'use strict';

const $ = (id) => document.getElementById(id);
const el = (tag, cls, text) => {
  const e = document.createElement(tag);
  if (cls) e.className = cls;
  if (text != null) e.textContent = text;
  return e;
};

const store = {
  get: (k, d) => { try { const v = localStorage.getItem(k); return v == null ? d : JSON.parse(v); } catch { return d; } },
  set: (k, v) => { try { localStorage.setItem(k, JSON.stringify(v)); } catch {} },
};

const monthFmt = new Intl.DateTimeFormat('de-DE', { month: 'long', year: 'numeric' });
const dateFmt = new Intl.DateTimeFormat('de-DE', { dateStyle: 'medium', timeStyle: 'short' });
const shortDate = new Intl.DateTimeFormat('de-DE', { month: 'short', year: 'numeric' });
const collator = new Intl.Collator('de', { numeric: true, sensitivity: 'base' });

function fmtSize(b) {
  if (!b) return '';
  const u = ['B', 'KB', 'MB', 'GB'];
  let i = 0;
  while (b >= 1024 && i < u.length - 1) { b /= 1024; i++; }
  return `${b.toFixed(i > 1 ? 1 : 0).replace('.', ',')} ${u[i]}`;
}

// ------------------------------------------------------------------ Bild-URLs

const fileUrl = (item) => `nc://file/?h=${encodeURIComponent(item.href)}`;
const previewUrl = (fileId, s) => `nc://preview/?id=${encodeURIComponent(fileId)}&s=${s}`;

function thumbSize() {
  const px = state.zoom * (window.devicePixelRatio || 1);
  return px <= 256 ? 256 : px <= 512 ? 512 : 768;
}

function thumbUrl(item) {
  if (item.fileId && (item.hasPreview || item.kind === 'video')) return previewUrl(item.fileId, thumbSize());
  if (item.kind === 'image') return fileUrl(item);
  return null;
}

// ------------------------------------------------------------------ Zustand

const state = {
  source: store.get('source', 'timeline'),
  path: store.get('path', ''),
  sort: store.get('sort', 'name'),
  zoom: store.get('zoom', 180),
  album: null,          // { href, name } wenn ein Album offen ist
  media: [],            // aktuell sichtbare Bilder/Videos (für den Betrachter)
  timeline: { offset: 0, done: false, loading: false, lastMonth: null, grid: null },
  loadToken: 0,
};

// ------------------------------------------------------------------ Anmeldung

function showScreen(name) {
  for (const id of ['login', 'connecting', 'app']) $(id).hidden = id !== name;
}

function loginError(msg) {
  $('login-error').textContent = msg || '';
  $('login-error').hidden = !msg;
}

function setWaiting(on) {
  $('waiting').hidden = !on;
  $('browser-login').hidden = on;
  $('manual').hidden = on;
  $('server').disabled = on;
}

async function afterLogin(info) {
  $('acc-name').textContent = info.displayName;
  $('acc-server').textContent = info.server.replace(/^https?:\/\//, '');
  showScreen('app');
  selectSource(state.source, true);
}

$('btn-browser').addEventListener('click', async () => {
  loginError();
  setWaiting(true);
  try {
    const info = await window.nc.loginBrowser($('server').value, $('remember').checked);
    await afterLogin(info);
  } catch (e) {
    loginError(e.message);
  } finally {
    setWaiting(false);
  }
});

$('btn-cancel').addEventListener('click', () => window.nc.loginCancel());

async function passwordLogin() {
  loginError();
  const btn = $('btn-password');
  btn.disabled = true;
  try {
    const info = await window.nc.loginPassword($('server').value, $('user').value.trim(), $('pass').value, $('remember').checked);
    $('pass').value = '';
    await afterLogin(info);
  } catch (e) {
    loginError(e.message);
  } finally {
    btn.disabled = false;
  }
}
$('btn-password').addEventListener('click', passwordLogin);
$('pass').addEventListener('keydown', (e) => { if (e.key === 'Enter') passwordLogin(); });
$('server').addEventListener('keydown', (e) => { if (e.key === 'Enter') $('btn-browser').click(); });

$('btn-logout').addEventListener('click', async () => {
  await window.nc.logout();
  $('content').replaceChildren();
  showScreen('login');
});

