// Combine the two vtracer runs for a pose into one shipping SVG.
// usage: yarn node - <traceDir> <outDir> < assemble-pose-svg.cjs
//
// companion.md: the character and the shadow are traced separately because vtracer blends a
// sentinel-coloured shadow with neighbouring ink and fringes it. This puts them back together
// in the shipped order — shadow first so the character paints over it — and re-tints the
// shadow with the authored opacity rather than whatever grey the trace produced.
const fs = require('node:fs');
const SRC = process.argv[2] + '/', OUT = process.argv[3] + '/';
const SHADOW_INK = '#113833', SHADOW_OPACITY = '0.194';   // matches the shipped twenty
fs.mkdirSync(OUT, { recursive: true });

const paths = (svg) => [...svg.matchAll(/<path[^>]*?\/>/gs)].map(m => m[0]);
const fillOf = (p) => (/fill="(#[0-9A-Fa-f]{6})"/).exec(p)?.[1];
const dOf = (p) => (/\bd="([^"]+)"/).exec(p)?.[1];

for (const f of fs.readdirSync(SRC).filter(f => f.endsWith('-char.svg')).sort()) {
  const name = f.replace('-char.svg', '');
  const charSvg = fs.readFileSync(SRC + f, 'utf8');
  // Sticker poses keep their own crop size rather than the 409x370 UI frame.
  const W = +/width="(\d+)"/.exec(charSvg)[1], H = +/height="(\d+)"/.exec(charSvg)[1];
  const charPaths = paths(charSvg);
  // The shadow run traces ink on white, so the white plate is dropped and only the ink kept.
  const shadowPaths = paths(fs.readFileSync(`${SRC}${name}-shadow.svg`, 'utf8'))
    .filter(p => fillOf(p) === SHADOW_INK);

  const out = [`<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 ${W} ${H}" width="${W}" height="${H}">`, ''];
  for (const p of shadowPaths) {
    out.push(`<path fill-opacity="${SHADOW_OPACITY}" d="${dOf(p)}" fill="${SHADOW_INK}"/>`);
  }
  out.push('');
  for (const p of charPaths) out.push(`<path d="${dOf(p)}" fill="${fillOf(p)}"/>`);
  out.push('</svg>', '');
  fs.writeFileSync(OUT + name + '.svg', out.join('\n'));
  console.log(`  ${name.padEnd(14)} ${shadowPaths.length} shadow + ${charPaths.length} char paths`);
}