Ajoute les amis et les invitations temps reel

ChessCubing.App/ChessCubing.App.csproj

@@ -13,6 +13,7 @@
     <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly" Version="10.0.2" />
     <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.Authentication" Version="10.0.2" />
     <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.DevServer" Version="10.0.2" PrivateAssets="all" />
+    <PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="10.0.2" />
   </ItemGroup>
 
   <ItemGroup>

ChessCubing.App/Components/PlayInviteOverlay.razor

@@ -0,0 +1,61 @@
+@implements IDisposable
+@inject SocialRealtimeService Realtime
+@inject NavigationManager Navigation
+
+@if (Realtime.IncomingPlayInvite is not null)
+{
+    <div class="play-overlay">
+        <div class="modal-backdrop"></div>
+        <section class="modal-card play-overlay-card" role="dialog" aria-modal="true" aria-labelledby="playInviteTitle">
+            <div class="modal-head">
+                <div>
+                    <p class="eyebrow">Invitation de partie</p>
+                    <h2 id="playInviteTitle">@Realtime.IncomingPlayInvite.SenderDisplayName veut jouer</h2>
+                </div>
+            </div>
+
+            <p class="play-overlay-copy">
+                @Realtime.IncomingPlayInvite.SenderDisplayName te propose une partie ChessCubing et te place cote @RecipientColorLabel.
+            </p>
+
+            <div class="play-overlay-actions">
+                <button class="button secondary small" type="button" @onclick="AcceptAsync">Accepter</button>
+                <button class="button ghost small" type="button" @onclick="DeclineAsync">Refuser</button>
+            </div>
+        </section>
+    </div>
+}
+
+@code {
+    private string RecipientColorLabel
+        => string.Equals(Realtime.IncomingPlayInvite?.RecipientColor, "white", StringComparison.Ordinal)
+            ? "blanc"
+            : "noir";
+
+    protected override async Task OnInitializedAsync()
+    {
+        Realtime.Changed += HandleRealtimeChanged;
+        await Realtime.EnsureStartedAsync();
+    }
+
+    private void HandleRealtimeChanged()
+        => _ = InvokeAsync(StateHasChanged);
+
+    private async Task AcceptAsync()
+    {
+        await Realtime.RespondToIncomingPlayInviteAsync(accept: true);
+
+        var currentPath = new Uri(Navigation.Uri).AbsolutePath.Trim('/');
+        if (!string.Equals(currentPath, "application", StringComparison.OrdinalIgnoreCase) &&
+            !string.Equals(currentPath, "application.html", StringComparison.OrdinalIgnoreCase))
+        {
+            Navigation.NavigateTo("/application.html");
+        }
+    }
+
+    private Task DeclineAsync()
+        => Realtime.RespondToIncomingPlayInviteAsync(accept: false);
+
+    public void Dispose()
+        => Realtime.Changed -= HandleRealtimeChanged;
+}

ChessCubing.App/Layout/MainLayout.razor

@@ -13,6 +13,8 @@ else
     @Body
 }
 
+<PlayInviteOverlay />
+
 @code {
     private bool HideGlobalMenu
     {

ChessCubing.App/Models/Social/SocialModels.cs

@@ -0,0 +1,135 @@
+namespace ChessCubing.App.Models.Social;
+
+public sealed class SocialOverviewResponse
+{
+    public SocialFriendResponse[] Friends { get; init; } = [];
+
+    public SocialInvitationResponse[] ReceivedInvitations { get; init; } = [];
+
+    public SocialInvitationResponse[] SentInvitations { get; init; } = [];
+}
+
+public sealed class SocialFriendResponse
+{
+    public string Subject { get; init; } = string.Empty;
+
+    public string Username { get; init; } = string.Empty;
+
+    public string DisplayName { get; init; } = string.Empty;
+
+    public string? Email { get; init; }
+
+    public string? Club { get; init; }
+
+    public string? City { get; init; }
+
+    public bool IsOnline { get; init; }
+}
+
+public sealed class SocialInvitationResponse
+{
+    public long InvitationId { get; init; }
+
+    public string Subject { get; init; } = string.Empty;
+
+    public string Username { get; init; } = string.Empty;
+
+    public string DisplayName { get; init; } = string.Empty;
+
+    public string? Email { get; init; }
+
+    public bool IsOnline { get; init; }
+
+    public DateTime CreatedUtc { get; init; }
+}
+
+public sealed class SocialSearchUserResponse
+{
+    public string Subject { get; init; } = string.Empty;
+
+    public string Username { get; init; } = string.Empty;
+
+    public string DisplayName { get; init; } = string.Empty;
+
+    public string? Email { get; init; }
+
+    public string? Club { get; init; }
+
+    public string? City { get; init; }
+
+    public bool IsOnline { get; init; }
+
+    public bool IsFriend { get; init; }
+
+    public bool HasSentInvitation { get; init; }
+
+    public bool HasReceivedInvitation { get; init; }
+}
+
+public sealed class SendFriendInvitationRequest
+{
+    public string TargetSubject { get; init; } = string.Empty;
+}
+
+public sealed class PresenceSnapshotMessage
+{
+    public string[] OnlineSubjects { get; init; } = [];
+}
+
+public sealed class PresenceChangedMessage
+{
+    public string Subject { get; init; } = string.Empty;
+
+    public bool IsOnline { get; init; }
+}
+
+public sealed class PlayInviteMessage
+{
+    public string InviteId { get; init; } = string.Empty;
+
+    public string SenderSubject { get; init; } = string.Empty;
+
+    public string SenderUsername { get; init; } = string.Empty;
+
+    public string SenderDisplayName { get; init; } = string.Empty;
+
+    public string RecipientSubject { get; init; } = string.Empty;
+
+    public string RecipientUsername { get; init; } = string.Empty;
+
+    public string RecipientDisplayName { get; init; } = string.Empty;
+
+    public string RecipientColor { get; init; } = string.Empty;
+
+    public DateTime CreatedUtc { get; init; }
+
+    public DateTime ExpiresUtc { get; init; }
+}
+
+public sealed class PlayInviteClosedMessage
+{
+    public string InviteId { get; init; } = string.Empty;
+
+    public string Reason { get; init; } = string.Empty;
+
+    public string Message { get; init; } = string.Empty;
+}
+
+public sealed class PlaySessionResponse
+{
+    public string SessionId { get; init; } = string.Empty;
+
+    public string WhiteSubject { get; init; } = string.Empty;
+
+    public string WhiteName { get; init; } = string.Empty;
+
+    public string BlackSubject { get; init; } = string.Empty;
+
+    public string BlackName { get; init; } = string.Empty;
+
+    public string InitiatorSubject { get; init; } = string.Empty;
+
+    public string RecipientSubject { get; init; } = string.Empty;
+
+    public DateTime ConfirmedUtc { get; init; }
+}

ChessCubing.App/Pages/ApplicationPage.razor

@@ -10,6 +10,7 @@
 @inject NavigationManager Navigation
 @inject AuthenticationStateProvider AuthenticationStateProvider
 @inject HttpClient Http
+@inject SocialRealtimeService Realtime
 
 <PageTitle>ChessCubing Arena | Application</PageTitle>
 <PageBody Page="setup" BodyClass="@SetupBodyClass" />
@@ -180,6 +181,93 @@
                     <input @bind="Form.BlackName" @bind:event="oninput" name="blackName" type="text" maxlength="40" placeholder="Noir" />
                 </label>
 
+                @if (IsAuthenticated)
+                {
+                    <section class="setup-social-card span-2">
+                        <div class="social-card-head">
+                            <div>
+                                <span class="micro-label">Amis connectes</span>
+                                <strong>Inviter un ami a jouer</strong>
+                            </div>
+
+                            <button class="button ghost small icon-button" type="button" title="Rafraichir les amis" aria-label="Rafraichir les amis" @onclick="LoadSocialOverviewAsync">
+                                <span class="material-icons action-icon" aria-hidden="true">refresh</span>
+                            </button>
+                        </div>
+
+                        <p class="social-empty">
+                            Choisis rapidement un ami en ligne et decide de quel cote il doit etre pre-rempli.
+                        </p>
+
+                        @if (!string.IsNullOrWhiteSpace(SocialLoadError))
+                        {
+                            <p class="profile-feedback error">@SocialLoadError</p>
+                        }
+
+                        @if (!string.IsNullOrWhiteSpace(InviteActionError))
+                        {
+                            <p class="profile-feedback error">@InviteActionError</p>
+                        }
+
+                        @if (!string.IsNullOrWhiteSpace(Realtime.LastInviteNotice))
+                        {
+                            <div class="social-inline-feedback">
+                                <span>@Realtime.LastInviteNotice</span>
+                                <button class="button ghost small" type="button" @onclick="Realtime.ClearInviteNotice">Masquer</button>
+                            </div>
+                        }
+
+                        @if (Realtime.OutgoingPlayInvite is not null)
+                        {
+                            <div class="play-invite-pending">
+                                <div>
+                                    <span class="micro-label">En attente</span>
+                                    <strong>@Realtime.OutgoingPlayInvite.RecipientDisplayName</strong>
+                                    <p>Invitation envoyee pour jouer cote @(BuildColorLabel(Realtime.OutgoingPlayInvite.RecipientColor)).</p>
+                                </div>
+                                <button class="button ghost small" type="button" @onclick="CancelOutgoingPlayInviteAsync">
+                                    Annuler
+                                </button>
+                            </div>
+                        }
+
+                        @if (IsSocialLoading)
+                        {
+                            <p class="social-empty">Chargement des amis connectes...</p>
+                        }
+                        else if (OnlineFriends.Length > 0)
+                        {
+                            <div class="play-friends-list">
+                                @foreach (var friend in OnlineFriends)
+                                {
+                                    <article class="play-friend-item">
+                                        <div class="social-item-meta">
+                                            <div class="social-item-title-row">
+                                                <strong>@friend.DisplayName</strong>
+                                                <span class="@BuildPresenceClass(friend.Subject, friend.IsOnline)">@BuildPresenceLabel(friend.Subject, friend.IsOnline)</span>
+                                            </div>
+                                            <span class="social-item-subtitle">@friend.Username</span>
+                                        </div>
+
+                                        <div class="play-friend-actions">
+                                            <button class="button ghost small" type="button" disabled="@(Realtime.OutgoingPlayInvite is not null)" @onclick="() => InviteFriendAsWhiteAsync(friend.Subject)">
+                                                Ami blanc
+                                            </button>
+                                            <button class="button ghost small" type="button" disabled="@(Realtime.OutgoingPlayInvite is not null)" @onclick="() => InviteFriendAsBlackAsync(friend.Subject)">
+                                                Ami noir
+                                            </button>
+                                        </div>
+                                    </article>
+                                }
+                            </div>
+                        }
+                        else
+                        {
+                            <p class="social-empty">Aucun ami connecte. Gere tes amis sur la page utilisateur puis attends qu'ils se connectent.</p>
+                        }
+                    </section>
+                }
+
                 @if (Form.CompetitionMode)
                 {
                     <label class="field" id="arbiterField">
@@ -287,12 +375,24 @@
 @code {
     private SetupFormModel Form { get; set; } = new();
     private bool _ready;
+    private bool IsAuthenticated;
+    private bool IsSocialLoading;
+    private int _knownSocialVersion;
     private string? ConnectedPlayerName;
+    private string? SocialLoadError;
+    private string? InviteActionError;
+    private SocialOverviewResponse? SocialOverview;
 
     private MatchState? CurrentMatch => Store.Current;
 
     private string SetupBodyClass => UsesMoveLimit ? string.Empty : "time-setup-mode";
     private bool CanUseConnectedPlayerName => !string.IsNullOrWhiteSpace(ConnectedPlayerName);
+    private SocialFriendResponse[] OnlineFriends
+        => SocialOverview?.Friends
+            .Where(friend => ResolveOnlineStatus(friend.Subject, friend.IsOnline))
+            .OrderBy(friend => friend.DisplayName, StringComparer.OrdinalIgnoreCase)
+            .ToArray()
+            ?? [];
 
     private bool UsesMoveLimit => MatchEngine.UsesMoveLimit(Form.Mode);
 
@@ -324,7 +424,9 @@
     protected override async Task OnInitializedAsync()
     {
         AuthenticationStateProvider.AuthenticationStateChanged += HandleAuthenticationStateChanged;
-        await LoadConnectedPlayerAsync();
+        Realtime.Changed += HandleRealtimeChanged;
+        await Realtime.EnsureStartedAsync();
+        await LoadApplicationContextAsync();
     }
 
     protected override async Task OnAfterRenderAsync(bool firstRender)
@@ -340,9 +442,26 @@
     }
 
     private void HandleAuthenticationStateChanged(Task<AuthenticationState> authenticationStateTask)
-        => _ = InvokeAsync(LoadConnectedPlayerAsync);
+        => _ = InvokeAsync(LoadApplicationContextAsync);
 
-    private async Task LoadConnectedPlayerAsync()
+    private void HandleRealtimeChanged()
+        => _ = InvokeAsync(HandleRealtimeChangedAsync);
+
+    private async Task HandleRealtimeChangedAsync()
+    {
+        ApplyAcceptedPlaySession();
+
+        if (IsAuthenticated && _knownSocialVersion != Realtime.SocialVersion)
+        {
+            _knownSocialVersion = Realtime.SocialVersion;
+            await LoadSocialOverviewAsync();
+            return;
+        }
+
+        StateHasChanged();
+    }
+
+    private async Task LoadApplicationContextAsync()
     {
         string? fallbackName = null;
 
@@ -353,19 +472,30 @@
 
             if (user.Identity?.IsAuthenticated != true)
             {
+                IsAuthenticated = false;
                 ConnectedPlayerName = null;
+                ResetSocialState();
                 await InvokeAsync(StateHasChanged);
                 return;
             }
 
+            IsAuthenticated = true;
             fallbackName = BuildConnectedPlayerFallback(user);
 
             var response = await Http.GetAsync("api/users/me");
             if (!response.IsSuccessStatusCode)
             {
-                ConnectedPlayerName = response.StatusCode is HttpStatusCode.Unauthorized or HttpStatusCode.Forbidden
+                if (response.StatusCode is HttpStatusCode.Unauthorized or HttpStatusCode.Forbidden)
-                    ? null
+                {
-                    : fallbackName;
+                    IsAuthenticated = false;
+                    ConnectedPlayerName = null;
+                    ResetSocialState();
+                    await InvokeAsync(StateHasChanged);
+                    return;
+                }
+
+                ConnectedPlayerName = fallbackName;
+                await LoadSocialOverviewAsync();
 
                 await InvokeAsync(StateHasChanged);
                 return;
@@ -375,15 +505,62 @@
             ConnectedPlayerName = !string.IsNullOrWhiteSpace(profile?.DisplayName)
                 ? profile.DisplayName
                 : fallbackName;
+            await LoadSocialOverviewAsync();
         }
         catch
         {
             ConnectedPlayerName = fallbackName;
         }
 
+        ApplyAcceptedPlaySession();
         await InvokeAsync(StateHasChanged);
     }
 
