From ba384ba4c0dbfd03cd292300806397aa553c69d0 Mon Sep 17 00:00:00 2001
From: Paul Schneider <paul@pschneider.fr>
Date: Sun, 18 Oct 2026 15:56:58 +0100
Subject: [PATCH] feat(PostIt): unify moderator administration and restore
 Android navigation

Group users and usage in the moderator administration page; retain personal profile management and show personal usage. Allow moderators to read the corresponding API lists while preserving administrator-only mutations. Restore navigation pages after Android activity recreation. Update tests, architecture documentation and CHANGELOG for 1.0.8-rc27.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 CHANGELOG.md                                  |  12 +
 doc/architecture/postit.md                    |  34 +++
 .../PostIt.Tests/ActivityNavigationTests.cs   |  60 +++++
 .../PostIt.Tests/AdministrationAccessTests.cs | 241 ++++++++++++++++++
 .../PostIt.Tests/HomePageProviderFlowTests.cs |   2 +-
 src/PostIt/PostIt/App.axaml.cs                | 104 +++++---
 .../Helpers/ServiceCollectionHelpers.cs       |  24 +-
 src/PostIt/PostIt/ViewLocator.cs              |   1 -
 .../ViewModels/AdministrationPageViewModel.cs |  45 +++-
 .../ViewModels/Layout/HomePageViewModel.cs    |  33 +--
 .../Layout/ResourceUsagePageViewModel.cs      |  90 -------
 .../Layout/SessionStatusViewModel.cs          |  37 ++-
 .../Layout/UserProfilePageViewModel.cs        |  27 +-
 .../Views/Layout/AdministrationPage.axaml     |  99 ++++---
 src/PostIt/PostIt/Views/Layout/HomePage.axaml |   6 +-
 .../Views/Layout/ResourceUsagePage.axaml      |  57 -----
 .../Views/Layout/ResourceUsagePage.axaml.cs   |  11 -
 .../PostIt/Views/Layout/UserProfilePage.axaml |  19 +-
 .../ResourceUsageApiController.cs             |   2 +-
 .../ApplicationUserApiController.cs           |  14 +-
 .../ResourceUsageApiControllerTests.cs        |  43 ++++
 21 files changed, 682 insertions(+), 279 deletions(-)
 create mode 100644 src/PostIt/PostIt.Tests/ActivityNavigationTests.cs
 create mode 100644 src/PostIt/PostIt.Tests/AdministrationAccessTests.cs
 delete mode 100644 src/PostIt/PostIt/ViewModels/Layout/ResourceUsagePageViewModel.cs
 delete mode 100644 src/PostIt/PostIt/Views/Layout/ResourceUsagePage.axaml
 delete mode 100644 src/PostIt/PostIt/Views/Layout/ResourceUsagePage.axaml.cs

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 951ce2d05..81eba2037 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,15 @@
 
 ### Changed
 
+* [PostIt] Une seule page Administration regroupe les utilisateurs et
+  leurs usages, avec le détail d’usage de l’utilisateur sélectionné.
+  L’accès depuis l’accueil et sa commande sont réservés au rôle `Moderator`,
+  vérifié via le profil du backend. « Mon profil » conserve la gestion
+  du compte et accueille l’usage personnel, sans consulter les usages globaux.
+* [Yavsc.Api] Le rôle `Moderator` peut lire les listes d’utilisateurs et
+  d’usages ; les administrateurs conservent leurs droits existants et
+  les autres opérations sur les utilisateurs restent administrateur uniquement.
+
 * [PostIt] La page des blogs passe en deux colonnes lorsque la largeur de
   la fenêtre atteint sa hauteur : billet à gauche, recherche, commandes et
   liste à droite, avec séparateur vertical redimensionnable. La disposition
@@ -19,6 +28,9 @@
 
 ### Fixed
 
+* [PostIt.Android] Restauration de la pile de navigation lors de la
+  recréation de l'activité après suspension : nouvelles pages liées aux
+  mêmes modèles de vue, sans plus de procès.
 * [PostIt] Le changement de disposition de la page des blogs est différé
   sur le thread UI, évitant l'exception « Visual was invalidated during
   the render pass » au redimensionnement.
diff --git a/doc/architecture/postit.md b/doc/architecture/postit.md
index 476137a8b..faa67ad38 100644
--- a/doc/architecture/postit.md
+++ b/doc/architecture/postit.md
@@ -40,6 +40,40 @@ spécifiques (IntentFilter Android, `app.manifest` Desktop).
 Toute la logique (VM, services, navigation, settings, OIDC) est
 dans le code-base partagé.
 
+## Reprise Android
+
+`IActivityApplicationLifetime.MainViewFactory` crée une nouvelle `MainView`
+pour chaque activité Android. Avant de remplacer la racine, PostIt relève
+les types et les modèles de vue des pages de la pile précédente, puis
+recrée ces pages dans le même ordre, sans animation. Les contrôles de
+l'ancienne activité ne sont pas réutilisés ; les modèles de vue conservent
+les sélections et brouillons en mémoire. Une nouvelle racine sans historique
+reçoit la page d'accueil, même si l'initialisation de session a déjà eu lieu.
+Le rafraîchissement silencieux de session reste unique par processus.
+Cette restauration couvre la recréation d'activité dans le même processus,
+pas la destruction du processus par Android.
+
+## Administration et profil personnel
+
+L'accueil présente un seul accès **Administration**, visible et exécutable
+uniquement pour le rôle exact `Moderator`. `SessionStatusViewModel.RefreshAsync`
+lit les rôles dans `GET account/me` après le rafraîchissement de session ;
+une erreur de lecture masque l'accès et affiche une erreur dans la bannière.
+La déconnexion invalide aussi les vérifications de droits encore en vol.
+
+`AdministrationPage` regroupe deux onglets : utilisateurs et usages globaux.
+Le détail d'un utilisateur associe son usage par `UserId`, sans dépendre
+du nom affiché. Les erreurs ne déclenchent pas de repli sur l'usage personnel.
+Le backend autorise la lecture des listes aux rôles `Moderator` et
+`Administrator`, mais garde les autres opérations utilisateurs sous la
+politique `AdministratorOnly`. L'autorisation serveur reste indispensable,
+indépendamment de la visibilité du bouton dans PostIt.
+
+**Mon profil** réutilise la page de gestion du compte existante et les
+endpoints `account/me` pour lire et enregistrer les informations personnelles.
+Elle affiche aussi `resource-usage/me`, sans appeler la liste des usages
+globaux. Une indisponibilité de l'usage n'empêche pas la gestion du profil.
+
 ## Lecture des billets et fichiers utilisateur
 
