src/ui/GameUI.js

/**
 * GameUI — DOM bindings for the game card, grade track, sidebar, settings.
 * Wires GSAP, confetti, cheers, TTS, translator.
 */

import gsap from 'gsap';
import confetti from 'canvas-confetti';

import { gradeFor, gradeDesc, starsForWord, starsStr } from '../game/Grades.js';
import { getMeaning } from '../game/Translator.js';
import * as Store from '../game/Store.js';
import { Cheer } from '../audio/Cheer.js';
import { STAGES, stageForLen } from '../game/Stages.js';

const disp = (w) => (w === 'i' ? 'I' : w);

export class GameUI {
  constructor({ game, tts, scene3d, leaderboardUI }) {
    this.game = game;
    this.tts = tts;
    this.scene3d = scene3d;
    this.lbUI = leaderboardUI;

    this.tilesEl = this.$('tiles');
    this.typedEl = this.$('typed');
    this.fb = this.$('feedback');
    this.speakerEl = this.$('speaker');

    this._bindGame();
    this._bindUI();
    this._buildWeatherDebug();
    this._buildSaveIndicator();
    this._buildReportButton();
  }

  /** Bottom-right pill that flashes "💾 Saved" each time Store persists a word. */
  _buildSaveIndicator() {
    const el = document.createElement('div');
    el.id = 'saveIndicator';
    el.style.cssText = `
      position:fixed;right:18px;bottom:18px;z-index:9998;
      background:rgba(26,32,46,.92);color:#fff;
      padding:8px 14px;border-radius:999px;
      font:600 13px/1 system-ui,sans-serif;
      box-shadow:0 4px 12px rgba(0,0,0,.4);
      opacity:0;transform:translateY(8px);
      transition:opacity .25s ease, transform .25s ease;
      pointer-events:none;
    `;
    document.body.appendChild(el);
    this._saveIndicatorEl = el;

    Store.onSave((info) => {
      let label, color;
      if (info.idb)       { label = '💾 Saved'; color = '#46D39A'; }
      else if (info.ls)   { label = '💾 Saved (local)'; color = '#F0A830'; }
      else if (info.mem)  { label = '⚠ In memory only'; color = '#FF6B6B'; }
      else                { label = '⚠ Save failed'; color = '#FF6B6B'; }
      el.textContent = `${label} · ${info.word}`;
      el.style.borderLeft = `4px solid ${color}`;
      el.style.opacity = '1';
      el.style.transform = 'translateY(0)';
      clearTimeout(this._saveTimer);
      this._saveTimer = setTimeout(() => {
        el.style.opacity = '0';
        el.style.transform = 'translateY(8px)';
      }, 1400);
    });
  }

  /** Top-right "🆘 Report Problem" button with diagnostics + WhatsApp link. */
  _buildReportButton() {
    // Container so the button + "recent fixes" card stay aligned to the same
    // right edge regardless of width.
    const col = document.createElement('div');
    col.id = 'reportColumn';
    col.style.cssText = `
      position:fixed;right:18px;top:18px;z-index:9999;
      display:flex;flex-direction:column;align-items:flex-end;gap:10px;
      max-width:300px;
    `;

    const btn = document.createElement('button');
    btn.type = 'button';
    btn.id = 'reportBtn';
    btn.textContent = '🆘 Report Problem';
    btn.style.cssText = `
      background:#FF6B6B;color:#fff;border:none;
      padding:8px 14px;border-radius:8px;
      font:600 13px/1 system-ui,sans-serif;cursor:pointer;
      box-shadow:0 4px 10px rgba(0,0,0,.35);
      align-self:stretch;
    `;
    btn.addEventListener('click', () => this._openReportDialog());
    col.appendChild(btn);

    col.appendChild(this._buildRecentFixesCard());
    document.body.appendChild(col);
  }

