/* global window, document */

(function () {
  'use strict';

  function initGalleryThumbs() {
    var imgs = document.querySelectorAll('div.luxtools-gallery img[data-thumb-src]');
    if (!imgs || !imgs.length) return;

    function loadThumb(img) {
      var src = img.getAttribute('data-thumb-src') || '';
      if (!src) return;
      if (img.getAttribute('data-thumb-loading') === '1') return;
      img.setAttribute('data-thumb-loading', '1');

      var pre = new window.Image();
      pre.onload = function () {
        img.src = src;
        img.removeAttribute('data-thumb-src');
        img.removeAttribute('data-thumb-loading');
      };
      pre.onerror = function () {
        img.removeAttribute('data-thumb-loading');
      };
      pre.src = src;
    }

    if ('IntersectionObserver' in window) {
      var io = new window.IntersectionObserver(function (entries) {
        entries.forEach(function (entry) {
          if (!entry.isIntersecting) return;
          loadThumb(entry.target);
          io.unobserve(entry.target);
        });
      }, { rootMargin: '200px' });

      imgs.forEach(function (img) { io.observe(img); });
    } else {
      // Fallback: load soon after initial render
      window.setTimeout(function () {
        imgs.forEach(loadThumb);
      }, 0);
    }
  }

  function ensureLightbox() {
    var existing = document.querySelector('.luxtools-lightbox');
    if (existing) return existing;

    var root = document.createElement('div');
    root.className = 'luxtools-lightbox';
    root.setAttribute('role', 'dialog');
    root.setAttribute('aria-modal', 'true');
    root.setAttribute('aria-hidden', 'true');

    root.innerHTML =
      '<div class="luxtools-lightbox-backdrop" data-luxtools-action="close"></div>' +
      '<div class="luxtools-lightbox-stage">' +
        '<button type="button" class="luxtools-lightbox-btn luxtools-lightbox-close" data-luxtools-action="close" aria-label="Close">×</button>' +
        '<button type="button" class="luxtools-lightbox-btn luxtools-lightbox-prev" data-luxtools-action="prev" aria-label="Previous">‹</button>' +
        '<img class="luxtools-lightbox-img" alt="" />' +
        '<button type="button" class="luxtools-lightbox-btn luxtools-lightbox-next" data-luxtools-action="next" aria-label="Next">›</button>' +
        '<button type="button" class="luxtools-lightbox-btn luxtools-lightbox-opennew" data-luxtools-action="newtab" aria-label="Open in new tab">↗</button>' +
        '<div class="luxtools-lightbox-caption"></div>' +
      '</div>';

    document.body.appendChild(root);
    return root;
  }

  function getGalleryItems(galleryEl) {
    var links = galleryEl.querySelectorAll('a.luxtools-gallery-item[data-luxtools-full]');
    var items = [];
    links.forEach(function (a) {
      var full = a.getAttribute('data-luxtools-full') || a.getAttribute('href') || '';
      var name = a.getAttribute('data-luxtools-name') || a.getAttribute('title') || '';
      if (!full) return;
      items.push({ el: a, full: full, name: name });
    });
    return items;
  }

  function openLightboxFor(galleryEl, startEl) {
    var items = getGalleryItems(galleryEl);
    if (!items.length) return;

    var index = 0;
    for (var i = 0; i < items.length; i++) {
      if (items[i].el === startEl) { index = i; break; }
    }

    var lb = ensureLightbox();
    var img = lb.querySelector('img.luxtools-lightbox-img');
    var cap = lb.querySelector('.luxtools-lightbox-caption');

    var pushedHistory = false;
    var closingFromPopstate = false;

    function clamp(n) {
      if (n < 0) return items.length - 1;
      if (n >= items.length) return 0;
      return n;
    }

    function render() {
      var it = items[index];
      img.src = it.full;
      img.setAttribute('data-luxtools-index', String(index));
      cap.textContent = (it.name || '').trim();
    }

    function openInNewTab() {
      var it = items[index];
      if (!it || !it.full) return;
      try {
        window.open(it.full, '_blank', 'noopener');
      } catch (e) {
        // ignore
      }
    }

    function close() {
      lb.classList.remove('is-open');
      lb.setAttribute('aria-hidden', 'true');
      try { document.documentElement.classList.remove('luxtools-noscroll'); } catch (e) {}
      try { document.body.style.overflow = ''; } catch (e) {}
      // Clear src to stop downloads on close.
      img.src = '';
      document.removeEventListener('keydown', onKeyDown, true);
      window.removeEventListener('popstate', onPopState, true);

      // If we opened by pushing a state, pop it when closing via UI.
      if (pushedHistory && !closingFromPopstate) {
        try {
          if (window.history && window.history.state && window.history.state.luxtoolsLightbox === 1) {
            window.history.back();
          }
        } catch (e) {
          // ignore
        }
      }
    }

    function next() {
      index = clamp(index + 1);
      render();
    }

    function prev() {
      index = clamp(index - 1);
      render();
    }

    function onKeyDown(e) {
      if (!lb.classList.contains('is-open')) return;
      var key = e.key || '';
      if (key === 'Escape') {
        e.preventDefault();
        close();
      } else if (key === 'ArrowRight') {
        e.preventDefault();
        next();
      } else if (key === 'ArrowLeft') {
        e.preventDefault();
        prev();
      }
    }

    function onPopState() {
      if (!lb.classList.contains('is-open')) return;
      closingFromPopstate = true;
      try { close(); } finally { closingFromPopstate = false; }
    }

    lb.onclick = function (e) {
      var t = e.target;
      if (!t || !t.getAttribute) return;
      var action = t.getAttribute('data-luxtools-action') || '';
      if (action === 'close') { e.preventDefault(); close(); }
      if (action === 'next') { e.preventDefault(); next(); }
      if (action === 'prev') { e.preventDefault(); prev(); }
      if (action === 'newtab') { e.preventDefault(); openInNewTab(); }