 La page des blogs affiche par défaut une vue de lecture : titre, login
diff --git a/src/PostIt/PostIt.Tests/ActivityNavigationTests.cs b/src/PostIt/PostIt.Tests/ActivityNavigationTests.cs
new file mode 100644
index 000000000..607523deb
--- /dev/null
+++ b/src/PostIt/PostIt.Tests/ActivityNavigationTests.cs
@@ -0,0 +1,60 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Headless.XUnit;
+using Avalonia.Threading;
+using PostIt.ViewModels;
+using PostIt.Views;
+
+namespace PostIt.Tests;
+
+public class ActivityNavigationTests
+{
+    [AvaloniaFact]
+    public async Task Activity_recreation_restores_fresh_pages_and_back_navigation()
+    {
+        var app = Assert.IsType<App>(Application.Current);
+        var previousView = app.View;
+        var original = new MainView();
+        var home = new HomePage();
+        var draft = new Settings { SelectedLanguage = "fr" };
+        var editor = new ContentPage { DataContext = draft };
+        await original.NavRoot.PushAsync(home, null);
+        await original.NavRoot.PushAsync(editor, null);
+        app.AttachMainWindow(original);
+        var window = new Window();
+        try
+        {
+            var restored = app.CreateActivityView(new Settings());
+            window.Content = restored;
+            window.Show();
+            Dispatcher.UIThread.RunJobs();
+
+            Assert.Equal(2, restored.NavRoot.NavigationStack.Count);
+            Assert.IsType<HomePage>(restored.NavRoot.NavigationStack[0]);
+            Assert.NotSame(home, restored.NavRoot.NavigationStack[0]);
+            Assert.NotSame(editor, restored.NavRoot.NavigationStack[1]);
+            Assert.Same(draft, restored.NavRoot.NavigationStack[1].DataContext);
+            Assert.Equal("fr", draft.SelectedLanguage);
+
+            window.Content = null;
+            window.Content = restored;
+            Dispatcher.UIThread.RunJobs();
+            Assert.Equal(2, restored.NavRoot.NavigationStack.Count);
+
+            // Another activity recreation must retain the already-restored stack.
+            window.Content = null;
+            var recreatedAgain = app.CreateActivityView(new Settings());
+            window.Content = recreatedAgain;
+            Dispatcher.UIThread.RunJobs();
+            Assert.Equal(2, recreatedAgain.NavRoot.NavigationStack.Count);
+            Assert.Same(draft, recreatedAgain.NavRoot.NavigationStack[1].DataContext);
+            await recreatedAgain.NavRoot.PopAsync(null);
+            Assert.IsType<HomePage>(Assert.Single(recreatedAgain.NavRoot.NavigationStack));
+        }
+        finally
+        {
+            window.Close();
+            app.AttachMainWindow(previousView ?? new MainView());
+        }
+    }
+}
diff --git a/src/PostIt/PostIt.Tests/AdministrationAccessTests.cs b/src/PostIt/PostIt.Tests/AdministrationAccessTests.cs
new file mode 100644
index 000000000..ef1466e5f
--- /dev/null
+++ b/src/PostIt/PostIt.Tests/AdministrationAccessTests.cs
@@ -0,0 +1,241 @@
+using System.Net.Http;
+using System.Text.Json;
+using Avalonia.Controls;
+using Avalonia.Headless.XUnit;
+using Avalonia.Threading;
+using Avalonia.VisualTree;
+using PostIt.Services;
+using PostIt.ViewModels;
+using PostIt.Views;
+using Yavsc.Abstract.Identity;
+using Yavsc.Abstract.Resources;
+using Yavsc.Api.Client;
+
+namespace PostIt.Tests;
+
+public class AdministrationAccessTests
+{
+    [AvaloniaTheory]
+    [InlineData("Moderator", true)]
+    [InlineData("Administrator", false)]
+    [InlineData("Performer", false)]
+    [InlineData("moderator", false)]
+    [InlineData("", false)]
+    public async Task Home_administration_visibility_and_command_follow_the_moderator_role(string role, bool allowed)
+    {
+        await using var api = new ProfileTransport(role);
+        var session = new SessionStatusViewModel { Api = api };
+        var vm = new HomePageViewModel(api, api.Settings, session, null!);
+        var page = new HomePage { DataContext = vm };
+        var window = new Window { Content = page };
+        try
+        {
+            window.Show();
+            var button = Assert.Single(page.GetVisualDescendants().OfType<Button>(),
+                button => Equals(button.Content, "Administration"));
+            Assert.False(button.IsVisible);
+            await session.RefreshAsync();
+            Assert.Equal(allowed, session.IsModerator);
+            Assert.Equal(allowed, button.IsVisible);
+            Assert.Equal(allowed, vm.OpenAdministration.CanExecute(null));
+            Assert.DoesNotContain(page.GetVisualDescendants().OfType<Button>(),
+                button => Equals(button.Content, "Mon usage / administration"));
+
+            session.Api = null;
+            session.Refresh();
+            Assert.False(button.IsVisible);
+            Assert.False(vm.OpenAdministration.CanExecute(null));
+        }
+        finally
+        {
+            window.Close();
+        }
+    }
+
+    [Fact]
+    public async Task Late_role_response_cannot_restore_access_after_logout()
+    {
+        await using var api = new ProfileTransport("Moderator");
+        var pending = new TaskCompletionSource<Me>();
+        api.PendingProfile = pending.Task;
+        var session = new SessionStatusViewModel { Api = api };
+        var refresh = session.RefreshAsync();
+        session.Api = null;
+        session.Refresh();
+        pending.SetResult(new Me { Roles = ["Moderator"] });
+        await refresh;
+        Assert.False(session.IsModerator);
+    }
+
+    [Fact]
+    public async Task Role_lookup_failure_denies_access_and_reports_the_error()
+    {
+        await using var api = new ProfileTransport("Moderator") { FailProfile = true };
+        var session = new SessionStatusViewModel { Api = api };
+        await session.RefreshAsync();
+        Assert.False(session.IsModerator);
+        Assert.Contains("Impossible de vérifier les droits", session.SessionLabel);
+    }
+
+    [Fact]
+    public async Task Administration_loads_users_and_usage_and_matches_by_id()
+    {
+        await using var api = new ProfileTransport("Moderator");
+        var session = new SessionStatusViewModel { Api = api };
+        await session.RefreshAsync();
+        var vm = new AdministrationPageViewModel(api, api.UsageClient, session);
+        await vm.RefreshAsync();
+        vm.SelectedUser = Assert.Single(vm.Users);
+        Assert.Equal("alice", vm.SelectedUsage?.UserName);
+        Assert.Equal(12m, vm.SelectedUsage?.ApiCalls);
+        Assert.Single(vm.UsageOverview);
+        Assert.Contains(api.Requests, path => path.EndsWith("/resource-usage/admin"));
+        Assert.DoesNotContain(api.Requests, path => path.EndsWith("/resource-usage/me"));
+    }
+
+    [AvaloniaFact]
+    public async Task Administration_displays_both_tabs_and_selected_user_usage()
+    {
+        await using var api = new ProfileTransport("Moderator");
+        var session = new SessionStatusViewModel { Api = api };
+        await session.RefreshAsync();
+        var vm = new AdministrationPageViewModel(api, api.UsageClient, session);
+        await vm.RefreshAsync();
+        vm.SelectedUser = Assert.Single(vm.Users);
+        var page = new AdministrationPage { DataContext = vm };
+        var window = new Window { Content = page, Width = 800, Height = 600 };
+        try
+        {
+            window.Show();
+            Dispatcher.UIThread.RunJobs();
+            var tabs = Assert.Single(page.GetVisualDescendants().OfType<TabControl>());
+            Assert.Equal(2, tabs.Items.Count);
+            Assert.Contains(page.GetVisualDescendants().OfType<TextBlock>(),
+                text => text.Text == "Appels API : 12");
+            tabs.SelectedIndex = 1;
+            Dispatcher.UIThread.RunJobs();
+            Assert.Contains(page.GetVisualDescendants().OfType<TextBlock>(),
+                text => text.Text == "alice-id");
+            Assert.Contains(page.GetVisualDescendants().OfType<TextBlock>(),
+                text => text.Text == "Appels API : 12");
+        }
+        finally
+        {
+            window.Close();
+        }
+    }
+
+    [Fact]
+    public async Task Administration_denies_non_moderators_without_requesting_private_data()
+    {
+        await using var api = new ProfileTransport("Administrator");
+        var session = new SessionStatusViewModel { Api = api };
+        await session.RefreshAsync();
+        api.Requests.Clear();
+        var vm = new AdministrationPageViewModel(api, api.UsageClient, session);
+        await vm.RefreshAsync();
+        Assert.Empty(api.Requests);
+        Assert.Empty(vm.Users);
+        Assert.Contains("Moderator", vm.StatusMessage);
+    }
+
+    [Fact]
+    public async Task Administration_failure_reports_error_without_falling_back_to_personal_usage()
+    {
+        await using var api = new ProfileTransport("Moderator") { FailUsage = true };
+        var session = new SessionStatusViewModel { Api = api };
+        await session.RefreshAsync();
+        var vm = new AdministrationPageViewModel(api, api.UsageClient, session);
+        await vm.RefreshAsync();
+        Assert.Empty(vm.Users);
+        Assert.Empty(vm.UsageOverview);
+        Assert.Contains("indisponible", vm.StatusMessage);
+        Assert.DoesNotContain(api.Requests, path => path.EndsWith("/resource-usage/me"));
+    }
+
+    [Fact]
+    public async Task My_profile_loads_own_profile_enables_saving_and_only_loads_personal_usage()
+    {
+        await using var api = new ProfileTransport("Performer");
+        var vm = new UserProfilePageViewModel(api, usageClient: api.UsageClient);
+        await vm.RefreshAsync();
+        Assert.True(vm.IsProfileLoaded);
+        Assert.Equal(12m, vm.ResourceUsage?.ApiCalls);
+        Assert.True(vm.SaveProfileCommand.CanExecute(null));
+        vm.FullName = "Alice Updated";
+        Assert.Equal("Alice Updated", vm.BuildProfileUpdateRequest().FullName);
+        Assert.DoesNotContain(api.Requests, path => path.EndsWith("/resource-usage/admin"));
+    }
+
+    [Fact]
+    public async Task Usage_failure_does_not_disable_profile_management()
+    {
+        await using var api = new ProfileTransport("Performer") { FailUsage = true };
+        var vm = new UserProfilePageViewModel(api, usageClient: api.UsageClient);
+        await vm.RefreshAsync();
+        Assert.True(vm.IsProfileLoaded);
+        Assert.True(vm.SaveProfileCommand.CanExecute(null));
+        Assert.Null(vm.ResourceUsage);
+        Assert.Contains("Impossible de charger mon usage", vm.UsageError);
+    }
+
+    private sealed class ProfileTransport : YavscApiClient
+    {
+        private readonly string _tokenPath;
+        private readonly string _role;
+        public List<string> Requests { get; } = [];
+        public Task<Me>? PendingProfile { get; set; }
+        public bool FailProfile { get; set; }
+        public bool FailUsage { get; set; }
+        public ResourceUsageApiClient UsageClient => new(this, Settings.ApiUrl);
+
+        public ProfileTransport(string role)
+            : this(role, Path.Combine(Path.GetTempPath(), $"postit-admin-{Guid.NewGuid():N}.json")) { }
+
+        private ProfileTransport(string role, string path) : base(new Settings(), CreateStore(path))
+        {
+            _role = role;
+            _tokenPath = path;
+        }
+
+        private static TokenStore CreateStore(string path)
+        {
+            var store = new TokenStore(path);
+            store.Save(new RefreshTokenRecord("access", "refresh", DateTimeOffset.UtcNow.AddHours(1), null));
+            return store;
+        }
+
+        public override async Task<T> CallAsync<T>(HttpMethod method, string path, object? body = null,
+            CancellationToken ct = default)
+        {
+            Requests.Add(path);
+            object result;
+            if (path.EndsWith("/account/me"))
+            {
+                if (FailProfile)
+                    throw new HttpRequestException("Profile unavailable");
+                result = PendingProfile is not null ? await PendingProfile
+                    : new Me { UserId = "alice-id", UserName = "alice", Roles = [_role] };
+            }
+            else if (path.Contains("/resource-usage/"))
+            {
+                if (FailUsage)
+                    throw new HttpRequestException("Usage unavailable");
+                var usage = new ResourceUsageSummary { UserId = "alice-id", UserName = "alice", ApiCalls = 12m };
+                result = path.EndsWith("/admin") ? new List<ResourceUsageSummary> { usage } : usage;
+            }
+            else if (path.EndsWith("/users"))
+                result = new List<UserInfo> { new() { UserId = "alice-id", UserName = "alice" } };
+            else
+                throw new InvalidOperationException($"Unexpected endpoint: {path}");
+
+            return JsonSerializer.Deserialize<T>(JsonSerializer.Serialize(result))!;
+        }
+
+        public new async ValueTask DisposeAsync()
+        {
+            await base.DisposeAsync();
+            File.Delete(_tokenPath);
+        }
+    }
+}
diff --git a/src/PostIt/PostIt.Tests/HomePageProviderFlowTests.cs b/src/PostIt/PostIt.Tests/HomePageProviderFlowTests.cs
index e002e534d..756d14af0 100644
--- a/src/PostIt/PostIt.Tests/HomePageProviderFlowTests.cs
+++ b/src/PostIt/PostIt.Tests/HomePageProviderFlowTests.cs
@@ -38,7 +38,7 @@ public class HomePageProviderFlowTests
         var vm = new HomePageViewModel();
 