+    private async Task LoadSocialOverviewAsync()
+    {
+        if (!IsAuthenticated)
+        {
+            ResetSocialState();
+            return;
+        }
+
+        IsSocialLoading = true;
+        SocialLoadError = null;
+
+        try
+        {
+            var response = await Http.GetAsync("api/social/overview");
+            if (!response.IsSuccessStatusCode)
+            {
+                SocialLoadError = response.StatusCode switch
+                {
+                    HttpStatusCode.Unauthorized => "La session a expire. Reconnecte-toi puis recharge la page.",
+                    _ => "Le chargement des amis a echoue.",
+                };
+                SocialOverview = null;
+                return;
+            }
+
+            SocialOverview = await response.Content.ReadFromJsonAsync<SocialOverviewResponse>() ?? new SocialOverviewResponse();
+            _knownSocialVersion = Realtime.SocialVersion;
+        }
+        catch (HttpRequestException)
+        {
+            SocialLoadError = "Le service social est temporairement indisponible.";
+            SocialOverview = null;
+        }
+        catch (TaskCanceledException)
+        {
+            SocialLoadError = "Le chargement des amis a pris trop de temps.";
+            SocialOverview = null;
+        }
+        finally
+        {
+            IsSocialLoading = false;
+            StateHasChanged();
+        }
+    }
+
     private async Task HandleSubmit()
     {
         await Store.EnsureLoadedAsync();
@@ -426,6 +603,48 @@
         Form.BlackName = ConnectedPlayerName!;
     }
 
+    private async Task InviteFriendToPlayAsync(string friendSubject, string recipientColor)
+    {
+        InviteActionError = null;
+
+        try
+        {
+            await Realtime.SendPlayInviteAsync(friendSubject, recipientColor);
+        }
+        catch (InvalidOperationException exception)
+        {
+            InviteActionError = exception.Message;
+        }
+        catch (Exception exception)
+        {
+            InviteActionError = string.IsNullOrWhiteSpace(exception.Message)
+                ? "L'invitation de partie n'a pas pu etre envoyee."
+                : exception.Message;
+        }
+    }
+
+    private async Task CancelOutgoingPlayInviteAsync()
+    {
+        InviteActionError = null;
+
+        try
+        {
+            await Realtime.CancelOutgoingPlayInviteAsync();
+        }
+        catch (Exception exception)
+        {
+            InviteActionError = string.IsNullOrWhiteSpace(exception.Message)
+                ? "L'invitation de partie n'a pas pu etre annulee."
+                : exception.Message;
+        }
+    }
+
+    private Task InviteFriendAsWhiteAsync(string friendSubject)
+        => InviteFriendToPlayAsync(friendSubject, "white");
+
+    private Task InviteFriendAsBlackAsync(string friendSubject)
+        => InviteFriendToPlayAsync(friendSubject, "black");
+
     private void SetMode(string mode)
         => Form.Mode = mode;
 
@@ -470,6 +689,44 @@
     private string BuildPrefillTitle(string color)
         => $"Utiliser mon nom cote {color}";
 
+    private void ApplyAcceptedPlaySession()
+    {
+        var session = Realtime.TakeAcceptedPlaySession();
+        if (session is null)
+        {
+            return;
+        }
+
+        Form.WhiteName = session.WhiteName;
+        Form.BlackName = session.BlackName;
+    }
+
+    private bool ResolveOnlineStatus(string subject, bool fallbackStatus)
+        => Realtime.GetKnownOnlineStatus(subject) ?? fallbackStatus;
+
+    private string BuildPresenceClass(string subject, bool fallbackStatus)
+        => ResolveOnlineStatus(subject, fallbackStatus)
+            ? "presence-badge online"
+            : "presence-badge";
+
+    private string BuildPresenceLabel(string subject, bool fallbackStatus)
+        => ResolveOnlineStatus(subject, fallbackStatus)
+            ? "En ligne"
+            : "Hors ligne";
+
+    private static string BuildColorLabel(string color)
+        => string.Equals(color, "white", StringComparison.OrdinalIgnoreCase)
+            ? "blanc"
+            : "noir";
+
+    private void ResetSocialState()
+    {
+        SocialOverview = null;
+        SocialLoadError = null;
+        InviteActionError = null;
+        _knownSocialVersion = Realtime.SocialVersion;
+    }
+
     private static string? BuildConnectedPlayerFallback(ClaimsPrincipal user)
         => FirstNonEmpty(
             user.FindFirst("name")?.Value,
@@ -481,5 +738,8 @@
         => candidates.FirstOrDefault(candidate => !string.IsNullOrWhiteSpace(candidate));
 
     public void Dispose()
-        => AuthenticationStateProvider.AuthenticationStateChanged -= HandleAuthenticationStateChanged;
+    {
+        AuthenticationStateProvider.AuthenticationStateChanged -= HandleAuthenticationStateChanged;
+        Realtime.Changed -= HandleRealtimeChanged;
+    }
 }

ChessCubing.App/Pages/UserPage.razor

@@ -7,6 +7,7 @@
 @implements IDisposable
 @inject AuthenticationStateProvider AuthenticationStateProvider
 @inject HttpClient Http
+@inject SocialRealtimeService Realtime
 
 <PageTitle>ChessCubing Arena | Utilisateur</PageTitle>
 <PageBody BodyClass="home-body" />
@@ -18,12 +19,11 @@
     <header class="hero hero-home user-hero">
         <div class="hero-copy">
             <p class="eyebrow">Espace utilisateur</p>
-            <h1>Gerer les donnees du site pour chaque joueur</h1>
+            <h1>Profil joueur, amis et invitations</h1>
             <p class="lead">
-                Cette page relie le compte connecte a une fiche utilisateur stockee
+                Cette page regroupe le profil du site, la gestion des amis ChessCubing,
-                cote serveur en MySQL. L'authentification reste geree par Keycloak,
+                ainsi que les invitations recues ou envoyees. Les confirmations de partie
-                mais les informations metier du site sont maintenant pretes pour des
+                sont ensuite synchronisees en direct avec SignalR.
-                evolutions futures.
             </p>
             <div class="hero-actions">
                 <a class="button secondary" href="application.html">Ouvrir l'application</a>
@@ -33,11 +33,11 @@
 
         <aside class="hero-preview">
             <div class="preview-card">
-                <p class="micro-label">Persistance</p>
+                <p class="micro-label">Temps reel</p>
-                <strong>Profil du site stocke en MySQL</strong>
+                <strong>Presence et invitations synchronisees</strong>
                 <p>
-                    Username et email restent lies au compte authentifie, pendant que
+                    Les amis connectes apparaissent en direct, et les invitations de
-                    le profil ChessCubing ajoute les donnees utiles au site.
+                    partie peuvent etre confirmees depuis un autre device.
                 </p>
             </div>
             <div class="preview-banner">
@@ -55,11 +55,12 @@
                 <div class="section-heading">
                     <div>
                         <p class="eyebrow">Connexion requise</p>
-                        <h2>Connecte-toi pour gerer ton profil</h2>
+                        <h2>Connecte-toi pour gerer ton profil et tes amis</h2>
                     </div>
                     <p class="section-copy">
                         Utilise les boutons Se connecter ou Creer un compte dans le menu
-                        en haut de page, puis reviens ici pour enregistrer tes informations.
+                        en haut de page, puis reviens ici pour enregistrer tes informations
+                        et inviter d'autres joueurs.
                     </p>
                 </div>
 
@@ -86,15 +87,15 @@
         {
             <section class="panel panel-wide">
                 <p class="eyebrow">Chargement</p>
-                <h2>Recuperation du profil utilisateur</h2>
+                <h2>Recuperation de l'espace utilisateur</h2>
-                <p class="section-copy">Le serveur recharge les donnees enregistrees pour ce compte.</p>
+                <p class="section-copy">Le serveur recharge le profil, les amis et les invitations de ce compte.</p>
             </section>
         }
         else if (!string.IsNullOrWhiteSpace(LoadError))
         {
             <section class="panel panel-wide">
                 <p class="eyebrow">Serveur</p>
-                <h2>Impossible de charger le profil</h2>
+                <h2>Impossible de charger l'espace utilisateur</h2>
                 <p class="profile-feedback error">@LoadError</p>
                 <div class="hero-actions">
                     <button class="button secondary" type="button" @onclick="LoadProfileAsync">Reessayer</button>
@@ -217,6 +218,235 @@
                     </div>
                 </EditForm>
             </section>
+
+            <section class="panel panel-wide user-social-panel">
+                <div class="section-heading user-profile-heading">
+                    <div>
+                        <p class="eyebrow">Reseau joueur</p>
+                        <h2>Amis et invitations</h2>
+                    </div>
+
+                    <div class="hero-actions">
+                        <button class="button ghost small icon-button" type="button" title="Rafraichir" aria-label="Rafraichir" @onclick="ReloadSocialAsync">
+                            <span class="material-icons action-icon" aria-hidden="true">refresh</span>
+                        </button>
+                    </div>
+                </div>
+
+                <p class="user-profile-note">Invite des joueurs du site, suis les invitations en cours et retrouve rapidement les amis connectes.</p>
+
+                @if (!string.IsNullOrWhiteSpace(SocialLoadError))
+                {
+                    <p class="profile-feedback error">@SocialLoadError</p>
+                }
+
+                @if (!string.IsNullOrWhiteSpace(SocialActionError))
+                {
+                    <p class="profile-feedback error">@SocialActionError</p>
+                }
+
+                @if (!string.IsNullOrWhiteSpace(SocialActionMessage))
+                {
+                    <p class="profile-feedback success">@SocialActionMessage</p>
+                }
+
+                <form class="social-search-form" @onsubmit="HandleSearchSubmit" @onsubmit:preventDefault="true">
+                    <label class="field">
+                        <span>Rechercher un joueur</span>
+                        <input @bind="SearchQuery" @bind:event="oninput" type="text" maxlength="80" placeholder="Nom, pseudo, club, ville..." />
+                    </label>
+
+                    <div class="social-search-actions">
+                        <button class="button secondary small" type="submit" disabled="@IsSearching">
+                            @(IsSearching ? "Recherche..." : "Chercher")
+                        </button>
+                    </div>
+                </form>
+
+                @if (!string.IsNullOrWhiteSpace(SearchError))
+                {
+                    <p class="profile-feedback error">@SearchError</p>
+                }
+
+                @if (SearchResults.Length > 0)
+                {
+                    <div class="social-search-results">
+                        @foreach (var result in SearchResults)
+                        {
+                            <article class="social-item">
+                                <div class="social-item-meta">
+                                    <div class="social-item-title-row">
+                                        <strong>@result.DisplayName</strong>
+                                        <span class="@BuildPresenceClass(result.Subject, result.IsOnline)">@BuildPresenceLabel(result.Subject, result.IsOnline)</span>
+                                    </div>
+                                    <span class="social-item-subtitle">@result.Username</span>
+                                    @if (!string.IsNullOrWhiteSpace(result.Club) || !string.IsNullOrWhiteSpace(result.City))
+                                    {
+                                        <span class="social-item-caption">@JoinNonEmpty(result.Club, result.City)</span>
+                                    }
+                                </div>
+
+                                <div class="social-item-actions">
+                                    @if (result.IsFriend)
+                                    {
+                                        <span class="mini-chip admin-chip-neutral">Deja ami</span>
+                                    }
+                                    else if (FindReceivedInvitation(result.Subject) is { } receivedInvitation)
+                                    {
+                                        <button class="button secondary small" type="button" @onclick="() => AcceptInvitationAsync(receivedInvitation.InvitationId)">
+                                            Accepter
+                                        </button>
+                                        <button class="button ghost small" type="button" @onclick="() => DeclineInvitationAsync(receivedInvitation.InvitationId)">
+                                            Refuser
+                                        </button>
+                                    }
+                                    else if (FindSentInvitation(result.Subject) is { } sentInvitation)
+                                    {
+                                        <span class="mini-chip admin-chip-outline">Invitation envoyee</span>
+                                        <button class="button ghost small" type="button" @onclick="() => CancelInvitationAsync(sentInvitation.InvitationId)">
+                                            Annuler
+                                        </button>
+                                    }
+                                    else
+                                    {
+                                        <button class="button secondary small" type="button" @onclick="() => SendInvitationAsync(result.Subject)">
+                                            Inviter
+                                        </button>
+                                    }
+                                </div>
+                            </article>
+                        }
+                    </div>
+                }
+
+                <div class="social-columns">
+                    <section class="social-card">
+                        <div class="social-card-head">
+                            <strong>Amis</strong>
+                            <span class="mini-chip admin-chip-outline">@FriendCountLabel</span>
+                        </div>
+
+                        @if (IsSocialLoading)
+                        {
+                            <p class="social-empty">Chargement des amis...</p>
+                        }
+                        else if (SocialOverview?.Friends.Length > 0)
+                        {
+                            <div class="social-list">
+                                @foreach (var friend in SocialOverview.Friends.OrderByDescending(friend => ResolveOnlineStatus(friend.Subject, friend.IsOnline)).ThenBy(friend => friend.DisplayName, StringComparer.OrdinalIgnoreCase))
+                                {
+                                    <article class="social-item">
+                                        <div class="social-item-meta">
+                                            <div class="social-item-title-row">
+                                                <strong>@friend.DisplayName</strong>
+                                                <span class="@BuildPresenceClass(friend.Subject, friend.IsOnline)">@BuildPresenceLabel(friend.Subject, friend.IsOnline)</span>
+                                            </div>
+                                            <span class="social-item-subtitle">@friend.Username</span>
+                                            @if (!string.IsNullOrWhiteSpace(friend.Club) || !string.IsNullOrWhiteSpace(friend.City))
+                                            {
+                                                <span class="social-item-caption">@JoinNonEmpty(friend.Club, friend.City)</span>
+                                            }
+                                        </div>
+
+                                        <div class="social-item-actions">
+                                            <button class="button ghost small" type="button" @onclick="() => RemoveFriendAsync(friend.Subject)">
+                                                Retirer
+                                            </button>
+                                        </div>
+                                    </article>
+                                }
+                            </div>
+                        }
+                        else
+                        {
+                            <p class="social-empty">Aucun ami pour le moment. Utilise la recherche ci-dessus pour commencer.</p>
+                        }
+                    </section>
+
+                    <section class="social-card">
+                        <div class="social-card-head">
+                            <strong>Invitations recues</strong>
+                            <span class="mini-chip admin-chip-outline">@ReceivedCountLabel</span>
+                        </div>
+
+                        @if (IsSocialLoading)
+                        {
+                            <p class="social-empty">Chargement des invitations...</p>
+                        }
+                        else if (SocialOverview?.ReceivedInvitations.Length > 0)
+                        {
+                            <div class="social-list">
+                                @foreach (var invitation in SocialOverview.ReceivedInvitations.OrderByDescending(invitation => invitation.CreatedUtc))
+                                {
+                                    <article class="social-item">
+                                        <div class="social-item-meta">
+                                            <div class="social-item-title-row">
+                                                <strong>@invitation.DisplayName</strong>
+                                                <span class="@BuildPresenceClass(invitation.Subject, invitation.IsOnline)">@BuildPresenceLabel(invitation.Subject, invitation.IsOnline)</span>
+                                            </div>
+                                            <span class="social-item-subtitle">@invitation.Username</span>
+                                            <span class="social-item-caption">Recue le @FormatDate(invitation.CreatedUtc)</span>
+                                        </div>
+
+                                        <div class="social-item-actions">
+                                            <button class="button secondary small" type="button" @onclick="() => AcceptInvitationAsync(invitation.InvitationId)">
+                                                Accepter
+                                            </button>
+                                            <button class="button ghost small" type="button" @onclick="() => DeclineInvitationAsync(invitation.InvitationId)">
+                                                Refuser
+                                            </button>
+                                        </div>
+                                    </article>
+                                }
+                            </div>
+                        }
+                        else
+                        {
+                            <p class="social-empty">Aucune invitation recue pour l'instant.</p>
+                        }
+                    </section>
+
+                    <section class="social-card">
+                        <div class="social-card-head">
+                            <strong>Invitations envoyees</strong>
+                            <span class="mini-chip admin-chip-outline">@SentCountLabel</span>
+                        </div>
+
+                        @if (IsSocialLoading)
+                        {
+                            <p class="social-empty">Chargement des invitations...</p>
+                        }
+                        else if (SocialOverview?.SentInvitations.Length > 0)
+                        {
+                            <div class="social-list">
+                                @foreach (var invitation in SocialOverview.SentInvitations.OrderByDescending(invitation => invitation.CreatedUtc))
+                                {
+                                    <article class="social-item">
+                                        <div class="social-item-meta">
+                                            <div class="social-item-title-row">
+                                                <strong>@invitation.DisplayName</strong>
+                                                <span class="@BuildPresenceClass(invitation.Subject, invitation.IsOnline)">@BuildPresenceLabel(invitation.Subject, invitation.IsOnline)</span>
+                                            </div>
+                                            <span class="social-item-subtitle">@invitation.Username</span>
+                                            <span class="social-item-caption">Envoyee le @FormatDate(invitation.CreatedUtc)</span>
+                                        </div>
+
+                                        <div class="social-item-actions">
+                                            <button class="button ghost small" type="button" @onclick="() => CancelInvitationAsync(invitation.InvitationId)">
+                                                Annuler
+                                            </button>
+                                        </div>
+                                    </article>
+                                }
+                            </div>
+                        }
+                        else
+                        {
+                            <p class="social-empty">Aucune invitation envoyee pour l'instant.</p>
+                        }
+                    </section>
+                </div>
+            </section>
         }
     </main>
 </div>
@@ -225,12 +455,22 @@
     private readonly UserProfileFormModel Form = new();
 