  /** Small green card listing recently shipped fixes — visible reassurance
   *  that the developer is actively working on reported issues. Dismissable;
   *  the dismissal persists in localStorage so it doesn't nag returning users.
   *  Bump RECENT_FIXES_VERSION when adding new entries to re-show the card. */
  _buildRecentFixesCard() {
    const RECENT_FIXES_VERSION = 'v4-2026-06-13';
    const DISMISS_KEY = 'echo3d:fixesDismissedVersion';
    const card = document.createElement('div');
    card.id = 'recentFixes';

    let dismissed = false;
    try { dismissed = localStorage.getItem(DISMISS_KEY) === RECENT_FIXES_VERSION; } catch {}

    card.style.cssText = `
      background:rgba(20,28,40,.94);
      color:#e6f6ec;
      border:1px solid rgba(70,211,154,.55);
      border-left:4px solid #46D39A;
      border-radius:10px;
      padding:10px 12px 12px;
      font:13px/1.4 system-ui,sans-serif;
      box-shadow:0 6px 16px rgba(0,0,0,.4);
      width:100%;box-sizing:border-box;
      ${dismissed ? 'display:none;' : ''}
    `;
    card.innerHTML = `
      <div style="display:flex;justify-content:space-between;align-items:center;gap:8px;margin-bottom:6px">
        <strong style="color:#46D39A;font-size:13px">✅ Recently fixed</strong>
        <button id="fixesDismiss" title="Dismiss" style="
          background:transparent;color:#9aa6b2;border:none;
          font-size:18px;line-height:1;cursor:pointer;padding:0 4px;
        ">×</button>
      </div>
      <ul style="margin:0;padding-left:18px;font-size:12.5px;line-height:1.5">
        <li><b>Level/word progress saving fixed</b> — IndexedDB + localStorage + server sync</li>
        <li><b>Cross-device sync</b> — login on any browser (incl. incognito) and your progress follows you</li>
        <li><b>Sea waves redesigned</b> — irregular open-sea wavelets instead of straight ridges</li>
        <li><b>🆘 Report Problem</b> button — one tap to send diagnostics via WhatsApp</li>
      </ul>
      <div style="margin-top:8px;font-size:11.5px;opacity:.7">
        Updated ${new Date().toLocaleDateString()}
      </div>
    `;
    card.querySelector('#fixesDismiss').addEventListener('click', () => {
      card.style.display = 'none';
      try { localStorage.setItem(DISMISS_KEY, RECENT_FIXES_VERSION); } catch {}
    });
    return card;
  }

  _openReportDialog() {
    const diag = Store.diagnostics();
    const ua = navigator.userAgent;
    const summary = [
      `ECHO 3D problem report`,
      `When: ${new Date().toLocaleString()}`,
      `Storage: IDB=${diag.idbWorking ? 'ok' : 'NO'} LS=${diag.lsWorking ? 'ok' : 'NO'} mem-only=${diag.useMemory}`,
      `User namespace: ${diag.namespace}`,
      `Word records (localStorage): ${diag.wordCountLs}`,
      `Mastered (this session): ${this.game.totalMastered()}`,
      `Current level: ${this.game.len}-letter`,
      `Writes — IDB ok/err: ${diag.stats.idbWriteOk}/${diag.stats.idbWriteErr}, LS ok/err: ${diag.stats.lsWriteOk}/${diag.stats.lsWriteErr}`,
      `Last error: ${diag.stats.lastError || 'none'}`,
      `Browser: ${ua}`,
      ``,
      `Describe what went wrong:`,
      ``,
    ].join('\n');

