/* =====================================================================
 *  loader.js — 无界笺的加载动画外壳。
 *
 *  绘画引擎与 12 幅画作来自 Painting Loaders
 *  (https://painterly.design-tools.workers.dev，作者 Sasha / x.com/aleksksaa)，
 *  engine.js 与 style-*.js 原样保留。这里只负责：随机挑一幅（不与上次重复），
 *  把画布铺满本页，并通知父页面已经开始作画。
 *
 *  本页通过 iframe 嵌入，p5 的全局模式不会污染主应用。
 * ===================================================================== */

const PAINTINGS = [
  { key: 'garden', style: 'impressionismGarden', name: '花园', label: 'Garden' },
  { key: 'dawn', style: 'impressionismDawn', name: '晨曦', label: 'Dawn' },
  { key: 'willow', style: 'impressionismWillow', name: '垂柳', label: 'Willow' },
  { key: 'wisteria', style: 'impressionismWisteria', name: '紫藤', label: 'Wisteria' },
  { key: 'orchard', style: 'impressionismOrchard', name: '果园', label: 'Orchard' },
  { key: 'irises', style: 'impressionismIrises', name: '鸢尾', label: 'Irises' },
  { key: 'poppies', style: 'impressionismPoppies', name: '虞美人', label: 'Poppies' },
  { key: 'koi', style: 'impressionismKoi', name: '锦鲤', label: 'Koi' },
  { key: 'roses', style: 'impressionismRoses', name: '玫瑰', label: 'Roses' },
  { key: 'oranges', style: 'impressionismOranges', name: '橘子', label: 'Oranges' },
  { key: 'sail', style: 'impressionismSail', name: '远帆', label: 'Sail' },
  { key: 'dusk', style: 'abstractionDusk', name: '黄昏', label: 'Dusk' },
];

const LAST_KEY = 'boundless-last-painting';

function choosePainting() {
  const wanted = new URLSearchParams(location.search).get('p');
  const exact = PAINTINGS.find((item) => item.key === wanted);
  if (exact) return exact;

  let last = null;
  try { last = localStorage.getItem(LAST_KEY); } catch (e) { /* 隐私模式 */ }
  const pool = PAINTINGS.filter((item) => item.key !== last);
  const picked = pool[Math.floor(Math.random() * pool.length)] || PAINTINGS[0];
  try { localStorage.setItem(LAST_KEY, picked.key); } catch (e) { /* 隐私模式 */ }
  return picked;
}

const painting = choosePainting();
const config = window.STYLES[painting.style];
document.documentElement.style.background = config.palette.ground;

function notifyParent(type) {
  if (window.parent === window) return;
  window.parent.postMessage(
    { source: 'boundless-painterly', type, key: painting.key, name: painting.name, label: painting.label, ground: config.palette.ground },
    location.origin,
  );
}

notifyParent('chosen');

let engine = null;
const reduceMotion = window.matchMedia('(prefers-reduced-motion: reduce)').matches;

// p5 全局模式：页面加载后若 window 上有 setup / draw 就会自动开始。
// 系统要求减少动态效果时不作画，只留下画纸底色。
if (!reduceMotion) {
  window.setup = function () {
    // 画布内部固定 600×600，再由 CSS 缩放；不跟随设备像素比可以省下不少显存
    pixelDensity(1);
    engine = createEngine(config, { mount: document.body });
    engine.setup();
    notifyParent('start');
  };
  window.draw = function () {
    if (engine) engine.draw();
  };
}