1 files changed, 54 insertions, 0 deletions
diff --git a/Tests/LibMatrix.HomeserverEmulator/Services/PaginationTokenResolverService.cs b/Tests/LibMatrix.HomeserverEmulator/Services/PaginationTokenResolverService.cs
new file mode 100644
index 0000000..0128ba6
--- /dev/null
+++ b/Tests/LibMatrix.HomeserverEmulator/Services/PaginationTokenResolverService.cs
@@ -0,0 +1,54 @@
+namespace LibMatrix.HomeserverEmulator.Services;
+
+public class PaginationTokenResolverService(ILogger<PaginationTokenResolverService> logger, RoomStore roomStore, UserStore userStore) {
+    public async Task<long?> ResolveTokenToTimestamp(string token) {
+        logger.LogTrace("ResolveTokenToTimestamp({token})", token);
+        if (token.StartsWith('$')) {
+            //we have an event ID
+            foreach (var room in roomStore._rooms) {
+                var evt = await ResolveTokenToEvent(token, room);
+                if (evt is not null) return evt.OriginServerTs;
+            }
+
+            // event not found
+            throw new NotImplementedException();
+        }
+        else {
+            // we have a sync token 
+            foreach (var user in userStore._users) {
+                foreach (var (_, session) in user.AccessTokens) {
+                    if (!session.SyncStates.TryGetValue(token, out var syncState)) continue;
+                    long? maxTs = 0;
+                    foreach (var room in syncState.RoomPositions) {
+                        var roomObj = roomStore.GetRoomById(room.Key);
+                        if (roomObj is null)
+                            continue;
+                        var ts = roomObj.Timeline.Last().OriginServerTs;
+                        if (ts > maxTs) maxTs = ts;
+                    }
+
+                    return maxTs;
+                }
+            }
+
+            throw new NotImplementedException();
+        }
+    }
+
+    public async Task<StateEventResponse?> ResolveTokenToEvent(string token, RoomStore.Room room) {
+        if (token.StartsWith('$')) {
+            //we have an event ID
+            logger.LogTrace("ResolveTokenToEvent(EventId({token}), Room({room})): searching for event...", token, room.RoomId);
+
+            var evt = room.Timeline.SingleOrDefault(x => x.EventId == token);
+            if (evt is not null) return evt;
+            logger.LogTrace("ResolveTokenToEvent({token}, Room({room})): event not in requested room...", token, room.RoomId);
+            return null;
+        }
+        else {
+            // we have a sync token
+            logger.LogTrace("ResolveTokenToEvent(SyncToken({token}), Room({room}))", token, room.RoomId);
+            throw new NotImplementedException();
+        }
+    }
+}
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