1 files changed, 95 insertions, 0 deletions
diff --git a/ModAS.Server/Services/UserProviderService.cs b/ModAS.Server/Services/UserProviderService.cs
new file mode 100644
index 0000000..bb281c4
--- /dev/null
+++ b/ModAS.Server/Services/UserProviderService.cs
@@ -0,0 +1,95 @@
+using System.Collections.Concurrent;
+using ArcaneLibs.Extensions;
+using Elastic.Apm;
+using Elastic.Apm.Api;
+using LibMatrix;
+using LibMatrix.Homeservers;
+using LibMatrix.RoomTypes;
+using LibMatrix.Services;
+using MxApiExtensions.Services;
+
+namespace ModAS.Server.Services;
+
+public class UserProviderService(
+    AuthenticationService authenticationService,
+    HomeserverProviderService homeserverProviderService,
+    IHttpContextAccessor request,
+    ModASConfiguration config,
+    AppServiceRegistration asRegistration
+) {
+    public HttpContext? _context = request.HttpContext;
+
+    private static ITransaction currentTransaction => Agent.Tracer.CurrentTransaction;
+
+    private SemaphoreSlim updateLock = new(1,1);
+    
+    public ConcurrentDictionary<string, AuthenticatedHomeserverGeneric> KnownUsers { get; set; } = new();
+    public ConcurrentDictionary<string, DateTime> UserValidationExpiry { get; set; } = new();
+    public ConcurrentDictionary<string, List<string>> CachedUserRooms { get; set; } = new();
+    public ConcurrentDictionary<string, DateTime> CachedUserRoomsExpiry { get; set; } = new();
+    
+
+    public async Task<AuthenticatedHomeserverGeneric> GetImpersonatedHomeserver(string mxid) {
+        var span = currentTransaction.StartSpan("GetImpersonatedHomeserver", ApiConstants.TypeApp);
+        if (!KnownUsers.TryGetValue(mxid, out var homeserver)) {
+            var getUserSpan = currentTransaction.StartSpan($"GetUser - {mxid}", ApiConstants.TypeApp);
+            homeserver = await homeserverProviderService.GetAuthenticatedWithToken(config.ServerName, asRegistration.AppServiceToken, config.HomeserverUrl, mxid);
+            KnownUsers.TryAdd(mxid, homeserver);
+            getUserSpan.End();
+        }
+
+        await homeserver.SetImpersonate(mxid);
+        span.End();
+        return homeserver;
+    }
+
+    public async Task<Dictionary<string, AuthenticatedHomeserverGeneric>> GetValidUsers() {
+        var span = currentTransaction.StartSpan("GetValidUsers", ApiConstants.TypeApp);
+        var tasks = KnownUsers.Select(kvp => ValidateUser(kvp.Key, kvp.Value)).ToList();
+        var results = await Task.WhenAll(tasks);
+        var validUsers = results.Where(r => r.Value is not null).ToDictionary(r => r.Key, r => r.Value!);
+        span.End();
+        return validUsers;
+    }
+    
+    public async Task<List<GenericRoom>> GetUserRoomsCached(string mxid) {
+        var span = currentTransaction.StartSpan($"GetUserRoomsCached - {mxid}", ApiConstants.TypeApp);
+        var hs = await GetImpersonatedHomeserver(mxid);
+        if (CachedUserRoomsExpiry.TryGetValue(mxid, out var expiry) && expiry > DateTime.Now) {
+            if (CachedUserRooms.TryGetValue(mxid, out var rooms)) {
+                span.End();
+                return rooms.Select(hs.GetRoom).ToList();
+            }
+        }
+
+        var userRooms = await hs.GetJoinedRooms();
+        await updateLock.WaitAsync();
+        CachedUserRooms[mxid] = userRooms.Select(r => r.RoomId).ToList();
+        CachedUserRoomsExpiry[mxid] = DateTime.Now + TimeSpan.FromMinutes(5);
+        updateLock.Release();
+        span.End();
+        return userRooms;
+    }
+
+    private async Task<KeyValuePair<string, AuthenticatedHomeserverGeneric?>> ValidateUser(string mxid, AuthenticatedHomeserverGeneric hs) {
+        if(UserValidationExpiry.TryGetValue(mxid, out var expires))
+            if(DateTime.Now < expires) return new KeyValuePair<string, AuthenticatedHomeserverGeneric?>(mxid, hs);
+        var span = currentTransaction.StartSpan($"ValidateUser - {mxid}", ApiConstants.TypeApp);
+        try {
+            await hs.GetJoinedRooms();
+            await updateLock.WaitAsync();
+            UserValidationExpiry[mxid] = DateTime.Now + TimeSpan.FromMinutes(5);
+            updateLock.Release();
+            return new KeyValuePair<string, AuthenticatedHomeserverGeneric?>(mxid, hs);
+        }
+        catch (MatrixException e) {
+            if (e.ErrorCode == "M_FORBIDDEN") {
+                return new KeyValuePair<string, AuthenticatedHomeserverGeneric?>(mxid, null);
+            }
+            throw;
+        }
+        finally {
+            span.End();
+        }
+    }
+}
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