/**
 * cli:aggregate-component-registry — atomic disk writer.
 *
 * ② The aggregator is an app-wide reducer: N parallel `/ba-develop` module
 * subagents each run it over the FULL app and overwrite the SAME two shared files
 * (`componentRegistry.generated.ts` + `moduleResources.generated.ts`). A plain
 * `writeFileSync` can be observed half-written by a reader or a racing aggregator.
 * Writing to a per-process temp file then `rename()` (atomic on the same volume)
 * makes every observed state a complete file, and concurrent runs never collide on
 * the temp name (it carries `process.pid`).
 */
import { mkdirSync, writeFileSync, renameSync } from 'node:fs'
import { dirname, resolve } from 'node:path'
import type { GeneratedFile } from './types.js'

/** Write each generated file atomically (tmp + rename). Returns the absolute
 *  paths written, in input order. */
export function writeGeneratedFilesAtomic(
  projectPath: string,
  files: GeneratedFile[],
): string[] {
  const written: string[] = []
  for (const file of files) {
    const abs = resolve(projectPath, file.path)
    mkdirSync(dirname(abs), { recursive: true })
    const tmp = `${abs}.tmp-${process.pid}`
    writeFileSync(tmp, file.content, 'utf-8')
    renameSync(tmp, abs)
    written.push(abs)
  }
  return written
}