     private UserProfileResponse? Profile;
+    private SocialOverviewResponse? SocialOverview;
+    private SocialSearchUserResponse[] SearchResults = [];
     private bool IsAuthenticated;
     private bool IsLoading = true;
     private bool IsSaving;
+    private bool IsSocialLoading;
+    private bool IsSearching;
+    private int _knownSocialVersion;
     private string? LoadError;
     private string? SaveError;
     private string? SaveMessage;
+    private string? SocialLoadError;
+    private string? SocialActionError;
+    private string? SocialActionMessage;
+    private string? SearchError;
+    private string SearchQuery = string.Empty;
 
     private string HeroStatusTitle
         => !IsAuthenticated
@@ -241,20 +481,55 @@
 
     private string HeroStatusDescription
         => !IsAuthenticated
-            ? "Le profil du site apparait des qu'un compte joueur est connecte."
+            ? "Le profil du site et le reseau d'amis apparaissent des qu'un compte joueur est connecte."
             : IsLoading
-                ? "Le serveur verifie la fiche utilisateur associee a ce compte."
+                ? "Le serveur verifie la fiche utilisateur et les relations sociales associees a ce compte."
-                : $"Compte lie a {Profile?.Username ?? "l'utilisateur connecte"} et stocke en base MySQL.";
+                : $"Compte lie a {Profile?.Username ?? "l'utilisateur connecte"} avec synchronisation sociale en direct.";
+
+    private string FriendCountLabel => $"{SocialOverview?.Friends.Length ?? 0} ami(s)";
+
+    private string ReceivedCountLabel => $"{SocialOverview?.ReceivedInvitations.Length ?? 0} recue(s)";
+
+    private string SentCountLabel => $"{SocialOverview?.SentInvitations.Length ?? 0} envoyee(s)";
 
     protected override async Task OnInitializedAsync()
     {
         AuthenticationStateProvider.AuthenticationStateChanged += HandleAuthenticationStateChanged;
+        Realtime.Changed += HandleRealtimeChanged;
+        await Realtime.EnsureStartedAsync();
         await LoadProfileAsync();
     }
 
     private void HandleAuthenticationStateChanged(Task<AuthenticationState> authenticationStateTask)
         => _ = InvokeAsync(LoadProfileAsync);
 
+    private void HandleRealtimeChanged()
+        => _ = InvokeAsync(HandleRealtimeChangedAsync);
+
+    private async Task HandleRealtimeChangedAsync()
+    {
+        if (!IsAuthenticated)
+        {
+            StateHasChanged();
+            return;
+        }
+
+        if (_knownSocialVersion != Realtime.SocialVersion)
+        {
+            _knownSocialVersion = Realtime.SocialVersion;
+            await LoadSocialOverviewAsync();
+
+            if (!string.IsNullOrWhiteSpace(SearchQuery))
+            {
+                await SearchUsersAsync();
+            }
+
+            return;
+        }
+
+        StateHasChanged();
+    }
+
     private async Task LoadProfileAsync()
     {
         LoadError = null;
@@ -268,6 +543,7 @@
             if (authState.User.Identity?.IsAuthenticated != true)
             {
                 ResetProfileState();
+                ResetSocialState();
                 return;
             }
 
@@ -277,6 +553,7 @@
             if (response.StatusCode == HttpStatusCode.Unauthorized)
             {
                 ResetProfileState();
+                ResetSocialState();
                 return;
             }
 
@@ -284,6 +561,7 @@
             {
                 LoadError = await ReadErrorAsync(response, "Le profil utilisateur n'a pas pu etre charge.");
                 Profile = null;
+                ResetSocialState();
                 return;
             }
 
@@ -291,20 +569,24 @@
             if (Profile is null)
             {
                 LoadError = "Le serveur a retourne une reponse vide.";
+                ResetSocialState();
                 return;
             }
 
             FillForm(Profile);
+            await LoadSocialOverviewAsync();
         }
         catch (HttpRequestException)
         {
             LoadError = "Le service utilisateur est temporairement indisponible.";
             Profile = null;
+            ResetSocialState();
         }
         catch (TaskCanceledException)
         {
             LoadError = "La reponse du service utilisateur a pris trop de temps.";
             Profile = null;
+            ResetSocialState();
         }
         finally
         {
@@ -313,6 +595,43 @@
         }
     }
 
+    private async Task LoadSocialOverviewAsync()
+    {
+        SocialLoadError = null;
+        IsSocialLoading = true;
+
+        try
+        {
+            var response = await Http.GetAsync("api/social/overview");
+            if (!response.IsSuccessStatusCode)
+            {
+                SocialLoadError = await ReadErrorAsync(response, "Le reseau social n'a pas pu etre charge.");
+                SocialOverview = null;
+                SearchResults = [];
+                return;
+            }
+
+            SocialOverview = await response.Content.ReadFromJsonAsync<SocialOverviewResponse>();
+            SocialOverview ??= new SocialOverviewResponse();
+            _knownSocialVersion = Realtime.SocialVersion;
+        }
+        catch (HttpRequestException)
+        {
+            SocialLoadError = "Le service social est temporairement indisponible.";
+            SocialOverview = null;
+        }
+        catch (TaskCanceledException)
+        {
+            SocialLoadError = "Le chargement du reseau social a pris trop de temps.";
+            SocialOverview = null;
+        }
+        finally
+        {
+            IsSocialLoading = false;
+            StateHasChanged();
+        }
+    }
+
     private async Task SaveProfileAsync()
     {
         if (IsSaving || !IsAuthenticated)
@@ -367,6 +686,165 @@
         }
     }
 
+    private Task HandleSearchSubmit()
+        => SearchUsersAsync();
+
+    private async Task SearchUsersAsync()
+    {
+        SearchError = null;
+        SocialActionError = null;
+        SocialActionMessage = null;
+
+        var normalizedQuery = SearchQuery.Trim();
+        if (string.IsNullOrWhiteSpace(normalizedQuery))
+        {
+            SearchResults = [];
+            StateHasChanged();
+            return;
+        }
+
+        IsSearching = true;
+
+        try
+        {
+            var response = await Http.GetAsync($"api/social/search?query={Uri.EscapeDataString(normalizedQuery)}");
+            if (!response.IsSuccessStatusCode)
+            {
+                SearchError = await ReadErrorAsync(response, "La recherche de joueurs a echoue.");
+                SearchResults = [];
+                return;
+            }
+
+            SearchResults = await response.Content.ReadFromJsonAsync<SocialSearchUserResponse[]>() ?? [];
+        }
+        catch (HttpRequestException)
+        {
+            SearchError = "Le service social est temporairement indisponible.";
+            SearchResults = [];
+        }
+        catch (TaskCanceledException)
+        {
+            SearchError = "La recherche a pris trop de temps.";
+            SearchResults = [];
+        }
+        finally
+        {
+            IsSearching = false;
+            StateHasChanged();
+        }
+    }
+
+    private async Task ReloadSocialAsync()
+    {
+        await LoadSocialOverviewAsync();
+
+        if (!string.IsNullOrWhiteSpace(SearchQuery))
+        {
+            await SearchUsersAsync();
+        }
+    }
+
+    private async Task SendInvitationAsync(string subject)
+    {
+        await RunSocialActionAsync(
+            async () =>
+            {
+                var payload = new SendFriendInvitationRequest { TargetSubject = subject };
+                var response = await Http.PostAsJsonAsync("api/social/invitations", payload);
+                if (!response.IsSuccessStatusCode)
+                {
+                    throw new InvalidOperationException(await ReadErrorAsync(response, "L'invitation n'a pas pu etre envoyee."));
+                }
+            },
+            "Invitation d'ami envoyee.");
+    }
+
+    private async Task AcceptInvitationAsync(long invitationId)
+    {
+        await RunSocialActionAsync(
+            async () =>
+            {
+                var response = await Http.PostAsync($"api/social/invitations/{invitationId}/accept", content: null);
+                if (!response.IsSuccessStatusCode)
+                {
+                    throw new InvalidOperationException(await ReadErrorAsync(response, "L'invitation n'a pas pu etre acceptee."));
+                }
+            },
+            "Invitation acceptee. Le joueur a ete ajoute aux amis.");
+    }
+
+    private async Task DeclineInvitationAsync(long invitationId)
+    {
+        await RunSocialActionAsync(
+            async () =>
+            {
+                var response = await Http.PostAsync($"api/social/invitations/{invitationId}/decline", content: null);
+                if (!response.IsSuccessStatusCode)
+                {
+                    throw new InvalidOperationException(await ReadErrorAsync(response, "L'invitation n'a pas pu etre refusee."));
+                }
+            },
+            "Invitation refusee.");
+    }
+
+    private async Task CancelInvitationAsync(long invitationId)
+    {
+        await RunSocialActionAsync(
+            async () =>
+            {
+                var response = await Http.DeleteAsync($"api/social/invitations/{invitationId}");
+                if (!response.IsSuccessStatusCode)
+                {
+                    throw new InvalidOperationException(await ReadErrorAsync(response, "L'invitation n'a pas pu etre annulee."));
+                }
+            },
+            "Invitation annulee.");
+    }
+
+    private async Task RemoveFriendAsync(string friendSubject)
+    {
+        await RunSocialActionAsync(
+            async () =>
+            {
+                var response = await Http.DeleteAsync($"api/social/friends/{Uri.EscapeDataString(friendSubject)}");
+                if (!response.IsSuccessStatusCode)
+                {
+                    throw new InvalidOperationException(await ReadErrorAsync(response, "L'ami n'a pas pu etre retire."));
+                }
+            },
+            "Relation d'amitie retiree.");
+    }
+
+    private async Task RunSocialActionAsync(Func<Task> action, string successMessage)
+    {
+        SocialActionError = null;
+        SocialActionMessage = null;
+
+        try
+        {
+            await action();
+            SocialActionMessage = successMessage;
+            await LoadSocialOverviewAsync();
+
+            if (!string.IsNullOrWhiteSpace(SearchQuery))
+            {
+                await SearchUsersAsync();
+            }
+        }
+        catch (InvalidOperationException exception)
+        {
+            SocialActionError = exception.Message;
+        }
+        catch (HttpRequestException)
+        {
+            SocialActionError = "Le service social est temporairement indisponible.";
+        }
+        catch (TaskCanceledException)
+        {
+            SocialActionError = "L'action sociale a pris trop de temps.";
+        }
+    }
+
     private void ResetProfileState()
     {
         IsAuthenticated = false;
@@ -374,6 +852,18 @@
         Form.Reset();
     }
 
+    private void ResetSocialState()
+    {
+        SocialOverview = null;
+        SearchResults = [];
+        SearchQuery = string.Empty;
+        SearchError = null;
+        SocialLoadError = null;
+        SocialActionError = null;
+        SocialActionMessage = null;
+        _knownSocialVersion = Realtime.SocialVersion;
+    }
+
     private void FillForm(UserProfileResponse profile)
     {
         Form.DisplayName = profile.DisplayName;
@@ -384,6 +874,28 @@
         Form.Bio = profile.Bio;
     }
 
+    private bool ResolveOnlineStatus(string subject, bool fallbackStatus)
+        => Realtime.GetKnownOnlineStatus(subject) ?? fallbackStatus;
+
+    private string BuildPresenceClass(string subject, bool fallbackStatus)
+        => ResolveOnlineStatus(subject, fallbackStatus)
+            ? "presence-badge online"
+            : "presence-badge";
+
+    private string BuildPresenceLabel(string subject, bool fallbackStatus)
+        => ResolveOnlineStatus(subject, fallbackStatus)
+            ? "En ligne"
+            : "Hors ligne";
+
+    private SocialInvitationResponse? FindReceivedInvitation(string subject)
+        => SocialOverview?.ReceivedInvitations.FirstOrDefault(invitation => string.Equals(invitation.Subject, subject, StringComparison.Ordinal));
+
+    private SocialInvitationResponse? FindSentInvitation(string subject)
+        => SocialOverview?.SentInvitations.FirstOrDefault(invitation => string.Equals(invitation.Subject, subject, StringComparison.Ordinal));
+
+    private static string JoinNonEmpty(params string?[] values)
+        => string.Join(" • ", values.Where(value => !string.IsNullOrWhiteSpace(value)));
+
     private static async Task<string> ReadErrorAsync(HttpResponseMessage response, string fallbackMessage)
     {
         try
@@ -409,7 +921,10 @@
         => value.ToLocalTime().ToString("dd MMM yyyy 'a' HH:mm", CultureInfo.GetCultureInfo("fr-FR"));
 
     public void Dispose()
-        => AuthenticationStateProvider.AuthenticationStateChanged -= HandleAuthenticationStateChanged;
+    {
+        AuthenticationStateProvider.AuthenticationStateChanged -= HandleAuthenticationStateChanged;
+        Realtime.Changed -= HandleRealtimeChanged;
+    }
 
     private sealed class ApiErrorMessage
     {

ChessCubing.App/Program.cs

@@ -15,5 +15,6 @@ builder.Services.AddScoped<AuthenticationStateProvider>(sp => sp.GetRequiredServ
 builder.Services.AddScoped<BrowserBridge>();
 builder.Services.AddScoped<UserSession>();
 builder.Services.AddScoped<MatchStore>();
+builder.Services.AddScoped<SocialRealtimeService>();
 
 await builder.Build().RunAsync();

