import { describe, it, expect } from 'vitest';
import { promises as fs } from 'node:fs';
import nodePath from 'node:path';
import { fileURLToPath } from 'node:url';
import { unified } from 'unified';
import remarkParse from 'remark-parse';
import remarkStringify from 'remark-stringify';
import remarkGfm from 'remark-gfm';
import remarkMath from 'remark-math';

const __dirname = nodePath.dirname(fileURLToPath(import.meta.url));
const fxDir = nodePath.join(__dirname, '..', 'fixtures', 'roundtrip');

const parse = (md: string) => unified().use(remarkParse).use(remarkGfm).use(remarkMath).parse(md);
const roundtrip = (md: string) =>
  unified().use(remarkParse).use(remarkGfm).use(remarkMath)
    .use(remarkStringify).use(remarkGfm).use(remarkMath).processSync(md).toString();

function normalize(node: any): any {
  if (node === null || typeof node !== 'object') return node;
  if (Array.isArray(node)) return node.map(normalize);
  const { position, ...rest } = node;
  for (const k of Object.keys(rest)) rest[k] = normalize(rest[k]);
  return rest;
}

const CASES = ['emphasis-nested','escaping','tables','codeblock','tasklist','headings','thematic-break','blockquote','lists-nested','whitespace','breaks','links','images','math'];

describe('Markdown 往返 fixture 集（mdast 等价）', () => {
  it('fixture 数量足够', async () => {
    const names = (await fs.readdir(fxDir)).filter(f => f.endsWith('.md') && f !== 'README.md');
    expect(names.length).toBeGreaterThanOrEqual(15);
  });

  for (const name of CASES) {
    it(name + ' 往返 mdast 等价', async () => {
      const md = await fs.readFile(nodePath.join(fxDir, name + '.md'), 'utf8');
      const mdPrime = roundtrip(md);
      expect(normalize(parse(mdPrime))).toEqual(normalize(parse(md)));
    });
  }
});