         Assert.NotNull(vm.OpenAdministration);
-        Assert.True(vm.OpenAdministration.CanExecute(null));
+        Assert.False(vm.OpenAdministration.CanExecute(null));
     }
 
     [Fact]
diff --git a/src/PostIt/PostIt/App.axaml.cs b/src/PostIt/PostIt/App.axaml.cs
index b0f1c30cd..65530fed6 100644
--- a/src/PostIt/PostIt/App.axaml.cs
+++ b/src/PostIt/PostIt/App.axaml.cs
@@ -1,5 +1,4 @@
 using System;
-using System.Threading;
 using System.Threading.Tasks;
 using Avalonia;
 using Avalonia.Controls;
@@ -24,7 +23,8 @@ namespace PostIt;
 public partial class App : Application, ILiveView, IVMPusherApp
 {
     public static bool LiveMode { get; private set; }
-    private int _bootStarted;
+    private Task? _bootTask;
+    private bool _sessionNavigationConfigured;
     public static string? CliConfigFileSpecification { get; private set; }
 
     /// <summary>
@@ -125,6 +125,14 @@ public partial class App : Application, ILiveView, IVMPusherApp
 
     public async Task<Page> PushPageAsync(ViewModelBase viewModel)
     {
+        var mainView = View ?? throw new InvalidOperationException("The navigation root is not initialized.");
+        if (OperatingSystem.IsAndroid() &&
+            mainView.NavRoot.NavigationStack.LastOrDefault() is { } currentPage &&
+            ReferenceEquals(currentPage.DataContext, viewModel))
+        {
+            return currentPage;
+        }
+
         var template = DataTemplates.FirstOrDefault(t => t.Match(viewModel));
         if (template is null)
         {
@@ -148,8 +156,6 @@ public partial class App : Application, ILiveView, IVMPusherApp
 
         page.DataContext = viewModel;
 
-        MainView? mainView = (Current as App).View;
-
         // Avoid stacking the same singleton page twice (e.g. SettingsPage).
         var stack = mainView.NavRoot.NavigationStack;
         if (stack.Count > 0 && ReferenceEquals(stack[stack.Count - 1], page))
@@ -171,12 +177,25 @@ public partial class App : Application, ILiveView, IVMPusherApp
     public void InitializeActivityLifetime(Settings settings, IActivityApplicationLifetime singleViewFactoryApplicationLifetime)
     {
         singleViewFactoryApplicationLifetime.MainViewFactory =
-                        () =>
-                        {
-                            this.ConfigureRootView(ServiceProvider!.GetRequiredService<MainView>());
-                            ApplyStettings(settings);
-                            return View!;
-                        };
+            () => CreateActivityView(settings);
+    }
+
+    internal MainView CreateActivityView(Settings settings)
+    {
+        var pages = View?.NavRoot.NavigationStack
+            .Select(page => (PageType: page.GetType(), page.DataContext))
+            .ToArray();
+        var rootView = ServiceProvider!.GetRequiredService<MainView>();
+        var restoredPages = pages?.Select(state =>
+        {
+            // Do not reuse controls belonging to a destroyed Android activity.
+            var page = (Page)ActivatorUtilities.CreateInstance(ServiceProvider, state.PageType);
+            page.DataContext = state.DataContext;
+            return page;
+        }).ToArray();
+        ConfigureRootView(rootView, restoredPages);
+        ApplyStettings(settings);
+        return rootView;
     }
 
     public void InitializeClassicDesktopLifetime(Settings settings, IClassicDesktopStyleApplicationLifetime desktop)
@@ -196,16 +215,42 @@ public partial class App : Application, ILiveView, IVMPusherApp
     }
 
     public void ConfigureRootView(MainView rootView)
+        => ConfigureRootView(rootView, null);
+
+    private void ConfigureRootView(MainView rootView, Page[]? restoredPages)
     {
+        var initialized = false;
         rootView.AttachedToVisualTree += (_, _) =>
-            Dispatcher.UIThread.Post(() => _ = BootOnceAsync());
+            Dispatcher.UIThread.Post(async () =>
+            {
+                if (initialized)
+                    return;
+                initialized = true;
+                if (restoredPages is { Length: > 0 })
+                {
+                    foreach (var page in restoredPages)
+                        await rootView.NavRoot.PushAsync(page, null);
+                }
+                else
+                {
+                    await BootOnceAsync();
+                    if (rootView.NavRoot.NavigationStack.Count == 0)
+                    {
+                        var home = new HomePage
+                        {
+                            DataContext = ServiceProvider!.GetRequiredService<HomePageViewModel>()
+                        };
+                        await rootView.NavRoot.PushAsync(home, null);
+                    }
+                }
+            });
 
         var sessionStatus = ServiceProvider!.GetRequiredService<SessionStatusViewModel>();
-        sessionStatus.LogoutCompleted += () =>
+        if (!_sessionNavigationConfigured)
         {
-            // Remplacer Window.NavRoot par rootView.NavRoot
-            rootView.NavRoot.PopToRootAsync();
-        };
+            sessionStatus.LogoutCompleted += () => View!.NavRoot.PopToRootAsync();
+            _sessionNavigationConfigured = true;
+        }
         if (rootView.DataContext==null)
             rootView.DataContext = ServiceProvider!.GetRequiredService<HomePageViewModel>();
 
@@ -233,44 +278,29 @@ public partial class App : Application, ILiveView, IVMPusherApp
     }
 
 
-    private async Task BootOnceAsync()
+    private Task BootOnceAsync()
     {
-        if (Interlocked.Exchange(ref _bootStarted, 1) == 1)
-        {
-            return;
-        }
-
         var api = ServiceProvider!.GetRequiredService<YavscApiClient>();
-        await BootAsync(this.ServiceProvider!, api);
+        return _bootTask ??= BootAsync(ServiceProvider!, api);
     }
 
     /// <summary>
-    /// Run once after the main window is shown: try to refresh the
-    /// cached OIDC tokens silently; on success, push MainPage on top
-    /// of HomePage so the user lands on the blog editor already
-    /// authenticated. On failure (refresh token rejected, no bundle
-    /// on disk), leave them on HomePage and the Login button is the
-    /// next step.
+    /// Refresh cached OIDC tokens once per application process.
+    /// Each root view initializes or restores its own navigation stack separately.
     /// </summary>
     private static async Task BootAsync(
         IServiceProvider provider,
         YavscApiClient api)
     {
-        var refreshed = await api.TrySilentLoginAsync().ConfigureAwait(true);
+        await api.TrySilentLoginAsync().ConfigureAwait(true);
         var sessionStatus = provider.GetRequiredService<SessionStatusViewModel>();
-        sessionStatus.Refresh();
-        var homePageVm = provider.GetRequiredService<HomePageViewModel>();
-        var app = (App)Current!;
-        await app.PushPageAsync(homePageVm);
+        await sessionStatus.RefreshAsync();
     }
 
