import { BaseSchema } from '@adonisjs/lucid/schema'

/**
 * Header backfill (CONCEPT.md D32): a group walks backwards from
 * `backfill_next_id` down to `backfill_until_id` in low-priority,
 * header-only fetch ranges (`fetch_ranges.backfill`).
 */
export default class extends BaseSchema {
  async up() {
    this.schema.alterTable('groups', (table) => {
      table.bigInteger('backfill_until_id')
      table.bigInteger('backfill_next_id')
    })
    this.schema.alterTable('fetch_ranges', (table) => {
      table.boolean('backfill').notNullable().defaultTo(false)
    })
  }

  async down() {
    this.schema.alterTable('groups', (table) => {
      table.dropColumn('backfill_until_id')
      table.dropColumn('backfill_next_id')
    })
    this.schema.alterTable('fetch_ranges', (table) => table.dropColumn('backfill'))
  }
}