feat: game lobby service

lobby/internal/ports/streamoffsetstore.go

@@ -0,0 +1,20 @@
+package ports
+
+import "context"
+
+// StreamOffsetStore persists the last successfully processed Redis
+// Stream entry id per stream. Workers call Load on startup to resume
+// from the persisted offset and Save after every successful message
+// handling so the next iteration advances past the just-processed
+// entry. Lobby uses one logical store with the per-stream key encoded
+// inside the implementation.
+type StreamOffsetStore interface {
+	// Load returns the last processed entry id for stream when one is
+	// stored. The boolean return reports whether a value was present;
+	// implementations must not return an error for a missing key.
+	Load(ctx context.Context, stream string) (entryID string, found bool, err error)
+
+	// Save stores entryID as the new last processed offset for stream.
+	// Implementations overwrite any previous value unconditionally.
+	Save(ctx context.Context, stream, entryID string) error
+}