     /// <summary>
     /// Resolve a fresh <c>MainPageViewModel</c> from DI and push its
     /// mapped page (via <see cref="ViewLocator"/>) on top
-    /// of the current navigation stack. Used both by <see cref="BootAsync"/>
-    /// (silent refresh at boot) and by <c>SessionStatusViewModel.LoginSucceeded</c>
-    /// (interactive login from the banner). Pulled out as a helper so
-    /// the two callers can't drift apart.
+    /// of the current navigation stack.
     /// </summary>
     public static async Task PushBlogsPageAsync()
     {
diff --git a/src/PostIt/PostIt/Helpers/ServiceCollectionHelpers.cs b/src/PostIt/PostIt/Helpers/ServiceCollectionHelpers.cs
index fc2388949..10ce04d93 100644
--- a/src/PostIt/PostIt/Helpers/ServiceCollectionHelpers.cs
+++ b/src/PostIt/PostIt/Helpers/ServiceCollectionHelpers.cs
@@ -50,7 +50,16 @@ public static class ServiceCollectionHelpers
         // Models
         services.AddSingleton<ChatViewModel>();
 
-        // SettingsPage is a singleton: there must be one and only one
+        // Android activities need fresh controls; retain state in singleton VMs.
+        void AddReusablePage<TPage>() where TPage : class
+        {
+            if (OperatingSystem.IsAndroid())
+                services.AddTransient<TPage>();
+            else
+                services.AddSingleton<TPage>();
+        }
+
+        // On other platforms SettingsPage is a singleton: one and only one
         // instance of the settings UI for the lifetime of the app.
         // This guarantees that (a) the bindings always reflect the
         // current in-memory Settings state, (b) the page already has
@@ -61,12 +70,12 @@ public static class ServiceCollectionHelpers
         // let the user accumulate stale SettingsPage instances on
         // the navigation stack, each bound to a fresh
         // SettingsViewModel and missing any in-flight edits.
-        services.AddSingleton<SettingsPage>();
-        services.AddSingleton<AboutPage>();
-        services.AddSingleton<HomePage>();
-        services.AddSingleton<SignaturePage>();
-        services.AddSingleton<CirclesPage>();
-        services.AddSingleton<ActivitiesPage>();
+        AddReusablePage<SettingsPage>();
+        AddReusablePage<AboutPage>();
+        AddReusablePage<HomePage>();
+        AddReusablePage<SignaturePage>();
+        AddReusablePage<CirclesPage>();
+        AddReusablePage<ActivitiesPage>();
         services.AddTransient<CommandFormsPage>();
         services.AddTransient<ChatPage>();
         services.AddTransient<RdvPage>();
@@ -81,7 +90,6 @@ public static class ServiceCollectionHelpers
         services.AddTransient<UserProfilePage>();
         services.AddTransient<PerformerConfigurationPage>();
         services.AddTransient<AdministrationPage>();
-        services.AddTransient<ResourceUsagePage>();
 
         // ViewModels
         services.AddSingleton(settings);
diff --git a/src/PostIt/PostIt/ViewLocator.cs b/src/PostIt/PostIt/ViewLocator.cs
index b8e242753..5807df93a 100644
--- a/src/PostIt/PostIt/ViewLocator.cs
+++ b/src/PostIt/PostIt/ViewLocator.cs
@@ -64,7 +64,6 @@ public class ViewLocator : IDataTemplate
             UserProfilePageViewModel => services.GetRequiredService<UserProfilePage>(),
             PerformerConfigurationPageViewModel => services.GetRequiredService<PerformerConfigurationPage>(),
             AdministrationPageViewModel => services.GetRequiredService<AdministrationPage>(),
-            ResourceUsagePageViewModel => services.GetRequiredService<ResourceUsagePage>(),
             ChatViewModel => services.GetRequiredService<ChatPage>(),
             null => new TextBlock { Text = "No view for <null>" },
             _ => new TextBlock { Text = $"No view for {data.GetType().Name}" }
diff --git a/src/PostIt/PostIt/ViewModels/AdministrationPageViewModel.cs b/src/PostIt/PostIt/ViewModels/AdministrationPageViewModel.cs
index 85841bfbc..81853f2eb 100644
--- a/src/PostIt/PostIt/ViewModels/AdministrationPageViewModel.cs
+++ b/src/PostIt/PostIt/ViewModels/AdministrationPageViewModel.cs
@@ -8,12 +8,21 @@ using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
 using PostIt.Services;
 using Yavsc.Abstract.Identity;
+using Yavsc.Abstract.Resources;
+using Yavsc.Api.Client;
 
 namespace PostIt.ViewModels;
 
 public partial class AdministrationPageViewModel : ViewModelBase
 {
     private readonly YavscApiClient? _api;
+    private readonly ResourceUsageApiClient? _usageClient;
+    private readonly SessionStatusViewModel? _session;
+
+    public ObservableCollection<ResourceUsageSummary> UsageOverview { get; } = new();
+
+    public ResourceUsageSummary? SelectedUsage =>
+        UsageOverview.FirstOrDefault(usage => usage.UserId == SelectedUser?.UserId);
 
     [ObservableProperty]
     public partial bool IsBusy { get; set; }
@@ -43,9 +52,12 @@ public partial class AdministrationPageViewModel : ViewModelBase
     public override bool CanNavigateNext { get => false; protected set { _ = value; } }
     public override bool CanNavigatePrevious { get => true; protected set { _ = value; } }
 
-    public AdministrationPageViewModel(YavscApiClient? api)
+    public AdministrationPageViewModel(YavscApiClient? api,
+        ResourceUsageApiClient? usageClient = null, SessionStatusViewModel? session = null)
     {
         _api = api;
+        _usageClient = usageClient;
+        _session = session;
     }
 
     public AdministrationPageViewModel() : this(null) { }
@@ -57,10 +69,22 @@ public partial class AdministrationPageViewModel : ViewModelBase
         OnPropertyChanged(nameof(FilteredUsers));
     }
 
+    partial void OnSelectedUserChanged(UserInfo? value) => OnPropertyChanged(nameof(SelectedUsage));
+
     [RelayCommand]
     public async Task RefreshAsync()
     {
-        if (_api is null)
+        Users.Clear();
+        UsageOverview.Clear();
+        SelectedUser = null;
+        OnPropertyChanged(nameof(FilteredUsers));
+        OnPropertyChanged(nameof(SelectedUsage));
+        if (_session?.IsModerator != true)
+        {
+            StatusMessage = "Le rôle Moderator est requis.";
+            return;
+        }
+        if (_api is null || _usageClient is null)
         {
             StatusMessage = "Client API d’administration indisponible.";
             return;
@@ -74,15 +98,26 @@ public partial class AdministrationPageViewModel : ViewModelBase
                 ? new Uri(new Uri(_api.Settings.ApiUrl.TrimEnd('/') + "/", UriKind.Absolute), "users").ToString()
                 : new Uri(new Uri(_api.Settings.ApiUrl.TrimEnd('/') + "/", UriKind.Absolute), $"users/search/{Uri.EscapeDataString(query)}").ToString();
 
-            var users = await _api.CallAsync<List<UserInfo>>(HttpMethod.Get, usersEndpoint).ConfigureAwait(true);
+            var users = await _api.CallAsync<List<UserInfo>>(HttpMethod.Get, usersEndpoint).ConfigureAwait(true)
+                ?? throw new InvalidOperationException("Le serveur a renvoyé une liste d’utilisateurs vide.");
+            var usage = await _usageClient.GetAdminOverviewAsync().ConfigureAwait(true)
+                ?? throw new InvalidOperationException("Le serveur a renvoyé une liste d’usages vide.");
 
-            Users.Clear();
-            foreach (var user in users ?? [])
+            if (!_session.IsModerator)
+            {
+                StatusMessage = "Le rôle Moderator est requis.";
+                return;
+            }
+
+            foreach (var user in users)
             {
                 Users.Add(user);
             }
+            foreach (var item in usage)
+                UsageOverview.Add(item);
 
