import chokidar from 'chokidar'
import { openSessionsDb } from './db.js'
import { indexFile, PROJECTS_ROOT } from './indexer.js'

export async function startWatcher(dbPath: string): Promise<void> {
  const db = openSessionsDb(dbPath)
  const watcher = chokidar.watch(`${PROJECTS_ROOT}/**/*.jsonl`, {
    persistent: true,
    ignoreInitial: true,
    awaitWriteFinish: { stabilityThreshold: 2000, pollInterval: 500 },
  })

  async function reindex(path: string): Promise<void> {
    try {
      await indexFile(db, path)
      console.log(`[watcher] indexed ${path}`)
    } catch (err) {
      console.error(`[watcher] erro ${path}:`, err)
    }
  }

  watcher
    .on('add', reindex)
    .on('change', reindex)
    .on('unlink', (path) => {
      db.deleteByJsonlPath(path)
      console.log(`[watcher] removed ${path}`)
    })
    .on('error', (err) => console.error('[watcher] error:', err))

  console.log('[watcher] pronto')

  // Registar handler SIGTERM/SIGINT para fechar DB limpa (evita WAL corruption em Task 9 systemd restart)
  const cleanup = async (): Promise<void> => {
    console.log('[watcher] SIGTERM/SIGINT — a fechar watcher e DB')
    await watcher.close()
    db.close()
    process.exit(0)
  }
  process.on('SIGTERM', () => { void cleanup() })
  process.on('SIGINT', () => { void cleanup() })

  return new Promise(() => {}) // nunca resolve — processo mantém-se vivo
}