added initial roadmap and implementation

migrations/20240101000004_realtime_triggers.sql

@@ -0,0 +1,49 @@
+
+-- Realtime schema
+CREATE SCHEMA IF NOT EXISTS madbase_realtime;
+
+-- Generic Trigger Function
+CREATE OR REPLACE FUNCTION madbase_realtime.broadcast_changes()
+RETURNS trigger AS $$
+DECLARE
+    payload jsonb;
+    topic text;
+BEGIN
+    -- Construct payload
+    payload = jsonb_build_object(
+        'schema', TG_TABLE_SCHEMA,
+        'table', TG_TABLE_NAME,
+        'type', TG_OP,
+        'timestamp', now()
+    );
+
+    IF (TG_OP = 'INSERT') THEN
+        payload = payload || jsonb_build_object('record', row_to_json(NEW)::jsonb);
+    ELSIF (TG_OP = 'UPDATE') THEN
+        payload = payload || jsonb_build_object(
+            'record', row_to_json(NEW)::jsonb,
+            'old_record', row_to_json(OLD)::jsonb
+        );
+    ELSIF (TG_OP = 'DELETE') THEN
+        payload = payload || jsonb_build_object('old_record', row_to_json(OLD)::jsonb);
+    END IF;
+
+    -- Send notification
+    -- Payload limit is 8000 bytes. Larger payloads will fail or need truncation.
+    -- For MVP, we assume it fits.
+    PERFORM pg_notify('madbase_realtime', payload::text);
+    
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+-- Example: Enable for public.users (if it exists)
+-- DO $$
+-- BEGIN
+--     IF EXISTS (SELECT FROM pg_tables WHERE schemaname = 'public' AND tablename = 'users') THEN
+--         CREATE TRIGGER realtime_users_changes
+--         AFTER INSERT OR UPDATE OR DELETE ON public.users
+--         FOR EACH ROW EXECUTE FUNCTION madbase_realtime.broadcast_changes();
+--     END IF;
+-- END
+-- $$;