/**
 * Static shell read-more — preview/rest split; full HTML always in DOM for SEO.
 * Preview: first N plain-text words. Rest: complete original HTML (collapsed until toggle).
 * Override per host: data-read-more-words="55" on .nse-read-more-host
 */
(function () {
  'use strict';

  var READ_MORE_WORD_LIMIT = 110;

  function extractPlainText(html) {
    return String(html)
      .replace(/<[^>]+>/g, ' ')
      .replace(/\s+/g, ' ')
      .trim();
  }

  function countWords(text) {
    if (!text) return 0;
    return text.split(/\s+/).filter(Boolean).length;
  }

  function truncateToWords(text, limit) {
    var words = text.split(/\s+/).filter(Boolean);
    if (words.length <= limit) {
      return null;
    }
    return words.slice(0, limit).join(' ') + '…';
  }

  function escapeHtml(text) {
    return String(text)
      .replace(/&/g, '&amp;')
      .replace(/</g, '&lt;')
      .replace(/>/g, '&gt;')
      .replace(/"/g, '&quot;');
  }

  function uniqueId() {
    return 'nse-rm-' + Math.random().toString(36).slice(2, 9);
  }

  function resolveWordLimit(host) {
    if (host) {
      var attr = host.getAttribute('data-read-more-words');
      if (attr !== null && attr !== '') {
        var parsed = parseInt(attr, 10);
        if (!isNaN(parsed) && parsed > 0) {
          return Math.min(Math.max(parsed, 10), 200);
        }
      }
    }
    return READ_MORE_WORD_LIMIT;
  }

  /** Split single <p> with <br> breaks into multiple paragraphs (mirrors NSE PHP). */
  function normalizeParagraphMarkup(html) {
    html = String(html).trim();
    if (!html) return html;

    var pCount = (html.match(/<\/p>/gi) || []).length;
    if (pCount >= 2) return html;

    var pClose = html.toLowerCase().split('</p>').length - 1;
    var pm = html.match(/<p[^>]*>([\s\S]*)<\/p>/i);
    if (pClose === 1 && pm) {
      var inner = pm[1];
      if (/<br\s*\/?>\s*<br\s*\/?>/i.test(inner)) {
        var chunks = inner.split(/<br\s*\/?>\s*<br\s*\/?>/i).map(function (c) {
          return c.trim();
        }).filter(Boolean);
        if (chunks.length >= 2) {
          return chunks.map(function (c) {
            return '<p>' + c + '</p>';
          }).join('');
        }
      } else if ((inner.match(/<br\s*\/?>/gi) || []).length >= 2) {
        var lines = inner.split(/<br\s*\/?>\s*/i).map(function (c) {
          return c.trim();
        }).filter(Boolean);
        if (lines.length >= 2) {
          return lines.map(function (c) {
            return '<p>' + c + '</p>';
          }).join('');
        }
      } else {
        var plain = inner.replace(/<[^>]+>/g, ' ').replace(/\s+/g, ' ').trim();
        if (plain.length > 360) {
          var cut = plain.search(/[.!?]\s+\S/);
          if (cut > 99 && cut < plain.length - 40) {
            var a = plain.slice(0, cut + 1).trim();
            var b = plain.slice(cut + 1).trim();
            if (a && b) {
              return '<p>' + escapeHtml(a) + '</p><p>' + escapeHtml(b) + '</p>';
            }
          }
        }
      }
    }
    return html;
  }

  function buildWrappedMarkup(excerpt, fullHtml) {
    fullHtml = String(fullHtml).trim();
    if (!fullHtml) return '';

    var uid = uniqueId();
    var iconPlus =
      '<svg class="nse-field-read-more__svg nse-field-read-more__svg--plus" width="16" height="16" viewBox="0 0 16 16" fill="none" aria-hidden="true" focusable="false"><path d="M8 1v14M1 8h14" stroke="currentColor" stroke-width="2" stroke-linecap="round"/></svg>';
    var iconMinus =
      '<svg class="nse-field-read-more__svg nse-field-read-more__svg--minus" width="16" height="16" viewBox="0 0 16 16" fill="none" aria-hidden="true" focusable="false"><path d="M1 8h14" stroke="currentColor" stroke-width="2" stroke-linecap="round"/></svg>';
    var out = '<div class="nse-field-read-more" data-nse-read-more="1">';
    out += excerpt;
    out +=
      '<div id="' +
      uid +
      '" class="nse-read-more-rest nse-field-read-more__more nse-field-read-more__more--collapsed" aria-hidden="true">';
    out += fullHtml;
    out += '</div>';
    out +=
      '<button type="button" class="nse-field-read-more__btn" aria-expanded="false" aria-controls="' +
      uid +
      '" data-nse-label-more="Read more" data-nse-label-less="Read less">';
    out += '<span class="nse-field-read-more__label">Read more</span>';
    out += '<span class="nse-field-read-more__icons" aria-hidden="true">' + iconPlus + iconMinus + '</span>';
    out += '</button></div>';
    return out;
  }

