let friends = [];
let bookTitle = 'Unser Freundesbuch';
let currentIndex = -1; // -1 = Deckblatt, 0..n-1 = Freunde

const STECKBRIEF_LABELS = {
  spitzname: 'Spitzname',
  geburtstag: 'Geburtstag',
  adresse: 'Adresse / Wohnort',
  lieblingsfarbe: 'Lieblingsfarbe',
  lieblingsessen: 'Lieblingsessen',
  lieblingstier: 'Lieblingstier',
  hobbys: 'Hobbys',
  lieblingsmusik: 'Lieblingsmusik',
  lieblingsfilm: 'Lieblingsfilm/-serie',
  traumberuf: 'Traumberuf',
  bestefreunde: 'Beste Freunde',
  motto: 'Motto / Lebensweisheit',
  sonstiges: 'Sonstiges',
};

const COVER_MAX_STICKERS = 24;

function escapeHtml(str) {
  const div = document.createElement('div');
  div.textContent = str || '';
  return div.innerHTML;
}

function randomRotation(seed) {
  const angles = [-6, -4, -2, 2, 4, 6, -3, 3, 5, -5];
  return angles[seed % angles.length];
}

// Einfacher, deterministischer Pseudo-Zufallsgenerator (gleiche Seed -> gleiches Ergebnis),
// damit das Deckblatt bei jedem Aufruf ähnlich aussieht statt bei jedem Reload zu "springen".
function seededRandom(seed) {
  let t = (seed += 0x6d2b79f5);
  t = Math.imul(t ^ (t >>> 15), t | 1);
  t ^= t + Math.imul(t ^ (t >>> 7), t | 61);
  return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
}

function uploadUrl(folder, filename) {
  return `/uploads/${encodeURIComponent(folder)}/${encodeURIComponent(filename)}`;
}

async function load() {
  const [bookRes, settingsRes] = await Promise.all([fetch('/api/book'), fetch('/api/settings')]);
  if (bookRes.status === 401 || settingsRes.status === 401) { window.location.href = '/'; return; }
  const bookData = await bookRes.json();
  const settingsData = await settingsRes.json();
  friends = bookData.friends || [];
  bookTitle = (settingsData.settings && settingsData.settings.bookTitle) || 'Unser Freundesbuch';

  document.getElementById('bookNav').style.display = 'flex';
  renderPage();
}

// --- Deckblatt: Titel + "sticker-gebombte" Foto-Collage ---
function collectStickerImages() {
  const imgs = [];
  friends.forEach((f) => {
    if (f.profileImage) imgs.push({ folder: f.folderName, filename: f.profileImage });
    (f.blocks || []).forEach((b) => {
      if (b.type === 'image' && b.filename) imgs.push({ folder: f.folderName, filename: b.filename });
      if (b.type === 'audio' && b.coverFilename) imgs.push({ folder: f.folderName, filename: b.coverFilename });
    });
  });
  return imgs;
}

function renderCoverPage() {
  const root = document.getElementById('bookRoot');
  let imgs = collectStickerImages();

  if (imgs.length > COVER_MAX_STICKERS) {
    const step = imgs.length / COVER_MAX_STICKERS;
    imgs = Array.from({ length: COVER_MAX_STICKERS }, (_, i) => imgs[Math.floor(i * step)]);
  }

  let stickersHtml = '';
  if (imgs.length) {
    const cols = Math.min(6, Math.max(3, Math.ceil(Math.sqrt(imgs.length * 1.6))));
    const rows = Math.ceil(imgs.length / cols);
    stickersHtml = imgs
      .map((img, i) => {
        const cellX = i % cols;
        const cellY = Math.floor(i / cols);
        const rx = seededRandom(i * 13 + 1);
        const ry = seededRandom(i * 17 + 2);
        const rr = seededRandom(i * 7 + 3);
        const rs = seededRandom(i * 5 + 4);
        const leftPct = ((cellX + 0.1 + rx * 0.8) / cols) * 100;
        const topPct = ((cellY + 0.1 + ry * 0.8) / rows) * 100;
        const rot = (rr * 50 - 25).toFixed(1);
        const size = Math.round(85 + rs * 65);
        return `<img class="cover-sticker" style="left:${leftPct}%; top:${topPct}%; width:${size}px; transform: rotate(${rot}deg);" src="${uploadUrl(img.folder, img.filename)}" />`;
      })
      .join('');
  }

  root.innerHTML = `
    <div class="cover-page">
      <div class="cover-stickers">${stickersHtml}</div>
      <div class="cover-title-wrap">
        <div class="tape" style="position:static; margin: 0 auto 0.4em; transform: rotate(-4deg);"></div>
        <h1 class="cover-title">${escapeHtml(bookTitle)}</h1>
      </div>
    </div>
  `;
}

function renderFriendPage(f) {
  const root = document.getElementById('bookRoot');

