'use strict';

// ---------------------------------------------------------------------------
// Articles in the book reader (DioraArticle) — blog posts and news (feeds.js)
// read like books: the same overlay, typography and colours (⚙, kept for all
// articles together), pages or scrolling (63-pages.js) with the notes at the
// page's foot, search, read-aloud, full screen. Bookmarks, markings and the
// notes margin stay with books (an article has nowhere to keep them).
//
// The article is one "chapter" in #reader-content; currentBookId stays null,
// so nothing of a book's position or annotations is saved. Where it was read
// to goes back to its owner (onProgress), as do clicks on its own buttons.
// ---------------------------------------------------------------------------
(function () {
  let session = null;   // {title, html, startFraction, onProgress, onClick, onClose, actions}
  let progressTimer = 0;

  const overlay = () => document.getElementById('reader-overlay');
  const content = () => document.getElementById('reader-content');

  // Same-page links: the notes of a blog post ("¹" → "#fn1") become references
  // like in books; other jumps inside the post must not change the app's
  // address (#books, #feeds …): kept as internal links (the apps follow them).
  function markLinks(root) {
    root.querySelectorAll('a[href^="#"]').forEach(a => {
      const href = a.getAttribute('href');
      a.removeAttribute('href');
      if (href.length < 2) return;
      // "#t=754": a second in a podcast's article, never a note.
      if (!/^#t=\d+$/.test(href) && !_isNoteBacklink(a) && _looksLikeFootnoteLink(a, href)) {
        a.dataset.footnoteRef = href.slice(1);
        a.dataset.footnoteHref = href;
        a.style.cursor = 'pointer';
      } else {
        a.dataset.internalHref = href;
      }
    });
    // Everything else opens outside.
    root.querySelectorAll('a[href]').forEach(a => {
      a.target = '_blank';
      a.rel = 'noopener noreferrer';
    });
  }

  // How far it is read: down to the bottom of what is on screen (0-1).
  function fraction() {
    const c = content();
    const ch = c && c.querySelector(':scope > [data-epub-src]');
    if (!ch || !ch.offsetHeight) return 0;
    return Math.max(0, Math.min(1, (c.scrollTop + c.clientHeight - ch.offsetTop) / ch.offsetHeight));
  }

  function report() {
    if (session && session.onProgress) session.onProgress(fraction());
  }

  function onScroll() {
    clearTimeout(progressTimer);
    progressTimer = setTimeout(report, 1200);
  }

  function onClick(e) {
    if (session && session.onClick) session.onClick(e);
  }

  // The article's own buttons (star, project, original): in the browser's
  // header; the apps put them into their reader menu (native-ui.js asks actions()).
  function renderActions() {
    const bar = document.querySelector('#reader-overlay .reader-header-actions');
    if (!bar) return;
    let box = bar.querySelector('.reader-article-actions');
    if (!box) {
      box = document.createElement('span');
      box.className = 'reader-article-actions';
      bar.insertBefore(box, bar.firstChild);
    }
    box.textContent = '';
    actions().forEach(a => {
      const b = document.createElement('button');
      b.type = 'button';
      b.className = 'btn-icon' + (a.active ? ' active' : '');
      b.title = a.label;
      b.textContent = a.icon;
      b.addEventListener('click', e => { e.stopPropagation(); a.action(); });
      box.appendChild(b);
    });
  }

  function actions() {
    return session && session.actions ? session.actions().filter(Boolean) : [];
  }

  async function open(o) {
    const ov = overlay();
    const c = content();
    if (!ov || !c) return;
    if (session) {
      report();
      stopReadAloud();   // the next article: the voice was reading the last one
    }
    else if (ov.style.display !== 'none') closeReader();   // a book was open
    session = o;
    loadReaderSettings('article');
    _charIndex = null;
    _readPos = null;
    currentBookId = null;
    ov.classList.add('reader-article-mode');
    $('reader-title').textContent = o.title || '';
    c.textContent = '';
    const ch = document.createElement('div');
    ch.setAttribute('data-epub-src', 'article');
    ch.id = 'epub-chapter-0';
    ch.className = 'fd-artview';
    ch.innerHTML = o.html;
    markLinks(ch);
    c.appendChild(ch);
    ov.style.display = '';
    applyReaderSettings(false);
    enterReaderImmersiveMode();
    renderActions();
    c.scrollTop = 0;
    if (window.DioraPages) DioraPages.opened();
    if (window.DioraUI && DioraUI.updateFooter) DioraUI.updateFooter();
    const f = o.startFraction || 0;
    if (f > 0.02 && f < 0.9) {
      // Back where reading stopped (on any device).
      await new Promise(r => requestAnimationFrame(r));
      if (session !== o) return;
      _suppressScrollJumpDetect();
      c.scrollTop = Math.max(0, f * ch.offsetHeight + ch.offsetTop - c.clientHeight);
    } else {
      setTimeout(() => { if (session === o) report(); }, 1500);   // short enough to fit: read at once
    }
  }

  // Replaces what is shown (the overview of a story arrived) without moving.
  function update(html) {
    const ch = content() && content().querySelector(':scope > [data-epub-src="article"]');
    if (!ch || !session) return;
    session.html = html;
    ch.innerHTML = html;
    markLinks(ch);
  }

  // closeReader (62-reader.js) calls this before it empties the reader.
  window._articleReaderClosed = function () {
    if (!session) return;
    clearTimeout(progressTimer);
    report();
    const s = session;
    session = null;
    overlay().classList.remove('reader-article-mode');
    const box = document.querySelector('#reader-overlay .reader-article-actions');
    if (box) box.remove();
    if (s.onClose) setTimeout(s.onClose, 0);
  };

  window.DioraArticle = {
    open,
    update,
    isOpen: () => !!session,
    close: () => { if (session) closeReader(); },
    actions,
    refreshActions: renderActions,
    fraction,
  };

  document.addEventListener('DOMContentLoaded', () => {
    const c = content();
    if (!c) return;
    c.addEventListener('scroll', () => { if (session) onScroll(); }, {passive: true});
    c.addEventListener('click', e => { if (session) onClick(e); });
  });
})();