(function ($) {
  var PDFJS_BASE = '/statics/js/pdfjs/';
  var pdfjsPromise = null;
  var resizeTimer = null;

  function hasPdfExtension(href) {
    return /\.pdf(?:[?#].*)?$/i.test(href || '');
  }

  function parseHref(href) {
    var parser = document.createElement('a');
    parser.href = href;
    return parser;
  }

  function normalizePathname(pathname) {
    if (!pathname) {
      return '/';
    }
    return pathname.charAt(0) === '/' ? pathname : '/' + pathname;
  }

  function pdfSource(href) {
    if (!href || href.charAt(0) === '#') {
      return '';
    }

    var parser = parseHref(href);
    var protocol = (parser.protocol || '').toLowerCase();
    var isHttp = protocol === 'http:' || protocol === 'https:';

    if (isHttp && parser.host !== window.location.host) {
      return '';
    }

    if (isHttp) {
      return normalizePathname(parser.pathname) + parser.search + parser.hash;
    }

    if (protocol && protocol !== ':') {
      return '';
    }

    return href;
  }

  function pdfFrameSource(src) {
    var hashIndex = src.indexOf('#');
    var base = hashIndex === -1 ? src : src.substring(0, hashIndex);
    var hash = hashIndex === -1 ? '' : src.substring(hashIndex + 1);
    var params = hash ? hash.split('&') : [];

    function hasParam(name) {
      var prefix = name.toLowerCase() + '=';
      var i;

      for (i = 0; i < params.length; i++) {
        if (params[i].toLowerCase().indexOf(prefix) === 0) {
          return true;
        }
      }
      return false;
    }

    if (!hasParam('toolbar')) {
      params.push('toolbar=0');
    }
    if (!hasParam('navpanes')) {
      params.push('navpanes=0');
    }
    if (!hasParam('scrollbar')) {
      params.push('scrollbar=1');
    }

    return base + '#' + params.join('&');
  }

  function decodeFilename(filename) {
    try {
      return decodeURIComponent(filename.replace(/\+/g, '%20'));
    } catch (e) {
      return filename;
    }
  }

  function pdfTitle($link, href) {
    var title = $.trim($link.text());
    var parser;
    var filename;

    if (title && title !== href) {
      return title;
    }

    parser = parseHref(href);
    filename = normalizePathname(parser.pathname).split('/').pop();
    return decodeFilename(filename || 'PDF');
  }

  function addStyle() {
    if (document.getElementById('cms-pdf-inline-style')) {
      return;
    }

    $('head').append(
      '<style id="cms-pdf-inline-style">' +
        '.cms-pdf-viewer{margin:18px 0;border:1px solid #d8dce3;background:#f4f6f9;overflow:hidden;}' +
        '.cms-pdf-pages{padding:14px 10px;background:#f4f6f9;}' +
        '.cms-pdf-page{display:block;margin:0 auto 14px;background:#fff;box-shadow:0 0 0 1px #dde2ea;max-width:100%;}' +
        '.cms-pdf-page:last-child{margin-bottom:0;}' +
        '.cms-pdf-status{padding:18px 12px;text-align:center;color:#666;background:#fff;font-size:14px;line-height:1.8;}' +
        '.cms-pdf-frame{display:block;width:100%;height:760px;border:0;background:#fff;}' +
        '@media(max-width:768px){.cms-pdf-pages{padding:10px 6px;}.cms-pdf-page{margin-bottom:10px;}.cms-pdf-frame{height:70vh;min-height:420px;}}' +
      '</style>'
    );
  }

  function canUsePdfJs() {
    var canvas = document.createElement('canvas');
    return !!(window.Promise && window.Uint8Array && canvas.getContext && window.Function);
  }

  function importModule(url) {
    try {
      return new Function('url', 'return import(url);')(url);
    } catch (e) {
      return Promise.reject(e);
    }
  }

  function loadPdfJs() {
    if (!pdfjsPromise) {
      pdfjsPromise = importModule(PDFJS_BASE + 'build/pdf.min.js').then(function (pdfjsLib) {
        pdfjsLib.GlobalWorkerOptions.workerSrc = PDFJS_BASE + 'build/pdf.worker.min.js';
        return pdfjsLib;
      });
    }
    return pdfjsPromise;
  }

  function buildFallbackViewer(src, title) {
    var $viewer = $('<div class="cms-pdf-viewer"></div>');
    var $frame = $('<iframe class="cms-pdf-frame" loading="lazy"></iframe>')
      .attr('src', pdfFrameSource(src))
      .attr('title', title);