// ------------------------------------------------------------------ Navigation

document.querySelectorAll('.sources button').forEach((b) =>
  b.addEventListener('click', () => selectSource(b.dataset.source)));

function selectSource(source, initial = false) {
  state.source = source;
  store.set('source', source);
  if (!initial) state.album = null;
  document.querySelectorAll('.sources button').forEach((b) =>
    b.setAttribute('aria-current', String(b.dataset.source === source)));
  load();
}

function renderCrumbs() {
  const c = $('crumbs');
  c.replaceChildren();
  const add = (label, fn) => {
    if (c.childElementCount) c.append(el('span', 'sep', '›'));
    const b = el('button', null, label);
    if (fn) b.addEventListener('click', fn);
    c.append(b);
  };
  if (state.source === 'timeline') add('Alle Fotos');
  if (state.source === 'albums') {
    add('Alben', state.album ? () => { state.album = null; selectSource('albums'); } : null);
    if (state.album) add(state.album.name);
  }
  if (state.source === 'folder') {
    add('Dateien', () => openFolder(''));
    const parts = state.path.split('/').filter(Boolean);
    parts.forEach((p, i) => add(p, () => openFolder(parts.slice(0, i + 1).join('/'))));
  }
}

function openFolder(path) {
  state.path = path.replace(/^\/+|\/+$/g, '');
  store.set('path', state.path);
  load();
}

function goUp() {
  if (state.source === 'folder' && state.path) openFolder(state.path.split('/').slice(0, -1).join('/'));
  else if (state.source === 'albums' && state.album) { state.album = null; selectSource('albums'); }
}

// ------------------------------------------------------------------ Laden

function notice(title, text, action) {
  const n = el('div', 'notice');
  n.append(el('strong', null, title));
  if (text) n.append(el('span', null, text));
  if (action) {
    const b = el('button', null, action.label);
    b.addEventListener('click', action.fn);
    n.append(b);
  }
  return n;
}

function errorNotice(e) {
  const n = notice('Das hat nicht geklappt', e.message, { label: 'Erneut versuchen', fn: load });
  n.classList.add('error');
  return n;
}

async function load() {
  const token = ++state.loadToken;
  const content = $('content');
  content.replaceChildren(el('div', 'loading-more', 'Lade …'));
  content.scrollTop = 0;
  state.media = [];
  renderCrumbs();
  $('sort').hidden = !(state.source === 'folder' || (state.source === 'albums' && state.album));

  try {
    if (state.source === 'folder') {
      const items = await window.nc.folder(state.path);
      if (token !== state.loadToken) return;
      renderFolder(items);
    } else if (state.source === 'albums') {
      if (state.album) {
        const items = await window.nc.album(state.album.href);
        if (token !== state.loadToken) return;
        renderMediaList(items, 'Dieses Album ist leer.');
      } else {
        const res = await window.nc.albums();
        if (token !== state.loadToken) return;
        renderAlbums(res);
      }
    } else {
      startTimeline(token);
    }
  } catch (e) {
    if (token !== state.loadToken) return;
    // Gespeicherter Ordner existiert nicht mehr: zurück zur Wurzel
    if (state.source === 'folder' && state.path && /Nicht gefunden/.test(e.message)) return openFolder('');
    content.replaceChildren(errorNotice(e));
  }
}

function sortItems(items) {
  const s = state.sort;
  const by = (i) => i.taken || i.mtime;
  const arr = [...items];
  if (s === 'name') arr.sort((a, b) => collator.compare(a.name, b.name));
  if (s === 'new') arr.sort((a, b) => by(b) - by(a));
  if (s === 'old') arr.sort((a, b) => by(a) - by(b));
  return arr;
}

// ------------------------------------------------------------------ Kacheln

function attachImg(img, src, holder) {
  img.alt = '';
  img.loading = 'lazy';
  img.decoding = 'async';
  img.draggable = false;
  img.addEventListener('load', () => img.classList.add('loaded'));
  img.addEventListener('error', () => { holder.classList.add('broken'); img.remove(); });
  img.src = src;
}

function mediaTile(item, index) {
  const b = el('button', 'tile');
  b.dataset.name = item.name;
  b.title = item.name;
  const src = thumbUrl(item);
  if (src) {
    const img = el('img');
    attachImg(img, src, b);
    b.append(img);
  } else {
    b.classList.add('broken');
  }
  if (item.kind === 'video') b.append(el('span', 'badge', '▶'));
  b.addEventListener('click', () => openViewer(index));
  return b;
}

