// SKATEMAKER PRO — exports. A park leaves here two ways:
//   1. park.json           — the native data format
//   2. level.<name>.js     — a drop-in for BOOKQUOY: exports the exact interface
//                            bookquoy's js/level.js has (heightAt, normalAt, BOUNDS,
//                            RAILS, GAPS, LETTERS, SPAWN, buildLevel). Ship it with
//                            parkmath.js + parkbuild.js + assets/uploads/.

function download(name, text, type = 'application/octet-stream') {
  const a = document.createElement('a');
  a.href = URL.createObjectURL(new Blob([text], { type }));
  a.download = name;
  a.click();
  setTimeout(() => URL.revokeObjectURL(a.href), 5000);
}

const slug = park => (park.name || 'park').toLowerCase().replace(/[^\w]+/g, '_');

export function downloadParkJSON(park) {
  download(slug(park) + '.json', JSON.stringify(park, null, 1), 'application/json');
}

export function generateLevelJS(park) {
  return `// ${park.name} — generated by SKATEMAKER PRO ${new Date().toISOString().slice(0, 10)}
// Drop-in for BOOKQUOY: copy this file + parkmath.js + parkbuild.js (+ assets/uploads/)
// into bookquoy/js/ and point main.js/player.js imports at it. Same contract as level.js:
// heightAt(x,z) is the single source of truth for visuals AND collision.
import { makeHeightAt, makeNormalAt, flattenRails } from './parkmath.js';
import { buildParkScene } from './parkbuild.js';

export const PARK = ${JSON.stringify(park, null, 1)};

export const BOUNDS = PARK.bounds;
export const RAILS = flattenRails(PARK);
export const GAPS = PARK.gaps;
export const LETTERS = PARK.letters;
export const SPAWN = PARK.spawn;
export const heightAt = makeHeightAt(PARK);
export const normalAt = makeNormalAt(heightAt);

export function buildLevel(scene) {
  const { ground, letterMeshes } = buildParkScene(scene, PARK);
  return { ground, letterMeshes };
}
`;
}

export function downloadLevelJS(park) {
  download('level.' + slug(park) + '.js', generateLevelJS(park), 'text/javascript');
}