    $viewer.append($frame);
    return $viewer;
  }

  function showFallback($viewer, src, title) {
    var $fallback = buildFallbackViewer(src, title);
    $viewer.replaceWith($fallback);
  }

  function buildViewer(src, title) {
    var $viewer = $('<div class="cms-pdf-viewer"></div>');
    var $status = $('<div class="cms-pdf-status"></div>').text('PDF加载中...');
    var $pages = $('<div class="cms-pdf-pages"></div>');

    if (!canUsePdfJs()) {
      return buildFallbackViewer(src, title);
    }

    $viewer
      .attr('data-pdf-src', src)
      .attr('data-pdf-title', title)
      .append($status, $pages);

    renderPdf($viewer, src, title);
    return $viewer;
  }

  function renderPdf($viewer, src, title) {
    loadPdfJs()
      .then(function (pdfjsLib) {
        return pdfjsLib.getDocument({
          url: src,
          cMapUrl: PDFJS_BASE + 'cmaps/',
          cMapPacked: true,
          standardFontDataUrl: PDFJS_BASE + 'standard_fonts/',
          wasmUrl: PDFJS_BASE + 'wasm/',
          iccUrl: PDFJS_BASE + 'iccs/'
        }).promise;
      })
      .then(function (pdf) {
        $viewer.data('cmsPdfDoc', pdf);
        $viewer.find('.cms-pdf-status').remove();
        renderPages($viewer, pdf);
      })
      .catch(function () {
        showFallback($viewer, src, title);
      });
  }

  function renderPages($viewer, pdf) {
    var $pages = $viewer.find('.cms-pdf-pages');
    var renderId = ($viewer.data('cmsPdfRenderId') || 0) + 1;
    var maxWidth = Math.max(260, $viewer.innerWidth() - 20);
    var outputScale = Math.min(window.devicePixelRatio || 1, 2);

    $viewer.data('cmsPdfRenderId', renderId);
    $viewer.data('cmsPdfWidth', $viewer.innerWidth());
    $pages.empty();

    function renderPage(pageNumber) {
      if ($viewer.data('cmsPdfRenderId') !== renderId || pageNumber > pdf.numPages) {
        return Promise.resolve();
      }

      return pdf.getPage(pageNumber).then(function (page) {
        var baseViewport = page.getViewport({ scale: 1 });
        var scale = maxWidth / baseViewport.width;
        var viewport = page.getViewport({ scale: scale });
        var canvas = document.createElement('canvas');
        var context = canvas.getContext('2d');
        var transform = outputScale !== 1 ? [outputScale, 0, 0, outputScale, 0, 0] : null;

        canvas.className = 'cms-pdf-page';
        canvas.width = Math.floor(viewport.width * outputScale);
        canvas.height = Math.floor(viewport.height * outputScale);
        canvas.style.width = Math.floor(viewport.width) + 'px';
        canvas.style.height = Math.floor(viewport.height) + 'px';

        context.fillStyle = '#fff';
        context.fillRect(0, 0, canvas.width, canvas.height);
        $pages.append(canvas);

        return page.render({
          canvasContext: context,
          viewport: viewport,
          transform: transform
        }).promise.then(function () {
          return renderPage(pageNumber + 1);
        });
      });
    }

    renderPage(1);
  }

  function simpleLinkParent($link) {
    var $parent = $link.parent();
    var textWithoutLink;

    if (!$parent.is('p')) {
      return null;
    }

    if ($parent.find('a[href]').length !== 1) {
      return null;
    }

    textWithoutLink = $.trim($parent.clone().find('a').remove().end().text());
    return textWithoutLink ? null : $parent;
  }

  function rerenderVisiblePdfs() {
    $('.cms-pdf-viewer').each(function () {
      var $viewer = $(this);
      var pdf = $viewer.data('cmsPdfDoc');
      var oldWidth = $viewer.data('cmsPdfWidth') || 0;
      var newWidth = $viewer.innerWidth();

      if (pdf && Math.abs(newWidth - oldWidth) > 20) {
        renderPages($viewer, pdf);
      }
    });
  }

  function bindResize() {
    $(window).on('resize', function () {
      window.clearTimeout(resizeTimer);
      resizeTimer = window.setTimeout(rerenderVisiblePdfs, 180);
    });
  }

  function renderPdfLinks() {
    var $content = $('.wp_articlecontent');

    if (!$content.length) {
      $content = $('body');
    }

    addStyle();
    bindResize();

    $content.find('a[href]').each(function () {
      var $link = $(this);
      var href = $link.attr('href');
      var src;
      var title;
      var $viewer;
      var $simpleParent;

      if ($link.data('cmsPdfReady') || $link.closest('.cms-pdf-viewer').length) {
        return;
      }

      if (!hasPdfExtension(href)) {
        return;
      }

      src = pdfSource(href);
      if (!src) {
        return;
      }

      $link.data('cmsPdfReady', true);
      title = pdfTitle($link, href);
      $viewer = buildViewer(src, title);
      $simpleParent = simpleLinkParent($link);

      if ($simpleParent) {
        $simpleParent.replaceWith($viewer);
      } else {
        $link.after($viewer);
      }
    });
  }

  $(renderPdfLinks);
})(jQuery);