function folderTile(item) {
  const b = el('button', 'tile folder');
  const cover = el('div', 'cover');
  cover.append(el('div', 'folder-shape'));
  b.append(cover, el('div', 'label', item.name));
  b.title = item.name;
  b.addEventListener('click', () => openFolder(item.path));
  return b;
}

function renderMediaList(items, emptyText) {
  const media = sortItems(items.filter((i) => i.kind === 'image' || i.kind === 'video'));
  state.media = media;
  const content = $('content');
  if (!media.length) { content.replaceChildren(notice(emptyText)); return; }
  const grid = el('div', 'grid');
  media.forEach((m, i) => grid.append(mediaTile(m, i)));
  content.replaceChildren(grid);
}

function renderFolder(items) {
  const dirs = items.filter((i) => i.isDir).sort((a, b) => collator.compare(a.name, b.name));
  const media = sortItems(items.filter((i) => i.kind === 'image' || i.kind === 'video'));
  state.media = media;
  const content = $('content');
  content.replaceChildren();

  if (dirs.length) {
    const g = el('div', 'grid folders');
    dirs.forEach((d) => g.append(folderTile(d)));
    content.append(g);
  }
  if (media.length) {
    const g = el('div', 'grid');
    media.forEach((m, i) => g.append(mediaTile(m, i)));
    content.append(g);
  }
  if (!dirs.length && !media.length) {
    content.append(notice('Hier liegen keine Fotos.', state.path ? 'Über den Pfad oben kommst du zurück.' : null));
  }
}

function renderAlbums({ available, albums }) {
  const content = $('content');
  if (!available) {
    content.replaceChildren(notice('Alben sind nicht verfügbar.', 'Dafür muss auf deiner Nextcloud die App „Fotos“ installiert sein. Die Ansichten „Alle Fotos“ und „Ordner“ funktionieren trotzdem.'));
    return;
  }
  if (!albums.length) {
    content.replaceChildren(notice('Du hast noch keine Alben.', 'Alben legst du in der Fotos-App deiner Nextcloud an.'));
    return;
  }
  const g = el('div', 'grid folders');
  albums
    .sort((a, b) => (b.end || 0) - (a.end || 0) || collator.compare(a.name, b.name))
    .forEach((a) => {
      const b = el('button', 'tile album');
      const cover = el('div', 'cover');
      if (a.cover) {
        const img = el('img');
        attachImg(img, previewUrl(a.cover, thumbSize()), cover);
        cover.append(img);
      } else {
        cover.append(el('div', 'folder-shape'));
      }
      const bits = [`${a.count} ${a.count === 1 ? 'Foto' : 'Fotos'}`];
      if (a.start) bits.push(shortDate.format(a.start));
      if (a.shared) bits.push('geteilt');
      b.append(cover, el('div', 'label', a.name), el('div', 'sublabel', bits.join(', ')));
      b.title = a.name;
      b.addEventListener('click', () => { state.album = { href: a.href, name: a.name }; load(); });
      g.append(b);
    });
  content.replaceChildren(g);
}

// ------------------------------------------------------------------ Zeitleiste

let timelineObserver = null;

function startTimeline(token) {
  state.timeline = { offset: 0, done: false, loading: false, lastMonth: null, grid: null, token };
  const content = $('content');
  content.replaceChildren();
  const sentinel = el('div', 'sentinel');
  const more = el('div', 'loading-more', 'Lade Fotos …');
  content.append(sentinel, more);

  if (timelineObserver) timelineObserver.disconnect();
  timelineObserver = new IntersectionObserver((entries) => {
    if (entries.some((e) => e.isIntersecting)) loadTimelinePage();
  }, { root: content, rootMargin: '1200px' });
  timelineObserver.observe(sentinel);
  loadTimelinePage();
}

