import { MigrationInterface, QueryRunner } from 'typeorm';

/**
 * Composite index on `webhook_delivery_failures (webhookId, idempotencyKey)`, backing the
 * before-insert lookup in `recordWebhookDeliveryFailure` that keeps one row per lost delivery
 * rather than one per replay attempt. The table is append-only and never pruned, so without an
 * index that lookup scans it once per terminal failure: during exactly the receiver outage the
 * table exists to record, the scan grows with the rows the outage is adding.
 *
 * Hand-authored because `synchronize` is off for the data connection on PostgreSQL (and optional on
 * SQLite). The explicit name matches the entity's @Index, so the synchronize and migration schema
 * paths converge on one index. Idempotent via IF NOT EXISTS (supported by both dialects).
 */
export class AddWebhookDeliveryFailureLookupIndex1786300000000 implements MigrationInterface {
  name = 'AddWebhookDeliveryFailureLookupIndex1786300000000';

  public async up(queryRunner: QueryRunner): Promise<void> {
    // The data pool boots with a runtime statement_timeout (default 30s), and MigrationExecutor
    // wraps a lone pending migration in its own transaction, so no earlier SET LOCAL is in effect.
    // Lift it for this transaction only, exactly like AddMessageMediaPathIndex.
    if (queryRunner.dataSource.options.type === 'postgres') {
      await queryRunner.query('SET LOCAL statement_timeout = 0');
    }
    await queryRunner.query(
      `CREATE INDEX IF NOT EXISTS "IDX_webhook_delivery_failures_delivery" ON "webhook_delivery_failures" ("webhookId", "idempotencyKey")`,
    );
  }

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