/**
 * LeaderboardUI — renders the live leaderboard and user chip.
 */

import { Auth } from '../auth/Auth.js';
import { Leaderboard } from '../auth/Leaderboard.js';

export class LeaderboardUI {
  constructor() {
    this._interval = null;
  }

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

  startAutoRefresh() {
    if (this._interval) clearInterval(this._interval);
    this._interval = setInterval(() => { Leaderboard.bumpPeers(); this.render(); }, 12000);
  }

  refreshUserChip() {
    const u = Auth.current();
    if (u) {
      this.$('userName').textContent = u.name || u.email.split('@')[0];
      this.$('userAvatar').textContent = (u.name || u.email).slice(0, 1).toUpperCase();
      this.$('signOutBtn').style.display = '';
      // Sync persisted star count to header
      this.$('t-stars').textContent = (u.stars || 0).toLocaleString();
    } else {
      this.$('userName').textContent = 'Guest';
      this.$('userAvatar').textContent = 'G';
      this.$('signOutBtn').style.display = 'none';
      this.$('t-stars').textContent = '0';
    }
  }

  render() {
    const u = Auth.current();
    const rows = Leaderboard.combinedRanks(u);
    const top = rows.slice(0, 8);
    const meRow = rows.find(r => r.me);
    if (meRow && !top.find(r => r.me)) top.push(meRow);

    const html = top.map(r => {
      const rankCls = r.rank <= 3 ? ` r${r.rank}` : '';
      const meCls = r.me ? ' me' : '';
      const rankIcon = r.rank <= 3 ? ['🥇', '🥈', '🥉'][r.rank - 1] : r.rank;
      return `<div class="lb-row${rankCls}${meCls}">
        <div class="rank">${rankIcon}</div>
        <div class="who"><div class="a">${r.avatar || r.name.slice(0, 1).toUpperCase()}</div><div class="n">${r.me ? '<b>You</b>' : r.name}</div></div>
        <div class="pts">⭐ ${r.stars.toLocaleString()}</div>
      </div>`;
    }).join('');
    this.$('lbList').innerHTML = html;
    this.$('lb-total').textContent = rows.length.toLocaleString();
    this.$('lb-globalStars').textContent = rows.reduce((s, r) => s + r.stars, 0).toLocaleString();
    this.$('onlineCount').textContent = Leaderboard.onlineCount();
    if (u && meRow) this.$('userRank').textContent = `Rank #${meRow.rank} · ⭐ ${u.stars || 0}`;
    else this.$('userRank').textContent = u ? `⭐ ${u.stars || 0}` : 'Guest mode';
  }

  bumpUserStats(deltaStars, deltaMastered, currentLen) {
    const u = Auth.current();
    if (!u) return;
    const patch = {
      stars: (u.stars || 0) + deltaStars,
      mastered: (u.mastered || 0) + deltaMastered,
      grade: currentLen,
    };
    Auth.update(patch);
    // Also push to the backend (no-op when offline).
    Auth.saveProgress(patch).catch(() => {});
    this.refreshUserChip();
    this.render();
    const fresh = Auth.current();
    const el = document.getElementById('t-stars');
    el.textContent = (fresh.stars || 0).toLocaleString();
    el.classList.remove('bump'); void el.offsetWidth; el.classList.add('bump');
  }
}