             OnPropertyChanged(nameof(FilteredUsers));
+            OnPropertyChanged(nameof(SelectedUsage));
             StatusMessage = Users.Count > 0 ? $"{Users.Count} utilisateur(s) chargé(s)." : "Aucun utilisateur trouvé.";
         }
         catch (Exception ex)
diff --git a/src/PostIt/PostIt/ViewModels/Layout/HomePageViewModel.cs b/src/PostIt/PostIt/ViewModels/Layout/HomePageViewModel.cs
index 1906b613e..c62f3fff5 100644
--- a/src/PostIt/PostIt/ViewModels/Layout/HomePageViewModel.cs
+++ b/src/PostIt/PostIt/ViewModels/Layout/HomePageViewModel.cs
@@ -72,8 +72,7 @@ public class HomePageViewModel : ViewModelBase
         OpenMyFiles = new AsyncRelayCommand(OpenMyFilesAsync);
         OpenProfile = new AsyncRelayCommand(OpenProfileAsync);
         OpenPerformerConfiguration = new AsyncRelayCommand(OpenPerformerConfigurationAsync);
-        OpenAdministration = new AsyncRelayCommand(OpenAdministrationAsync);
-        OpenResourceUsage = new AsyncRelayCommand(OpenResourceUsageAsync);
+        OpenAdministration = new AsyncRelayCommand(OpenAdministrationAsync, () => SessionStatus.IsModerator);
         OpenChat = new AsyncRelayCommand(OpenChatAsync);
     }
 
@@ -83,7 +82,6 @@ public class HomePageViewModel : ViewModelBase
     public IAsyncRelayCommand OpenProfile { get; }
     public IAsyncRelayCommand OpenPerformerConfiguration { get; }
     public IAsyncRelayCommand OpenAdministration { get; }
-    public IAsyncRelayCommand OpenResourceUsage { get; }
     public IAsyncRelayCommand OpenActivities { get; }
     public IAsyncRelayCommand OpenProviderRequests { get; }
     public IAsyncRelayCommand OpenClientEstimates { get; }
@@ -158,6 +156,13 @@ public class HomePageViewModel : ViewModelBase
 
     private void OnSessionStatusChanged(object? sender, PropertyChangedEventArgs e)
     {
+        if (e.PropertyName == nameof(SessionStatusViewModel.IsModerator))
+        {
+            if (Dispatcher.UIThread.CheckAccess())
+                OpenAdministration.NotifyCanExecuteChanged();
+            else
+                Dispatcher.UIThread.Post(OpenAdministration.NotifyCanExecuteChanged);
+        }
         if (e.PropertyName != nameof(SessionStatusViewModel.IsLoggedIn) || _notificationsClient is null)
             return;
 
@@ -302,6 +307,9 @@ public class HomePageViewModel : ViewModelBase
 
     private async Task OpenAdministrationAsync()
     {
+        if (!SessionStatus.IsModerator)
+            throw new UnauthorizedAccessException("Le rôle Moderator est requis.");
+
         var app = (App?)Application.Current;
         if (app is null)
         {
@@ -318,25 +326,6 @@ public class HomePageViewModel : ViewModelBase
         await app.PushPageAsync(vm);
     }
 
-    private async Task OpenResourceUsageAsync()
-    {
-        var app = (App?)Application.Current;
-        if (app is null)
-        {
-            throw new InvalidOperationException("Application PostIt indisponible.");
-        }
-
-        var resourceUsageClient = app.ServiceProvider?.GetRequiredService<ResourceUsageApiClient>();
-        if (resourceUsageClient is null)
-        {
-            throw new InvalidOperationException("Client usage indisponible.");
-        }
-
-        var vm = new ResourceUsagePageViewModel(resourceUsageClient);
-        await vm.InitializeAsync();
-        await app.PushPageAsync(vm);
-    }
-
     /// <summary>
     /// Avalonia designer constructor. Builds a self-contained VM
     /// with a freshly-constructed Settings so the XAML preview can
diff --git a/src/PostIt/PostIt/ViewModels/Layout/ResourceUsagePageViewModel.cs b/src/PostIt/PostIt/ViewModels/Layout/ResourceUsagePageViewModel.cs
deleted file mode 100644
index d1c0d754c..000000000
--- a/src/PostIt/PostIt/ViewModels/Layout/ResourceUsagePageViewModel.cs
+++ /dev/null
@@ -1,90 +0,0 @@
-using System;
-using System.Collections.ObjectModel;
-using System.Threading.Tasks;
-using CommunityToolkit.Mvvm.ComponentModel;
-using CommunityToolkit.Mvvm.Input;
-using Yavsc.Abstract.Resources;
-using Yavsc.Api.Client;
-
-namespace PostIt.ViewModels;
-
-public partial class ResourceUsagePageViewModel : ViewModelBase
-{
-    private readonly ResourceUsageApiClient _client;
-
-    [ObservableProperty]
-    public partial bool IsBusy { get; set; }
-
-    [ObservableProperty]
-    public partial bool IsAdminView { get; set; }
-
-    [ObservableProperty]
-    public partial ResourceUsageSummary? CurrentSummary { get; set; }
-
-    [ObservableProperty]
-    public partial ObservableCollection<ResourceUsageSummary> Overview { get; set; } = new();
-
-    public string Heading => IsAdminView ? "Vue d'administration des usages" : "Mon usage des ressources";
-
-    public override bool CanNavigateNext { get => false; protected set { _ = value; } }
-    public override bool CanNavigatePrevious { get => true; protected set { _ = value; } }
-
-    public ResourceUsagePageViewModel(ResourceUsageApiClient client)
-    {
-        _client = client ?? throw new ArgumentNullException(nameof(client));
-    }
-
-    public Task InitializeAsync() => RefreshAsync();
-
-    [RelayCommand]
-    public async Task RefreshAsync()
-    {
-        IsBusy = true;
-        try
-        {
-            Overview.Clear();
-
-            try
-            {
-                var adminOverview = await _client.GetAdminOverviewAsync().ConfigureAwait(true);
-                if (adminOverview is { Count: > 0 })
-                {
-                    foreach (var item in adminOverview)
-                    {
-                        Overview.Add(item);
-                    }
-
-                    CurrentSummary = adminOverview[0];
-                    IsAdminView = true;
-                    return;
-                }
-            }
-            catch (Exception)
-            {
-                // Non-admin users are not allowed on the admin route; fall back
-                // to the current-user summary below.
-            }
-
-            var current = await _client.GetCurrentAsync().ConfigureAwait(true);
-            CurrentSummary = current;
-            if (current is not null)
-            {
-                Overview.Clear();
-                Overview.Add(current);
-            }
-
-            IsAdminView = false;
-        }
-        catch (Exception ex)
-        {
-            CurrentSummary = null;
-            Overview.Clear();
-            IsAdminView = false;
-            throw new InvalidOperationException($"Impossible de charger l'usage des ressources : {ex.Message}", ex);
-        }
-        finally
-        {
-            IsBusy = false;
-        }
-    }
-}
diff --git a/src/PostIt/PostIt/ViewModels/Layout/SessionStatusViewModel.cs b/src/PostIt/PostIt/ViewModels/Layout/SessionStatusViewModel.cs
index f55d1d9fb..3b8507079 100644
--- a/src/PostIt/PostIt/ViewModels/Layout/SessionStatusViewModel.cs
+++ b/src/PostIt/PostIt/ViewModels/Layout/SessionStatusViewModel.cs
@@ -1,4 +1,6 @@
 using System;
+using System.Linq;
+using System.Net.Http;
 using System.Threading.Tasks;
 using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
@@ -37,6 +39,11 @@ public partial class SessionStatusViewModel : ViewModelBase
     [ObservableProperty]
     public partial bool IsLoggedIn { get; private set; }
 
+    [ObservableProperty]
+    public partial bool IsModerator { get; private set; }
+
+    private int _accessVersion;
+
     /// <summary>Inverse of <see cref="IsLoggedIn"/>, for XAML bindings
     /// (the banner shows the Login button when the user is logged out).
     /// Updated from <see cref="Refresh"/>.</summary>
@@ -73,12 +80,38 @@ public partial class SessionStatusViewModel : ViewModelBase
 
     public void Refresh()
     {
+        ++_accessVersion;
+        IsModerator = false;
         var has = Api?.HasValidSession ?? false;
         IsLoggedIn = has;
         IsLoggedOut = !has;
         SessionLabel = has ? "Connecté" : "Déconnecté";
     }
 
+    public async Task RefreshAsync()
+    {
+        Refresh();
+        var version = _accessVersion;
+        var api = Api;
+        if (!IsLoggedIn || api is null)
+            return;
+
+        try
+        {
+            var endpoint = new Uri(new Uri(api.Settings.ApiUrl.TrimEnd('/') + "/"), "account/me");
+            var profile = await api.CallAsync<Yavsc.Abstract.Identity.Me>(HttpMethod.Get, endpoint.ToString());
+            if (profile is null)
+                throw new InvalidOperationException("Le serveur a renvoyé un profil vide.");
+            if (version == _accessVersion)
+                IsModerator = profile.Roles.Contains(Yavsc.Constants.BlogModeratorGroupName, StringComparer.Ordinal);
+        }
+        catch (Exception ex)
+        {
+            if (version == _accessVersion)
+                SessionLabel = $"Impossible de vérifier les droits : {ex.Message}";
+        }
+    }
+
     /// <summary>
     /// Override the banner label with an error message. Used when
     /// an interactive login attempt fails so the operator sees
@@ -88,6 +121,8 @@ public partial class SessionStatusViewModel : ViewModelBase
     /// </summary>
     public void SetError(string message)
     {
+        ++_accessVersion;
+        IsModerator = false;
         IsLoggedIn = false;
         IsLoggedOut = true;
         SessionLabel = message;
@@ -118,7 +153,7 @@ public partial class SessionStatusViewModel : ViewModelBase
             IsBusy = false;
         }
 
