// Page geometry shared by the PDF header (render-sdlc.mjs) and the Word header
// band (render-ci-band.mjs), so both draw the same letterhead for a page.
//
// Portrait is the audited reference layout. Landscape pages are 87mm wider: the
// grey ribbon stretches and the blue banner keeps its distance from the right
// edge, while the logo and company block stay where they are.
export const PAGE_MM = { portrait: 210, landscape: 297 };
const EXTRA_MM = PAGE_MM.landscape - PAGE_MM.portrait;

export function headerValues(title, landscape) {
  const extra = landscape ? EXTRA_MM : 0;
  return {
    documentTitle: title,
    // The banner holds about 22 characters at 13.5pt; longer titles shrink to fit.
    titleSize: `${Math.min(13.5, (13.5 * 22) / title.length).toFixed(1)}pt`,
    pageWidth: `${landscape ? PAGE_MM.landscape : PAGE_MM.portrait}mm`,
    ribbonWidth: `${64.7 + extra}mm`,
    bannerLeft: `${127.2 + extra}mm`
  };
}

/** Orientation of a rendered PDF, read from its first /MediaBox. */
export function isLandscapePdf(bytes) {
  const box = bytes.toString('latin1').match(/\/MediaBox\s*\[\s*([\d.]+)\s+([\d.]+)\s+([\d.]+)\s+([\d.]+)\s*\]/);
  if (!box) throw new Error('PDF has no /MediaBox');
  const [x0, y0, x1, y1] = box.slice(1).map(Number);
  return x1 - x0 > y1 - y0;
}