function plural(n, one, few, many) {
  n = Math.abs(n) % 100; const n1 = n % 10;
  if (n > 10 && n < 20) return many;
  if (n1 > 1 && n1 < 5) return few;
  if (n1 === 1) return one;
  return many;
}

function renderStats(s, disk) {
  let diskHtml = '';
  if (disk) {
    const pct = disk.used_pct;
    const color = pct > 90 ? '#ef4444' : pct > 70 ? '#f59e0b' : '#16a34a';
    diskHtml = `
    <div class="stat">
      <div>${disk.used} <span class="stat-sub">/ ${disk.total}</span></div>
      <div class="label">Диск: свободно ${disk.free} (${100 - pct}%)</div>
      <div class="stat-bar"><i style="width:${pct}%;background:${color}"></i></div>
    </div>`;
  }
  document.getElementById('stats').innerHTML = `
    <div class="stat"><div class="num">${s.entries}</div><div class="label">Всего записей</div></div>
    <div class="stat"><div class="num">${s.students}</div><div class="label">Учеников</div></div>
    <div class="stat"><div class="num">${s.groups}</div><div class="label">Групп</div></div>
    <div class="stat"><div class="num">${s.today}</div><div class="label">Сегодня</div></div>
    <div class="stat"><div class="num" style="color:${s.trash ? '#ef4444' : 'var(--muted)'}">${s.trash}</div><div class="label"><a href="trash.html">В корзине →</a></div></div>
    ${diskHtml}
  `;
}

function last14days() {
  const out = [];
  for (let i = 13; i >= 0; i--) { const d = new Date(); d.setDate(d.getDate() - i); out.push(d); }
  return out;
}

function renderActivity(activity) {
  const map = {};
  activity.forEach(a => { map[a.d] = a.n; });
  const days = last14days().map(d => {
    const iso = d.toISOString().slice(0, 10);
    return { iso, label: d.toLocaleDateString('ru', { day: '2-digit', month: '2-digit' }), n: map[iso] || 0 };
  });
  const max = Math.max(1, ...days.map(x => x.n));
  const todayIso = new Date().toISOString().slice(0, 10);
  document.getElementById('activityChart').innerHTML = days.map(x => `
    <div class="bar-col" title="${x.iso} — ${x.n} ${plural(x.n, 'запись', 'записи', 'записей')}">
      <div class="bar ${x.iso === todayIso ? 'today' : ''}" style="height:${Math.round(x.n / max * 100)}%"></div>
      <div class="bar-day">${x.label}</div>
    </div>`).join('');
}

function renderRecent(rows) {
  const el = document.getElementById('recentList');
  if (!rows.length) { el.innerHTML = '<div class="dash-empty">Записей пока нет</div>'; return; }
  el.innerHTML = rows.map(e => `
    <div class="recent-item">
      ${e.photo_path
        ? `<img src="${thumbSrc(e.photo_path)}" data-img="${API}${e.photo_path}" loading="lazy" decoding="async" alt="">`
        : `<div class="thumb"><i data-lucide="graduation-cap"></i></div>`}
      <div class="r-info">
        <div class="r-name">${esc(e.student_name)}</div>
        <div class="r-meta">${esc(e.group_name)} · ${new Date(e.created_at).toLocaleString('ru', { day: '2-digit', month: '2-digit', hour: '2-digit', minute: '2-digit' })}</div>
      </div>
      <a class="r-link" href="journal.html" title="В журнал">→</a>
    </div>`).join('');
}

function renderActive(rows) {
  const el = document.getElementById('activeList');
  if (!rows.length) { el.innerHTML = '<div class="dash-empty">Сейчас нет идущих групп</div>'; return; }
  el.innerHTML = rows.map(g => `
    <div class="active-item">
      <span class="a-name">${esc(g.name)}</span>
      <span class="a-right">
        <span class="a-time">${g.day_label} ${g.time_start}–${g.time_end}</span>
        <span class="a-now">сейчас</span>
      </span>
    </div>`).join('');
}

function renderTop(rows) {
  const el = document.getElementById('topList');
  if (!rows.length) { el.innerHTML = '<div class="dash-empty">Пока нет данных</div>'; return; }
  el.innerHTML = rows.map((x, i) => `
    <div class="top-item">
      <span class="top-rank ${i > 2 ? 'alt' : ''}">${i + 1}</span>
      <span class="top-name">${esc(x.student_name)}</span>
      <span class="top-count">${x.n}</span>
    </div>`).join('');
}

function renderPhotos(rows) {
  const el = document.getElementById('dashPhotos');
  if (!rows.length) { el.innerHTML = '<div class="dash-empty">Фото групп пока нет</div>'; return; }
  el.innerHTML = rows.map(p => `
    <div class="dash-photo" title="${esc(p.group_name)}">
      <img src="${thumbSrc(p.photo_path)}" data-img="${API}${p.photo_path}" loading="lazy" decoding="async" alt="">
      ${p.caption ? `<div class="pcap">${esc(p.caption)}</div>` : ''}
    </div>`).join('');
}

function renderLessons(rows) {
  const el = document.getElementById('lessonList');
  if (!el) return;
  if (!rows.length) { el.innerHTML = '<div class="dash-empty">Отчётов пока нет</div>'; return; }
  el.innerHTML = rows.map(r => {
    const date = String(r.lesson_date || '').slice(0, 10).split('-').reverse().join('.');
    const time = r.lesson_time ? String(r.lesson_time).slice(0, 5) : '';
    return `
      <div class="lesson-dash-item" data-lesson="${r.id}">
        <div class="lesson-dash-head">
          <span class="lesson-dash-group">${esc(r.group_name)}</span>
          <span class="lesson-dash-when">${esc(date + (time ? ' · ' + time : ''))}</span>
        </div>
        <div class="lesson-dash-text">${esc(r.text)}</div>
      </div>`;
  }).join('');
}

async function loadDashboard() {
  const res = await fetch(`${API}/api/dashboard`, { headers: hdr() });
  if (!res.ok) { document.getElementById('stats').innerHTML = '<div class="dash-empty">Не удалось загрузить данные</div>'; return; }
  const d = await res.json();
  renderStats(d.stats, d.disk);
  renderActivity(d.activity);
  renderRecent(d.recent_entries);
  renderActive(d.active_groups);
  renderTop(d.top_students);
  renderPhotos(d.photos);
  renderLessons(d.recent_lessons || []);
  renderIcons();
}

document.getElementById('imgModal').addEventListener('click', e => e.currentTarget.classList.remove('open'));

const lessonBtn = document.getElementById('lessonReportBtn');
if (lessonBtn) lessonBtn.addEventListener('click', () => openLessonModal());

function onLessonReportSaved() {
  loadDashboard();
}

document.addEventListener('click', e => {
  const item = e.target.closest('[data-lesson]');
  if (item && !e.target.closest('button')) openLessonModal({ id: item.dataset.lesson });
});

(async () => {
  if (await checkAuth()) {
    buildSidebar(document.body.dataset.page);
    loadDashboard();
  }
})();