesFile image;
+  final BytesFile? image;
 
   const NewComment({
-    @required this.postID,
+    required this.postID,
-    @required this.content,
+    required this.content,
-    @required this.image,
+    required this.image,
-  }) : assert(postID != null);
+  });
 
-  bool get hasContent => content != null && content.length > 0;
+  bool get hasContent => content.length > 0;
 
   bool get hasImage => image != null;
 }