// =====================================================
// App — router, sidebar, theme toggle
// =====================================================

const view = document.getElementById('view');
const crumbCurrent = document.getElementById('crumbCurrent');

function parseRoute() {
  const hash = location.hash.replace(/^#\/?/, '');
  if (!hash || hash === '/') return { name: 'home' };
  const parts = hash.split('/').filter(Boolean);
  if (parts[0] === 'uke' && parts[1]) return { name: 'uke', weekId: parseInt(parts[1], 10) };
  if (parts[0] === 'tema' && parts[1]) return { name: 'tema', temaId: parts[1] };
  if (parts[0] === 'fast-track') {
    return parts[1] ? { name: 'fasttrack-module', moduleId: parseInt(parts[1], 10) } : { name: 'fasttrack' };
  }
  if (parts[0] === 'tldr') return { name: 'tldr' };
  if (parts[0] === 'flashcards') return { name: 'flashcards' };
  if (parts[0] === 'quiz') return { name: 'quiz' };
  if (parts[0] === 'eksamen') return { name: 'eksamen' };
  return { name: 'home' };
}

async function route() {
  const r = parseRoute();
  view.innerHTML = '';
  let content;
  let crumb = 'Oversikt';

  switch (r.name) {
    case 'home':
      content = SMF.renderHome();
      crumb = 'Oversikt';
      break;
    case 'uke':
      content = await SMF.renderLesson(r.weekId);
      const w = SMF.WEEKS.find(x => x.id === r.weekId);
      crumb = w ? `Uke ${w.id} · ${w.title}` : 'Ukjent uke';
      break;
    case 'tema':
      content = await SMF.renderTema(r.temaId);
      const t = SMF.getTheme(r.temaId);
      crumb = t ? t.label : 'Tema';
      break;
    case 'fasttrack':
      content = await SMF.renderFastTrackHome();
      crumb = 'Fast-track';
      break;
    case 'fasttrack-module':
      content = await SMF.renderFastTrackModule(r.moduleId);
      const m = SMF.getFastTrack(r.moduleId);
      crumb = m ? `Fast-track · ${m.title}` : 'Fast-track';
      break;
    case 'tldr':
      content = await SMF.renderTldr();
      crumb = 'tl;dr · i farta';
      break;
    case 'flashcards':
      content = document.getElementById('t-flashcards').content.cloneNode(true);
      crumb = 'Flashcards';
      break;
    case 'quiz':
      content = document.getElementById('t-quiz').content.cloneNode(true);
      crumb = 'Selvtest';
      break;
    case 'eksamen':
      content = document.getElementById('t-eksamen').content.cloneNode(true);
      crumb = 'Eksamenstrener';
      break;
  }

  view.appendChild(content);
  crumbCurrent.textContent = crumb;

  // After DOM is in place, init relevant mode
  if (r.name === 'flashcards') await SMF.fcInit();
  else if (r.name === 'quiz') await SMF.quizInit();
  else if (r.name === 'eksamen') await SMF.examInit();

  updateActiveLinks(r);
  closeSidebar();
  window.scrollTo(0, 0);
}

function updateActiveLinks(r) {
  document.querySelectorAll('.sidebar__link').forEach(a => {
    a.classList.remove('sidebar__link--active');
  });
  if (r.name === 'home') {
    document.querySelector('.sidebar__link[data-route="home"]')?.classList.add('sidebar__link--active');
  } else if (r.name === 'tldr') {
    document.querySelector('.sidebar__link[data-route="tldr"]')?.classList.add('sidebar__link--active');
  } else if (r.name === 'fasttrack' || r.name === 'fasttrack-module') {
    document.querySelector('.sidebar__link[data-route="fasttrack"]')?.classList.add('sidebar__link--active');
  } else if (r.name === 'flashcards') {
    document.querySelector('.sidebar__link[data-route="flashcards"]')?.classList.add('sidebar__link--active');
  } else if (r.name === 'quiz') {
    document.querySelector('.sidebar__link[data-route="quiz"]')?.classList.add('sidebar__link--active');
  } else if (r.name === 'eksamen') {
    document.querySelector('.sidebar__link[data-route="eksamen"]')?.classList.add('sidebar__link--active');
  } else if (r.name === 'uke') {
    document.querySelector(`.sidebar__link[data-week="${r.weekId}"]`)?.classList.add('sidebar__link--active');
  } else if (r.name === 'tema') {
    // No specific active link for tema (could be added)
  }
}

function renderWeekNav() {
  const nav = document.getElementById('weekNav');
  if (!nav) return;
  nav.innerHTML = SMF.WEEKS.map(w => {
    return `
      <a href="#/uke/${w.id}" data-week="${w.id}" class="sidebar__link">
        <span class="sidebar__link-num">${String(w.id).padStart(2, '0')}</span>
        <span>${w.title}</span>
      </a>
    `;
  }).join('');
}

// ============= Sidebar (mobile) =============
function openSidebar() {
  document.getElementById('sidebar').classList.add('sidebar--open');
  document.getElementById('sidebarScrim').classList.add('sidebar-scrim--open');
}

function closeSidebar() {
  document.getElementById('sidebar').classList.remove('sidebar--open');
  document.getElementById('sidebarScrim').classList.remove('sidebar-scrim--open');
}

document.getElementById('sidebarToggle')?.addEventListener('click', () => {
  if (document.getElementById('sidebar').classList.contains('sidebar--open')) closeSidebar();
  else openSidebar();
});
document.getElementById('sidebarScrim')?.addEventListener('click', closeSidebar);

// ============= Theme toggle =============
function applyTheme(theme) {
  document.documentElement.dataset.theme = theme;
  localStorage.setItem('smf-theme', theme);
  // Update icon
  const icon = document.getElementById('themeIcon');
  if (theme === 'dark') {
    icon.innerHTML = `<path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z"/>`;
  } else {
    icon.innerHTML = `<circle cx="12" cy="12" r="5"/><line x1="12" y1="1" x2="12" y2="3"/><line x1="12" y1="21" x2="12" y2="23"/><line x1="4.22" y1="4.22" x2="5.64" y2="5.64"/><line x1="18.36" y1="18.36" x2="19.78" y2="19.78"/><line x1="1" y1="12" x2="3" y2="12"/><line x1="21" y1="12" x2="23" y2="12"/><line x1="4.22" y1="19.78" x2="5.64" y2="18.36"/><line x1="18.36" y1="5.64" x2="19.78" y2="4.22"/>`;
  }
}

function initTheme() {
  // dark default; only switch to light if explicitly saved
  const saved = localStorage.getItem('smf-theme');
  applyTheme(saved === 'light' ? 'light' : 'dark');
}

document.getElementById('themeBtn').addEventListener('click', () => {
  const current = document.documentElement.dataset.theme;
  applyTheme(current === 'dark' ? 'light' : 'dark');
});

// ============= Countdown =============
function updateCountdown() {
  const el = document.getElementById('examCountdown');
  if (!el) return;
  const c = SMF.daysToExam();
  el.textContent = c.label;
}

// ============= Init =============
async function init() {
  initTheme();
  renderWeekNav();
  updateCountdown();
  SMF.attachSearch();

  // Sidebar brand link
  document.querySelectorAll('[data-route="home"]').forEach(a => {
    a.addEventListener('click', (e) => {
      e.preventDefault();
      location.hash = '';
    });
  });

  // Initial route
  await route();
  // Build search index in background
  setTimeout(() => SMF.buildSearchIndex().catch(console.warn), 500);
}

window.addEventListener('hashchange', route);
window.addEventListener('DOMContentLoaded', init);
if (document.readyState !== 'loading') init();