// Bookmark UI. Deliberately small and dependency-free: the state is one
// verse reference, so it lives in localStorage rather than IndexedDB --
// localStorage reads synchronously, which lets the index page paint the
// bookmark link on first paint instead of flashing an empty slot.
(function () {
  'use strict';

  var KEY = 'bible:bookmark';
  var dialog = null;
  var current = null;

  // localStorage throws (not returns null) in some private-browsing modes,
  // so every access is guarded and the feature degrades to a no-op.
  function readBookmark() {
    try { return JSON.parse(localStorage.getItem(KEY) || 'null'); }
    catch (e) { return null; }
  }

  function writeBookmark(value) {
    try { localStorage.setItem(KEY, JSON.stringify(value)); return true; }
    catch (e) { return false; }
  }

  // -- index page ---------------------------------------------------------

  function renderBookmarkLink() {
    var slot = document.getElementById('bookmark');
    if (!slot) return;
    var mark = readBookmark();
    slot.textContent = '';
    if (!mark || !mark.href) { slot.hidden = true; return; }
    var label = document.createElement('span');
    label.className = 'bookmark-label';
    label.textContent = 'Bookmark';
    var link = document.createElement('a');
    link.className = 'bookmark-link';
    link.href = mark.href;
    link.textContent = mark.ref;
    slot.appendChild(label);
    slot.appendChild(document.createTextNode(' '));
    slot.appendChild(link);
    slot.hidden = false;
  }

  // -- dialog -------------------------------------------------------------

  function buildDialog() {
    var d = document.createElement('dialog');
    d.id = 'verse-dialog';
    d.className = 'verse-dialog';
    d.innerHTML =
      '<h2 class="verse-dialog-ref"></h2>' +
      '<p class="verse-dialog-note" hidden>Currently bookmarked.</p>' +
      '<div class="verse-dialog-actions">' +
        '<button type="button" data-action="bookmark">Set bookmark</button>' +
        '<button type="button" data-action="copy">Copy link</button>' +
        '<button type="button" data-action="close">Close</button>' +
      '</div>' +
      '<p class="verse-dialog-status" role="status" aria-live="polite"></p>';
    document.body.appendChild(d);
    d.addEventListener('click', onDialogClick);
    return d;
  }

  function status(text) {
    var el = dialog.querySelector('.verse-dialog-status');
    el.textContent = text || '';
    return el;
  }

  function closeSoon() {
    setTimeout(function () { if (dialog.open) dialog.close(); }, 900);
  }

  function onDialogClick(event) {
    // A click landing on the dialog itself is the backdrop, not the content.
    if (event.target === dialog) { dialog.close(); return; }

    var button = event.target.closest('button[data-action]');
    if (!button) return;
    var action = button.getAttribute('data-action');

    if (action === 'close') {
      dialog.close();
    } else if (action === 'bookmark') {
      var saved = writeBookmark({
        ref: current.ref, href: current.href, savedAt: Date.now()
      });
      status(saved ? 'Bookmark set.' : 'Could not save: storage unavailable.');
      renderBookmarkLink();
      dialog.querySelector('.verse-dialog-note').hidden = !saved;
      if (saved) closeSoon();
    } else if (action === 'copy') {
      copyLink(current.url);
    }
  }

  // navigator.clipboard only exists in a secure context, so over plain http
  // this always falls through to a selectable field rather than failing.
  function copyLink(url) {
    if (navigator.clipboard && window.isSecureContext) {
      navigator.clipboard.writeText(url).then(function () {
        status('Link copied.');
        closeSoon();
      }, function () { offerManualCopy(url); });
    } else {
      offerManualCopy(url);
    }
  }

  function offerManualCopy(url) {
    var el = status('Copy this link:');
    var field = document.createElement('input');
    field.type = 'text';
    field.readOnly = true;
    field.value = url;
    field.className = 'verse-dialog-url';
    el.appendChild(document.createTextNode(' '));
    el.appendChild(field);
    field.focus();
    field.select();
  }

  // -- verse numbers ------------------------------------------------------

  function verseInfo(span) {
    var article = document.querySelector('article.book');
    var section = span.closest('.chapter');
    var book = article
      ? (article.getAttribute('data-name') || article.getAttribute('data-book'))
      : '';
    var chapter = section ? section.getAttribute('data-chapter') : '';
    var page = location.pathname.split('/').pop() || 'index.html';
    return {
      ref: book + ' ' + chapter + ':' + (span.textContent || '').trim(),
      // Relative, so a saved bookmark survives a change of host or port.
      href: page + '#' + span.id,
      url: location.origin + location.pathname + '#' + span.id
    };
  }

  function openFor(span) {
    if (!dialog) dialog = buildDialog();
    current = verseInfo(span);
    dialog.querySelector('.verse-dialog-ref').textContent = current.ref;
    var mark = readBookmark();
    dialog.querySelector('.verse-dialog-note').hidden =
      !(mark && mark.href === current.href);
    status('');
    if (typeof dialog.showModal === 'function') dialog.showModal();
    else dialog.setAttribute('open', '');
  }

  function initVerses() {
    var verses = document.querySelectorAll('.chapter .v');
    if (!verses.length) return;
    // Applied here rather than baked into the HTML: without this script the
    // numbers are plain text, and announcing them as buttons would lie.
    for (var i = 0; i < verses.length; i++) {
      verses[i].setAttribute('role', 'button');
      verses[i].setAttribute('tabindex', '0');
      verses[i].setAttribute('aria-label',
        'Verse ' + (verses[i].textContent || '').trim() + ', options');
    }
    document.addEventListener('click', function (event) {
      var verse = event.target.closest ? event.target.closest('.v') : null;
      if (verse && verse.id) { event.preventDefault(); openFor(verse); }
    });
    document.addEventListener('keydown', function (event) {
      if (event.key !== 'Enter' && event.key !== ' ') return;
      var el = document.activeElement;
      if (el && el.classList && el.classList.contains('v') && el.id) {
        event.preventDefault();
        openFor(el);
      }
    });
  }

  function init() {
    renderBookmarkLink();
    initVerses();
  }

  // Another tab changing the bookmark updates this one's index link.
  window.addEventListener('storage', function (event) {
    if (event.key === KEY) renderBookmarkLink();
  });

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