import { mkdir, readFile, writeFile, access, chmod } from 'node:fs/promises';
import type { AssemblinkerCache, LinkEntry, SourceRun } from './types.js';
import { CACHE_PATH, CONFIG_DIR } from './paths.js';

const version = 1 as const;

export async function loadCache(): Promise<AssemblinkerCache> {
  try {
    await access(CACHE_PATH);
    const raw = await readFile(CACHE_PATH, 'utf8');
    return JSON.parse(raw) as AssemblinkerCache;
  } catch {
    return createEmptyCache();
  }
}

export function createEmptyCache(): AssemblinkerCache {
  return { version, cards: {}, links: {}, runs: {} };
}

export async function saveCache(cache: AssemblinkerCache): Promise<void> {
  await mkdir(CONFIG_DIR, { recursive: true, mode: 0o700 });
  await writeFile(CACHE_PATH, JSON.stringify(cache, null, 2), { mode: 0o600 });
  try {
    await chmod(CACHE_PATH, 0o600);
  } catch {}
}

export function getLinkEntry(cache: AssemblinkerCache, url: string): LinkEntry | undefined {
  return cache.links[url];
}

export function setLinkEntry(cache: AssemblinkerCache, url: string, entry: LinkEntry): void {
  cache.links[url] = entry;
}

export function getSourceRun(cache: AssemblinkerCache, sourceUrl: string): SourceRun {
  if (!cache.runs[sourceUrl]) {
    cache.runs[sourceUrl] = { links: {}, updatedAt: new Date().toISOString() };
  }
  return cache.runs[sourceUrl];
}

export function isLinked(cache: AssemblinkerCache, sourceUrl: string, targetUrl: string): boolean {
  return !!cache.runs[sourceUrl]?.links[targetUrl]?.connected;
}