import { MigrationInterface, QueryRunner } from 'typeorm';

/**
 * Drop the redundant single-column index on messages(sessionId). Every lookup it can serve is
 * already covered by a composite index that leads with sessionId — IDX_399833…(sessionId,
 * createdAt) and the unique (sessionId, waMessageId) — so the standalone index adds only
 * write-time maintenance on a hot, high-volume table.
 *
 * Runs on the `data` connection. `IF EXISTS` keeps it idempotent and portable across SQLite and
 * Postgres (and safe on a synchronize-built schema). The name is the one TypeORM generated for the
 * `@Index()` on the sessionId column — hardcoded in the baseline migration (1770108659848).
 */
export class DropRedundantMessagesSessionIdIndex1781600000000 implements MigrationInterface {
  name = 'DropRedundantMessagesSessionIdIndex1781600000000';

  public async up(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.query(`DROP INDEX IF EXISTS "IDX_066163c46cda7e8187f96bc87a"`);
  }

  public async down(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.query(`CREATE INDEX IF NOT EXISTS "IDX_066163c46cda7e8187f96bc87a" ON "messages" ("sessionId")`);
  }
}