chesscubing/ChessCubing.App/Services/UserSession.cs

using System.Security.Claims;
using Microsoft.AspNetCore.Components.Authorization;

namespace ChessCubing.App.Services;

public sealed class UserSession(AuthenticationStateProvider authenticationStateProvider)
{
    public async ValueTask<UserStorageScope> GetStorageScopeAsync()
    {
        try
        {
            var authState = await authenticationStateProvider.GetAuthenticationStateAsync();
            var userId = ResolveUserId(authState.User);

            return CreateStorageScope(userId);
        }
        catch
        {
            return CreateStorageScope("anonymous");
        }
    }

    private static string ResolveUserId(ClaimsPrincipal user)
    {
        if (user.Identity?.IsAuthenticated != true)
        {
            return "anonymous";
        }

        var rawIdentifier = user.FindFirst("sub")?.Value
            ?? user.FindFirst(ClaimTypes.NameIdentifier)?.Value
            ?? user.FindFirst("preferred_username")?.Value
            ?? user.Identity?.Name;

        if (string.IsNullOrWhiteSpace(rawIdentifier))
        {
            return "authenticated";
        }

        return Uri.EscapeDataString(rawIdentifier.Trim());
    }

    private static UserStorageScope CreateStorageScope(string userId)
        => new(
            $"{MatchStore.StorageKeyPrefix}:{userId}",
            $"{MatchStore.WindowNameKeyPrefix}:{userId}:");
}

public readonly record struct UserStorageScope(string StorageKey, string WindowNameKey);