    // Build modal
    const back = document.createElement('div');
    back.id = 'reportModal';
    back.style.cssText = `
      position:fixed;inset:0;z-index:100000;
      background:rgba(0,0,0,.72);
      display:grid;place-items:center;
      padding:20px;
    `;
    const card = document.createElement('div');
    card.style.cssText = `
      background:#1a202e;color:#fff;border-radius:14px;
      max-width:560px;width:100%;padding:22px 24px;
      font:14px/1.5 system-ui,sans-serif;
      box-shadow:0 20px 60px rgba(0,0,0,.5);
    `;
    card.innerHTML = `
      <h2 style="margin:0 0 6px;font-size:20px">🆘 Report a Problem</h2>
      <p style="margin:0 0 14px;opacity:.8;font-size:13px">
        We'll attach diagnostic info so the developer can fix it fast.
      </p>
      <textarea id="reportText" style="
        width:100%;height:200px;background:#0f1420;color:#fff;
        border:1px solid #2a3346;border-radius:8px;
        padding:10px;font:12px/1.5 ui-monospace,monospace;
        resize:vertical;box-sizing:border-box;
      "></textarea>
      <div style="margin-top:14px;display:flex;gap:10px;flex-wrap:wrap">
        <a id="reportSendWa" target="_blank" rel="noopener" style="
          flex:1;min-width:170px;text-align:center;
          background:#25D366;color:#fff;text-decoration:none;
          padding:11px 16px;border-radius:8px;font-weight:700;
        ">📱 Send via WhatsApp</a>
        <button id="reportCopy" style="
          flex:1;min-width:120px;background:#3a4458;color:#fff;
          border:none;padding:11px 16px;border-radius:8px;
          font-weight:700;cursor:pointer;
        ">📋 Copy</button>
        <button id="reportClose" style="
          background:transparent;color:#fff;border:1px solid #3a4458;
          padding:11px 16px;border-radius:8px;font-weight:700;cursor:pointer;
        ">Close</button>
      </div>
      <p style="margin:14px 0 0;opacity:.7;font-size:12px;text-align:center">
        Or message <a href="https://wa.me/94777869736" target="_blank" rel="noopener"
        style="color:#46D39A;font-weight:700">+94 77 786 9736</a> on WhatsApp.
      </p>
    `;
    back.appendChild(card);
    document.body.appendChild(back);

    const ta = card.querySelector('#reportText');
    ta.value = summary;
    ta.focus();

    const updateWa = () => {
      const txt = ta.value;
      const url = `https://wa.me/94777869736?text=${encodeURIComponent(txt)}`;
      card.querySelector('#reportSendWa').href = url;
    };
    updateWa();
    ta.addEventListener('input', updateWa);

    card.querySelector('#reportCopy').addEventListener('click', async () => {
      try {
        await navigator.clipboard.writeText(ta.value);
        const b = card.querySelector('#reportCopy');
        const old = b.textContent; b.textContent = '✓ Copied';
        setTimeout(() => { b.textContent = old; }, 1200);
      } catch {
        ta.select();
      }
    });
    card.querySelector('#reportClose').addEventListener('click', () => back.remove());
    back.addEventListener('click', (e) => { if (e.target === back) back.remove(); });
  }

  /** TEMPORARY: compact icon-only climate switcher. Bottom-left, out of the way. */
  _buildWeatherDebug() {
    const bar = document.createElement('div');
    bar.id = 'weatherDebug';
    // Pin to the ECHO logo's left edge. .wrap is max-width:1180px centered
    // with 18px padding, so on wider viewports the logo isn't at x=0.
    bar.style.cssText = `
      position:fixed;
      left:max(18px, calc((100vw - 1180px) / 2 + 18px));
      top:74px;z-index:9999;
      display:flex;gap:8px;background:transparent;border:none;
      padding:0;box-shadow:none;
    `;
    STAGES.forEach((s, i) => {
      const b = document.createElement('button');
      b.type = 'button';
      b.dataset.stage = i;
      b.title = s.name;
      b.style.cssText = `
        width:30px;height:30px;display:grid;place-items:center;
        background:transparent;border:none;border-radius:8px;
        font-size:22px;line-height:1;padding:0;cursor:pointer;
        filter:drop-shadow(0 1px 2px rgba(0,0,0,.6));
        opacity:.55;transition:opacity .15s ease,transform .15s ease,filter .15s ease;
      `;
      b.textContent = s.emoji;
      b.addEventListener('click', () => this._forceStage(i, bar));
      b.addEventListener('mouseenter', () => { if (Number(b.dataset.stage) !== this._activeDebugStage) { b.style.opacity = '0.95'; b.style.transform = 'scale(1.1)'; } });
      b.addEventListener('mouseleave', () => { if (Number(b.dataset.stage) !== this._activeDebugStage) { b.style.opacity = '0.55'; b.style.transform = 'scale(1)'; } });
      bar.appendChild(b);
    });
    document.body.appendChild(bar);
    this._weatherDebugBar = bar;
    this._activeDebugStage = 0;
    this._highlightDebugStage(0);
  }