-        Refresh();
+        await RefreshAsync();
         if (Api.HasValidSession)
             LoginSucceeded?.Invoke();
     }
diff --git a/src/PostIt/PostIt/ViewModels/Layout/UserProfilePageViewModel.cs b/src/PostIt/PostIt/ViewModels/Layout/UserProfilePageViewModel.cs
index ed70665f0..449648ef3 100644
--- a/src/PostIt/PostIt/ViewModels/Layout/UserProfilePageViewModel.cs
+++ b/src/PostIt/PostIt/ViewModels/Layout/UserProfilePageViewModel.cs
@@ -7,6 +7,8 @@ using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
 using PostIt.Services;
 using Yavsc.Abstract.Identity;
+using Yavsc.Abstract.Resources;
+using Yavsc.Api.Client;
 
 namespace PostIt.ViewModels;
 
@@ -14,6 +16,13 @@ public partial class UserProfilePageViewModel : ViewModelBase
 {
     private readonly YavscApiClient? _api;
     private readonly SessionStatusViewModel? _sessionStatus;
+    private readonly ResourceUsageApiClient? _usageClient;
+
+    [ObservableProperty]
+    public partial ResourceUsageSummary? ResourceUsage { get; set; }
+
+    [ObservableProperty]
+    public partial string? UsageError { get; set; }
 
     [ObservableProperty]
     [NotifyCanExecuteChangedFor(nameof(SaveProfileCommand))]
@@ -140,10 +149,12 @@ public partial class UserProfilePageViewModel : ViewModelBase
     public override bool CanNavigateNext { get => false; protected set { _ = value; } }
     public override bool CanNavigatePrevious { get => true; protected set { _ = value; } }
 
-    public UserProfilePageViewModel(YavscApiClient? api, SessionStatusViewModel? sessionStatus = null)
+    public UserProfilePageViewModel(YavscApiClient? api, SessionStatusViewModel? sessionStatus = null,
+        ResourceUsageApiClient? usageClient = null)
     {
         _api = api;
         _sessionStatus = sessionStatus;
+        _usageClient = usageClient;
     }
 
     public UserProfilePageViewModel() : this(null, null) { }
@@ -162,6 +173,8 @@ public partial class UserProfilePageViewModel : ViewModelBase
 
         IsBusy = true;
         IsProfileLoaded = false;
+        ResourceUsage = null;
+        UsageError = null;
         try
         {
             var me = await _api.CallAsync<Me>(HttpMethod.Get, new Uri(new Uri(_api.Settings.ApiUrl.TrimEnd('/') + "/", UriKind.Absolute), "account/me").ToString()).ConfigureAwait(true);
@@ -201,6 +214,18 @@ public partial class UserProfilePageViewModel : ViewModelBase
             }
             IsProfileLoaded = true;
             StatusMessage = "Profil chargé.";
+            if (_usageClient is not null)
+            {
+                try
+                {
+                    ResourceUsage = await _usageClient.GetCurrentAsync()
+                        ?? throw new InvalidOperationException("Le serveur a renvoyé un usage vide.");
+                }
+                catch (Exception ex)
+                {
+                    UsageError = $"Impossible de charger mon usage : {ex.Message}";
+                }
+            }
         }
         catch (Exception ex)
         {
diff --git a/src/PostIt/PostIt/Views/Layout/AdministrationPage.axaml b/src/PostIt/PostIt/Views/Layout/AdministrationPage.axaml
index db1d3b490..978886e85 100644
--- a/src/PostIt/PostIt/Views/Layout/AdministrationPage.axaml
+++ b/src/PostIt/PostIt/Views/Layout/AdministrationPage.axaml
@@ -1,11 +1,12 @@
 <ContentPage xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:vm="using:PostIt.ViewModels"
+             xmlns:resources="using:Yavsc.Abstract.Resources"
              x:Class="PostIt.Views.AdministrationPage"
              x:DataType="vm:AdministrationPageViewModel"
              Header="Administration">
 
-  <Grid RowDefinitions="Auto,Auto,Auto,*" Margin="16" RowSpacing="12">
+  <Grid RowDefinitions="Auto,Auto,*" Margin="16" RowSpacing="12">
     <TextBlock Grid.Row="0"
                Text="Administration"
                FontSize="22"
@@ -24,36 +25,74 @@
                  TextWrapping="Wrap"/>
     </StackPanel>
 
