import { writeFileSync, renameSync, mkdirSync, existsSync } from 'fs'
import path from 'path'

/**
 * Atomically write JSON to a file by writing to a temp file first, then
 * renaming it into place. Prevents partial writes from corrupting the file.
 */
export function atomicWriteJSON(filePath: string, data: unknown): void {
  const dir = path.dirname(filePath)
  if (!existsSync(dir)) mkdirSync(dir, { recursive: true })
  const tmp = `${filePath}.tmp`
  writeFileSync(tmp, JSON.stringify(data, null, 2), 'utf-8')
  renameSync(tmp, filePath)
}