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

/**
 * Web interface (CONCEPT.md D22): trigram indexes for substring search, and
 * SQL versions of the "readable name" rule used for filtering.
 */
export default class extends BaseSchema {
  async up() {
    this.defer(async (db) => {
      await db.rawQuery('CREATE EXTENSION IF NOT EXISTS pg_trgm')
      // Per-file suffixes stripped, as in lib/release fileStem.
      await db.rawQuery(`
        CREATE OR REPLACE FUNCTION name_stem(name text) RETURNS text IMMUTABLE LANGUAGE sql AS $$
          SELECT regexp_replace(name,
            '(\\.(part\\d+\\.rar|r\\d{2,3}|rar|vol\\d+[+-]\\d+\\.par2|par2|7z(\\.\\d{3})?|zip|\\d{3}|nfo|sfv|nzb|tar|zst|gz|xz|mkv|mp4|avi|m4v|ts|iso|img|flac|mp3|epub|pdf|jpg|png))+$',
            '', 'i')
        $$`)
      // Not an obfuscated token (as in ArchiveService.looksRandom).
      await db.rawQuery(`
        CREATE OR REPLACE FUNCTION is_readable_name(name text) RETURNS boolean IMMUTABLE LANGUAGE sql AS $$
          SELECT name IS NOT NULL AND NOT (
            (name_stem(name) ~ '^[A-Za-z0-9]{16,}$' AND name_stem(name) ~ '\\d'
              AND name_stem(name) ~ '[a-z]' AND name_stem(name) ~ '[A-Z]')
            OR name_stem(name) ~* '^[0-9a-f]{16,}$')
        $$`)
      await db.rawQuery('CREATE INDEX IF NOT EXISTS releases_name_trgm ON releases USING gin (name gin_trgm_ops)')
      await db.rawQuery('CREATE INDEX IF NOT EXISTS files_filename_trgm ON files USING gin (filename gin_trgm_ops)')
      await db.rawQuery('CREATE INDEX IF NOT EXISTS files_real_name_trgm ON files USING gin (real_name gin_trgm_ops)')
      await db.rawQuery('CREATE INDEX IF NOT EXISTS releases_posted_at_idx ON releases (posted_at DESC NULLS LAST)')
    })
  }

  async down() {
    this.defer(async (db) => {
      await db.rawQuery('DROP INDEX IF EXISTS releases_posted_at_idx')
      await db.rawQuery('DROP INDEX IF EXISTS files_real_name_trgm')
      await db.rawQuery('DROP INDEX IF EXISTS files_filename_trgm')
      await db.rawQuery('DROP INDEX IF EXISTS releases_name_trgm')
      await db.rawQuery('DROP FUNCTION IF EXISTS is_readable_name(text)')
      await db.rawQuery('DROP FUNCTION IF EXISTS name_stem(text)')
    })
  }
}