ChessCubing.App/Services/SocialRealtimeService.cs

@@ -0,0 +1,329 @@
+using System.Security.Claims;
+using ChessCubing.App.Models.Social;
+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.Components.Authorization;
+using Microsoft.AspNetCore.SignalR.Client;
+
+namespace ChessCubing.App.Services;
+
+public sealed class SocialRealtimeService(
+    NavigationManager navigation,
+    AuthenticationStateProvider authenticationStateProvider) : IAsyncDisposable
+{
+    private readonly NavigationManager _navigation = navigation;
+    private readonly AuthenticationStateProvider _authenticationStateProvider = authenticationStateProvider;
+    private readonly SemaphoreSlim _gate = new(1, 1);
+
+    private HubConnection? _hubConnection;
+    private string? _currentSubject;
+    private HashSet<string> _knownPresenceSubjects = new(StringComparer.Ordinal);
+    private HashSet<string> _onlineSubjects = new(StringComparer.Ordinal);
+    private PlayInviteMessage? _incomingPlayInvite;
+    private PlayInviteMessage? _outgoingPlayInvite;
+    private PlaySessionResponse? _activePlaySession;
+    private string? _lastInviteNotice;
+    private int _socialVersion;
+    private bool _started;
+
+    public event Action? Changed;
+
+    public PlayInviteMessage? IncomingPlayInvite => _incomingPlayInvite;
+
+    public PlayInviteMessage? OutgoingPlayInvite => _outgoingPlayInvite;
+
+    public string? LastInviteNotice => _lastInviteNotice;
+
+    public int SocialVersion => _socialVersion;
+
+    public async Task EnsureStartedAsync()
+    {
+        if (_started)
+        {
+            await SyncConnectionAsync();
+            return;
+        }
+
+        _started = true;
+        _authenticationStateProvider.AuthenticationStateChanged += HandleAuthenticationStateChanged;
+        await SyncConnectionAsync();
+    }
+
+    public bool IsUserOnline(string subject)
+        => _onlineSubjects.Contains(subject);
+
+    public bool? GetKnownOnlineStatus(string subject)
+    {
+        if (_onlineSubjects.Contains(subject))
+        {
+            return true;
+        }
+
+        return _knownPresenceSubjects.Contains(subject)
+            ? false
+            : null;
+    }
+
+    public async Task SendPlayInviteAsync(string recipientSubject, string recipientColor)
+    {
+        _lastInviteNotice = null;
+
+        if (_hubConnection is null)
+        {
+            throw new InvalidOperationException("La connexion temps reel n'est pas prete.");
+        }
+
+        var invite = await _hubConnection.InvokeAsync<PlayInviteMessage>("SendPlayInvite", recipientSubject, recipientColor);
+        ApplyInvite(invite);
+        RaiseChanged();
+    }
+
+    public async Task RespondToIncomingPlayInviteAsync(bool accept)
+    {
+        if (_hubConnection is null || _incomingPlayInvite is null)
+        {
+            return;
+        }
+
+        var inviteId = _incomingPlayInvite.InviteId;
+        await _hubConnection.InvokeAsync("RespondToPlayInvite", inviteId, accept);
+
+        if (!accept)
+        {
+            _incomingPlayInvite = null;
+            RaiseChanged();
+        }
+    }
+
+    public async Task CancelOutgoingPlayInviteAsync()
+    {
+        if (_hubConnection is null || _outgoingPlayInvite is null)
+        {
+            return;
+        }
+
+        var inviteId = _outgoingPlayInvite.InviteId;
+        await _hubConnection.InvokeAsync("CancelPlayInvite", inviteId);
+    }
+
+    public PlaySessionResponse? TakeAcceptedPlaySession()
+    {
+        var session = _activePlaySession;
+        _activePlaySession = null;
+        return session;
+    }
+
+    public void ClearInviteNotice()
+    {
+        if (string.IsNullOrWhiteSpace(_lastInviteNotice))
+        {
+            return;
+        }
+
+        _lastInviteNotice = null;
+        RaiseChanged();
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        _authenticationStateProvider.AuthenticationStateChanged -= HandleAuthenticationStateChanged;
+
+        await _gate.WaitAsync();
+        try
+        {
+            if (_hubConnection is not null)
+            {
+                await _hubConnection.DisposeAsync();
+                _hubConnection = null;
+            }
+        }
+        finally
+        {
+            _gate.Release();
+            _gate.Dispose();
+        }
+    }
+
+    private void HandleAuthenticationStateChanged(Task<AuthenticationState> authenticationStateTask)
+        => _ = SyncConnectionAsync();
+
+    private async Task SyncConnectionAsync()
+    {
+        await _gate.WaitAsync();
+        try
+        {
+            var authState = await _authenticationStateProvider.GetAuthenticationStateAsync();
+            var user = authState.User;
+            var subject = ResolveSubject(user);
+
+            if (string.IsNullOrWhiteSpace(subject))
+            {
+                await DisconnectUnsafeAsync();
+                return;
+            }
+
+            if (_hubConnection is not null &&
+                string.Equals(subject, _currentSubject, StringComparison.Ordinal) &&
+                _hubConnection.State is HubConnectionState.Connected or HubConnectionState.Connecting or HubConnectionState.Reconnecting)
+            {
+                return;
+            }
+
+            await DisconnectUnsafeAsync();
+
+            _currentSubject = subject;
+            _hubConnection = BuildHubConnection();
+            RegisterHandlers(_hubConnection);
+            await _hubConnection.StartAsync();
+        }
+        finally
+        {
+            _gate.Release();
+        }
+    }
+
+    private HubConnection BuildHubConnection()
+        => new HubConnectionBuilder()
+            .WithUrl(_navigation.ToAbsoluteUri("/hubs/social"))
+            .WithAutomaticReconnect()
+            .Build();
+
+    private void RegisterHandlers(HubConnection connection)
+    {
+        connection.On<PresenceSnapshotMessage>("PresenceSnapshot", message =>
+        {
+            _knownPresenceSubjects = message.OnlineSubjects.ToHashSet(StringComparer.Ordinal);
+            _onlineSubjects = message.OnlineSubjects.ToHashSet(StringComparer.Ordinal);
+            RaiseChanged();
+        });
+
+        connection.On<PresenceChangedMessage>("PresenceChanged", message =>
+        {
+            _knownPresenceSubjects.Add(message.Subject);
+
+            if (message.IsOnline)
+            {
+                _onlineSubjects.Add(message.Subject);
+            }
+            else
+            {
+                _onlineSubjects.Remove(message.Subject);
+            }
+
+            RaiseChanged();
+        });
+
+        connection.On("SocialChanged", async () =>
+        {
+            Interlocked.Increment(ref _socialVersion);
+            await RequestPresenceSnapshotAsync();
+            RaiseChanged();
+        });
+
+        connection.On<PlayInviteMessage>("PlayInviteUpdated", message =>
+        {
+            ApplyInvite(message);
+            RaiseChanged();
+        });
+
+        connection.On<PlayInviteClosedMessage>("PlayInviteClosed", message =>
+        {
+            if (_incomingPlayInvite?.InviteId == message.InviteId)
+            {
+                _incomingPlayInvite = null;
+            }
+
+            if (_outgoingPlayInvite?.InviteId == message.InviteId)
+            {
+                _outgoingPlayInvite = null;
+            }
+
+            _lastInviteNotice = message.Message;
+            RaiseChanged();
+        });
+
+        connection.On<PlaySessionResponse>("PlayInviteAccepted", session =>
+        {
+            _incomingPlayInvite = null;
+            _outgoingPlayInvite = null;
+            _activePlaySession = session;
+            _lastInviteNotice = "La partie est confirmee. Les noms ont ete pre-remplis dans l'application.";
+            RaiseChanged();
+        });
+
+        connection.Reconnected += async _ =>
+        {
+            await RequestPresenceSnapshotAsync();
+            RaiseChanged();
+        };
+
+        connection.Closed += async _ =>
+        {
+            if (!string.IsNullOrWhiteSpace(_currentSubject))
+            {
+                await SyncConnectionAsync();
+            }
+        };
+    }
+
+    private async Task RequestPresenceSnapshotAsync()
+    {
+        if (_hubConnection is null || _hubConnection.State != HubConnectionState.Connected)
+        {
+            return;
+        }
+
+        try
+        {
+            await _hubConnection.InvokeAsync("RequestPresenceSnapshot");
+        }
+        catch
+        {
+            // La vue peut continuer avec le dernier etat connu si le snapshot echoue ponctuellement.
+        }
+    }
+
+    private void ApplyInvite(PlayInviteMessage invite)
+    {
+        if (string.IsNullOrWhiteSpace(_currentSubject))
+        {
+            return;
+        }
+
+        if (string.Equals(invite.RecipientSubject, _currentSubject, StringComparison.Ordinal))
+        {
+            _incomingPlayInvite = invite;
+        }
+
+        if (string.Equals(invite.SenderSubject, _currentSubject, StringComparison.Ordinal))
+        {
+            _outgoingPlayInvite = invite;
+        }
+    }
+
+    private async Task DisconnectUnsafeAsync()
+    {
+        _currentSubject = null;
+        _knownPresenceSubjects.Clear();
+        _onlineSubjects.Clear();
+        _incomingPlayInvite = null;
+        _outgoingPlayInvite = null;
+        _activePlaySession = null;
+        _lastInviteNotice = null;
+
+        if (_hubConnection is not null)
+        {
+            await _hubConnection.DisposeAsync();
+            _hubConnection = null;
+        }
+
+        RaiseChanged();
+    }
+
+    private void RaiseChanged()
+        => Changed?.Invoke();
+
+    private static string? ResolveSubject(ClaimsPrincipal user)
+        => user.Identity?.IsAuthenticated == true
+            ? user.FindFirst("sub")?.Value ?? user.FindFirst(ClaimTypes.NameIdentifier)?.Value
+            : null;
+}

ChessCubing.App/_Imports.razor

@@ -3,6 +3,7 @@
 @using ChessCubing.App
 @using ChessCubing.App.Components
 @using ChessCubing.App.Models
+@using ChessCubing.App.Models.Social
 @using ChessCubing.App.Services
 @using Microsoft.AspNetCore.Authorization
 @using Microsoft.AspNetCore.Components.Authorization

ChessCubing.Server/Program.cs

@@ -3,10 +3,12 @@ using System.Net.Mail;
 using ChessCubing.Server.Admin;
 using ChessCubing.Server.Auth;
 using ChessCubing.Server.Data;
+using ChessCubing.Server.Social;
 using ChessCubing.Server.Users;
 using Microsoft.AspNetCore.Authentication;
 using Microsoft.AspNetCore.Authentication.Cookies;
 using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.SignalR;
 
 var builder = WebApplication.CreateBuilder(args);
 
@@ -67,15 +69,21 @@ builder.Services.AddAuthorization(options =>
 {
     options.AddPolicy("AdminOnly", policy => policy.RequireRole("admin"));
 });
+builder.Services.AddSignalR();
 builder.Services.AddHttpClient<KeycloakAuthService>();
 builder.Services.AddSingleton<MySqlUserProfileStore>();
+builder.Services.AddSingleton<MySqlSocialStore>();
+builder.Services.AddSingleton<ConnectedUserTracker>();
+builder.Services.AddSingleton<PlayInviteCoordinator>();
 
 var app = builder.Build();
 
 await using (var scope = app.Services.CreateAsyncScope())
 {
     var profileStore = scope.ServiceProvider.GetRequiredService<MySqlUserProfileStore>();
+    var socialStore = scope.ServiceProvider.GetRequiredService<MySqlSocialStore>();
     await profileStore.InitializeAsync(CancellationToken.None);
+    await socialStore.InitializeAsync(CancellationToken.None);
 }
 
 app.UseAuthentication();
@@ -124,6 +132,169 @@ app.MapPut("/api/users/me", async Task<IResult> (
     }
 }).RequireAuthorization();
 
+var socialGroup = app.MapGroup("/api/social")
+    .RequireAuthorization();
+
+socialGroup.MapGet("/overview", async Task<IResult> (
+    ClaimsPrincipal user,
+    MySqlSocialStore socialStore,
+    ConnectedUserTracker tracker,
+    CancellationToken cancellationToken) =>
+{
+    var siteUser = AuthenticatedSiteUserFactory.FromClaimsPrincipal(user);
+    if (siteUser is null)
+    {
+        return TypedResults.BadRequest(new ApiErrorResponse("La session utilisateur est incomplete."));
+    }
+
+    var overview = await socialStore.GetOverviewAsync(siteUser.Subject, tracker.IsOnline, cancellationToken);
+    return TypedResults.Ok(overview);
+});
+
+socialGroup.MapGet("/search", async Task<IResult> (
+    string? query,
+    ClaimsPrincipal user,
+    MySqlSocialStore socialStore,
+    ConnectedUserTracker tracker,
+    CancellationToken cancellationToken) =>
+{
+    var siteUser = AuthenticatedSiteUserFactory.FromClaimsPrincipal(user);
+    if (siteUser is null)
+    {
+        return TypedResults.BadRequest(new ApiErrorResponse("La session utilisateur est incomplete."));
+    }
+
+    try
+    {
+        var results = await socialStore.SearchUsersAsync(siteUser.Subject, query, tracker.IsOnline, cancellationToken);
+        return TypedResults.Ok(results);
+    }
+    catch (SocialValidationException exception)
+    {
+        return TypedResults.BadRequest(new ApiErrorResponse(exception.Message));
+    }
+});
+
+socialGroup.MapPost("/invitations", async Task<IResult> (
+    SendFriendInvitationRequest request,
+    ClaimsPrincipal user,
+    MySqlSocialStore socialStore,
+    IHubContext<SocialHub> hubContext,
+    CancellationToken cancellationToken) =>
+{
+    var siteUser = AuthenticatedSiteUserFactory.FromClaimsPrincipal(user);
+    if (siteUser is null)
+    {
+        return TypedResults.BadRequest(new ApiErrorResponse("La session utilisateur est incomplete."));
+    }
+
+    try
+    {
+        var targetSubject = request.TargetSubject?.Trim() ?? string.Empty;
+        await socialStore.SendInvitationAsync(siteUser.Subject, targetSubject, cancellationToken);
+        await NotifySocialChangedAsync(hubContext, siteUser.Subject, targetSubject);
+        return TypedResults.NoContent();
+    }
+    catch (SocialValidationException exception)
+    {
+        return TypedResults.BadRequest(new ApiErrorResponse(exception.Message));
+    }
+});
+
+socialGroup.MapPost("/invitations/{invitationId:long}/accept", async Task<IResult> (
+    long invitationId,
+    ClaimsPrincipal user,
+    MySqlSocialStore socialStore,
+    IHubContext<SocialHub> hubContext,
+    CancellationToken cancellationToken) =>
+{
+    var siteUser = AuthenticatedSiteUserFactory.FromClaimsPrincipal(user);
+    if (siteUser is null)
+    {
+        return TypedResults.BadRequest(new ApiErrorResponse("La session utilisateur est incomplete."));
+    }
+
+    try
+    {
+        var senderSubject = await socialStore.AcceptInvitationAsync(invitationId, siteUser.Subject, cancellationToken);
+        await NotifySocialChangedAsync(hubContext, siteUser.Subject, senderSubject);
+        return TypedResults.NoContent();
+    }
+    catch (SocialValidationException exception)
+    {
+        return TypedResults.BadRequest(new ApiErrorResponse(exception.Message));
+    }
+});
+
+socialGroup.MapPost("/invitations/{invitationId:long}/decline", async Task<IResult> (
+    long invitationId,
+    ClaimsPrincipal user,
+    MySqlSocialStore socialStore,
+    IHubContext<SocialHub> hubContext,
+    CancellationToken cancellationToken) =>
+{
+    var siteUser = AuthenticatedSiteUserFactory.FromClaimsPrincipal(user);
+    if (siteUser is null)
+    {
+        return TypedResults.BadRequest(new ApiErrorResponse("La session utilisateur est incomplete."));
+    }
+
+    try
+    {
+        var senderSubject = await socialStore.DeclineInvitationAsync(invitationId, siteUser.Subject, cancellationToken);
+        await NotifySocialChangedAsync(hubContext, siteUser.Subject, senderSubject);
+        return TypedResults.NoContent();
+    }
+    catch (SocialValidationException exception)
+    {
+        return TypedResults.BadRequest(new ApiErrorResponse(exception.Message));
+    }
+});
+
+socialGroup.MapDelete("/invitations/{invitationId:long}", async Task<IResult> (
+    long invitationId,
+    ClaimsPrincipal user,
+    MySqlSocialStore socialStore,
+    IHubContext<SocialHub> hubContext,
+    CancellationToken cancellationToken) =>
+{
+    var siteUser = AuthenticatedSiteUserFactory.FromClaimsPrincipal(user);
+    if (siteUser is null)
+    {
+        return TypedResults.BadRequest(new ApiErrorResponse("La session utilisateur est incomplete."));
+    }
+
+    try
+    {
+        var recipientSubject = await socialStore.CancelInvitationAsync(invitationId, siteUser.Subject, cancellationToken);
+        await NotifySocialChangedAsync(hubContext, siteUser.Subject, recipientSubject);
+        return TypedResults.NoContent();
+    }
+    catch (SocialValidationException exception)
+    {
+        return TypedResults.BadRequest(new ApiErrorResponse(exception.Message));
+    }
+});
+
+socialGroup.MapDelete("/friends/{friendSubject}", async Task<IResult> (
+    string friendSubject,
+    ClaimsPrincipal user,
+    MySqlSocialStore socialStore,
+    IHubContext<SocialHub> hubContext,
+    CancellationToken cancellationToken) =>
+{
+    var siteUser = AuthenticatedSiteUserFactory.FromClaimsPrincipal(user);
+    if (siteUser is null)
+    {
+        return TypedResults.BadRequest(new ApiErrorResponse("La session utilisateur est incomplete."));
+    }
+
+    var normalizedFriendSubject = friendSubject.Trim();
+    await socialStore.RemoveFriendAsync(siteUser.Subject, normalizedFriendSubject, cancellationToken);
+    await NotifySocialChangedAsync(hubContext, siteUser.Subject, normalizedFriendSubject);
+    return TypedResults.NoContent();
+});
+
 var adminGroup = app.MapGroup("/api/admin")
     .RequireAuthorization("AdminOnly");
 
