import { existsSync, readdirSync, readFileSync, statSync } from "node:fs";
import { extname, join, normalize } from "node:path";

const root = new URL("../dist/", import.meta.url);
const rootPath = root.pathname;

function walk(directory) {
  return readdirSync(directory).flatMap((name) => {
    const path = join(directory, name);
    return statSync(path).isDirectory() ? walk(path) : [path];
  });
}

function routeFile(pathname) {
  const clean = decodeURIComponent(pathname).replace(/^\/+/, "");
  if (!clean) return join(rootPath, "index.html");
  const local = normalize(join(rootPath, clean));
  if (!local.startsWith(normalize(rootPath))) return null;
  if (extname(local)) return local;
  return join(local, "index.html");
}

if (!existsSync(rootPath)) {
  console.error("dist/ 不存在；请先运行 npm run build。");
  process.exit(1);
}

const htmlFiles = walk(rootPath).filter((file) => file.endsWith(".html"));
const anchors = new Map();
for (const file of htmlFiles) {
  const html = readFileSync(file, "utf8");
  anchors.set(file, new Set([...html.matchAll(/\sid=["']([^"']+)["']/g)].map((match) => match[1])));
}

let references = 0;
let anchorReferences = 0;
const failures = [];

for (const source of htmlFiles) {
  const html = readFileSync(source, "utf8");
  const hrefs = [...html.matchAll(/\shref=["']([^"']+)["']/g)].map((match) => match[1]);
  for (const href of hrefs) {
    if (!href.startsWith("/") || href.startsWith("//")) continue;
    references += 1;
    const url = new URL(href, "https://llm-atlas.local");
    const target = routeFile(url.pathname);
    if (!target || !existsSync(target)) {
      failures.push(`${source.replace(rootPath, "/")} → ${href}（目标不存在）`);
      continue;
    }
    if (url.hash) {
      anchorReferences += 1;
      const id = decodeURIComponent(url.hash.slice(1));
      if (!anchors.get(target)?.has(id)) {
        failures.push(`${source.replace(rootPath, "/")} → ${href}（锚点不存在）`);
      }
    }
  }
}

console.log(
  `${htmlFiles.length} 个页面，${references} 个站内引用，${anchorReferences} 个跨页锚点，${failures.length} 个失败。`,
);
if (failures.length) {
  failures.forEach((failure) => console.error(`- ${failure}`));
  process.exit(1);
}