  const profileHtml = f.profileImage
    ? `<img class="page-profile-pic" src="${uploadUrl(f.folderName, f.profileImage)}" />`
    : `<div class="page-profile-pic placeholder">${(f.name || '?')[0].toUpperCase()}</div>`;

  const sbEntries = Object.entries(f.steckbrief || {}).filter(([, v]) => v && String(v).trim());
  const sbHtml = sbEntries.length
    ? `<div class="sb-grid">${sbEntries.map(([k, v]) => `
        <div class="sb-row"><span class="sb-key">${escapeHtml(STECKBRIEF_LABELS[k] || k)}</span><span class="sb-val">${escapeHtml(v)}</span></div>
      `).join('')}</div>`
    : `<p class="muted">Noch nichts eingetragen.</p>`;

  const blocks = [...(f.blocks || [])].sort((a, b) => a.order - b.order);
  const blocksHtml = blocks.length
    ? blocks.map((b, i) => {
        const rot = randomRotation(i + f.id.length);
        if (b.type === 'image') {
          return `<div class="scrap-item polaroid" style="transform: rotate(${rot}deg);">
            <img src="${uploadUrl(f.folderName, b.filename)}" />
            ${b.caption ? `<div class="scrap-caption">${escapeHtml(b.caption)}</div>` : ''}
          </div>`;
        }
        if (b.type === 'audio') {
          return `<div class="scrap-item audio-note" style="transform: rotate(${rot * 0.5}deg);">
            ${b.coverFilename ? `<img class="audio-cover" src="${uploadUrl(f.folderName, b.coverFilename)}" />` : ''}
            <div>🎙️${b.caption ? ' ' + escapeHtml(b.caption) : ''}</div>
            <audio controls src="${uploadUrl(f.folderName, b.filename)}"></audio>
          </div>`;
        }
        return `<div class="scrap-item text-note" style="transform: rotate(${rot * 0.5}deg);">
          <p>${escapeHtml(b.content).replace(/\n/g, '<br/>')}</p>
          ${b.caption ? `<div class="scrap-caption">${escapeHtml(b.caption)}</div>` : ''}
        </div>`;
      }).join('')
    : '<p class="muted">Noch keine Erinnerungen hinzugefügt.</p>';

  root.innerHTML = `
    <div class="friend-page">
      <div class="page-head">
        <div class="tape"></div>
        ${profileHtml}
        <h1>${escapeHtml(f.name)}</h1>
      </div>
      <div class="steckbrief-card">
        <h2>Steckbrief</h2>
        ${sbHtml}
      </div>
      <div class="scrap-grid">
        ${blocksHtml}
      </div>
    </div>
  `;
}

function renderPage() {
  const root = document.getElementById('bookRoot');

  if (currentIndex === -1) {
    renderCoverPage();
  } else if (!friends.length) {
    root.innerHTML = `
      <div class="empty-book">
        <h2>Noch ist dieses Buch leer 📖</h2>
        <p class="muted">Lege im Admin-Bereich Freunde an und teile den Link mit ihnen.</p>
      </div>`;
  } else {
    renderFriendPage(friends[currentIndex]);
  }

  const indicator = document.getElementById('pageIndicator');
  indicator.textContent = currentIndex === -1 ? 'Deckblatt' : `Seite ${currentIndex + 1} von ${friends.length}`;
  document.getElementById('prevBtn').disabled = currentIndex === -1;
  document.getElementById('nextBtn').disabled = currentIndex >= friends.length - 1;
}

document.getElementById('prevBtn').addEventListener('click', () => {
  if (currentIndex > -1) { currentIndex--; renderPage(); window.scrollTo({ top: 0, behavior: 'smooth' }); }
});
document.getElementById('nextBtn').addEventListener('click', () => {
  if (currentIndex < friends.length - 1) { currentIndex++; renderPage(); window.scrollTo({ top: 0, behavior: 'smooth' }); }
});
document.addEventListener('keydown', (e) => {
  if (e.key === 'ArrowLeft') document.getElementById('prevBtn').click();
  if (e.key === 'ArrowRight') document.getElementById('nextBtn').click();
});

document.getElementById('pdfBtn').addEventListener('click', async () => {
  const btn = document.getElementById('pdfBtn');
  btn.disabled = true;
  btn.textContent = 'Erzeuge PDF...';
  try {
    const res = await fetch('/api/book/pdf');
    if (!res.ok) throw new Error('PDF-Export fehlgeschlagen.');
    const blob = await res.blob();
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = 'freundesbuch.pdf';
    document.body.appendChild(a);
    a.click();
    a.remove();
    URL.revokeObjectURL(url);
  } catch (err) {
    alert(err.message);
  } finally {
    btn.disabled = false;
    btn.textContent = '⬇️ Als PDF exportieren';
  }
});

load();