#!/usr/bin/env node
// Assemble rendered slide PNGs into a 16:9 PPTX: one full-bleed image per slide,
// native speaker notes, document metadata.
//
// Usage:
//   node build.mjs <pngdir> <out.pptx> [--notes notes.json] [--title T] [--author A] [--subject S]
import { createRequire } from 'node:module';
import { execSync } from 'node:child_process';
import { readdirSync, readFileSync, existsSync } from 'node:fs';
import path from 'node:path';

const require = createRequire(import.meta.url);
function req(name) {
  try { return require(name); } catch {}
  const g = execSync('npm root -g').toString().trim();
  return require(path.join(g, name));
}

const args = process.argv.slice(2);
const dir = path.resolve(args[0]);
const out = path.resolve(args[1]);
if (!args[0] || !args[1]) {
  console.error('usage: node build.mjs <pngdir> <out.pptx> [--notes notes.json] [--title T] [--author A] [--subject S]');
  process.exit(1);
}
const opt = (f, d) => { const i = args.indexOf(f); return i >= 0 ? args[i + 1] : d; };

const pptxgen = req('pptxgenjs');
const P = new pptxgen();
P.layout = 'LAYOUT_WIDE'; // 13.333 x 7.5 in
P.title = opt('--title', path.basename(out, '.pptx'));
P.author = opt('--author', 'ThothII');
P.subject = opt('--subject', '');

const notesPath = opt('--notes', path.join(dir, 'notes.json'));
const notes = existsSync(notesPath) ? JSON.parse(readFileSync(notesPath, 'utf8')) : {};

const pngs = readdirSync(dir).filter(f => /^\d+\.png$/.test(f)).sort();
if (!pngs.length) { console.error('no NN.png files in ' + dir); process.exit(1); }

for (const f of pngs) {
  const n = parseInt(f, 10);
  const s = P.addSlide();
  s.background = { color: 'FCFAFA' };
  s.addImage({ path: path.join(dir, f), x: 0, y: 0, w: 13.333, h: 7.5 });
  if (notes[n]) s.addNotes(notes[n]);
}
await P.writeFile({ fileName: out });
console.log('built', out, '-', pngs.length, 'slides');