/**
 * WAL-safe SQLite backup via better-sqlite3 backup API (not a raw file copy).
 * Usage: DB_PATH=./data/app.db BACKUP_DIR=./backups node scripts/sqlite-backup.mjs
 */
import Database from 'better-sqlite3'
import { mkdirSync, existsSync, readdirSync, statSync, unlinkSync } from 'node:fs'
import { join } from 'node:path'

const srcPath = process.env.DB_PATH ?? join(process.cwd(), 'data', 'app.db')
const backupDir = process.env.BACKUP_DIR ?? join(process.cwd(), 'backups')
const retentionDays = Number(process.env.BACKUP_RETENTION_DAYS ?? '0')

if (!existsSync(srcPath)) {
  console.error(`Source database not found: ${srcPath}`)
  process.exit(1)
}

mkdirSync(backupDir, { recursive: true })

const stamp = new Date().toISOString().replace(/[:.]/g, '-')
const destPath = join(backupDir, `app-${stamp}.db`)

const src = new Database(srcPath, { readonly: true })
try {
  await src.backup(destPath)
} finally {
  src.close()
}

const verify = new Database(destPath, { readonly: true })
try {
  const integrity = verify.pragma('integrity_check', { simple: true })
  if (integrity !== 'ok') {
    console.error(`Backup integrity check failed: ${integrity}`)
    process.exit(1)
  }
} finally {
  verify.close()
}

console.log(`Backup written: ${destPath}`)

if (retentionDays > 0) {
  const cutoff = Date.now() - retentionDays * 86_400_000
  for (const name of readdirSync(backupDir)) {
    if (!name.startsWith('app-') || !name.endsWith('.db')) continue
    const full = join(backupDir, name)
    if (statSync(full).mtimeMs < cutoff) {
      unlinkSync(full)
      console.log(`Removed old backup: ${name}`)
    }
  }
}