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

/**
 * Spot listings (CONCEPT.md D29): old spots become a release without files
 * (source `spot`), whose NZB is fetched when first downloaded. Search shows
 * releases with files or spot listings, so the partial release indexes
 * cover both. Spots are verified from their overview when fetched.
 */
const VISIBLE = `(file_count > 0 OR source = 'spot')`
const INDEXES: [name: string, definition: string][] = [
  ['releases_name_trgm', `USING gin (name gin_trgm_ops)`],
  ['releases_contents_trgm', `USING gin ((contents::text) gin_trgm_ops)`],
  ['releases_posted_at_idx', `(posted_at DESC NULLS LAST)`],
  ['releases_size_index', `(size)`],
  ['releases_file_count_index', `(file_count)`],
  ['releases_complete_idx', `(complete)`],
  ['releases_category_idx', `(category)`],
]

export default class extends BaseSchema {
  static disableTransactions = true

  async up() {
    await this.db.rawQuery(`ALTER TABLE spots ADD COLUMN IF NOT EXISTS verified boolean`)
    // worker:spots claims recent spots first, then the history in posting order.
    await this.db.rawQuery(`CREATE INDEX CONCURRENTLY IF NOT EXISTS spots_status_article_idx ON spots (status, article_number)`)
    await this.db.rawQuery(`CREATE INDEX CONCURRENTLY IF NOT EXISTS spots_status_posted_idx ON spots (status, posted_at)`)
    await this.swap(VISIBLE)
  }

  async down() {
    await this.swap('file_count > 0')
    await this.db.rawQuery(`DROP INDEX CONCURRENTLY IF EXISTS spots_status_article_idx`)
    await this.db.rawQuery(`DROP INDEX CONCURRENTLY IF EXISTS spots_status_posted_idx`)
    await this.db.rawQuery(`ALTER TABLE spots DROP COLUMN IF EXISTS verified`)
  }

  private async swap(predicate: string) {
    for (const [name, definition] of INDEXES) {
      await this.db.rawQuery(`DROP INDEX CONCURRENTLY IF EXISTS ${name}_next`)
      await this.db.rawQuery(`CREATE INDEX CONCURRENTLY ${name}_next ON releases ${definition} WHERE ${predicate}`)
      await this.db.rawQuery(`DROP INDEX CONCURRENTLY IF EXISTS ${name}`)
      await this.db.rawQuery(`ALTER INDEX ${name}_next RENAME TO ${name}`)
    }
  }
}