@@ -230,11 +401,13 @@ adminGroup.MapDelete("/users/{subject}", async Task<IResult> (
     string subject,
     KeycloakAuthService keycloak,
     MySqlUserProfileStore profileStore,
+    MySqlSocialStore socialStore,
     CancellationToken cancellationToken) =>
 {
     try
     {
         await keycloak.DeleteAdminUserAsync(subject, cancellationToken);
+        await socialStore.DeleteUserAsync(subject, cancellationToken);
         await profileStore.DeleteAsync(subject, cancellationToken);
         return TypedResults.NoContent();
     }
@@ -307,6 +480,7 @@ app.MapPost("/api/auth/login", async Task<IResult> (
     LoginRequest request,
     HttpContext httpContext,
     KeycloakAuthService keycloak,
+    MySqlUserProfileStore profileStore,
     CancellationToken cancellationToken) =>
 {
     if (string.IsNullOrWhiteSpace(request.Username) || string.IsNullOrWhiteSpace(request.Password))
@@ -318,6 +492,7 @@ app.MapPost("/api/auth/login", async Task<IResult> (
     {
         var userInfo = await keycloak.LoginAsync(request.Username.Trim(), request.Password, cancellationToken);
         await SignInAsync(httpContext, userInfo);
+        await EnsureSiteUserAsync(profileStore, userInfo, cancellationToken);
         return TypedResults.Ok(AuthSessionResponse.FromUser(httpContext.User));
     }
     catch (KeycloakAuthException exception)
@@ -330,6 +505,7 @@ app.MapPost("/api/auth/register", async Task<IResult> (
     RegisterRequest request,
     HttpContext httpContext,
     KeycloakAuthService keycloak,
+    MySqlUserProfileStore profileStore,
     CancellationToken cancellationToken) =>
 {
     if (string.IsNullOrWhiteSpace(request.Username) ||
@@ -355,6 +531,7 @@ app.MapPost("/api/auth/register", async Task<IResult> (
         }, cancellationToken);
 
         await SignInAsync(httpContext, userInfo);
+        await EnsureSiteUserAsync(profileStore, userInfo, cancellationToken);
         return TypedResults.Ok(AuthSessionResponse.FromUser(httpContext.User));
     }
     catch (KeycloakAuthException exception)
@@ -375,6 +552,9 @@ app.MapGet("/api/auth/logout/browser", async Task<IResult> (HttpContext httpCont
     return TypedResults.Redirect("/index.html");
 });
 
+app.MapHub<SocialHub>("/hubs/social")
+    .RequireAuthorization();
+
 app.Run();
 
 static AdminUserSummaryResponse MapAdminSummary(AdminIdentityUser identity, UserProfileResponse? profile)
@@ -577,6 +757,32 @@ static async Task SignInAsync(HttpContext httpContext, KeycloakUserInfo userInfo
     httpContext.User = principal;
 }
 
+static async Task EnsureSiteUserAsync(
+    MySqlUserProfileStore profileStore,
+    KeycloakUserInfo userInfo,
+    CancellationToken cancellationToken)
+{
+    var siteUser = AuthenticatedSiteUserFactory.FromKeycloakUserInfo(userInfo);
+    if (siteUser is null)
+    {
+        return;
+    }
+
+    await profileStore.GetOrCreateAsync(siteUser, cancellationToken);
+}
+
+static Task NotifySocialChangedAsync(IHubContext<SocialHub> hubContext, params string[] subjects)
+{
+    var distinctSubjects = subjects
+        .Where(subject => !string.IsNullOrWhiteSpace(subject))
+        .Distinct(StringComparer.Ordinal)
+        .ToArray();
+
+    return distinctSubjects.Length == 0
+        ? Task.CompletedTask
+        : hubContext.Clients.Users(distinctSubjects).SendAsync("SocialChanged");
+}
+
 sealed record NormalizedAdminUserUpdate(
     string? Email,
     string? FirstName,

ChessCubing.Server/Social/ConnectedUserTracker.cs

@@ -0,0 +1,60 @@
+namespace ChessCubing.Server.Social;
+
+public sealed class ConnectedUserTracker
+{
+    private readonly object _sync = new();
+    private readonly Dictionary<string, string> _subjectByConnection = new(StringComparer.Ordinal);
+    private readonly Dictionary<string, HashSet<string>> _connectionsBySubject = new(StringComparer.Ordinal);
+
+    public bool TrackConnection(string connectionId, string subject)
+    {
+        lock (_sync)
+        {
+            _subjectByConnection[connectionId] = subject;
+
+            if (!_connectionsBySubject.TryGetValue(subject, out var connections))
+            {
+                connections = new HashSet<string>(StringComparer.Ordinal);
+                _connectionsBySubject[subject] = connections;
+            }
+
+            var wasOffline = connections.Count == 0;
+            connections.Add(connectionId);
+            return wasOffline;
+        }
+    }
+
+    public (string? Subject, bool BecameOffline) RemoveConnection(string connectionId)
+    {
+        lock (_sync)
+        {
+            if (!_subjectByConnection.Remove(connectionId, out var subject))
+            {
+                return (null, false);
+            }
+
+            if (!_connectionsBySubject.TryGetValue(subject, out var connections))
+            {
+                return (subject, false);
+            }
+
+            connections.Remove(connectionId);
+            if (connections.Count > 0)
+            {
+                return (subject, false);
+            }
+
+            _connectionsBySubject.Remove(subject);
+            return (subject, true);
+        }
+    }
+
+    public bool IsOnline(string subject)
+    {
+        lock (_sync)
+        {
+            return _connectionsBySubject.TryGetValue(subject, out var connections)
+                && connections.Count > 0;
+        }
+    }
+}