  _highlightDebugStage(idx) {
    if (!this._weatherDebugBar) return;
    this._activeDebugStage = idx;
    [...this._weatherDebugBar.querySelectorAll('button')].forEach((b, i) => {
      const on = i === idx;
      b.style.opacity   = on ? '1' : '0.55';
      b.style.transform = on ? 'scale(1.18)' : 'scale(1)';
      b.style.filter    = on
        ? 'drop-shadow(0 0 6px rgba(255,224,138,.85)) drop-shadow(0 1px 2px rgba(0,0,0,.6))'
        : 'drop-shadow(0 1px 2px rgba(0,0,0,.6))';
    });
  }

  _forceStage(idx) {
    if (this.scene3d.setWeatherStage) this.scene3d.setWeatherStage(idx);
    if (window.__sounds) window.__sounds.setWeatherStage(idx);
    this._highestStage = Math.max(this._highestStage ?? 0, idx);
    this._renderMedals();
    this._highlightDebugStage(idx);
  }

  $(id) { return document.getElementById(id); }

  _bindGame() {
    this.game.on('word', () => this._onWordLoaded());
    this.game.on('levelup', (n) => this._onLevelUp(n));
    this.game.on('finish', () => this._onFinish());
  }

  _bindUI() {
    this.typedEl.addEventListener('input', () => { this.game.revealed = false; this._renderTiles(); });
    this.typedEl.addEventListener('keydown', (e) => {
      if (e.key === 'Enter') { e.preventDefault(); this._submit(); }
      if (e.key === 'Tab')   { e.preventDefault(); if (this.game.current) this.tts.speak(this.game.current.w); }
    });
    this.speakerEl.addEventListener('click', () => { Cheer.prime(); if (this.game.current) this.tts.speak(this.game.current.w); });
    this.speakerEl.addEventListener('keydown', (e) => {
      if (e.key === 'Enter' || e.key === ' ') { e.preventDefault(); if (this.game.current) this.tts.speak(this.game.current.w); }
    });

    this.$('revealBtn').addEventListener('click', () => {
      if (!this.game.current) return;
      this.game.revealed = true;
      this.typedEl.value = '';
      this._renderTiles();
      this.fb.className = 'feedback';
      this.fb.innerHTML = `It's <span class="ans">${disp(this.game.current.w)}</span>.`;
      this.typedEl.focus();
    });
    this.$('skipBtn').addEventListener('click', () => { if (this.game.current) this.game.advance(); });
    this.$('hearAgainBtn').addEventListener('click', () => {
      if (!this.game.current) return;
      const w = this.game.current.w;
      this.tts.speak(`${w}. ${w.split('').join(', ')}.`);
    });

    this.$('rate').addEventListener('input', (e) => {
      const r = parseFloat(e.target.value);
      this.tts.setRate(r);
      this.$('rateVal').textContent = r.toFixed(2) + '×';
      Store.setMeta('rate', r);
    });
    this.$('thr').addEventListener('input', (e) => {
      const t = parseInt(e.target.value);
      this.game.threshold = t;
      this.$('thrVal').textContent = t;
      Store.setMeta('threshold', t);
      this.renderAll();
    });
    this.$('engineSel').addEventListener('change', (e) => {
      this.tts.setEngine(e.target.value);
      Store.setMeta('engine', e.target.value);
      if (this.game.current) this.tts.speak(this.game.current.w);
    });

    this.$('showMeaning').addEventListener('change', (e) => {
      this.showMeaning = e.target.checked;
      Store.setMeta('showMeaning', e.target.checked);
      this.$('meaning').style.display = e.target.checked ? 'grid' : 'none';
      if (this.game.current && e.target.checked) this._showMeaningFor(this.game.current.w);
    });
    this.$('cheerSound').addEventListener('change', (e) => {
      Cheer.enabled = e.target.checked;
      Store.setMeta('cheerSound', e.target.checked);
    });
    this.$('ambient3D').addEventListener('change', (e) => {
      this.scene3d.setAmbient(e.target.checked);
      Store.setMeta('ambient3D', e.target.checked);
    });
    this.$('ambientAudio').addEventListener('change', (e) => {
      if (window.__ambient) window.__ambient.setEnabled(e.target.checked);
      if (window.__sounds)  window.__sounds.setEnabled(e.target.checked);
      Store.setMeta('ambientAudio', e.target.checked);
    });