-    <Grid Grid.Row="3" ColumnDefinitions="1.3*,0.7*" ColumnSpacing="12">
-      <ListBox ItemsSource="{Binding FilteredUsers}"
-               SelectedItem="{Binding SelectedUser, Mode=TwoWay}">
-        <ListBox.ItemTemplate>
-          <DataTemplate>
-            <Border Padding="8" BorderBrush="#D0D7DE" BorderThickness="1" CornerRadius="6">
-              <StackPanel Spacing="4">
-                <TextBlock Text="{Binding UserName, StringFormat='Nom : {0}'}" FontWeight="SemiBold"/>
-                <TextBlock Text="{Binding FullName, StringFormat='Nom complet : {0}'}" TextWrapping="Wrap"/>
-                <TextBlock Text="{Binding Email, StringFormat='Email : {0}'}" TextWrapping="Wrap"/>
-                <TextBlock Text="{Binding DedicatedGoogleCalendar, StringFormat='Calendrier : {0}'}" TextWrapping="Wrap"/>
-                <TextBlock Text="{Binding UserId, StringFormat='ID : {0}'}" Foreground="#4B5563" TextWrapping="Wrap"/>
+    <TabControl Grid.Row="2">
+      <TabItem Header="Utilisateurs">
+        <Grid ColumnDefinitions="1.3*,0.7*" ColumnSpacing="12">
+          <ListBox ItemsSource="{Binding FilteredUsers}"
+                   SelectedItem="{Binding SelectedUser, Mode=TwoWay}">
+            <ListBox.ItemTemplate>
+              <DataTemplate>
+                <Border Padding="8" BorderBrush="#D0D7DE" BorderThickness="1" CornerRadius="6">
+                  <StackPanel Spacing="4">
+                    <TextBlock Text="{Binding UserName, StringFormat='Nom : {0}'}" FontWeight="SemiBold"/>
+                    <TextBlock Text="{Binding FullName, StringFormat='Nom complet : {0}'}" TextWrapping="Wrap"/>
+                    <TextBlock Text="{Binding Email, StringFormat='Email : {0}'}" TextWrapping="Wrap"/>
+                    <TextBlock Text="{Binding DedicatedGoogleCalendar, StringFormat='Calendrier : {0}'}" TextWrapping="Wrap"/>
+                    <TextBlock Text="{Binding UserId, StringFormat='ID : {0}'}" Foreground="#4B5563" TextWrapping="Wrap"/>
+                  </StackPanel>
+                </Border>
+              </DataTemplate>
+            </ListBox.ItemTemplate>
+          </ListBox>
+
+          <ScrollViewer Grid.Column="1">
+            <Border Padding="12" BorderBrush="#D0D7DE" BorderThickness="1" CornerRadius="6">
+              <StackPanel Spacing="8">
+                <TextBlock Text="Détails" FontWeight="SemiBold" FontSize="18"/>
+                <TextBlock Text="{Binding SelectedUser.UserName, StringFormat='Nom d’utilisateur : {0}'}" TextWrapping="Wrap"/>
+                <TextBlock Text="{Binding SelectedUser.FullName, StringFormat='Nom complet : {0}'}" TextWrapping="Wrap"/>
+                <TextBlock Text="{Binding SelectedUser.Email, StringFormat='Email : {0}'}" TextWrapping="Wrap"/>
+                <TextBlock Text="{Binding SelectedUser.Address, StringFormat='Adresse : {0}'}" TextWrapping="Wrap"/>
+                <TextBlock Text="{Binding SelectedUser.DedicatedGoogleCalendar, StringFormat='Calendrier : {0}'}" TextWrapping="Wrap"/>
+                <TextBlock Text="{Binding SelectedUser.BankInfoSummary, StringFormat='Banque : {0}'}" TextWrapping="Wrap"/>
+                <TextBlock Text="{Binding SelectedUser.UserId, StringFormat='ID : {0}'}" Foreground="#4B5563" TextWrapping="Wrap"/>
+                <StackPanel DataContext="{Binding SelectedUsage}" Spacing="4">
+                  <TextBlock Text="Usage des ressources" FontWeight="Bold"/>
+                  <TextBlock Text="{Binding ApiCalls, StringFormat='Appels API : {0:F0}'}"/>
+                  <TextBlock Text="{Binding CpuSeconds, StringFormat='CPU : {0:F3} s'}"/>
+                  <TextBlock Text="{Binding BandwidthMb, StringFormat='Bande passante : {0:F3} Mo'}"/>
+                  <TextBlock Text="{Binding StorageMb, StringFormat='Stockage : {0:F3} Mo'}"/>
+                  <TextBlock Text="{Binding EstimatedCompensation, StringFormat='Estimation : {0:F2}'}"/>
+                  <TextBlock Text="{Binding Currency}"/>
+                </StackPanel>
               </StackPanel>
             </Border>
-          </DataTemplate>
-        </ListBox.ItemTemplate>
-      </ListBox>
-
-      <Border Grid.Column="1" Padding="12" BorderBrush="#D0D7DE" BorderThickness="1" CornerRadius="6" Background="#F6F8FA">
-        <StackPanel Spacing="8">
-          <TextBlock Text="Détails" FontWeight="SemiBold" FontSize="18"/>
-          <TextBlock Text="{Binding SelectedUser.UserName, StringFormat='Nom d’utilisateur : {0}'}" TextWrapping="Wrap"/>
-          <TextBlock Text="{Binding SelectedUser.FullName, StringFormat='Nom complet : {0}'}" TextWrapping="Wrap"/>
-          <TextBlock Text="{Binding SelectedUser.Email, StringFormat='Email : {0}'}" TextWrapping="Wrap"/>
-          <TextBlock Text="{Binding SelectedUser.Address, StringFormat='Adresse : {0}'}" TextWrapping="Wrap"/>
-          <TextBlock Text="{Binding SelectedUser.DedicatedGoogleCalendar, StringFormat='Calendrier : {0}'}" TextWrapping="Wrap"/>
-          <TextBlock Text="{Binding SelectedUser.BankInfoSummary, StringFormat='Banque : {0}'}" TextWrapping="Wrap"/>
-          <TextBlock Text="{Binding SelectedUser.UserId, StringFormat='ID : {0}'}" Foreground="#4B5563" TextWrapping="Wrap"/>
-        </StackPanel>
-      </Border>
-    </Grid>
+          </ScrollViewer>
+        </Grid>
+      </TabItem>
+      <TabItem Header="Usages">
+        <ScrollViewer>
+          <ItemsControl ItemsSource="{Binding UsageOverview}">
+            <ItemsControl.ItemTemplate>
+              <DataTemplate x:DataType="resources:ResourceUsageSummary">
+                <Border Margin="0,0,0,8" Padding="12" CornerRadius="8"
+                        BorderBrush="#D0D7DE" BorderThickness="1">
+                  <StackPanel Spacing="4">
+                    <TextBlock Text="{Binding UserName}" FontWeight="Bold"/>
+                    <TextBlock Text="{Binding UserId}"/>
+                    <TextBlock Text="{Binding ApiCalls, StringFormat='Appels API : {0:F0}'}"/>
+                    <TextBlock Text="{Binding CpuSeconds, StringFormat='CPU : {0:F3} s'}"/>
+                    <TextBlock Text="{Binding BandwidthMb, StringFormat='Bande passante : {0:F3} Mo'}"/>
+                    <TextBlock Text="{Binding StorageMb, StringFormat='Stockage : {0:F3} Mo'}"/>
+                    <TextBlock Text="{Binding EstimatedCompensation, StringFormat='Estimation : {0:F2}'}"/>
+                    <TextBlock Text="{Binding Currency}"/>
+                  </StackPanel>
+                </Border>
+              </DataTemplate>
+            </ItemsControl.ItemTemplate>
+          </ItemsControl>
+        </ScrollViewer>
+      </TabItem>
+    </TabControl>
   </Grid>
 </ContentPage>
diff --git a/src/PostIt/PostIt/Views/Layout/HomePage.axaml b/src/PostIt/PostIt/Views/Layout/HomePage.axaml
index 7a1099431..e689c1044 100644
--- a/src/PostIt/PostIt/Views/Layout/HomePage.axaml
+++ b/src/PostIt/PostIt/Views/Layout/HomePage.axaml
@@ -92,11 +92,7 @@
           <Button Content="Administration"
               Command="{Binding OpenAdministration}"
               HorizontalAlignment="Center"
-              IsEnabled="{Binding SessionStatus.IsLoggedIn}"/>
-          <Button Content="Mon usage / administration"
-              Command="{Binding OpenResourceUsage}"
-              HorizontalAlignment="Center"
-              IsEnabled="{Binding SessionStatus.IsLoggedIn}"/>
+              IsVisible="{Binding SessionStatus.IsModerator}"/>
         </StackPanel>
         </ScrollViewer>
 </ContentPage>
diff --git a/src/PostIt/PostIt/Views/Layout/ResourceUsagePage.axaml b/src/PostIt/PostIt/Views/Layout/ResourceUsagePage.axaml
deleted file mode 100644
index 5576f4f3a..000000000
--- a/src/PostIt/PostIt/Views/Layout/ResourceUsagePage.axaml
+++ /dev/null
@@ -1,57 +0,0 @@
-<ContentPage xmlns="https://github.com/avaloniaui"
-             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:vm="using:PostIt.ViewModels"
-             xmlns:resources="using:Yavsc.Abstract.Resources"
-             x:Class="PostIt.Views.ResourceUsagePage"
-             x:DataType="vm:ResourceUsagePageViewModel"
-             Header="Usage des ressources">
-
-  <StackPanel Margin="16" Spacing="12">
-    <TextBlock Text="{Binding Heading}"
-               FontSize="22"
-               FontWeight="SemiBold"/>
-
-    <Button Content="Actualiser"
-            Command="{Binding RefreshCommand}"
-            IsEnabled="{Binding !IsBusy}"/>
-
-    <ProgressBar IsVisible="{Binding IsBusy}"
-                 IsIndeterminate="True"
-                 Height="8"/>
-
-    <StackPanel IsVisible="{Binding !IsAdminView}">
-      <TextBlock Text="Résumé personnel" FontWeight="Bold"/>
-      <StackPanel DataContext="{Binding CurrentSummary}" Spacing="4">
-        <TextBlock Text="{Binding UserName, StringFormat='Utilisateur : {0}'}"/>
-        <TextBlock Text="{Binding ApiCalls, StringFormat='Appels API : {0:F0}'}"/>
-        <TextBlock Text="{Binding CpuSeconds, StringFormat='CPU : {0:F3} s'}"/>
-        <TextBlock Text="{Binding BandwidthMb, StringFormat='Bande passante : {0:F3} Mo'}"/>
-        <TextBlock Text="{Binding StorageMb, StringFormat='Stockage : {0:F3} Mo'}"/>
-        <TextBlock Text="{Binding EstimatedCompensation, StringFormat='Estimation : {0:F2}'}"/>
-      </StackPanel>
-    </StackPanel>
-
-    <ItemsControl ItemsSource="{Binding Overview}"
-                  IsVisible="{Binding IsAdminView}">
-      <ItemsControl.ItemTemplate>
-        <DataTemplate x:DataType="resources:ResourceUsageSummary">
-          <Border Margin="0,0,0,8"
-                  Padding="12"
-                  CornerRadius="8"
-                  BorderBrush="#D0D7DE"
-                  BorderThickness="1">
-            <StackPanel Spacing="4">
-              <TextBlock Text="{Binding UserName}"
-                         FontWeight="Bold"/>
-              <TextBlock Text="{Binding ApiCalls, StringFormat='Appels API : {0:F0}'}"/>
-              <TextBlock Text="{Binding CpuSeconds, StringFormat='CPU : {0:F3} s'}"/>
-              <TextBlock Text="{Binding BandwidthMb, StringFormat='Bande passante : {0:F3} Mo'}"/>
-              <TextBlock Text="{Binding StorageMb, StringFormat='Stockage : {0:F3} Mo'}"/>
-              <TextBlock Text="{Binding EstimatedCompensation, StringFormat='Estimation : {0:F2}'}"/>
-            </StackPanel>
-          </Border>
-        </DataTemplate>
-      </ItemsControl.ItemTemplate>
-    </ItemsControl>
-  </StackPanel>
-</ContentPage>
diff --git a/src/PostIt/PostIt/Views/Layout/ResourceUsagePage.axaml.cs b/src/PostIt/PostIt/Views/Layout/ResourceUsagePage.axaml.cs
deleted file mode 100644
index c8ad85fc9..000000000
--- a/src/PostIt/PostIt/Views/Layout/ResourceUsagePage.axaml.cs
+++ /dev/null
@@ -1,11 +0,0 @@
-using Avalonia.Controls;
-
-namespace PostIt.Views;
-
-public partial class ResourceUsagePage : ContentPage
-{
-    public ResourceUsagePage()
-    {
-        InitializeComponent();
-    }
-}
diff --git a/src/PostIt/PostIt/Views/Layout/UserProfilePage.axaml b/src/PostIt/PostIt/Views/Layout/UserProfilePage.axaml
index 5e469a0f5..2c2ccf483 100644
--- a/src/PostIt/PostIt/Views/Layout/UserProfilePage.axaml
+++ b/src/PostIt/PostIt/Views/Layout/UserProfilePage.axaml
@@ -4,13 +4,13 @@
              xmlns:identity="using:Yavsc.Abstract.Identity"
              x:Class="PostIt.Views.UserProfilePage"
              x:DataType="vm:UserProfilePageViewModel"
-             Header="Mon compte">
+             Header="Mon profil">
 
