/* ============================================================================
   SoftSPM - wejście bloków i liczniki
   Delikatne pojawianie się sekcji przy przewijaniu oraz naliczanie liczb
   w pasku Akademii. Wszystko wyłącza się przy prefers-reduced-motion,
   a bez JavaScriptu treść i tak jest widoczna - styl startowy nakładamy
   dopiero po dodaniu klasy js-reveal.
   ========================================================================= */
(function () {
  'use strict';

  var supported = 'IntersectionObserver' in window && 'classList' in document.documentElement;
  var reduced = window.matchMedia && window.matchMedia('(prefers-reduced-motion: reduce)').matches;

  if (!supported || reduced) {
    return;
  }

  document.documentElement.classList.add('js-reveal');

  function countUp(node) {
    var target = parseInt(node.getAttribute('data-count'), 10);
    if (isNaN(target)) { return; }
    var suffix = node.getAttribute('data-suffix') || '';
    var duration = 900;
    var started = null;

    function step(now) {
      if (started === null) { started = now; }
      var progress = Math.min(1, (now - started) / duration);
      // wyhamowanie na końcu - liczba dobija do wartości, nie przeskakuje
      var eased = 1 - Math.pow(1 - progress, 3);
      node.textContent = Math.round(target * eased) + suffix;
      if (progress < 1) { requestAnimationFrame(step); }
    }

    node.textContent = '0' + suffix;
    requestAnimationFrame(step);
  }

  var observer = new IntersectionObserver(function (entries) {
    for (var i = 0; i < entries.length; i++) {
      var entry = entries[i];
      if (!entry.isIntersecting) { continue; }
      var node = entry.target;
      node.classList.add('is-in');
      observer.unobserve(node);

      var counters = node.querySelectorAll('[data-count]');
      for (var c = 0; c < counters.length; c++) { countUp(counters[c]); }
    }
  }, { rootMargin: '0px 0px -12% 0px', threshold: 0.12 });

  var blocks = document.querySelectorAll('[data-reveal]');
  for (var i = 0; i < blocks.length; i++) { observer.observe(blocks[i]); }
})();