ChessCubing.Server/Social/MySqlSocialStore.cs

@@ -0,0 +1,787 @@
+using ChessCubing.Server.Data;
+using Microsoft.Extensions.Options;
+using MySqlConnector;
+
+namespace ChessCubing.Server.Social;
+
+public sealed class MySqlSocialStore(
+    IOptions<SiteDataOptions> options,
+    ILogger<MySqlSocialStore> logger)
+{
+    private const string CreateFriendshipsTableSql = """
+        CREATE TABLE IF NOT EXISTS social_friendships (
+            id BIGINT NOT NULL AUTO_INCREMENT,
+            subject_low VARCHAR(190) NOT NULL,
+            subject_high VARCHAR(190) NOT NULL,
+            created_utc DATETIME(6) NOT NULL,
+            PRIMARY KEY (id),
+            UNIQUE KEY uq_social_friendships_pair (subject_low, subject_high),
+            KEY ix_social_friendships_low (subject_low),
+            KEY ix_social_friendships_high (subject_high)
+        ) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
+        """;
+
+    private const string CreateInvitationsTableSql = """
+        CREATE TABLE IF NOT EXISTS social_friend_invitations (
+            id BIGINT NOT NULL AUTO_INCREMENT,
+            sender_subject VARCHAR(190) NOT NULL,
+            recipient_subject VARCHAR(190) NOT NULL,
+            created_utc DATETIME(6) NOT NULL,
+            PRIMARY KEY (id),
+            UNIQUE KEY uq_social_friend_invitations_pair (sender_subject, recipient_subject),
+            KEY ix_social_friend_invitations_sender (sender_subject),
+            KEY ix_social_friend_invitations_recipient (recipient_subject)
+        ) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
+        """;
+
+    private const string SelectOverviewFriendsSql = """
+        SELECT
+            u.subject,
+            u.username,
+            u.display_name,
+            u.email,
+            u.club,
+            u.city
+        FROM social_friendships f
+        INNER JOIN site_users u
+            ON u.subject = CASE
+                WHEN f.subject_low = @subject THEN f.subject_high
+                ELSE f.subject_low
+            END
+        WHERE f.subject_low = @subject OR f.subject_high = @subject
+        ORDER BY u.display_name ASC, u.username ASC;
+        """;
+
+    private const string SelectReceivedInvitationsSql = """
+        SELECT
+            i.id,
+            u.subject,
+            u.username,
+            u.display_name,
+            u.email,
+            i.created_utc
+        FROM social_friend_invitations i
+        INNER JOIN site_users u
+            ON u.subject = i.sender_subject
+        WHERE i.recipient_subject = @subject
+        ORDER BY i.created_utc DESC, u.display_name ASC, u.username ASC;
+        """;
+
+    private const string SelectSentInvitationsSql = """
+        SELECT
+            i.id,
+            u.subject,
+            u.username,
+            u.display_name,
+            u.email,
+            i.created_utc
+        FROM social_friend_invitations i
+        INNER JOIN site_users u
+            ON u.subject = i.recipient_subject
+        WHERE i.sender_subject = @subject
+        ORDER BY i.created_utc DESC, u.display_name ASC, u.username ASC;
+        """;
+
+    private const string SearchUsersTemplateSql = """
+        SELECT
+            u.subject,
+            u.username,
+            u.display_name,
+            u.email,
+            u.club,
+            u.city,
+            EXISTS(
+                SELECT 1
+                FROM social_friendships f
+                WHERE (f.subject_low = @subject AND f.subject_high = u.subject)
+                   OR (f.subject_high = @subject AND f.subject_low = u.subject)
+            ) AS is_friend,
+            EXISTS(
+                SELECT 1
+                FROM social_friend_invitations i
+                WHERE i.sender_subject = @subject
+                  AND i.recipient_subject = u.subject
+            ) AS has_sent_invitation,
+            EXISTS(
+                SELECT 1
+                FROM social_friend_invitations i
+                WHERE i.sender_subject = u.subject
+                  AND i.recipient_subject = @subject
+            ) AS has_received_invitation
+        FROM site_users u
+        WHERE u.subject <> @subject
+          AND (
+            u.username LIKE @pattern
+            OR u.display_name LIKE @pattern
+            OR COALESCE(u.email, '') LIKE @pattern
+            OR COALESCE(u.club, '') LIKE @pattern
+            OR COALESCE(u.city, '') LIKE @pattern
+          )
+        ORDER BY
+            is_friend DESC,
+            has_received_invitation DESC,
+            has_sent_invitation DESC,
+            u.display_name ASC,
+            u.username ASC
+        LIMIT @limit;
+        """;
+
+    private const string SelectRelevantPresenceSubjectsSql = """
+        SELECT participant_subject
+        FROM (
+            SELECT CASE
+                WHEN f.subject_low = @subject THEN f.subject_high
+                ELSE f.subject_low
+            END AS participant_subject
+            FROM social_friendships f
+            WHERE f.subject_low = @subject OR f.subject_high = @subject
+
+            UNION
+
+            SELECT i.sender_subject AS participant_subject
+            FROM social_friend_invitations i
+            WHERE i.recipient_subject = @subject
+
+            UNION
+
+            SELECT i.recipient_subject AS participant_subject
+            FROM social_friend_invitations i
+            WHERE i.sender_subject = @subject
+        ) participants
+        WHERE participant_subject <> @subject;
+        """;
+
+    private const string SelectFriendSubjectsSql = """
+        SELECT CASE
+            WHEN f.subject_low = @subject THEN f.subject_high
+            ELSE f.subject_low
+        END AS friend_subject
+        FROM social_friendships f
+        WHERE f.subject_low = @subject OR f.subject_high = @subject;
+        """;
+
+    private const string SelectKnownUserSubjectSql = """
+        SELECT subject
+        FROM site_users
+        WHERE subject = @subject
+        LIMIT 1;
+        """;
+
+    private const string SelectInvitationBetweenSql = """
+        SELECT
+            id,
+            sender_subject,
+            recipient_subject
+        FROM social_friend_invitations
+        WHERE (sender_subject = @subjectA AND recipient_subject = @subjectB)
+           OR (sender_subject = @subjectB AND recipient_subject = @subjectA)
+        LIMIT 1;
+        """;
+
+    private const string SelectInvitationForRecipientSql = """
+        SELECT
+            id,
+            sender_subject,
+            recipient_subject
+        FROM social_friend_invitations
+        WHERE id = @invitationId
+          AND recipient_subject = @recipientSubject
+        LIMIT 1;
+        """;
+
+    private const string SelectFriendshipExistsSql = """
+        SELECT 1
+        FROM social_friendships
+        WHERE subject_low = @subjectLow
+          AND subject_high = @subjectHigh
+        LIMIT 1;
+        """;
+
+    private const string InsertInvitationSql = """
+        INSERT INTO social_friend_invitations (
+            sender_subject,
+            recipient_subject,
+            created_utc
+        )
+        VALUES (
+            @senderSubject,
+            @recipientSubject,
+            @createdUtc
+        );
+        """;
+
+    private const string InsertFriendshipSql = """
+        INSERT IGNORE INTO social_friendships (
+            subject_low,
+            subject_high,
+            created_utc
+        )
+        VALUES (
+            @subjectLow,
+            @subjectHigh,
+            @createdUtc
+        );
+        """;
+
+    private const string DeleteInvitationByRecipientSql = """
+        DELETE FROM social_friend_invitations
+        WHERE id = @invitationId
+          AND recipient_subject = @recipientSubject;
+        """;
+
+    private const string DeleteInvitationBySenderSql = """
+        DELETE FROM social_friend_invitations
+        WHERE id = @invitationId
+          AND sender_subject = @senderSubject;
+        """;
+
+    private const string DeleteInvitationsBetweenSql = """
+        DELETE FROM social_friend_invitations
+        WHERE (sender_subject = @subjectA AND recipient_subject = @subjectB)
+           OR (sender_subject = @subjectB AND recipient_subject = @subjectA);
+        """;
+
+    private const string DeleteFriendshipSql = """
+        DELETE FROM social_friendships
+        WHERE subject_low = @subjectLow
+          AND subject_high = @subjectHigh;
+        """;
+
+    private const string DeleteUserFriendshipsSql = """
+        DELETE FROM social_friendships
+        WHERE subject_low = @subject
+           OR subject_high = @subject;
+        """;
+
+    private const string DeleteUserInvitationsSql = """
+        DELETE FROM social_friend_invitations
+        WHERE sender_subject = @subject
+           OR recipient_subject = @subject;
+        """;
+
+    private readonly SiteDataOptions _options = options.Value;
+    private readonly ILogger<MySqlSocialStore> _logger = logger;
+
+    public async Task InitializeAsync(CancellationToken cancellationToken)
+    {
+        for (var attempt = 1; attempt <= _options.InitializationRetries; attempt++)
+        {
+            try
+            {
+                await using var connection = new MySqlConnection(_options.BuildConnectionString());
+                await connection.OpenAsync(cancellationToken);
+                await CreateSchemaAsync(connection, cancellationToken);
+                return;
+            }
+            catch (Exception exception) when (attempt < _options.InitializationRetries)
+            {
+                _logger.LogWarning(
+                    exception,
+                    "Initialisation MySQL impossible pour le module social (tentative {Attempt}/{MaxAttempts}).",
+                    attempt,
+                    _options.InitializationRetries);
+
+                await Task.Delay(TimeSpan.FromSeconds(_options.InitializationDelaySeconds), cancellationToken);
+            }
+        }
+
+        await using var finalConnection = new MySqlConnection(_options.BuildConnectionString());
+        await finalConnection.OpenAsync(cancellationToken);
+        await CreateSchemaAsync(finalConnection, cancellationToken);
+    }
+
+    public async Task<SocialOverviewResponse> GetOverviewAsync(
+        string subject,
+        Func<string, bool> isOnline,
+        CancellationToken cancellationToken)
+    {
+        await using var connection = await OpenConnectionAsync(cancellationToken);
+
+        var friends = new List<SocialFriendResponse>();
+        await using (var command = connection.CreateCommand())
+        {
+            command.CommandText = SelectOverviewFriendsSql;
+            command.Parameters.AddWithValue("@subject", subject);
+
+            await using var reader = await command.ExecuteReaderAsync(cancellationToken);
+            while (await reader.ReadAsync(cancellationToken))
+            {
+                var friendSubject = ReadString(reader, "subject");
+                friends.Add(new SocialFriendResponse
+                {
+                    Subject = friendSubject,
+                    Username = ReadString(reader, "username"),
+                    DisplayName = ReadString(reader, "display_name"),
+                    Email = ReadNullableString(reader, "email"),
+                    Club = ReadNullableString(reader, "club"),
+                    City = ReadNullableString(reader, "city"),
+                    IsOnline = isOnline(friendSubject),
+                });
+            }
+        }
+
+        var receivedInvitations = new List<SocialInvitationResponse>();
+        await using (var command = connection.CreateCommand())
+        {
+            command.CommandText = SelectReceivedInvitationsSql;
+            command.Parameters.AddWithValue("@subject", subject);
+
+            await using var reader = await command.ExecuteReaderAsync(cancellationToken);
+            while (await reader.ReadAsync(cancellationToken))
+            {
+                var senderSubject = ReadString(reader, "subject");
+                receivedInvitations.Add(new SocialInvitationResponse
+                {
+                    InvitationId = ReadInt64(reader, "id"),
+                    Subject = senderSubject,
+                    Username = ReadString(reader, "username"),
+                    DisplayName = ReadString(reader, "display_name"),
+                    Email = ReadNullableString(reader, "email"),
+                    CreatedUtc = ReadDateTime(reader, "created_utc"),
+                    IsOnline = isOnline(senderSubject),
+                });
+            }
+        }
+
+        var sentInvitations = new List<SocialInvitationResponse>();
+        await using (var command = connection.CreateCommand())
+        {
+            command.CommandText = SelectSentInvitationsSql;
+            command.Parameters.AddWithValue("@subject", subject);
+
+            await using var reader = await command.ExecuteReaderAsync(cancellationToken);
+            while (await reader.ReadAsync(cancellationToken))
+            {
+                var recipientSubject = ReadString(reader, "subject");
+                sentInvitations.Add(new SocialInvitationResponse
+                {
+                    InvitationId = ReadInt64(reader, "id"),
+                    Subject = recipientSubject,
+                    Username = ReadString(reader, "username"),
+                    DisplayName = ReadString(reader, "display_name"),
+                    Email = ReadNullableString(reader, "email"),
+                    CreatedUtc = ReadDateTime(reader, "created_utc"),
+                    IsOnline = isOnline(recipientSubject),
+                });
+            }
+        }
+
+        return new SocialOverviewResponse
+        {
+            Friends = friends.ToArray(),
+            ReceivedInvitations = receivedInvitations.ToArray(),
+            SentInvitations = sentInvitations.ToArray(),
+        };
+    }
+
+    public async Task<IReadOnlyList<SocialSearchUserResponse>> SearchUsersAsync(
+        string subject,
+        string? query,
+        Func<string, bool> isOnline,
+        CancellationToken cancellationToken)
+    {
+        var normalizedQuery = NormalizeQuery(query);
+        if (normalizedQuery is null)
+        {
+            return [];
+        }
+
+        await using var connection = await OpenConnectionAsync(cancellationToken);
+        await using var command = connection.CreateCommand();
+        command.CommandText = SearchUsersTemplateSql;
+        command.Parameters.AddWithValue("@subject", subject);
+        command.Parameters.AddWithValue("@pattern", $"%{normalizedQuery}%");
+        command.Parameters.AddWithValue("@limit", 12);
+
+        var results = new List<SocialSearchUserResponse>();
+        await using var reader = await command.ExecuteReaderAsync(cancellationToken);
+        while (await reader.ReadAsync(cancellationToken))
+        {
+            var foundSubject = ReadString(reader, "subject");
+            results.Add(new SocialSearchUserResponse
+            {
+                Subject = foundSubject,
+                Username = ReadString(reader, "username"),
+                DisplayName = ReadString(reader, "display_name"),
+                Email = ReadNullableString(reader, "email"),
+                Club = ReadNullableString(reader, "club"),
+                City = ReadNullableString(reader, "city"),
+                IsOnline = isOnline(foundSubject),
+                IsFriend = ReadBoolean(reader, "is_friend"),
+                HasSentInvitation = ReadBoolean(reader, "has_sent_invitation"),
+                HasReceivedInvitation = ReadBoolean(reader, "has_received_invitation"),
+            });
+        }
+
+        return results;
+    }
+
+    public async Task SendInvitationAsync(
+        string senderSubject,
+        string recipientSubject,
+        CancellationToken cancellationToken)
+    {
+        if (string.Equals(senderSubject, recipientSubject, StringComparison.Ordinal))
+        {
+            throw new SocialValidationException("Impossible de t'inviter toi-meme en ami.");
+        }
+
+        await using var connection = await OpenConnectionAsync(cancellationToken);
+        await using var transaction = await connection.BeginTransactionAsync(cancellationToken);
+
+        if (!await UserExistsAsync(connection, transaction, recipientSubject, cancellationToken))
+        {
+            throw new SocialValidationException("Le joueur cible est introuvable.");
+        }
+
+        var pair = NormalizePair(senderSubject, recipientSubject);
+        if (await FriendshipExistsAsync(connection, transaction, pair.SubjectLow, pair.SubjectHigh, cancellationToken))
+        {
+            throw new SocialValidationException("Ce joueur fait deja partie de tes amis.");
+        }
+
+        var invitation = await ReadInvitationBetweenAsync(connection, transaction, senderSubject, recipientSubject, cancellationToken);
+        if (invitation is not null)
+        {
+            throw new SocialValidationException(
+                string.Equals(invitation.SenderSubject, senderSubject, StringComparison.Ordinal)
+                    ? "Une invitation est deja en attente pour ce joueur."
+                    : "Ce joueur t'a deja envoye une invitation. Accepte-la depuis la page utilisateur.");
+        }
+
+        await using (var command = connection.CreateCommand())
+        {
+            command.Transaction = transaction;
+            command.CommandText = InsertInvitationSql;
+            command.Parameters.AddWithValue("@senderSubject", senderSubject);
+            command.Parameters.AddWithValue("@recipientSubject", recipientSubject);
+            command.Parameters.AddWithValue("@createdUtc", DateTime.UtcNow);
+            await command.ExecuteNonQueryAsync(cancellationToken);
+        }
+
+        await transaction.CommitAsync(cancellationToken);
+    }
+
+    public async Task<string> AcceptInvitationAsync(long invitationId, string recipientSubject, CancellationToken cancellationToken)
+    {
+        await using var connection = await OpenConnectionAsync(cancellationToken);
+        await using var transaction = await connection.BeginTransactionAsync(cancellationToken);
+
+        var invitation = await ReadInvitationForRecipientAsync(connection, transaction, invitationId, recipientSubject, cancellationToken)
+            ?? throw new SocialValidationException("Invitation introuvable ou deja traitee.");
+
+        var pair = NormalizePair(invitation.SenderSubject, invitation.RecipientSubject);
+
+        await using (var command = connection.CreateCommand())
+        {
+            command.Transaction = transaction;
+            command.CommandText = InsertFriendshipSql;
+            command.Parameters.AddWithValue("@subjectLow", pair.SubjectLow);
+            command.Parameters.AddWithValue("@subjectHigh", pair.SubjectHigh);
+            command.Parameters.AddWithValue("@createdUtc", DateTime.UtcNow);
+            await command.ExecuteNonQueryAsync(cancellationToken);
+        }
+
+        await using (var command = connection.CreateCommand())
+        {
+            command.Transaction = transaction;
+            command.CommandText = DeleteInvitationsBetweenSql;
+            command.Parameters.AddWithValue("@subjectA", invitation.SenderSubject);
+            command.Parameters.AddWithValue("@subjectB", invitation.RecipientSubject);
+            await command.ExecuteNonQueryAsync(cancellationToken);
+        }
+
+        await transaction.CommitAsync(cancellationToken);
+        return invitation.SenderSubject;
+    }
+
+    public async Task<string> DeclineInvitationAsync(long invitationId, string recipientSubject, CancellationToken cancellationToken)
+    {
+        await using var connection = await OpenConnectionAsync(cancellationToken);
+        var invitation = await ReadInvitationForRecipientAsync(connection, transaction: null, invitationId, recipientSubject, cancellationToken)
+            ?? throw new SocialValidationException("Invitation introuvable ou deja traitee.");
+
+        await using var command = connection.CreateCommand();
+        command.CommandText = DeleteInvitationByRecipientSql;
+        command.Parameters.AddWithValue("@invitationId", invitationId);
+        command.Parameters.AddWithValue("@recipientSubject", recipientSubject);
+
+        var deleted = await command.ExecuteNonQueryAsync(cancellationToken);
+        if (deleted <= 0)
+        {
+            throw new SocialValidationException("Invitation introuvable ou deja traitee.");
+        }
+
+        return invitation.SenderSubject;
+    }
+
+    public async Task<string> CancelInvitationAsync(long invitationId, string senderSubject, CancellationToken cancellationToken)
+    {
+        await using var connection = await OpenConnectionAsync(cancellationToken);
+        var invitation = await ReadInvitationForSenderAsync(connection, transaction: null, invitationId, senderSubject, cancellationToken)
+            ?? throw new SocialValidationException("Invitation introuvable ou deja retiree.");
+
+        await using var command = connection.CreateCommand();
+        command.CommandText = DeleteInvitationBySenderSql;
+        command.Parameters.AddWithValue("@invitationId", invitationId);
+        command.Parameters.AddWithValue("@senderSubject", senderSubject);
+
+        var deleted = await command.ExecuteNonQueryAsync(cancellationToken);
+        if (deleted <= 0)
+        {
+            throw new SocialValidationException("Invitation introuvable ou deja retiree.");
+        }
+
+        return invitation.RecipientSubject;
+    }
+
+    public async Task RemoveFriendAsync(string subject, string friendSubject, CancellationToken cancellationToken)
+    {
+        var pair = NormalizePair(subject, friendSubject);
+
+        await using var connection = await OpenConnectionAsync(cancellationToken);
+        await using var command = connection.CreateCommand();
+        command.CommandText = DeleteFriendshipSql;
+        command.Parameters.AddWithValue("@subjectLow", pair.SubjectLow);
+        command.Parameters.AddWithValue("@subjectHigh", pair.SubjectHigh);
+        await command.ExecuteNonQueryAsync(cancellationToken);
+    }
+
+    public async Task<bool> AreFriendsAsync(string subject, string otherSubject, CancellationToken cancellationToken)
+    {
+        var pair = NormalizePair(subject, otherSubject);
+        await using var connection = await OpenConnectionAsync(cancellationToken);
+        return await FriendshipExistsAsync(connection, transaction: null, pair.SubjectLow, pair.SubjectHigh, cancellationToken);
+    }
+
+    public async Task<IReadOnlyList<string>> GetRelevantPresenceSubjectsAsync(string subject, CancellationToken cancellationToken)
+    {
+        await using var connection = await OpenConnectionAsync(cancellationToken);
+        await using var command = connection.CreateCommand();
+        command.CommandText = SelectRelevantPresenceSubjectsSql;
+        command.Parameters.AddWithValue("@subject", subject);
+
+        var subjects = new List<string>();
+        await using var reader = await command.ExecuteReaderAsync(cancellationToken);
+        while (await reader.ReadAsync(cancellationToken))
+        {
+            subjects.Add(ReadString(reader, "participant_subject"));
+        }
+
+        return subjects;
+    }
+
+    public async Task<IReadOnlyList<string>> GetFriendSubjectsAsync(string subject, CancellationToken cancellationToken)
+    {
+        await using var connection = await OpenConnectionAsync(cancellationToken);
+        await using var command = connection.CreateCommand();
+        command.CommandText = SelectFriendSubjectsSql;
+        command.Parameters.AddWithValue("@subject", subject);
+
+        var subjects = new List<string>();
+        await using var reader = await command.ExecuteReaderAsync(cancellationToken);
+        while (await reader.ReadAsync(cancellationToken))
+        {
+            subjects.Add(ReadString(reader, "friend_subject"));
+        }
+
+        return subjects;
+    }
+
+    public async Task DeleteUserAsync(string subject, CancellationToken cancellationToken)
+    {
+        await using var connection = await OpenConnectionAsync(cancellationToken);
+        await using (var command = connection.CreateCommand())
+        {
+            command.CommandText = DeleteUserFriendshipsSql;
+            command.Parameters.AddWithValue("@subject", subject);
+            await command.ExecuteNonQueryAsync(cancellationToken);
+        }
+
+        await using (var command = connection.CreateCommand())
+        {
+            command.CommandText = DeleteUserInvitationsSql;
+            command.Parameters.AddWithValue("@subject", subject);
+            await command.ExecuteNonQueryAsync(cancellationToken);
+        }
+    }
+
+    private async Task CreateSchemaAsync(MySqlConnection connection, CancellationToken cancellationToken)
+    {
+        await using (var command = connection.CreateCommand())
+        {
+            command.CommandText = CreateFriendshipsTableSql;
+            await command.ExecuteNonQueryAsync(cancellationToken);
+        }
+
+        await using (var command = connection.CreateCommand())
+        {
+            command.CommandText = CreateInvitationsTableSql;
+            await command.ExecuteNonQueryAsync(cancellationToken);
+        }
+    }
+
+    private async Task<MySqlConnection> OpenConnectionAsync(CancellationToken cancellationToken)
+    {
+        var connection = new MySqlConnection(_options.BuildConnectionString());
+        await connection.OpenAsync(cancellationToken);
+        return connection;
+    }
+
+    private static (string SubjectLow, string SubjectHigh) NormalizePair(string subjectA, string subjectB)
+        => string.CompareOrdinal(subjectA, subjectB) <= 0
+            ? (subjectA, subjectB)
+            : (subjectB, subjectA);
+
+    private static string? NormalizeQuery(string? query)
+    {
+        var trimmed = query?.Trim();
+        if (string.IsNullOrWhiteSpace(trimmed))
+        {
+            return null;
+        }
+
+        if (trimmed.Length < 2)
+        {
+            throw new SocialValidationException("La recherche d'amis demande au moins 2 caracteres.");
+        }
+
+        return trimmed.Length > 80
+            ? trimmed[..80]
+            : trimmed;
+    }
+
+    private static async Task<bool> UserExistsAsync(
+        MySqlConnection connection,
+        MySqlTransaction transaction,
+        string subject,
+        CancellationToken cancellationToken)
+    {
+        await using var command = connection.CreateCommand();
+        command.Transaction = transaction;
+        command.CommandText = SelectKnownUserSubjectSql;
+        command.Parameters.AddWithValue("@subject", subject);
+        return await command.ExecuteScalarAsync(cancellationToken) is not null;
+    }
+
+    private static async Task<bool> FriendshipExistsAsync(
+        MySqlConnection connection,
+        MySqlTransaction? transaction,
+        string subjectLow,
+        string subjectHigh,
+        CancellationToken cancellationToken)
+    {
+        await using var command = connection.CreateCommand();
+        command.Transaction = transaction;
+        command.CommandText = SelectFriendshipExistsSql;
+        command.Parameters.AddWithValue("@subjectLow", subjectLow);
+        command.Parameters.AddWithValue("@subjectHigh", subjectHigh);
+        return await command.ExecuteScalarAsync(cancellationToken) is not null;
+    }
+
+    private static async Task<InvitationRow?> ReadInvitationBetweenAsync(
+        MySqlConnection connection,
+        MySqlTransaction transaction,
+        string subjectA,
+        string subjectB,
+        CancellationToken cancellationToken)
+    {
+        await using var command = connection.CreateCommand();
+        command.Transaction = transaction;
+        command.CommandText = SelectInvitationBetweenSql;
+        command.Parameters.AddWithValue("@subjectA", subjectA);
+        command.Parameters.AddWithValue("@subjectB", subjectB);
+
+        await using var reader = await command.ExecuteReaderAsync(cancellationToken);
+        if (!await reader.ReadAsync(cancellationToken))
+        {
+            return null;
+        }
+
+        return new InvitationRow(
+            ReadInt64(reader, "id"),
+            ReadString(reader, "sender_subject"),
+            ReadString(reader, "recipient_subject"));
+    }
+
+    private static async Task<InvitationRow?> ReadInvitationForRecipientAsync(
+        MySqlConnection connection,
+        MySqlTransaction? transaction,
+        long invitationId,
+        string recipientSubject,
+        CancellationToken cancellationToken)
+    {
+        await using var command = connection.CreateCommand();
+        command.Transaction = transaction;
+        command.CommandText = SelectInvitationForRecipientSql;
+        command.Parameters.AddWithValue("@invitationId", invitationId);
+        command.Parameters.AddWithValue("@recipientSubject", recipientSubject);
+
+        await using var reader = await command.ExecuteReaderAsync(cancellationToken);
+        if (!await reader.ReadAsync(cancellationToken))
+        {
+            return null;
+        }
+
+        return new InvitationRow(
+            ReadInt64(reader, "id"),
+            ReadString(reader, "sender_subject"),
+            ReadString(reader, "recipient_subject"));
+    }
+
+    private static async Task<InvitationRow?> ReadInvitationForSenderAsync(
+        MySqlConnection connection,
+        MySqlTransaction? transaction,
+        long invitationId,
+        string senderSubject,
+        CancellationToken cancellationToken)
+    {
+        await using var command = connection.CreateCommand();
+        command.Transaction = transaction;
+        command.CommandText = """
+            SELECT
+                id,
+                sender_subject,
+                recipient_subject
+            FROM social_friend_invitations
+            WHERE id = @invitationId
+              AND sender_subject = @senderSubject
+            LIMIT 1;
+            """;
+        command.Parameters.AddWithValue("@invitationId", invitationId);
+        command.Parameters.AddWithValue("@senderSubject", senderSubject);
+
+        await using var reader = await command.ExecuteReaderAsync(cancellationToken);
+        if (!await reader.ReadAsync(cancellationToken))
+        {
+            return null;
+        }
+
+        return new InvitationRow(
+            ReadInt64(reader, "id"),
+            ReadString(reader, "sender_subject"),
+            ReadString(reader, "recipient_subject"));
+    }
+
+    private static bool ReadBoolean(MySqlDataReader reader, string columnName)
+        => Convert.ToInt32(reader[columnName]) > 0;
+
+    private static string ReadString(MySqlDataReader reader, string columnName)
+        => reader.GetString(reader.GetOrdinal(columnName));
+
+    private static long ReadInt64(MySqlDataReader reader, string columnName)
+        => reader.GetInt64(reader.GetOrdinal(columnName));
+
+    private static DateTime ReadDateTime(MySqlDataReader reader, string columnName)
+        => reader.GetDateTime(reader.GetOrdinal(columnName));
+
+    private static string? ReadNullableString(MySqlDataReader reader, string columnName)
+    {
+        var ordinal = reader.GetOrdinal(columnName);
+        return reader.IsDBNull(ordinal)
+            ? null
+            : reader.GetString(ordinal);
+    }
+
+    private sealed record InvitationRow(long Id, string SenderSubject, string RecipientSubject);
+}

