const API_URL = '../../api/waiter_feed.php';
const POLL_MS = 15000;

const feedList = document.getElementById('feedList');
const emptyState = document.getElementById('emptyState');
const syncDot = document.getElementById('syncDot');
const syncLabel = document.getElementById('syncLabel');
const notifyBanner = document.getElementById('notifyBanner');
const enableNotifyBtn = document.getElementById('enableNotifyBtn');

const statPending = document.getElementById('statPending');
const statWaiter = document.getElementById('statWaiter');
const statBill = document.getElementById('statBill');
const statTotal = document.getElementById('statTotal');

let knownIds = new Set();
let feedInitialized = false;
let pollTimer = null;
let lastPayload = '';
let swRegistration = null;

function escapeHtml(value) {
  return String(value ?? '')
    .replace(/&/g, '&')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;');
}

function formatTime(isoLike) {
  if (!isoLike) return '';
  const dt = new Date(String(isoLike).replace(' ', 'T'));
  if (Number.isNaN(dt.getTime())) return '';
  return dt.toLocaleTimeString('pl-PL', { hour: '2-digit', minute: '2-digit' });
}

function formatOperator(row) {
  const imie = (row.otwierajacy_imie || '').trim();
  const nazwisko = (row.otwierajacy_nazwisko || '').trim();
  return `${imie} ${nazwisko}`.trim();
}

function updateNotifyBanner() {
  if (!('Notification' in window)) {
    notifyBanner.classList.add('hidden');
    return;
  }

  if (Notification.permission === 'default') {
    notifyBanner.classList.remove('hidden');
    return;
  }

  notifyBanner.classList.add('hidden');
}

async function registerServiceWorker() {
  if (!('serviceWorker' in navigator)) {
    return null;
  }

  try {
    swRegistration = await navigator.serviceWorker.register('sw.js');
    await navigator.serviceWorker.ready;
    return swRegistration;
  } catch (err) {
    console.warn('[waiter] SW registration failed', err);
    return null;
  }
}

async function requestNotifications() {
  if (!('Notification' in window)) {
    alert('Ta przeglądarka nie obsługuje powiadomień.');
    return;
  }

  const permission = await Notification.requestPermission();
  updateNotifyBanner();

  if (permission === 'granted') {
    await registerServiceWorker();
  }
}

function showNotification(row) {
  const isWaiter = row.message_type === 'waiter_call';
  const title = isWaiter ? 'Wezwanie kelnera' : 'Prośba o rachunek';
  const firstLine = (row.message_text || '').split('\n')[0].trim();
  const body = `Stolik ${row.table_id || '?'}` + (firstLine ? `\n${firstLine}` : '');

  const payload = {
    type: 'notify',
    title,
    body,
    tag: `waiter-${row.id}`,
  };

  if (swRegistration && swRegistration.active) {
    swRegistration.active.postMessage(payload);
    return;
  }

  if (navigator.serviceWorker && navigator.serviceWorker.controller) {
    navigator.serviceWorker.controller.postMessage(payload);
    return;
  }

  if (Notification.permission === 'granted') {
    new Notification(title, {
      body,
      tag: payload.tag,
      renotify: true,
    });
  }
}

function handleNewRows(rows) {
  const fresh = [];

  for (const row of rows) {
    const id = Number(row.id);
    if (!feedInitialized) {
      knownIds.add(id);
      continue;
    }
    if (!knownIds.has(id)) {
      knownIds.add(id);
      fresh.push(row);
    }
  }

  feedInitialized = true;

  for (const row of fresh) {
    showNotification(row);
  }
}

function renderFeed(rows) {
  if (!rows.length) {
    feedList.innerHTML = '';
    emptyState.classList.remove('hidden');
    return;
  }

  emptyState.classList.add('hidden');

  feedList.innerHTML = rows.map((row) => {
    const isWaiter = row.message_type === 'waiter_call';
    const typeLabel = isWaiter ? 'Wezwanie kelnera' : 'Prośba o rachunek';
    const operator = formatOperator(row);
    const operatorHtml = operator
      ? `<div class="feed-operator">Kelner stolika: <strong>${escapeHtml(operator)}</strong></div>`
      : '';
    const pending = Number(row.status_kds) === 0;
    const cardClass = [
      'feed-card',
      isWaiter ? 'waiter' : 'bill',
      pending ? '' : 'done',
    ].filter(Boolean).join(' ');

    return `
      <article class="${cardClass}" data-id="${row.id}">
        <div class="feed-head">
          <div class="feed-title">${escapeHtml(typeLabel)}</div>
          <div class="feed-time">${escapeHtml(formatTime(row.created_at))}</div>
        </div>
        <div class="feed-table">Stolik ${escapeHtml(row.table_id || '?')}</div>
        ${operatorHtml}
        <div class="feed-msg">${escapeHtml(row.message_text || '')}</div>
        <div class="feed-badges">
          <span class="badge ${pending ? 'badge-pending' : 'badge-done'}">
            ${pending ? 'Aktywne w KDS' : 'Obsłużone w KDS'}
          </span>
        </div>
      </article>
    `;
  }).join('');
}

function updateStats(summary, total) {
  statPending.textContent = String(summary?.pending ?? 0);
  statWaiter.textContent = String(summary?.waiter_calls ?? 0);
  statBill.textContent = String(summary?.bill_requests ?? 0);
  statTotal.textContent = String(total ?? 0);
}

function setSyncState(ok, message) {
  syncDot.classList.toggle('ok', ok);
  syncDot.classList.toggle('err', !ok);
  syncLabel.textContent = message;
}

async function pollFeed() {
  try {
    const response = await fetch(API_URL, { cache: 'no-store' });
    const result = await response.json();

    if (result.status !== 'success') {
      setSyncState(false, 'Błąd API');
      return;
    }

    const payload = JSON.stringify(result.data || []);
    const rows = result.data || [];

    handleNewRows(rows);

    if (payload !== lastPayload) {
      renderFeed(rows);
      lastPayload = payload;
    }

    updateStats(result.summary, result.count);

    const now = new Date();
    setSyncState(true, `Sync ${now.toLocaleTimeString('pl-PL', { hour: '2-digit', minute: '2-digit', second: '2-digit' })}`);
  } catch {
    setSyncState(false, 'Brak połączenia');
  }
}

function startPolling() {
  pollFeed();
  if (pollTimer) clearInterval(pollTimer);
  pollTimer = setInterval(pollFeed, POLL_MS);
}

enableNotifyBtn?.addEventListener('click', () => {
  requestNotifications();
});

document.addEventListener('visibilitychange', () => {
  if (!document.hidden) {
    pollFeed();
  }
});

(async function init() {
  updateNotifyBanner();

  if ('Notification' in window && Notification.permission === 'granted') {
    await registerServiceWorker();
  } else if ('Notification' in window && Notification.permission === 'default') {
    notifyBanner.classList.remove('hidden');
  }

  startPolling();
})();