import db from '@adonisjs/lucid/services/db'
import logger from '@adonisjs/core/services/logger'

/**
 * Uploads split per poster (CONCEPT.md D35). Some uploaders post every
 * volume of a RAR set under a different poster; the post-id grouping then
 * makes one release per volume, all with the same name
 * (`Masters.of.the.Universe.1987…`: 191 one-file releases of one 199-volume
 * set). Such releases are one upload when all their files share one stem and
 * no file name repeats (a repost would repeat them, another upload would
 * bring another stem); their files move into the oldest of them, and GC
 * deletes the emptied ones.
 */
class ReleaseMergeService {
  async mergeSplitPosts({ dryRun = false } = {}): Promise<{ names: number; releases: number }> {
    const { rows } = await db.rawQuery(`
      WITH dup AS (
        SELECT name FROM releases
        WHERE file_count > 0 AND source = 'post' AND is_readable_name(name)
        GROUP BY name HAVING count(*) > 1
      )
      SELECT r.name, array_agg(DISTINCT r.id ORDER BY r.id) AS ids
      FROM dup JOIN releases r ON r.name = dup.name AND r.file_count > 0 AND r.source = 'post'
      JOIN files f ON f.release_id = r.id
      GROUP BY r.name
      HAVING count(DISTINCT name_stem(coalesce(f.real_name, f.filename))) = 1
        AND count(f.id) = count(DISTINCT coalesce(f.real_name, f.filename))
        AND max(r.posted_at) - min(r.posted_at) < interval '30 days'`)
    let releases = 0
    for (const { name, ids } of rows as { name: string; ids: (string | number)[] }[]) {
      const [target, ...others] = ids.map(Number)
      releases += others.length
      if (dryRun) continue
      await db.from('files').whereIn('release_id', others).update({ release_id: target })
      await db.from('binaries').whereIn('release_id', others).update({ release_id: target })
      logger.info(`Merged ${others.length + 1} releases of one upload split per poster into ${target} "${name}".`)
    }
    return { names: rows.length, releases }
  }
}

export default new ReleaseMergeService()