#!/usr/bin/env node
// Regenerate the export fidelity corpus (issue #69, ADR 0009) from the committed
// `*.md` sources: for each source and each office format, write the Markdown you
// get back after a full export → re-read round trip through the pinned pandoc.
// That round-trip snapshot is what the fidelity gate pins — a change in pandoc's
// docx/odt writer (e.g. a version bump) shifts the output and fails the suite.
//
//   docker run --rm -p 3030:3030 pandoc/core:3.6 server
//   PANDOC_URL=http://localhost:3030 node scripts/gen-export-fixtures.mjs
//
// Mirrors the export path (ExportService: gfm → <ext>, standalone) and then
// reads the document back (<ext> → gfm) exactly as export.fidelity.test.ts does.

import { readFileSync, writeFileSync, readdirSync } from 'node:fs';
import { fileURLToPath } from 'node:url';
import { dirname, join } from 'node:path';

const FIXTURES = join(dirname(fileURLToPath(import.meta.url)), '..', 'fixtures', 'export');
const PANDOC_URL = process.env.PANDOC_URL ?? 'http://localhost:3030';
// Match the import corpus reader so both directions normalise the same way.
const MARKDOWN_FORMAT = 'gfm-implicit_figures-raw_html';
const BINARY = new Set(['docx', 'odt']);

async function pandoc(params) {
  const res = await fetch(`${PANDOC_URL}/`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(params),
  });
  if (!res.ok) throw new Error(`pandoc ${res.status}: ${await res.text()}`);
  return BINARY.has(params.to) ? Buffer.from(await res.arrayBuffer()) : res.text();
}

/** Export markdown to an office document, then read it back to markdown. */
async function roundTrip(markdown, ext) {
  const document = await pandoc({ text: markdown, from: 'gfm', to: ext, standalone: true });
  return pandoc({
    text: document.toString('base64'),
    from: ext,
    to: MARKDOWN_FORMAT,
    standalone: false,
    wrap: 'none',
  });
}

const sources = readdirSync(FIXTURES).filter((f) => f.endsWith('.md') && !f.includes('.expected.'));
for (const source of sources) {
  const name = source.replace(/\.md$/, '');
  const markdown = readFileSync(join(FIXTURES, source), 'utf8');
  for (const ext of ['docx', 'odt']) {
    writeFileSync(join(FIXTURES, `${name}.${ext}.expected.md`), await roundTrip(markdown, ext));
    console.log(`wrote ${name}.${ext}.expected.md`);
  }
}