// SKATEMAKER PRO — kit thumbnails. Each GLB renders to a 128x96 sprite ONCE, is
// POSTed to serve.py, saved under assets/kit_thumbs/ and committed — so every
// machine gets instant thumbs and the offscreen renderer only ever runs for
// props that don't have one yet (new kit drops).
import * as THREE from 'three';
import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';
import { KIT_BASE } from './parkbuild.js';

const W = 128, H = 96;
let ctx = null;                          // lazy shared renderer

function getCtx() {
  if (ctx) return ctx;
  const renderer = new THREE.WebGLRenderer({ antialias: true, alpha: true,
    preserveDrawingBuffer: true });
  renderer.setSize(W, H);
  const scene = new THREE.Scene();
  scene.add(new THREE.HemisphereLight(0xffffff, 0x445544, 1.2));
  const sun = new THREE.DirectionalLight(0xfff3d9, 1.6);
  sun.position.set(3, 6, 4); scene.add(sun);
  const cam = new THREE.PerspectiveCamera(38, W / H, 0.05, 100);
  ctx = { renderer, scene, cam, loader: new GLTFLoader() };
  return ctx;
}

async function renderOne(def) {
  const { renderer, scene, cam, loader } = getCtx();
  const glb = await new Promise((res, rej) =>
    loader.load(KIT_BASE + 'props/' + def.id + '.glb', res, undefined, rej));
  const obj = glb.scene;
  scene.add(obj);
  const box = new THREE.Box3().setFromObject(obj);
  const c = box.getCenter(new THREE.Vector3()), s = box.getSize(new THREE.Vector3());
  const rad = Math.max(s.x, s.y, s.z) * 0.62 / Math.tan(cam.fov * Math.PI / 360);
  cam.position.set(c.x + rad * 0.72, c.y + rad * 0.5, c.z + rad * 0.72);
  cam.lookAt(c);
  renderer.render(scene, cam);
  scene.remove(obj);
  const blob = await new Promise(res => renderer.domElement.toBlob(res, 'image/png'));
  await fetch('/api/kit-thumb?name=' + def.id + '.png', { method: 'POST', body: blob });
  return true;
}

// ensure every kit prop has a thumb; returns ids rendered this pass
export async function ensureKitThumbs(kitList, onProgress) {
  const missing = [];
  await Promise.all(kitList.map(async d => {
    const r = await fetch('assets/kit_thumbs/' + d.id + '.png', { method: 'HEAD' });
    if (!r.ok) missing.push(d);
  }));
  const done = [];
  for (const def of missing) {
    try { await renderOne(def); done.push(def.id); onProgress?.(done.length, missing.length); }
    catch (e) { console.warn('thumb failed', def.id, e); }
  }
  if (ctx && done.length) { ctx.renderer.dispose(); ctx = null; }
  return done;
}