  /** Word-count cutoff — plain-text teaser, full HTML in expandable block (mirrors NSE PHP). */
  function wrapReadMoreHtml(html, wordLimit) {
    html = String(html).trim();
    if (!html || html.indexOf('nse-field-read-more') !== -1) return null;

    html = normalizeParagraphMarkup(html);
    var plain = extractPlainText(html);
    if (countWords(plain) <= wordLimit) return null;

    var teaserText = truncateToWords(plain, wordLimit);
    if (!teaserText) return null;

    var excerpt =
      '<p class="nse-read-more-preview nse-field-read-more__teaser">' + escapeHtml(teaserText) + '</p>';
    return buildWrappedMarkup(excerpt, html);
  }

  function syncCollapsedState(wrap) {
    if (!wrap) return;
    var btn = wrap.querySelector('.nse-field-read-more__btn');
    var more = wrap.querySelector('.nse-field-read-more__more');
    var label = btn && btn.querySelector('.nse-field-read-more__label');
    if (!btn || !more) return;

    var lm = btn.getAttribute('data-nse-label-more') || 'Read more';
    btn.setAttribute('aria-expanded', 'false');
    if (label) label.textContent = lm;
    wrap.classList.remove('nse-field-read-more--expanded');
    more.classList.add('nse-field-read-more__more--collapsed');
    more.style.maxHeight = '';
    more.setAttribute('aria-hidden', 'true');
    more.removeAttribute('data-nse-rm-anim');
  }

  function initHosts() {
    document.querySelectorAll('.nse-read-more-host').forEach(function (host) {
      if (host.querySelector('.nse-field-read-more')) {
        syncCollapsedState(host.querySelector('.nse-field-read-more'));
        return;
      }
      var originalHtml = host.innerHTML;
      var wrapped = wrapReadMoreHtml(originalHtml, resolveWordLimit(host));
      if (wrapped) {
        host.innerHTML = wrapped;
        syncCollapsedState(host.querySelector('.nse-field-read-more'));
      }
    });
  }

  function prefersReducedMotion() {
    return (
      typeof window.matchMedia === 'function' &&
      window.matchMedia('(prefers-reduced-motion: reduce)').matches
    );
  }

  function onceMaxHeightEnd(el, fn) {
    function handler(e) {
      if (e.propertyName !== 'max-height') return;
      el.removeEventListener('transitionend', handler);
      fn();
    }
    el.addEventListener('transitionend', handler);
  }

  document.addEventListener('click', function (e) {
    var btn = e.target.closest('.nse-field-read-more__btn');
    if (!btn) return;

    var wrap = btn.closest('.nse-field-read-more');
    if (!wrap) return;
    var more = wrap.querySelector('.nse-field-read-more__more');
    if (!more) return;
    if (more.getAttribute('data-nse-rm-anim') === '1') return;

    var label = btn.querySelector('.nse-field-read-more__label');
    var expanded = btn.getAttribute('aria-expanded') === 'true';
    var lm = btn.getAttribute('data-nse-label-more') || 'Read more';
    var ll = btn.getAttribute('data-nse-label-less') || 'Read less';
    var reduced = prefersReducedMotion();

    more.setAttribute('data-nse-rm-anim', '1');
    function finish() {
      more.removeAttribute('data-nse-rm-anim');
    }

    if (expanded) {
      btn.setAttribute('aria-expanded', 'false');
      if (label) label.textContent = lm;
      wrap.classList.remove('nse-field-read-more--expanded');

      if (reduced) {
        more.classList.add('nse-field-read-more__more--collapsed');
        more.style.maxHeight = '';
        more.setAttribute('aria-hidden', 'true');
        finish();
        return;
      }

      more.style.maxHeight = more.scrollHeight + 'px';
      void more.offsetHeight;
      more.style.maxHeight = '0px';
      onceMaxHeightEnd(more, function () {
        more.classList.add('nse-field-read-more__more--collapsed');
        more.style.maxHeight = '';
        more.setAttribute('aria-hidden', 'true');
        finish();
      });
    } else {
      btn.setAttribute('aria-expanded', 'true');
      if (label) label.textContent = ll;
      wrap.classList.add('nse-field-read-more--expanded');

      if (reduced) {
        more.classList.remove('nse-field-read-more__more--collapsed');
        more.style.maxHeight = 'none';
        more.setAttribute('aria-hidden', 'false');
        finish();
        return;
      }

      var xh = more.scrollHeight;
      more.style.maxHeight = '0px';
      more.classList.remove('nse-field-read-more__more--collapsed');
      more.setAttribute('aria-hidden', 'false');
      void more.offsetHeight;
      more.style.maxHeight = xh + 'px';
      onceMaxHeightEnd(more, function () {
        more.style.maxHeight = 'none';
        finish();
      });
    }
  });

  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', initHosts);
  } else {
    initHosts();
  }
})();