      // Click outside the image closes (but don't interfere with controls).
      if (t.closest && t.closest('button.luxtools-lightbox-btn')) return;
      if (t.closest && t.closest('img.luxtools-lightbox-img')) return;
      e.preventDefault();
      close();
    };

    // Open
    lb.classList.add('is-open');
    lb.setAttribute('aria-hidden', 'false');
    try { document.documentElement.classList.add('luxtools-noscroll'); } catch (e) {}
    try { document.body.style.overflow = 'hidden'; } catch (e) {}
    document.addEventListener('keydown', onKeyDown, true);
    window.addEventListener('popstate', onPopState, true);

    // Allow closing via browser back button.
    try {
      if (window.history && window.history.pushState) {
        window.history.pushState({ luxtoolsLightbox: 1 }, '', window.location.href);
        pushedHistory = true;
      }
    } catch (e) {
      // ignore
    }
    render();
  }

  function getServiceUrl(el) {
    var url = el.getAttribute('data-service-url') || '';
    url = (url || '').trim();
    if (!url) return '';
    // strip trailing slashes
    return url.replace(/\/+$/, '');
  }

  function pingOpenViaImage(el, rawPath) {
    var baseUrl = getServiceUrl(el);
    if (!baseUrl) return;
    var url = baseUrl + '/open?path=' + encodeURIComponent(rawPath);

    // Fire-and-forget without CORS.
    try {
      var img = new window.Image();
      img.src = url;
    } catch (e) {
      // ignore
    }
  }

  function openViaService(el, rawPath) {
    var baseUrl = getServiceUrl(el);
    if (!baseUrl) return Promise.reject(new Error('No client service configured'));

    var headers = {
      'Content-Type': 'application/json'
    };

    return window.fetch(baseUrl + '/open', {
      method: 'POST',
      mode: 'cors',
      credentials: 'omit',
      headers: headers,
      body: JSON.stringify({ path: rawPath })
    }).then(function (res) {
      if (!res.ok) {
        return res.json().catch(function () { return null; }).then(function (body) {
          var msg = (body && body.message) ? body.message : ('HTTP ' + res.status);
          throw new Error(msg);
        });
      }
      return res.json().catch(function () { return { ok: true }; });
    });
  }

  function normalizeToFileUrl(path) {
    if (!path) return '';

    // already a file URL
    if (/^file:\/\//i.test(path)) return path;

    // UNC path: \\server\share\path
    if (/^\\\\/.test(path)) {
      var p = path.replace(/^\\\\/, '');
      p = p.replace(/\\/g, '/');
      return 'file://///' + p;
    }

    // Windows drive: C:\path\to\file
    if (/^[a-zA-Z]:\\/.test(path)) {
      var drive = path[0].toUpperCase();
      var rest = path.slice(2).replace(/\\/g, '/');
      return 'file:///' + drive + ':' + rest;
    }

    // POSIX absolute: /home/user/file
    if (path[0] === '/') {
      return 'file://' + path;
    }

    // Fall back to using the provided string.
    return path;
  }

  function findOpenElement(target) {
    var el = target;
    while (el && el !== document) {
      if (el.classList && el.classList.contains('luxtools-open')) return el;
      el = el.parentNode;
    }
    return null;
  }

  function findGalleryItem(target) {
    var el = target;
    while (el && el !== document) {
      if (el.classList && el.classList.contains('luxtools-gallery-item')) return el;
      el = el.parentNode;
    }
    return null;
  }

  function onClick(event) {
    // Image gallery lightbox: intercept clicks so we don't navigate away.
    var galleryItem = findGalleryItem(event.target);
    if (galleryItem) {
      var gallery = galleryItem.closest ? galleryItem.closest('div.luxtools-gallery[data-luxtools-gallery="1"]') : null;
      if (gallery) {
        event.preventDefault();
        openLightboxFor(gallery, galleryItem);
        return;
      }
    }

    var el = findOpenElement(event.target);
    if (!el) return;

    // {{open>...}} renders as a link; avoid jumping to '#'.
    if (el.tagName && el.tagName.toLowerCase() === 'a') {
      event.preventDefault();
    }

    var raw = el.getAttribute('data-path') || '';
    if (!raw) return;

    // Prefer local client service.
    openViaService(el, raw)
      .catch(function (err) {
        // If the browser blocks the request before it reaches localhost (mixed-content,
        // extensions, stricter CORS handling), fall back to a no-CORS GET ping.
        pingOpenViaImage(el, raw);

        // Fallback to old behavior (often blocked in modern browsers).
        var url = normalizeToFileUrl(raw);
        if (!url) return;
        console.warn('Local client service failed, falling back to file:// navigation:', err);
        try {
          window.open(url, '_blank', 'noopener');
        } catch (e) {
          try {
            window.location.href = url;
          } catch (e2) {
            console.error('Failed to open file URL:', e2);
          }
        }
      });
  }

  document.addEventListener('click', onClick, false);
  document.addEventListener('DOMContentLoaded', initGalleryThumbs, false);
})();