import { MigrationInterface, QueryRunner } from 'typeorm';

export class AddPageUpdateHistoryTrigger1651992866220
  implements MigrationInterface
{
  public async up(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.query(`
      CREATE OR REPLACE FUNCTION update_page_history ()
        RETURNS TRIGGER
        AS $$
      BEGIN
        IF OLD IS NULL OR NEW.price <> OLD.price THEN
          INSERT INTO page_update_history ("pageId", price)
            VALUES (NEW.id, NEW.price);
        END IF;
        RETURN NEW;
      END;
      $$
      LANGUAGE plpgsql;
    `);

    await queryRunner.query(`
        CREATE TRIGGER update_page_history_trigger
        AFTER INSERT OR UPDATE ON pages
        FOR EACH ROW
        EXECUTE PROCEDURE update_page_history ();
    `);
  }

  public async down(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.query(`
        DROP TRIGGER update_page_history_trigger ON pages;
    `);

    await queryRunner.query(`
        DROP FUNCTION update_page_history ();
    `);
  }
}