async function loadTimelinePage() {
  const t = state.timeline;
  if (t.loading || t.done || t.token !== state.loadToken) return;
  t.loading = true;
  const content = $('content');
  const sentinel = content.querySelector('.sentinel');
  const more = content.querySelector('.loading-more');
  try {
    const { items, done } = await window.nc.timeline(t.offset);
    if (t.token !== state.loadToken) return;
    t.offset += items.length;
    t.done = done;
    for (const item of items) {
      const d = new Date(item.mtime);
      const key = `${d.getFullYear()}-${d.getMonth()}`;
      if (key !== t.lastMonth) {
        t.lastMonth = key;
        const sec = el('section', 'month');
        const h = el('h2', null, monthFmt.format(d));
        t.countEl = el('small');
        t.count = 0;
        h.append(t.countEl);
        t.grid = el('div', 'grid');
        sec.append(h, t.grid);
        content.insertBefore(sec, sentinel);
      }
      const index = state.media.length;
      state.media.push(item);
      t.grid.append(mediaTile(item, index));
      t.count++;
      t.countEl.textContent = `${t.count} ${t.count === 1 ? 'Foto' : 'Fotos'}`;
    }
    if (done) {
      more.remove();
      if (!state.media.length) content.replaceChildren(notice('Keine Fotos gefunden.', 'In deiner Nextcloud liegen noch keine Bilder oder Videos.'));
    }
  } catch (e) {
    if (t.token !== state.loadToken) return;
    t.done = true;
    more.replaceWith(errorNotice(e));
  } finally {
    t.loading = false;
  }
  // Falls der Bildschirm noch nicht gefüllt ist, direkt nachladen
  if (!t.done && sentinel.isConnected && sentinel.getBoundingClientRect().top < content.clientHeight + 1200) {
    loadTimelinePage();
  }
}

// ------------------------------------------------------------------ Werkzeugleiste

$('sort').value = state.sort;
$('sort').addEventListener('change', () => {
  state.sort = $('sort').value;
  store.set('sort', state.sort);
  load();
});

function applyZoom() {
  document.documentElement.style.setProperty('--thumb', `${state.zoom}px`);
}
$('zoom').value = state.zoom;
applyZoom();
$('zoom').addEventListener('input', () => {
  state.zoom = Number($('zoom').value);
  store.set('zoom', state.zoom);
  applyZoom();
});

// ------------------------------------------------------------------ Betrachter

const viewer = {
  index: 0,
  original: false,
  token: 0,
  idleTimer: null,
};

function openViewer(index) {
  viewer.index = index;
  viewer.original = false;
  $('viewer').hidden = false;
  showCurrent();
  wakeViewer();
}

function closeViewer() {
  $('viewer').hidden = true;
  const v = $('v-video');
  v.pause();
  v.removeAttribute('src');
  v.load();
  $('v-img').removeAttribute('src');
  // Fokus zurück auf die zuletzt gezeigte Kachel
  const tiles = $('content').querySelectorAll('.grid:not(.folders) .tile');
  tiles[viewer.index]?.focus({ preventScroll: false });
}

function bigSize() {
  const s = Math.max(window.innerWidth, window.innerHeight) * (window.devicePixelRatio || 1);
  return s <= 1600 ? 1600 : s <= 2560 ? 2560 : 4096;
}

function preload(item) {
  if (!item || item.kind !== 'image' || !item.fileId || !item.hasPreview) return;
  const i = new Image();
  i.src = previewUrl(item.fileId, bigSize());
}

function showCurrent() {
  const item = state.media[viewer.index];
  if (!item) return closeViewer();
  const token = ++viewer.token;
  const img = $('v-img');
  const video = $('v-video');
  const msg = $('v-msg');
  msg.hidden = true;

  $('v-name').textContent = item.name;
  const when = item.taken || item.mtime;
  const meta = [`${viewer.index + 1} von ${state.media.length}`];
  if (when) meta.push(dateFmt.format(when));
  if (item.size) meta.push(fmtSize(item.size));
  $('v-meta').replaceChildren(...meta.map((m) => el('span', null, m)));
  $('v-prev').disabled = viewer.index === 0;
  $('v-next').disabled = viewer.index >= state.media.length - 1;
  $('v-open').hidden = !item.fileId;
  $('v-original').hidden = item.kind !== 'image';
  $('v-original').classList.toggle('active', viewer.original);

  if (item.kind === 'video') {
    img.hidden = true;
    video.hidden = false;
    video.src = fileUrl(item);
    video.play().catch(() => {});
    return;
  }

  video.pause();
  video.hidden = true;
  video.removeAttribute('src');
  img.hidden = false;

  const canPreview = item.fileId && item.hasPreview;
  const target = viewer.original || !canPreview ? fileUrl(item) : previewUrl(item.fileId, bigSize());

