api shell

migrations/003_functions.sql

@@ -0,0 +1,13 @@
+-- Atomic sequence increment for message ordering
+CREATE OR REPLACE FUNCTION next_message_sequence(conv_id UUID)
+RETURNS BIGINT AS $$
+DECLARE
+  seq BIGINT;
+BEGIN
+  UPDATE conversations
+  SET next_sequence = next_sequence + 1, updated_at = now()
+  WHERE id = conv_id
+  RETURNING next_sequence INTO seq;
+  RETURN seq;
+END;
+$$ LANGUAGE plpgsql;