♻️ Refactor migrations.

backend/src/app/migrations/sql/0022-page-file-refactor.sql

@@ -0,0 +1,48 @@
+ALTER TABLE file
+  ADD COLUMN revn bigint NOT NULL DEFAULT 0,
+  ADD COLUMN data bytea NULL;
+
+CREATE TABLE file_change (
+  id uuid PRIMARY KEY DEFAULT uuid_generate_v4(),
+  file_id uuid NOT NULL REFERENCES file(id) ON DELETE CASCADE,
+  created_at timestamptz NOT NULL DEFAULT clock_timestamp(),
+  session_id uuid NULL DEFAULT NULL,
+  revn bigint NOT NULL DEFAULT 0,
+  data bytea NOT NULL,
+  changes bytea NULL DEFAULT NULL
+);
+
+CREATE TABLE file_share_token (
+  file_id uuid NOT NULL REFERENCES file(id) ON DELETE CASCADE,
+  page_id uuid NOT NULL,
+  token   text NOT NULL,
+
+  created_at timestamptz NOT NULL DEFAULT clock_timestamp(),
+
+  PRIMARY KEY (file_id, token)
+);
+
+CREATE INDEX page_change_file_id_idx
+    ON file_change(file_id);
+
+CREATE FUNCTION handle_file_update()
+  RETURNS TRIGGER AS $pagechange$
+  DECLARE
+    current_dt timestamptz := clock_timestamp();
+  BEGIN
+    NEW.modified_at := current_dt;
+
+    --- Update projects modified_at attribute when a
+    --- page of that project is modified.
+    UPDATE project
+       SET modified_at = current_dt
+     WHERE id = OLD.project_id;
+
+    RETURN NEW;
+  END;
+$pagechange$ LANGUAGE plpgsql;
+
+CREATE TRIGGER file_on_update_tgr
+BEFORE UPDATE ON file
+   FOR EACH ROW EXECUTE PROCEDURE handle_file_update();
+