    this.$('resetBtn').addEventListener('click', async () => {
      if (!confirm('Erase all progress?')) return;
      this.game.reset();
      this.tilesEl.innerHTML = '';
      this.typedEl.value = '';
      this.typedEl.disabled = true;
      this.fb.textContent = '';
      this.$('overlay').classList.remove('hidden');
      this.renderAll();
    });

    this.$('startBtn').addEventListener('click', () => {
      Cheer.prime();
      this.$('overlay').classList.add('hidden');
      this.game.advance();
    });
  }

  async applySettings() {
    this.$('thr').value = this.game.threshold;
    this.$('thrVal').textContent = this.game.threshold;
    const rate = parseFloat(await Store.getMeta('rate', 0.95));
    this.tts.setRate(rate);
    this.$('rate').value = rate;
    this.$('rateVal').textContent = rate.toFixed(2) + '×';
    const engine = await Store.getMeta('engine', 'stream:Brian');
    this.tts.setEngine(engine);
    this.$('engineSel').value = engine;
    this.showMeaning = (await Store.getMeta('showMeaning', true)) !== false;
    this.$('showMeaning').checked = this.showMeaning;
    if (!this.showMeaning) this.$('meaning').style.display = 'none';
    Cheer.enabled = (await Store.getMeta('cheerSound', true)) !== false;
    this.$('cheerSound').checked = Cheer.enabled;
    const ambient = (await Store.getMeta('ambient3D', true)) !== false;
    this.$('ambient3D').checked = ambient;
    this.scene3d.setAmbient(ambient);
    const ambAudio = (await Store.getMeta('ambientAudio', true)) !== false;
    this.$('ambientAudio').checked = ambAudio;
    if (window.__ambient) window.__ambient.setEnabled(ambAudio);
    if (window.__sounds)  window.__sounds.setEnabled(ambAudio);
  }

  // ----- game callbacks -----

  _onWordLoaded() {
    const r = this.game.current;
    this.typedEl.value = '';
    this.typedEl.disabled = false;
    this.fb.textContent = '';
    this.fb.className = 'feedback';
    this._renderTiles();
    this.typedEl.focus();
    this.tts.speak(r.w);
    if (this.showMeaning) this._showMeaningFor(r.w);
    this.renderAll();
  }

  _onLevelUp(n) {
    const g = gradeFor(n);
    const lengths = this.game.dict.lengths();
    const prevStage = this._highestStage ?? 0;
    const newStage  = stageForLen(n, lengths);
    if (newStage.idx > prevStage) {
      // Player just crossed into a new weather stage — celebrate.
      this._showBanner(`${newStage.emoji} ${newStage.name.toUpperCase()}\nstage cleared · ${this._medalLabel(newStage.medal)}`);
      if (window.__sounds) {
        window.__sounds.fire('winner');
        setTimeout(() => window.__sounds.fire('award'), 400);
      }
    } else {
      this._showBanner(`🎉 ${g.emoji} ${g.name.toUpperCase()}\n${n}-letter words`);
    }
    this._fireConfetti('big');
    Cheer.levelUp();
    this.scene3d.celebrate?.();
    this.renderAll();
  }

  _medalLabel(tier) {
    return ({ bronze: '🥉 bronze medal', silver: '🥈 silver medal', gold: '🥇 gold medal', trophy: '🏆 TROPHY' })[tier] || '';
  }

