// The PIN lock: in a new browser tab the panel asks for the admin's PIN
// before showing anything. The tab remembers it was unlocked (sessionStorage
// lives as long as the tab, through reloads, and a new tab starts empty), so
// a reload does not ask again. Loaded in <head>, before the page shows.
// A device can be set to trust the PIN for a while: for that many minutes
// after it was entered, new tabs there open without asking (localStorage,
// this browser only).
(function () {
  'use strict';
  var KEY = 'lpra.pin.ok';
  var ok = false;
  try { ok = sessionStorage.getItem(KEY) === '1'; } catch (e) { /* no storage: ask */ }
  if (ok) return;
  try {
    if (Date.now() < Number(localStorage.getItem('lpra.pin.until') || 0)) {
      sessionStorage.setItem(KEY, '1');
      return;
    }
  } catch (e) { /* ask */ }
  var root = document.documentElement;
  root.classList.add('pin-wait');
  function release() { root.classList.remove('pin-wait'); }
  function remember() { try { sessionStorage.setItem(KEY, '1'); } catch (e) { /* asked again next load */ } }
  // After the PIN itself: no asking on this device for the minutes it trusts.
  function trust() {
    try {
      var min = Number(localStorage.getItem('lpra.pin.grace') || 0);
      if (min > 0) localStorage.setItem('lpra.pin.until', String(Date.now() + min * 60000));
    } catch (e) { /* asks every tab */ }
  }

  fetch('/api/panel/pin', {cache: 'no-store'})
    .then(function (r) { return r.ok ? r.json() : {pin: false}; })
    .then(function (d) {
      if (!d.pin) { remember(); release(); return; }
      if (document.body) lock(); else document.addEventListener('DOMContentLoaded', lock);
    })
    .catch(release);

  function lock() {
    var LOCK = '<svg width="26" height="26" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><rect x="4" y="11" width="16" height="10" rx="2"/><path d="M8 11V7a4 4 0 0 1 8 0v4"/></svg>';
    var BACK = '<svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M21 5H9l-6 7 6 7h12a1 1 0 0 0 1-1V6a1 1 0 0 0-1-1z"/><path d="m16 9-5 6M11 9l5 6"/></svg>';
    var box = document.createElement('div');
    box.className = 'pinlock';
    box.setAttribute('role', 'dialog');
    box.setAttribute('aria-modal', 'true');
    box.setAttribute('aria-label', 'Ввод PIN-кода');
    var keys = '';
    ['1', '2', '3', '4', '5', '6', '7', '8', '9', '', '0', 'back'].forEach(function (k) {
      if (!k) { keys += '<span></span>'; return; }
      keys += '<button type="button" data-k="' + k + '"' + (k === 'back' ? ' aria-label="Стереть">' + BACK : '>' + k) + '</button>';
    });
    box.innerHTML =
      '<div class="pin-card">' +
      '<div class="pin-ico">' + LOCK + '</div>' +
      '<div class="pin-title">Введите PIN-код</div>' +
      '<div class="pin-dots"><i></i><i></i><i></i><i></i></div>' +
      '<div class="pin-msg" aria-live="polite"></div>' +
      '<div class="pin-pad">' + keys + '</div>' +
      '<form method="post" action="/logout" class="pin-out"><button type="submit">Выйти</button></form>' +
      '</div>';
    document.body.appendChild(box);
    requestAnimationFrame(function () { box.classList.add('on'); });
    var dots = box.querySelectorAll('.pin-dots i'), msg = box.querySelector('.pin-msg'), card = box.querySelector('.pin-card');
    var code = '', busy = false;
    function show() {
      for (var i = 0; i < 4; i++) dots[i].classList.toggle('on', i < code.length);
    }
    function press(k) {
      if (busy) return;
      if (k === 'back') { code = code.slice(0, -1); show(); return; }
      if (code.length >= 4) return;
      code += k;
      msg.textContent = '';
      card.classList.remove('bad');
      show();
      if (code.length === 4) check();
    }
    function check() {
      busy = true;
      fetch('/api/panel/pin/check', {method: 'POST', headers: {'Content-Type': 'application/json'}, body: JSON.stringify({pin: code})})
        .then(function (r) { return r.json(); })
        .then(function (r) {
          if (r.ok) {
            remember();
            trust();
            box.classList.add('done');
            release();
            setTimeout(function () { box.remove(); }, 320);
            document.removeEventListener('keydown', onKey, true);
            return;
          }
          if (r.out) { location.href = '/login'; return; }
          card.classList.remove('bad');
          void card.offsetWidth; // restart the shake
          card.classList.add('bad');
          msg.textContent = r.error + (r.left ? ' - осталось попыток: ' + r.left : '');
          setTimeout(function () { code = ''; show(); busy = false; }, 380);
        })
        .catch(function () { msg.textContent = 'нет связи с сервером'; code = ''; show(); busy = false; });
    }
    box.querySelector('.pin-pad').addEventListener('click', function (ev) {
      var b = ev.target.closest('button');
      if (b) press(b.dataset.k);
    });
    // Typed digits, ahead of anything on the page (the terminal included).
    function onKey(ev) {
      if (/^[0-9]$/.test(ev.key)) press(ev.key);
      else if (ev.key === 'Backspace') press('back');
      else if (ev.key !== 'Tab') return;
      ev.preventDefault();
      ev.stopPropagation();
    }
    document.addEventListener('keydown', onKey, true);
    if (document.activeElement && document.activeElement.blur) document.activeElement.blur();
  }
})();