import NzbService from '#services/nzb_service'

/** A file a par2 set describes (par2_files). */
export interface SetFile {
  name: string
  length: number
  hash16k: string
}

const base = (name: string) => name.replace(/^.*[\\/]/, '').toLowerCase()

/**
 * Whether a release holds every file its par2 sets describe (REBUILD.md, part 8): for one without an [i/N] counter,
 * whose completeness the settler leaves unknown. A described file is there when a file of the release has its name,
 * or a probed file of it its first 16 KiB and size (file_hashes). An upload renamed after its par2 was made (no
 * described name among its files) is complete when it has as many files besides par2 as the set describes, and as
 * many bytes (its articles' bytes, a little over the files' with yEnc).
 */
export function par2Complete(set: SetFile[], files: { name: string; size: number }[], hashes: { hash16k: string; size: number }[]): boolean {
  const names = new Set(files.map((f) => base(f.name)))
  const hashed = new Set(hashes.map((h) => `${h.hash16k}:${h.size}`))
  const byName = set.filter((f) => names.has(base(f.name))).length
  if (set.every((f) => names.has(base(f.name)) || hashed.has(`${f.hash16k}:${f.length}`))) return true
  if (byName > 0) return false
  const data = files.filter((f) => !/\.par2$/i.test(f.name))
  return data.length >= set.length && data.reduce((n, f) => n + f.size, 0) >= set.reduce((n, f) => n + f.length, 0)
}

/**
 * Decides `complete` for the settled releases among `releaseIds` that have no counter and a par2 set with its file
 * list (par2_files; the pruner drops it once the set is done, so it decides before). How many it decided. `client`:
 * a transaction that moved chunks (a merge) reads them as moved.
 */
export async function decidePar2Completeness(client: any, releaseIds: (number | string)[]): Promise<number> {
  if (releaseIds.length === 0) return 0
  const { rows: releases } = await client.rawQuery(
    `SELECT id FROM releases WHERE id = ANY(?) AND file_total IS NULL AND settled_at IS NOT NULL`,
    [releaseIds.map(String)]
  )
  let decided = 0
  for (const { id } of releases) {
    const { rows: set } = await client.rawQuery(
      `SELECT DISTINCT f.file_id, f.name, f.length::float8 AS length, f.hash16k FROM par2_sets s JOIN par2_files f ON f.set_id = s.set_id WHERE s.release_id = ?`,
      [id]
    )
    if (set.length === 0) continue
    const { rows: hashes } = await client.rawQuery(`SELECT hash16k, size::float8 AS size FROM file_hashes WHERE release_id = ?`, [id])
    const files = (await NzbService.files(Number(id), client)).map((f) => ({ name: f.name, size: f.segments.reduce((n, [, , bytes]) => n + bytes, 0) }))
    await client.rawQuery(`UPDATE releases SET complete = ? WHERE id = ?`, [par2Complete(set, files, hashes), id])
    decided++
  }
  return decided
}