  _onFinish() {
    this.game.current = null;
    this.typedEl.disabled = true;
    this.tilesEl.innerHTML = '';
    this.fb.className = 'feedback good';
    this.fb.innerHTML = '🏆 ICE AGE CONQUERED · Every grade cleared!';
    this._highestStage = STAGES.length - 1;
    if (this.scene3d.setWeatherStage) this.scene3d.setWeatherStage(STAGES.length - 1);
    if (window.__sounds) window.__sounds.setWeatherStage(STAGES.length - 1);
    this._renderMedals();
    this._showBanner(`🏆 TROPHY UNLOCKED\nIce Age conquered`);
    if (window.__sounds) {
      window.__sounds.fire('winner');
      setTimeout(() => window.__sounds.fire('award'), 500);
    }
    this._fireConfetti('big');
    Cheer.levelUp();
    // Trophy — fire the celebration three times for a bigger finale.
    this.scene3d.celebrate?.();
    setTimeout(() => this.scene3d.celebrate?.(),  600);
    setTimeout(() => this.scene3d.celebrate?.(), 1200);
    this.renderAll();
  }

  _submit() {
    const res = this.game.submit(this.typedEl.value);
    if (res.kind === 'replay') { this.tts.speak(this.game.current.w); return; }
    if (res.kind === 'correct') {
      this._renderTiles(true);
      this.fb.className = 'feedback good';
      this.fb.innerHTML = `✔ Correct &nbsp;(${res.streak}/${res.threshold})`;
      this._fireConfetti('small');
      Cheer.small();
      this._floatPlus('+1', '#46D39A');
      this.typedEl.disabled = true;
      setTimeout(() => this.game.advance(), 900);
      this.renderAll();
      return;
    }
    if (res.kind === 'master') {
      this._renderTiles(true);
      this.fb.className = 'feedback good';
      this.fb.innerHTML = `✨ Mastered <span class="ans">${disp(res.word)}</span> · ${starsStr(res.stars)}`;
      this._fireConfetti('big');
      Cheer.master();
      this._floatPlus('✨ ' + starsStr(res.stars), '#F0A830');
      this._starBurst();
      // Pond greeting — cascade jump from every fish + rainbow burst.
      this.scene3d.celebrate?.();
      this.lbUI.bumpUserStats(res.stars, 1, this.game.len);
      this.typedEl.disabled = true;
      setTimeout(() => this.game.advance(), 950);
      this.renderAll();
      return;
    }
    if (res.kind === 'wrong') {
      this.tilesEl.classList.remove('shake'); void this.tilesEl.offsetWidth; this.tilesEl.classList.add('shake');
      this._renderTiles();
      this.fb.className = 'feedback fail';
      if (res.reveal) this.fb.innerHTML = `Not quite — it's <span class="ans">${disp(res.word)}</span>. Listen again.`;
      else this.fb.textContent = 'Not quite — listen again and retype it.';
      this.typedEl.value = '';
      this.typedEl.focus();
      setTimeout(() => this.tts.speak(this.game.current.w), 250);
      this.renderAll();
    }
  }

  // ----- rendering -----

  _renderTiles(allOk) {
    const r = this.game.current;
    this.tilesEl.innerHTML = '';
    if (!r) return;
    const target = r.w;
    const typed = this.typedEl.value.toLowerCase();
    for (let i = 0; i < target.length; i++) {
      const t = document.createElement('div'); t.className = 'tile';
      if (this.game.revealed && !typed) { t.textContent = disp(target)[i] || target[i]; t.classList.add('reveal'); }
      else if (i < typed.length) {
        t.textContent = typed[i];
        t.classList.add(typed[i] === target[i] ? 'ok' : 'bad');
        if (allOk) { t.className = 'tile ok'; t.textContent = target[i]; }
      } else { t.classList.add('ghost'); t.textContent = '·'; }
      this.tilesEl.appendChild(t);
      // GSAP entry animation
      gsap.fromTo(t, { scale: 0.7, opacity: 0 }, { scale: 1, opacity: 1, duration: 0.22, ease: 'back.out(2)', delay: i * 0.02 });
    }
    if (typed.length > target.length && !allOk) {
      for (let i = target.length; i < typed.length; i++) {
        const t = document.createElement('div'); t.className = 'tile bad'; t.textContent = typed[i];
        this.tilesEl.appendChild(t);
      }
    }
  }

  async _showMeaningFor(w) {
    const m = this.$('meaning');
    if (!this.showMeaning) { m.style.display = 'none'; return; }
    m.style.display = 'grid';
    this.$('m-si').textContent = '…'; this.$('m-si').classList.add('loading');
    this.$('m-ta').textContent = '…'; this.$('m-ta').classList.add('loading');
    m.classList.remove('empty');
    const obj = await getMeaning(w);
    if (this.game.current && this.game.current.w === w) {
      this.$('m-si').textContent = obj.si; this.$('m-si').classList.remove('loading');
      this.$('m-ta').textContent = obj.ta; this.$('m-ta').classList.remove('loading');
    }
  }

  renderAll() {
    this._renderTrack();
    this._renderSidebar();
    this._updateDifficulty();
    this.lbUI.render();
  }