  // Zuerst das (meist schon geladene) Vorschaubild zeigen, dann scharf nachladen
  if (canPreview) {
    img.src = previewUrl(item.fileId, thumbSize());
    img.classList.add('lowres');
  } else {
    img.removeAttribute('src');
  }
  if (viewer.original) { msg.textContent = 'Original wird geladen …'; msg.hidden = false; }

  const full = new Image();
  full.onload = () => {
    if (token !== viewer.token) return;
    img.src = target;
    img.classList.remove('lowres');
    msg.hidden = true;
  };
  full.onerror = () => {
    if (token !== viewer.token) return;
    img.classList.remove('lowres');
    msg.textContent = viewer.original
      ? 'Dieses Dateiformat kann nur als Vorschau angezeigt werden.'
      : 'Das Bild konnte nicht geladen werden.';
    msg.hidden = false;
  };
  full.src = target;

  preload(state.media[viewer.index + 1]);
  preload(state.media[viewer.index - 1]);

  // In der Zeitleiste rechtzeitig weitere Fotos holen
  if (state.source === 'timeline' && viewer.index > state.media.length - 10) loadTimelinePage();
}

function step(d) {
  const n = viewer.index + d;
  if (n < 0 || n >= state.media.length) return;
  viewer.index = n;
  viewer.original = false;
  showCurrent();
}

function wakeViewer() {
  const v = $('viewer');
  v.classList.remove('idle');
  clearTimeout(viewer.idleTimer);
  viewer.idleTimer = setTimeout(() => v.classList.add('idle'), 2500);
}

$('v-prev').addEventListener('click', () => step(-1));
$('v-next').addEventListener('click', () => step(1));
$('v-close').addEventListener('click', closeViewer);
$('v-full').addEventListener('click', () => window.nc.toggleFullscreen());
$('v-original').addEventListener('click', () => { viewer.original = !viewer.original; showCurrent(); });
$('v-open').addEventListener('click', () => {
  const item = state.media[viewer.index];
  if (item?.fileId) window.nc.openInNextcloud(item.fileId);
});
$('viewer').addEventListener('mousemove', wakeViewer);
$('viewer').querySelector('.v-stage').addEventListener('dblclick', () => window.nc.toggleFullscreen());
$('viewer').addEventListener('wheel', (e) => {
  if (Math.abs(e.deltaY) < 30) return;
  step(e.deltaY > 0 ? 1 : -1);
}, { passive: true });

document.addEventListener('keydown', (e) => {
  if (!$('viewer').hidden) {
    const k = e.key;
    if (k === 'ArrowRight' || k === ' ' || k === 'PageDown') { e.preventDefault(); step(1); }
    else if (k === 'ArrowLeft' || k === 'PageUp') { e.preventDefault(); step(-1); }
    else if (k === 'Home') { viewer.index = 0; showCurrent(); }
    else if (k === 'End') { viewer.index = state.media.length - 1; showCurrent(); }
    else if (k === 'Escape') closeViewer();
    else if (k === 'f' || k === 'F11') { e.preventDefault(); window.nc.toggleFullscreen(); }
    else if (k === 'o') $('v-original').click();
    wakeViewer();
    return;
  }
  if ($('app').hidden) return;
  const typing = /INPUT|SELECT|TEXTAREA/.test(document.activeElement?.tagName);
  if (e.key === 'Backspace' && !typing) { e.preventDefault(); goUp(); }
  if (e.key === 'F5') { e.preventDefault(); load(); }
});

document.addEventListener('mouseup', (e) => {
  if (e.button === 3) { // Maus-Zurück-Taste
    if (!$('viewer').hidden) closeViewer(); else goUp();
  }
});

// ------------------------------------------------------------------ Start

(async function start() {
  const cfg = await window.nc.config();
  $('server').value = cfg.server;
  $('user').value = cfg.loginName;
  if (cfg.hasSecret) {
    showScreen('connecting');
    try {
      const info = await window.nc.restore();
      if (info) return afterLogin(info);
    } catch (e) {
      showScreen('login');
      loginError(e.message);
      return;
    }
  }
  showScreen('login');
  $('server').focus();
})();