   <ScrollViewer>
     <StackPanel Margin="16" Spacing="16">
       <Grid ColumnDefinitions="*,Auto">
         <StackPanel Spacing="4">
-          <TextBlock Text="Gérer votre compte"
+          <TextBlock Text="Mon profil"
                      FontSize="22"
                      FontWeight="SemiBold"/>
           <TextBlock Text="Paramètres de votre compte"
@@ -27,6 +27,21 @@
                    IsIndeterminate="True"
                    Height="8"/>
 
+      <Border Padding="16" BorderBrush="#D0D7DE" BorderThickness="1" CornerRadius="6">
+        <StackPanel Spacing="4">
+          <TextBlock Text="Mon usage des ressources" FontSize="18" FontWeight="SemiBold"/>
+          <TextBlock Text="{Binding UsageError}" TextWrapping="Wrap"/>
+          <StackPanel DataContext="{Binding ResourceUsage}" Spacing="4">
+            <TextBlock Text="{Binding ApiCalls, StringFormat='Appels API : {0:F0}'}"/>
+            <TextBlock Text="{Binding CpuSeconds, StringFormat='CPU : {0:F3} s'}"/>
+            <TextBlock Text="{Binding BandwidthMb, StringFormat='Bande passante : {0:F3} Mo'}"/>
+            <TextBlock Text="{Binding StorageMb, StringFormat='Stockage : {0:F3} Mo'}"/>
+            <TextBlock Text="{Binding EstimatedCompensation, StringFormat='Estimation : {0:F2}'}"/>
+            <TextBlock Text="{Binding Currency}"/>
+          </StackPanel>
+        </StackPanel>
+      </Border>
+
       <Border Padding="16"
               BorderBrush="#D0D7DE"
               BorderThickness="1"
diff --git a/src/Yavsc.Api/Controllers/Administration/ResourceUsageApiController.cs b/src/Yavsc.Api/Controllers/Administration/ResourceUsageApiController.cs
index 0f6af3083..b13112557 100644
--- a/src/Yavsc.Api/Controllers/Administration/ResourceUsageApiController.cs
+++ b/src/Yavsc.Api/Controllers/Administration/ResourceUsageApiController.cs
@@ -78,7 +78,7 @@ public sealed class ResourceUsageApiController : Controller
     [HttpGet(Constants.ResourceUsageAdminRoute)]
     public async Task<ActionResult<List<ResourceUsageSummary>>> GetAdminOverview()
     {
-        if (!User.IsInRole(Constants.AdminGroupName))
+        if (!User.IsInRole(Constants.AdminGroupName) && !User.IsInRole(Constants.BlogModeratorGroupName))
         {
             return Forbid();
         }
diff --git a/src/Yavsc.Api/Controllers/accounting/ApplicationUserApiController.cs b/src/Yavsc.Api/Controllers/accounting/ApplicationUserApiController.cs
index 8850cba59..326760b7c 100644
--- a/src/Yavsc.Api/Controllers/accounting/ApplicationUserApiController.cs
+++ b/src/Yavsc.Api/Controllers/accounting/ApplicationUserApiController.cs
@@ -7,7 +7,7 @@ using Yavsc.Server.Helpers;
 
 namespace Yavsc.Controllers
 {
-    [Produces("application/json"),Authorize("AdministratorOnly")]
+    [Produces("application/json"), Authorize]
     [Route(Constants.APIPrefix + "/users")]
     public class ApplicationUserApiController : Controller
     {
@@ -19,7 +19,7 @@ namespace Yavsc.Controllers
         }
 
         // GET: api/ApplicationUserApi
-        [HttpGet]
+        [HttpGet, Authorize(Roles = Constants.AdminGroupName + "," + Constants.BlogModeratorGroupName)]
         public IEnumerable<UserInfo> GetApplicationUser(int skip=0, int take = 25)
         {
             return _context.Users
@@ -41,7 +41,7 @@ namespace Yavsc.Controllers
                 });
         }
 
-        [HttpGet("search/{pattern}")]
+        [HttpGet("search/{pattern}"), Authorize(Roles = Constants.AdminGroupName + "," + Constants.BlogModeratorGroupName)]
         public IEnumerable<UserInfo> SearchApplicationUser(string pattern, int skip=0, int take = 25)
         {
             var normalizedPattern = pattern ?? string.Empty;
@@ -68,7 +68,7 @@ namespace Yavsc.Controllers
         }
 
         // GET: api/ApplicationUserApi/5
-        [HttpGet("{id}", Name = "GetApplicationUser")]
+        [HttpGet("{id}", Name = "GetApplicationUser"), Authorize("AdministratorOnly")]
         public IActionResult GetApplicationUser([FromRoute] string id)
         {
             if (!ModelState.IsValid)
@@ -87,7 +87,7 @@ namespace Yavsc.Controllers
         }
 
         // PUT: api/ApplicationUserApi/5
-        [HttpPut("{id}")]
+        [HttpPut("{id}"), Authorize("AdministratorOnly")]
         public IActionResult PutApplicationUser(string id, [FromBody] ApplicationUser applicationUser)
         {
             if (!ModelState.IsValid)
@@ -122,7 +122,7 @@ namespace Yavsc.Controllers
         }
 
         // POST: api/ApplicationUserApi
-        [HttpPost]
+        [HttpPost, Authorize("AdministratorOnly")]
         public IActionResult PostApplicationUser([FromBody] ApplicationUser applicationUser)
         {
             if (!ModelState.IsValid)
@@ -151,7 +151,7 @@ namespace Yavsc.Controllers
         }
 
         // DELETE: api/ApplicationUserApi/5
-        [HttpDelete("{id}")]
+        [HttpDelete("{id}"), Authorize("AdministratorOnly")]
         public IActionResult DeleteApplicationUser(string id)
         {
             if (!ModelState.IsValid)
diff --git a/src/test/Yavsc.Api.Tests/ResourceUsageApiControllerTests.cs b/src/test/Yavsc.Api.Tests/ResourceUsageApiControllerTests.cs
index 9bb278551..db7eb0898 100644
--- a/src/test/Yavsc.Api.Tests/ResourceUsageApiControllerTests.cs
+++ b/src/test/Yavsc.Api.Tests/ResourceUsageApiControllerTests.cs
@@ -182,4 +182,47 @@ public sealed class ResourceUsageApiControllerTests : IClassFixture<ApiWebServer
         Assert.NotNull(payload);
         Assert.Contains(payload!, item => item.UserId == "alice");
     }
+
+    [Theory]
+    [InlineData("Moderator", HttpStatusCode.OK)]
+    [InlineData("Administrator", HttpStatusCode.OK)]
+    [InlineData("Performer", HttpStatusCode.Forbidden)]
+    [InlineData("moderator", HttpStatusCode.Forbidden)]
+    [InlineData("", HttpStatusCode.Forbidden)]
+    public async Task Administration_read_endpoints_enforce_roles(string role, HttpStatusCode expected)
+    {
+        using var http = NewClient(_fixture, "reader", extraClaims:
+            [new Claim(Yavsc.Constants.RoleClaimType, role)]);
+        foreach (var path in new[] { "/api/v1/users", "/api/v1/users/search/alice", "/api/v1/resource-usage/admin" })
+        {
+            var response = await http.GetAsync(path, TestContext.Current.CancellationToken);
+            Assert.Equal(expected, response.StatusCode);
+        }
+    }
+
+    [Fact]
+    public async Task Moderator_cannot_access_administrator_only_user_operations()
+    {
+        using var http = NewClient(_fixture, "moderator", extraClaims:
+            [new Claim(Yavsc.Constants.RoleClaimType, Yavsc.Constants.BlogModeratorGroupName)]);
+        foreach (var method in new[] { HttpMethod.Get, HttpMethod.Put, HttpMethod.Delete, HttpMethod.Post })
+        {
+            using var request = new HttpRequestMessage(method,
+                method == HttpMethod.Post ? "/api/v1/users" : "/api/v1/users/alice");
+            using var response = await http.SendAsync(request, TestContext.Current.CancellationToken);
+            Assert.Equal(HttpStatusCode.Forbidden, response.StatusCode);
+        }
+    }
+
+    [Fact]
+    public async Task Anonymous_user_cannot_read_administration_data()
+    {
+        using var http = NewClient(_fixture);
+        http.DefaultRequestHeaders.Authorization = null;
+        foreach (var path in new[] { "/api/v1/users", "/api/v1/users/search/alice", "/api/v1/resource-usage/admin" })
+        {
+            using var response = await http.GetAsync(path, TestContext.Current.CancellationToken);
+            Assert.Equal(HttpStatusCode.Unauthorized, response.StatusCode);
+        }
+    }
 }