  _renderTrack() {
    const track = this.$('track');
    track.innerHTML = '';
    let currentEl = null;
    this.game.dict.lengths().forEach((len, i) => {
      const g = gradeFor(len);
      const pool = this.game.levelPool(len);
      const done = pool.filter(w => this.game.isMastered(w)).length;
      const total = pool.length;
      const pct = total ? Math.round(done / total * 100) : 0;
      const d = document.createElement('div'); d.className = 'lvl';
      if (len === this.game.len) { d.classList.add('current'); currentEl = d; }
      else if (total > 0 && done === total) d.classList.add('done');
      // 3D-extruded grade number replaces the unicode emoji icon.
      d.innerHTML = `
        <div class="g-num">${i + 1}</div>
        <div class="g-name">${g.name}</div>
        <div class="g-sub">${len} letters · ${total.toLocaleString()} words</div>
        <div class="g-pct">${pct}%</div>
        <div class="g-bar"><i style="width:${pct}%"></i></div>`;
      d.title = `${g.name} (${g.sub}) · ${len}-letter words · ${done}/${total} mastered`;
      d.addEventListener('click', () => { this.game.jumpTo(len); this.renderAll(); });
      track.appendChild(d);
    });
    if (currentEl) setTimeout(() => currentEl.scrollIntoView({ behavior: 'smooth', inline: 'center', block: 'nearest' }), 50);
  }

  _setCounter(id, value) {
    const el = this.$(id);
    if (!el) return;
    const next = String(value);
    if (el.textContent !== next) {
      el.textContent = next;
      el.classList.remove('bump');
      void el.offsetWidth;        // restart animation
      el.classList.add('bump');
    }
  }

  _renderSidebar() {
    const pool = this.game.levelPool(this.game.len);
    const done = pool.filter(w => this.game.isMastered(w)).length;
    const total = pool.length;
    const pct = total ? Math.round(done / total * 100) : 0;
    const g = gradeFor(this.game.len);
    this.$('p-lvlnum').textContent = `${g.emoji} ${g.name}`;
    this.$('p-lvldesc').textContent = `${this.game.len}-letter words · ${g.sub}`;
    this.$('p-done').textContent = done;
    this.$('p-total').textContent = total;
    this.$('p-pct').textContent = pct + '%';
    this.$('p-bar').style.width = pct + '%';
    this.$('p-remaining').textContent = Math.max(0, total - done);
    this.$('p-streak').textContent = this.game.current ? this.game.current.streak : 0;
    // Real-time counters (pulse on increment)
    this._setCounter('t-mastered', this.game.totalMastered().toLocaleString());
    const fam = this.game.familiarised();
    this.$('fam-count').textContent = fam.length;
    const list = this.$('famlist');
    if (!fam.length) { list.innerHTML = '<div class="famempty">Mastered words collect here.</div>'; }
    else {
      list.innerHTML = '';
      for (const r of fam) {
        const s = document.createElement('span'); s.className = 'fw';
        const n = r.stars || starsForWord(r);
        s.innerHTML = `${disp(r.w)} <span class="s">${'★'.repeat(n)}</span>`;
        s.title = `Click to hear · ${n}/3 stars`;
        s.addEventListener('click', () => this.tts.speak(r.w));
        list.appendChild(s);
      }
    }
  }

  _updateDifficulty() {
    const lengths = this.game.dict.lengths();
    const idx = Math.max(0, lengths.indexOf(this.game.len));
    const total = Math.max(1, lengths.length - 1);
    this.scene3d.setIntensity(idx / total);
    // Push the weather stage to both the 3D scene and the sound library.
    const stage = stageForLen(this.game.len, lengths);
    if (this.scene3d.setWeatherStage) this.scene3d.setWeatherStage(stage.idx);
    if (window.__sounds) window.__sounds.setWeatherStage(stage.idx);
    this._highestStage = Math.max(this._highestStage ?? 0, stage.idx);
    this._renderMedals();
    this._highlightDebugStage?.(stage.idx);
  }

