interim commit

src/StellaOps.Feedser.Storage.Mongo/Exporting/ExportStateManager.cs

@@ -31,6 +31,7 @@ public sealed class ExportStateManager
         string? cursor,
         string? targetRepository,
         string exporterVersion,
+        bool resetBaseline,
         CancellationToken cancellationToken)
     {
         ArgumentException.ThrowIfNullOrEmpty(exporterId);
@@ -39,36 +40,59 @@ public sealed class ExportStateManager
         ArgumentException.ThrowIfNullOrEmpty(exporterVersion);
 
         var existing = await _store.FindAsync(exporterId, cancellationToken).ConfigureAwait(false);
-        var repository = string.IsNullOrWhiteSpace(targetRepository) ? existing?.TargetRepository : targetRepository;
         var now = _timeProvider.GetUtcNow();
 
-        var baseExportId = existing?.BaseExportId ?? exportId;
-        var baseDigest = existing?.BaseDigest ?? exportDigest;
+        if (existing is null)
+        {
+            var resolvedRepository = string.IsNullOrWhiteSpace(targetRepository) ? null : targetRepository;
+            return await _store.UpsertAsync(
+                new ExportStateRecord(
+                    exporterId,
+                    BaseExportId: exportId,
+                    BaseDigest: exportDigest,
+                    LastFullDigest: exportDigest,
+                    LastDeltaDigest: null,
+                    ExportCursor: cursor ?? exportDigest,
+                    TargetRepository: resolvedRepository,
+                    ExporterVersion: exporterVersion,
+                    UpdatedAt: now),
+                cancellationToken).ConfigureAwait(false);
+        }
 
-        var record = existing is null
-            ? new ExportStateRecord(
-                exporterId,
-                baseExportId,
-                baseDigest,
-                exportDigest,
-                LastDeltaDigest: null,
-                ExportCursor: cursor ?? exportDigest,
-                TargetRepository: repository,
-                ExporterVersion: exporterVersion,
-                UpdatedAt: now)
+        var repositorySpecified = !string.IsNullOrWhiteSpace(targetRepository);
+        var resolvedRepo = repositorySpecified ? targetRepository : existing.TargetRepository;
+        var repositoryChanged = repositorySpecified
+            && !string.Equals(existing.TargetRepository, targetRepository, StringComparison.Ordinal);
+
+        var shouldResetBaseline =
+            resetBaseline
+            || string.IsNullOrWhiteSpace(existing.BaseExportId)
+            || string.IsNullOrWhiteSpace(existing.BaseDigest)
+            || repositoryChanged;
+
+        var updatedRecord = shouldResetBaseline
+            ? existing with
+            {
+                BaseExportId = exportId,
+                BaseDigest = exportDigest,
+                LastFullDigest = exportDigest,
+                LastDeltaDigest = null,
+                ExportCursor = cursor ?? exportDigest,
+                TargetRepository = resolvedRepo,
+                ExporterVersion = exporterVersion,
+                UpdatedAt = now,
+            }
             : existing with
             {
-                BaseExportId = baseExportId,
-                BaseDigest = baseDigest,
                 LastFullDigest = exportDigest,
                 LastDeltaDigest = null,
                 ExportCursor = cursor ?? existing.ExportCursor,
-                TargetRepository = repository,
+                TargetRepository = resolvedRepo,
                 ExporterVersion = exporterVersion,
                 UpdatedAt = now,
             };
 
-        return await _store.UpsertAsync(record, cancellationToken).ConfigureAwait(false);
+        return await _store.UpsertAsync(updatedRecord, cancellationToken).ConfigureAwait(false);
     }
 
     public async Task<ExportStateRecord> StoreDeltaExportAsync(