workos__skills/scripts/eval/cache.ts

import { createHash } from 'crypto';
import { mkdir, readFile, writeFile } from 'fs/promises';
import { join } from 'path';
import type { TokenUsage } from './types.ts';

const CACHE_DIR = join(process.cwd(), 'scripts', 'output', 'eval-cache');

export interface CachedResponse {
  output: string;
  usage: TokenUsage;
  model: string;
  cachedAt: string;
}

export function getCacheKey(model: string, system: string, user: string): string {
  return createHash('sha256').update(`${model}:0:${system}:${user}`).digest('hex').slice(0, 16);
}

export async function readCache(key: string): Promise<CachedResponse | null> {
  try {
    const data = await readFile(join(CACHE_DIR, `${key}.json`), 'utf8');
    return JSON.parse(data) as CachedResponse;
  } catch {
    return null;
  }
}

export async function writeCache(key: string, response: CachedResponse): Promise<void> {
  await mkdir(CACHE_DIR, { recursive: true });
  await writeFile(join(CACHE_DIR, `${key}.json`), JSON.stringify(response, null, 2));
}