  _renderMedals() {
    const row = this.$('medalRow');
    if (!row) return;
    if (row.children.length !== STAGES.length) {
      row.innerHTML = '';
      for (const s of STAGES) {
        const m = document.createElement('div');
        m.className = `medal medal-${s.medal}`;
        m.title = s.name;
        m.innerHTML = `<div class="m-emoji">${s.emoji}</div><div class="m-name">${s.short}</div>`;
        row.appendChild(m);
      }
    }
    const reached = this._highestStage ?? stageForLen(this.game.len, this.game.dict.lengths()).idx;
    [...row.children].forEach((el, i) => {
      el.classList.toggle('earned',  i <= reached);
      el.classList.toggle('current', i === reached);
    });
    const count = this.$('medals-count');
    if (count) count.textContent = `${Math.min(reached + 1, STAGES.length)}/${STAGES.length}`;
  }

  _showBanner(text) {
    const lu = this.$('levelup'); lu.style.display = 'grid';
    const sp = lu.querySelector('span'); sp.textContent = text;
    gsap.fromTo(sp, { scale: 0.4, rotate: -8, opacity: 0 }, { scale: 1.05, rotate: 0, opacity: 1, duration: 0.6, ease: 'back.out(2)' });
    gsap.to(sp, { opacity: 0, scale: 1.15, duration: 0.4, delay: 1.4 });
    setTimeout(() => lu.style.display = 'none', 1900);
  }

  _fireConfetti(intensity) {
    const count = intensity === 'big' ? 180 : 60;
    confetti({ particleCount: count, spread: 80, origin: { y: 0.7 }, colors: ['#F0A830', '#46D39A', '#8B7BFF', '#FF6B6B', '#ffd166'] });
    if (intensity === 'big') {
      setTimeout(() => confetti({ particleCount: 120, angle: 60, spread: 55, origin: { x: 0, y: 0.7 } }), 200);
      setTimeout(() => confetti({ particleCount: 120, angle: 120, spread: 55, origin: { x: 1, y: 0.7 } }), 400);
    }
  }

  _floatPlus(text, color) {
    const card = this.$('gameCard');
    const f = document.createElement('div');
    f.style.cssText = `position:absolute;font-family:var(--mono);font-weight:700;font-size:22px;color:${color || '#46D39A'};pointer-events:none;z-index:7;left:${30 + Math.random() * 40}%;top:55%`;
    f.textContent = text;
    card.appendChild(f);
    gsap.fromTo(f, { y: 0, opacity: 0, scale: 0.6 }, { y: -60, opacity: 1, scale: 1.1, duration: 0.4, ease: 'back.out(2)' });
    gsap.to(f, { opacity: 0, duration: 0.5, delay: 0.6, onComplete: () => f.remove() });
  }

  _starBurst() {
    const container = this.$('burst');
    if (!container) return;
    container.innerHTML = '';
    const N = 14;
    for (let i = 0; i < N; i++) {
      const s = document.createElement('div'); s.className = 'star';
      const rect = container.getBoundingClientRect();
      s.style.left = (rect.width / 2 - 7) + 'px';
      s.style.top  = (rect.height / 2 - 7) + 'px';
      container.appendChild(s);
      const angle = (i / N) * Math.PI * 2;
      const dist = 110 + Math.random() * 60;
      gsap.to(s, {
        x: Math.cos(angle) * dist, y: Math.sin(angle) * dist,
        opacity: 0, scale: 0.4, rotate: 360, duration: 1.1, ease: 'power2.out',
        onComplete: () => s.remove(),
      });
    }
  }

  startBootProgress(msg) { this.$('bootStatus').textContent = msg; }
  finishBoot(msg) {
    this.$('bootStatus').textContent = msg;
    this.$('startBtn').disabled = false;
    this.$('startBtn').textContent = '▶  Start';
  }
}