ChessCubing.Server/Social/PlayInviteCoordinator.cs

@@ -0,0 +1,211 @@
+namespace ChessCubing.Server.Social;
+
+public sealed class PlayInviteCoordinator
+{
+    private static readonly TimeSpan InviteLifetime = TimeSpan.FromMinutes(2);
+
+    private readonly object _sync = new();
+    private readonly Dictionary<string, PlayInviteState> _invitesById = new(StringComparer.Ordinal);
+    private readonly Dictionary<string, string> _inviteByParticipant = new(StringComparer.Ordinal);
+
+    public PlayInviteMessage CreateInvite(PlayInviteParticipant sender, PlayInviteParticipant recipient, string recipientColor)
+    {
+        var normalizedColor = NormalizeRecipientColor(recipientColor);
+
+        lock (_sync)
+        {
+            CleanupExpiredUnsafe();
+
+            if (_inviteByParticipant.ContainsKey(sender.Subject))
+            {
+                throw new SocialValidationException("Une invitation de partie est deja en cours pour ton compte.");
+            }
+
+            if (_inviteByParticipant.ContainsKey(recipient.Subject))
+            {
+                throw new SocialValidationException("Cet ami traite deja une autre invitation de partie.");
+            }
+
+            var nowUtc = DateTime.UtcNow;
+            var state = new PlayInviteState(
+                Guid.NewGuid().ToString("N"),
+                sender,
+                recipient,
+                normalizedColor,
+                nowUtc,
+                nowUtc.Add(InviteLifetime));
+
+            _invitesById[state.InviteId] = state;
+            _inviteByParticipant[sender.Subject] = state.InviteId;
+            _inviteByParticipant[recipient.Subject] = state.InviteId;
+
+            return MapInvite(state);
+        }
+    }
+
+    public PlayInviteCloseResult CancelInvite(string inviteId, string senderSubject)
+    {
+        lock (_sync)
+        {
+            var state = GetActiveInviteUnsafe(inviteId);
+            if (!string.Equals(state.Sender.Subject, senderSubject, StringComparison.Ordinal))
+            {
+                throw new SocialValidationException("Seul l'expediteur peut annuler cette invitation.");
+            }
+
+            RemoveInviteUnsafe(state);
+            return new PlayInviteCloseResult(
+                state.Sender.Subject,
+                state.Recipient.Subject,
+                new PlayInviteClosedMessage
+                {
+                    InviteId = state.InviteId,
+                    Reason = "cancelled",
+                    Message = $"{state.Sender.DisplayName} a annule l'invitation de partie.",
+                });
+        }
+    }
+
+    public PlayInviteCloseResult DeclineInvite(string inviteId, string recipientSubject)
+    {
+        lock (_sync)
+        {
+            var state = GetActiveInviteUnsafe(inviteId);
+            if (!string.Equals(state.Recipient.Subject, recipientSubject, StringComparison.Ordinal))
+            {
+                throw new SocialValidationException("Seul le destinataire peut refuser cette invitation.");
+            }
+
+            RemoveInviteUnsafe(state);
+            return new PlayInviteCloseResult(
+                state.Sender.Subject,
+                state.Recipient.Subject,
+                new PlayInviteClosedMessage
+                {
+                    InviteId = state.InviteId,
+                    Reason = "declined",
+                    Message = $"{state.Recipient.DisplayName} a refuse la partie.",
+                });
+        }
+    }
+
+    public PlayInviteAcceptResult AcceptInvite(string inviteId, string recipientSubject)
+    {
+        lock (_sync)
+        {
+            var state = GetActiveInviteUnsafe(inviteId);
+            if (!string.Equals(state.Recipient.Subject, recipientSubject, StringComparison.Ordinal))
+            {
+                throw new SocialValidationException("Seul le destinataire peut accepter cette invitation.");
+            }
+
+            RemoveInviteUnsafe(state);
+
+            var white = string.Equals(state.RecipientColor, "white", StringComparison.Ordinal)
+                ? state.Recipient
+                : state.Sender;
+            var black = string.Equals(state.RecipientColor, "white", StringComparison.Ordinal)
+                ? state.Sender
+                : state.Recipient;
+
+            var session = new PlaySessionResponse
+            {
+                SessionId = Guid.NewGuid().ToString("N"),
+                WhiteSubject = white.Subject,
+                WhiteName = white.DisplayName,
+                BlackSubject = black.Subject,
+                BlackName = black.DisplayName,
+                InitiatorSubject = state.Sender.Subject,
+                RecipientSubject = state.Recipient.Subject,
+                ConfirmedUtc = DateTime.UtcNow,
+            };
+
+            return new PlayInviteAcceptResult(state.Sender.Subject, state.Recipient.Subject, session);
+        }
+    }
+
+    private static string NormalizeRecipientColor(string recipientColor)
+    {
+        var normalized = recipientColor.Trim().ToLowerInvariant();
+        return normalized switch
+        {
+            "white" => "white",
+            "black" => "black",
+            _ => throw new SocialValidationException("La couleur demandee pour l'ami doit etre blanc ou noir."),
+        };
+    }
+
+    private static PlayInviteMessage MapInvite(PlayInviteState state)
+        => new()
+        {
+            InviteId = state.InviteId,
+            SenderSubject = state.Sender.Subject,
+            SenderUsername = state.Sender.Username,
+            SenderDisplayName = state.Sender.DisplayName,
+            RecipientSubject = state.Recipient.Subject,
+            RecipientUsername = state.Recipient.Username,
+            RecipientDisplayName = state.Recipient.DisplayName,
+            RecipientColor = state.RecipientColor,
+            CreatedUtc = state.CreatedUtc,
+            ExpiresUtc = state.ExpiresUtc,
+        };
+
+    private PlayInviteState GetActiveInviteUnsafe(string inviteId)
+    {
+        CleanupExpiredUnsafe();
+
+        if (!_invitesById.TryGetValue(inviteId, out var state))
+        {
+            throw new SocialValidationException("Cette invitation de partie n'est plus disponible.");
+        }
+
+        return state;
+    }
+
+    private void CleanupExpiredUnsafe()
+    {
+        var nowUtc = DateTime.UtcNow;
+        var expiredInviteIds = _invitesById.Values
+            .Where(state => state.ExpiresUtc <= nowUtc)
+            .Select(state => state.InviteId)
+            .ToArray();
+
+        foreach (var expiredInviteId in expiredInviteIds)
+        {
+            if (_invitesById.TryGetValue(expiredInviteId, out var state))
+            {
+                RemoveInviteUnsafe(state);
+            }
+        }
+    }
+
+    private void RemoveInviteUnsafe(PlayInviteState state)
+    {
+        _invitesById.Remove(state.InviteId);
+        _inviteByParticipant.Remove(state.Sender.Subject);
+        _inviteByParticipant.Remove(state.Recipient.Subject);
+    }
+
+    private sealed record PlayInviteState(
+        string InviteId,
+        PlayInviteParticipant Sender,
+        PlayInviteParticipant Recipient,
+        string RecipientColor,
+        DateTime CreatedUtc,
+        DateTime ExpiresUtc);
+}
+
+public readonly record struct PlayInviteParticipant(
+    string Subject,
+    string Username,
+    string DisplayName);
+
+public sealed record PlayInviteCloseResult(
+    string SenderSubject,
+    string RecipientSubject,
+    PlayInviteClosedMessage ClosedMessage);
+
+public sealed record PlayInviteAcceptResult(
+    string SenderSubject,
+    string RecipientSubject,
+    PlaySessionResponse Session);

