/**
 * front matter 解析器回归测试：拿仓库里全部真实文章跑无损往返。
 *
 *   node test/frontmatter-roundtrip.mjs [contentDir]
 *
 * 断言三件事：
 *   1. split → join 能**逐字节**还原原文件（说明切分没吃掉任何字符）
 *   2. parse → stringify → parse 后对象与首次解析**深相等**（说明丢了不信息）
 *   3. 记录所有解析失败的样本，便于判断是否需要补语法
 */
import fs from 'node:fs';
import path from 'node:path';
import { splitFrontMatter, joinFrontMatter, parse, stringify, deepEqual } from '../src/frontmatter.mjs';

const root = process.argv[2] || path.resolve(import.meta.dirname, '../../content/posts');

function walk(dir, out = []) {
  for (const name of fs.readdirSync(dir)) {
    const p = path.join(dir, name);
    const st = fs.statSync(p);
    if (st.isDirectory()) walk(p, out);
    else if (name.endsWith('.md')) out.push(p);
  }
  return out;
}

const files = walk(root);
let ok = 0;
const byteFail = [];
const parseFail = [];
const roundFail = [];

for (const f of files) {
  const text = fs.readFileSync(f, 'utf8');
  const rel = path.relative(root, f);

  const { raw, body, eol } = splitFrontMatter(text);
  if (raw == null) {
    parseFail.push([rel, '没有 front matter']);
    continue;
  }

  // 1. 逐字节还原（含原始换行风格）
  if (joinFrontMatter(raw, body, eol) !== text) byteFail.push(rel);

  // 2. 解析 + 往返
  let first;
  try {
    first = parse(raw);
  } catch (e) {
    parseFail.push([rel, e.message]);
    continue;
  }

  let second;
  try {
    second = parse(stringify(first));
  } catch (e) {
    roundFail.push([rel, 'stringify/parse 失败: ' + e.message]);
    continue;
  }

  if (!deepEqual(first, second)) {
    const diff = Object.keys(first).concat(Object.keys(second)).filter(
      (k, i, a) => a.indexOf(k) === i && !deepEqual(first[k], second[k]),
    );
    roundFail.push([rel, '字段不一致: ' + diff.join(', ')]);
    continue;
  }

  ok++;
}

const total = files.length;
console.log('样本总数        :', total);
console.log('解析 + 往返通过 :', ok);
console.log('切分不还原      :', byteFail.length);
console.log('解析失败        :', parseFail.length);
console.log('往返不一致      :', roundFail.length);

const show = (title, arr) => {
  if (!arr.length) return;
  console.log('\n--- ' + title + ' ---');
  for (const [f, why] of arr.slice(0, 12)) console.log('  ' + f + '  ||  ' + why);
  if (arr.length > 12) console.log('  … 另有 ' + (arr.length - 12) + ' 条');
};

show('切分不还原（必须为 0）', byteFail.map((f) => [f, 'join != 原文']));
show('解析失败', parseFail);
show('往返不一致', roundFail);

const bad = byteFail.length + parseFail.length + roundFail.length;
process.exit(bad === 0 ? 0 : 1);