ChessCubing.Server/Social/SocialContracts.cs

@@ -0,0 +1,137 @@
+namespace ChessCubing.Server.Social;
+
+public sealed class SocialOverviewResponse
+{
+    public SocialFriendResponse[] Friends { get; init; } = [];
+
+    public SocialInvitationResponse[] ReceivedInvitations { get; init; } = [];
+
+    public SocialInvitationResponse[] SentInvitations { get; init; } = [];
+}
+
+public sealed class SocialFriendResponse
+{
+    public string Subject { get; init; } = string.Empty;
+
+    public string Username { get; init; } = string.Empty;
+
+    public string DisplayName { get; init; } = string.Empty;
+
+    public string? Email { get; init; }
+
+    public string? Club { get; init; }
+
+    public string? City { get; init; }
+
+    public bool IsOnline { get; init; }
+}
+
+public sealed class SocialInvitationResponse
+{
+    public long InvitationId { get; init; }
+
+    public string Subject { get; init; } = string.Empty;
+
+    public string Username { get; init; } = string.Empty;
+
+    public string DisplayName { get; init; } = string.Empty;
+
+    public string? Email { get; init; }
+
+    public bool IsOnline { get; init; }
+
+    public DateTime CreatedUtc { get; init; }
+}
+
+public sealed class SocialSearchUserResponse
+{
+    public string Subject { get; init; } = string.Empty;
+
+    public string Username { get; init; } = string.Empty;
+
+    public string DisplayName { get; init; } = string.Empty;
+
+    public string? Email { get; init; }
+
+    public string? Club { get; init; }
+
+    public string? City { get; init; }
+
+    public bool IsOnline { get; init; }
+
+    public bool IsFriend { get; init; }
+
+    public bool HasSentInvitation { get; init; }
+
+    public bool HasReceivedInvitation { get; init; }
+}
+
+public sealed class SendFriendInvitationRequest
+{
+    public string TargetSubject { get; init; } = string.Empty;
+}
+
+public sealed class PresenceSnapshotMessage
+{
+    public string[] OnlineSubjects { get; init; } = [];
+}
+
+public sealed class PresenceChangedMessage
+{
+    public string Subject { get; init; } = string.Empty;
+
+    public bool IsOnline { get; init; }
+}
+
+public sealed class PlayInviteMessage
+{
+    public string InviteId { get; init; } = string.Empty;
+
+    public string SenderSubject { get; init; } = string.Empty;
+
+    public string SenderUsername { get; init; } = string.Empty;
+
+    public string SenderDisplayName { get; init; } = string.Empty;
+
+    public string RecipientSubject { get; init; } = string.Empty;
+
+    public string RecipientUsername { get; init; } = string.Empty;
+
+    public string RecipientDisplayName { get; init; } = string.Empty;
+
+    public string RecipientColor { get; init; } = string.Empty;
+
+    public DateTime CreatedUtc { get; init; }
+
+    public DateTime ExpiresUtc { get; init; }
+}
+
+public sealed class PlayInviteClosedMessage
+{
+    public string InviteId { get; init; } = string.Empty;
+
+    public string Reason { get; init; } = string.Empty;
+
+    public string Message { get; init; } = string.Empty;
+}
+
+public sealed class PlaySessionResponse
+{
+    public string SessionId { get; init; } = string.Empty;
+
+    public string WhiteSubject { get; init; } = string.Empty;
+
+    public string WhiteName { get; init; } = string.Empty;
+
+    public string BlackSubject { get; init; } = string.Empty;
+
+    public string BlackName { get; init; } = string.Empty;
+
+    public string InitiatorSubject { get; init; } = string.Empty;
+
+    public string RecipientSubject { get; init; } = string.Empty;
+
+    public DateTime ConfirmedUtc { get; init; }
+}
+
+public sealed class SocialValidationException(string message) : Exception(message);

ChessCubing.Server/Social/SocialHub.cs

@@ -0,0 +1,168 @@
+using ChessCubing.Server.Users;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.SignalR;
+
+namespace ChessCubing.Server.Social;
+
+[Authorize]
+public sealed class SocialHub(
+    ConnectedUserTracker tracker,
+    MySqlSocialStore socialStore,
+    MySqlUserProfileStore profileStore,
+    PlayInviteCoordinator playInviteCoordinator) : Hub
+{
+    private readonly ConnectedUserTracker _tracker = tracker;
+    private readonly MySqlSocialStore _socialStore = socialStore;
+    private readonly MySqlUserProfileStore _profileStore = profileStore;
+    private readonly PlayInviteCoordinator _playInviteCoordinator = playInviteCoordinator;
+
+    public override async Task OnConnectedAsync()
+    {
+        var siteUser = RequireCurrentUser();
+        var becameOnline = _tracker.TrackConnection(Context.ConnectionId, siteUser.Subject);
+
+        await SendPresenceSnapshotAsync(siteUser.Subject, Context.ConnectionAborted);
+
+        if (becameOnline)
+        {
+            var relevantSubjects = await _socialStore.GetRelevantPresenceSubjectsAsync(siteUser.Subject, Context.ConnectionAborted);
+            await NotifyPresenceChangedAsync(relevantSubjects, siteUser.Subject, isOnline: true);
+        }
+
+        await base.OnConnectedAsync();
+    }
+
+    public override async Task OnDisconnectedAsync(Exception? exception)
+    {
+        var (subject, becameOffline) = _tracker.RemoveConnection(Context.ConnectionId);
+        if (becameOffline && !string.IsNullOrWhiteSpace(subject))
+        {
+            var relevantSubjects = await _socialStore.GetRelevantPresenceSubjectsAsync(subject, CancellationToken.None);
+            await NotifyPresenceChangedAsync(relevantSubjects, subject, isOnline: false);
+        }
+
+        await base.OnDisconnectedAsync(exception);
+    }
+
+    public async Task RequestPresenceSnapshot()
+    {
+        var siteUser = RequireCurrentUser();
+        await SendPresenceSnapshotAsync(siteUser.Subject, Context.ConnectionAborted);
+    }
+
+    public async Task<PlayInviteMessage> SendPlayInvite(string recipientSubject, string recipientColor)
+    {
+        var sender = RequireCurrentUser();
+        var normalizedRecipientSubject = recipientSubject.Trim();
+
+        if (!await _socialStore.AreFriendsAsync(sender.Subject, normalizedRecipientSubject, Context.ConnectionAborted))
+        {
+            throw new HubException("Seuls tes amis peuvent recevoir une invitation de partie.");
+        }
+
+        if (!_tracker.IsOnline(normalizedRecipientSubject))
+        {
+            throw new HubException("Cet ami n'est plus connecte pour le moment.");
+        }
+
+        var senderProfile = await _profileStore.GetOrCreateAsync(sender, Context.ConnectionAborted);
+        var recipientProfile = await _profileStore.FindBySubjectAsync(normalizedRecipientSubject, Context.ConnectionAborted);
+        if (recipientProfile is null)
+        {
+            throw new HubException("Le profil de cet ami est introuvable.");
+        }
+
+        try
+        {
+            var message = _playInviteCoordinator.CreateInvite(
+                new PlayInviteParticipant(sender.Subject, sender.Username, senderProfile.DisplayName),
+                new PlayInviteParticipant(recipientProfile.Subject, recipientProfile.Username, recipientProfile.DisplayName),
+                recipientColor);
+
+            await Clients.Users([sender.Subject, recipientProfile.Subject])
+                .SendAsync("PlayInviteUpdated", message, Context.ConnectionAborted);
+
+            return message;
+        }
+        catch (SocialValidationException exception)
+        {
+            throw new HubException(exception.Message);
+        }
+    }
+
+    public async Task RespondToPlayInvite(string inviteId, bool accept)
+    {
+        var recipient = RequireCurrentUser();
+
+        try
+        {
+            if (accept)
+            {
+                var accepted = _playInviteCoordinator.AcceptInvite(inviteId, recipient.Subject);
+                await Clients.Users([accepted.SenderSubject, accepted.RecipientSubject])
+                    .SendAsync("PlayInviteAccepted", accepted.Session, Context.ConnectionAborted);
+                return;
+            }
+
+            var declined = _playInviteCoordinator.DeclineInvite(inviteId, recipient.Subject);
+            await Clients.Users([declined.SenderSubject, declined.RecipientSubject])
+                .SendAsync("PlayInviteClosed", declined.ClosedMessage, Context.ConnectionAborted);
+        }
+        catch (SocialValidationException exception)
+        {
+            throw new HubException(exception.Message);
+        }
+    }
+
+    public async Task CancelPlayInvite(string inviteId)
+    {
+        var sender = RequireCurrentUser();
+
+        try
+        {
+            var cancelled = _playInviteCoordinator.CancelInvite(inviteId, sender.Subject);
+            await Clients.Users([cancelled.SenderSubject, cancelled.RecipientSubject])
+                .SendAsync("PlayInviteClosed", cancelled.ClosedMessage, Context.ConnectionAborted);
+        }
+        catch (SocialValidationException exception)
+        {
+            throw new HubException(exception.Message);
+        }
+    }
+
+    private AuthenticatedSiteUser RequireCurrentUser()
+        => AuthenticatedSiteUserFactory.FromClaimsPrincipal(Context.User ?? new System.Security.Claims.ClaimsPrincipal())
+           ?? throw new HubException("La session utilisateur est incomplete.");
+
+    private async Task SendPresenceSnapshotAsync(string subject, CancellationToken cancellationToken)
+    {
+        var relevantSubjects = await _socialStore.GetRelevantPresenceSubjectsAsync(subject, cancellationToken);
+        var onlineSubjects = relevantSubjects
+            .Where(_tracker.IsOnline)
+            .Distinct(StringComparer.Ordinal)
+            .ToArray();
+
+        await Clients.Caller.SendAsync(
+            "PresenceSnapshot",
+            new PresenceSnapshotMessage { OnlineSubjects = onlineSubjects },
+            cancellationToken);
+    }
+
+    private Task NotifyPresenceChangedAsync(IReadOnlyList<string> subjects, string changedSubject, bool isOnline)
+    {
+        var distinctSubjects = subjects
+            .Where(subject => !string.IsNullOrWhiteSpace(subject))
+            .Distinct(StringComparer.Ordinal)
+            .ToArray();
+
+        return distinctSubjects.Length == 0
+            ? Task.CompletedTask
+            : Clients.Users(distinctSubjects).SendAsync(
+                "PresenceChanged",
+                new PresenceChangedMessage
+                {
+                    Subject = changedSubject,
+                    IsOnline = isOnline,
+                });
+    }
+}

ChessCubing.Server/Users/AuthenticatedSiteUser.cs

@@ -1,3 +1,4 @@
+using ChessCubing.Server.Auth;
 using System.Security.Claims;
 
 namespace ChessCubing.Server.Users;
@@ -10,6 +11,28 @@ public sealed record AuthenticatedSiteUser(
 
 public static class AuthenticatedSiteUserFactory
 {
+    public static AuthenticatedSiteUser? FromKeycloakUserInfo(KeycloakUserInfo userInfo)
+    {
+        if (string.IsNullOrWhiteSpace(userInfo.Subject))
+        {
+            return null;
+        }
+
+        var username = string.IsNullOrWhiteSpace(userInfo.PreferredUsername)
+            ? userInfo.Subject
+            : userInfo.PreferredUsername;
+
+        var displayName = string.IsNullOrWhiteSpace(userInfo.Name)
+            ? username
+            : userInfo.Name;
+
+        return new AuthenticatedSiteUser(
+            userInfo.Subject.Trim(),
+            username.Trim(),
+            string.IsNullOrWhiteSpace(userInfo.Email) ? null : userInfo.Email.Trim(),
+            displayName.Trim());
+    }
+
     public static AuthenticatedSiteUser? FromClaimsPrincipal(ClaimsPrincipal user)
     {
         if (user.Identity?.IsAuthenticated != true)

nginx.conf

@@ -41,6 +41,18 @@ server {
     proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
   }
 
+  location /hubs/ {
+    proxy_http_version 1.1;
+    proxy_pass http://auth:8080/hubs/;
+    proxy_set_header Host $http_host;
+    proxy_set_header X-Forwarded-Host $http_host;
+    proxy_set_header X-Forwarded-Proto $scheme;
+    proxy_set_header X-Forwarded-Port $server_port;
+    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+    proxy_set_header Upgrade $http_upgrade;
+    proxy_set_header Connection "upgrade";
+  }
+
   location / {
     try_files $uri $uri/ /index.html;
   }

styles.css

@@ -3571,3 +3571,205 @@ body[data-page="chrono"] .player-clock.negative-clock {
     font-size: clamp(1.05rem, 5.8vw, 1.7rem);
   }
 }
+
+.user-social-panel {
+  display: grid;
+  gap: 1.2rem;
+}
+
+.social-search-form {
+  display: grid;
+  grid-template-columns: minmax(0, 1fr) auto;
+  gap: 0.85rem;
+  align-items: end;
+}
+
+.social-search-actions {
+  display: flex;
+  align-items: flex-end;
+}
+
+.social-search-results,
+.social-list {
+  display: grid;
+  gap: 0.75rem;
+}
+
+.social-columns {
+  display: grid;
+  grid-template-columns: repeat(3, minmax(0, 1fr));
+  gap: 1rem;
+}
+
+.social-card,
+.setup-social-card {
+  display: grid;
+  gap: 0.9rem;
+  padding: 1rem 1.05rem;
+  border: 1px solid var(--panel-border);
+  border-radius: 24px;
+  background:
+    linear-gradient(180deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.03)),
+    rgba(10, 12, 20, 0.82);
+  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.02);
+}
+
+.social-card-head {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 1rem;
+}
+
+.social-card-head strong {
+  display: block;
+  font-size: 1.05rem;
+}
+
+.social-empty {
+  margin: 0;
+  color: var(--muted);
+  line-height: 1.55;
+}
+
+.social-item,
+.play-friend-item {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 1rem;
+  padding: 0.8rem 0.9rem;
+  border: 1px solid rgba(255, 255, 255, 0.08);
+  border-radius: 18px;
+  background: rgba(255, 255, 255, 0.03);
+}
+
+.social-item-meta {
+  display: grid;
+  gap: 0.22rem;
+  min-width: 0;
+}
+
+.social-item-title-row {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.55rem;
+}
+
+.social-item-title-row strong {
+  font-size: 1rem;
+}
+
+.social-item-subtitle,
+.social-item-caption {
+  color: var(--muted);
+  font-size: 0.94rem;
+}
+
+.social-item-actions,
+.play-friend-actions,
+.play-overlay-actions {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.55rem;
+  align-items: center;
+}
+
+.presence-badge {
+  display: inline-flex;
+  align-items: center;
+  padding: 0.22rem 0.58rem;
+  border: 1px solid rgba(255, 255, 255, 0.1);
+  border-radius: 999px;
+  background: rgba(255, 255, 255, 0.04);
+  color: var(--muted);
+  font-size: 0.72rem;
+  font-weight: 700;
+  letter-spacing: 0.09em;
+  text-transform: uppercase;
+}
+
+.presence-badge.online {
+  border-color: rgba(93, 219, 126, 0.32);
+  background: rgba(93, 219, 126, 0.12);
+  color: #baf3c6;
+}
+
+.social-inline-feedback,
+.play-invite-pending {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 0.9rem;
+  padding: 0.85rem 0.95rem;
+  border: 1px solid rgba(255, 177, 58, 0.22);
+  border-radius: 18px;
+  background: rgba(255, 177, 58, 0.08);
+}
+
+.social-inline-feedback span,
+.play-invite-pending p {
+  margin: 0;
+}
+
+.play-invite-pending strong {
+  display: block;
+  margin-top: 0.15rem;
+}
+
+.play-friends-list {
+  display: grid;
+  gap: 0.75rem;
+}
+
+.play-overlay {
+  position: fixed;
+  inset: 0;
+  z-index: 1200;
+  display: grid;
+  place-items: center;
+  padding: 1rem;
+}
+
+.play-overlay-card {
+  position: relative;
+  z-index: 1;
+  width: min(100%, 32rem);
+}
+
+.play-overlay-copy {
+  margin: 0 0 1rem;
+  color: var(--muted);
+  line-height: 1.6;
+}
+
+@media (max-width: 1100px) {
+  .social-columns {
+    grid-template-columns: 1fr;
+  }
+}
+
+@media (max-width: 900px) {
+  .social-search-form {
+    grid-template-columns: 1fr;
+  }
+
+  .social-search-actions {
+    justify-content: flex-start;
+  }
+
+  .social-item,
+  .play-friend-item,
+  .social-inline-feedback,
+  .play-invite-pending {
+    flex-direction: column;
+    align-items: stretch;
+  }
+
+  .social-item-actions,
+  .play-friend-actions,
+  .play-overlay-actions {
+    width: 100%;
+  }
+}