text: import Clipboard from "clipboard";
  import Code from "../services/code";
  
  class PageDisplay {
  
      constructor(elem) {
          this.elem = elem;
          this.pageId = elem.getAttribute('page-display');
  
          Code.highlight();
          this.setupPointer();
          this.setupStickySidebar();
          this.setupNavHighlighting();
  
          // Check the hash on load
          if (window.location.hash) {
              let text = window.location.hash.replace(/\%20/g, ' ').substr(1);
              this.goToText(text);
          }
  
          // Sidebar page nav click event
          $('.sidebar-page-nav').on('click', 'a', event => {
              goToText(event.target.getAttribute('href').substr(1));
          });
      }
  
      goToText(text) {
          let idElem = document.getElementById(text);
          $('.page-content [data-highlighted]').attr('data-highlighted', '').css('background-color', '');
          if (idElem !== null) {
              window.scrollAndHighlight(idElem);
          } else {
              $('.page-content').find(':contains("' + text + '")').smoothScrollTo();
          }
      }
  
      setupPointer() {
          if (document.getElementById('pointer') === null) return;
          // Set up pointer
          let $pointer = $('#pointer').detach();
          let pointerShowing = false;
          let $pointerInner = $pointer.children('div.pointer').first();
          let isSelection = false;
          let pointerModeLink = true;
          let pointerSectionId = '';
  
          // Select all contents on input click
          $pointer.on('click', 'input', event => {
              $(this).select();
              event.stopPropagation();
          });
  
          $pointer.on('click focus', event => {
              event.stopPropagation();
          });
  
          // Pointer mode toggle
          $pointer.on('click', 'span.icon', event => {
              event.stopPropagation();
              let $icon = $(event.currentTarget);
              pointerModeLink = !pointerModeLink;
              $icon.find('[data-icon="include"]').toggle(!pointerModeLink);
              $icon.find('[data-icon="link"]').toggle(pointerModeLink);
              updatePointerContent();
          });
  
          // Set up clipboard
          let clipboard = new Clipboard($pointer[0].querySelector('button'));
  
          // Hide pointer when clicking away
          $(document.body).find('*').on('click focus', event => {
              if (!pointerShowing || isSelection) return;
              $pointer.detach();
              pointerShowing = false;
          });
  
          let updatePointerContent = () => {
              let inputText = pointerModeLink ? window.baseUrl(`/link/${this.pageId}#${pointerSectionId}`) : `{{@${this.pageId}#${pointerSectionId}}}`;
              if (pointerModeLink && inputText.indexOf('http') !== 0) inputText = window.location.protocol + "//" + window.location.host + inputText;
  
              $pointer.find('input').val(inputText);
          };
  
          // Show pointer when selecting a single block of tagged content
          $('.page-content [id^="bkmrk"]').on('mouseup keyup', function (e) {
              e.stopPropagation();
              let selection = window.getSelection();
              if (selection.toString().length === 0) return;
  
              // Show pointer and set link
              let $elem = $(this);
              pointerSectionId = $elem.attr('id');
              updatePointerContent();
  
              $elem.before($pointer);
              $pointer.show();
              pointerShowing = true;
  
              // Set pointer to sit near mouse-up position
              let pointerLeftOffset = (e.pageX - $elem.offset().left - ($pointerInner.width() / 2));
              if (pointerLeftOffset < 0) pointerLeftOffset = 0;
              let pointerLeftOffsetPercent = (pointerLeftOffset / $elem.width()) * 100;
              $pointerInner.css('left', pointerLeftOffsetPercent + '%');
  
              isSelection = true;
              setTimeout(() => {
                  isSelection = false;
              }, 100);
          });
      }
  
      setupStickySidebar() {
          // Make the sidebar stick in view on scroll
          let $window = $(window);
          let $sidebar = $("#sidebar .scroll-body");
          let $bookTreeParent = $sidebar.parent();
  
          // Check the page is scrollable and the content is taller than the tree
          let pageScrollable = ($(document).height() > $window.height()) && ($sidebar.height() < $('.page-content').height());
  
          // Get current tree's width and header height
          let headerHeight = $("#header").height() + $(".toolbar").height();
          let isFixed = $window.scrollTop() > headerHeight;
  
          // Fix the tree as a sidebar
          function stickTree() {
              $sidebar.width($bookTreeParent.width() + 15);
              $sidebar.addClass("fixed");
              isFixed = true;
          }
  
          // Un-fix the tree back into position
          function unstickTree() {
              $sidebar.css('width', 'auto');
              $sidebar.removeClass("fixed");
              isFixed = false;
          }
  
          // Checks if the tree stickiness state should change
          function checkTreeStickiness(skipCheck) {
              let shouldBeFixed = $window.scrollTop() > headerHeight;
              if (shouldBeFixed && (!isFixed || skipCheck)) {
                  stickTree();
              } else if (!shouldBeFixed && (isFixed || skipCheck)) {
                  unstickTree();
              }
          }
          // The event ran when the window scrolls
          function windowScrollEvent() {
              checkTreeStickiness(false);
          }
  
          // If the page is scrollable and the window is wide enough listen to scroll events
          // and evaluate tree stickiness.
          if (pageScrollable && $window.width() > 1000) {
              $window.on('scroll', windowScrollEvent);
              checkTreeStickiness(true);
          }
  
          // Handle window resizing and switch between desktop/mobile views
          $window.on('resize', event => {
              if (pageScrollable && $window.width() > 1000) {
                  $window.on('scroll', windowScrollEvent);
                  checkTreeStickiness(true);
              } else {
                  $window.off('scroll', windowScrollEvent);
                  unstickTree();
              }
          });
      }
  
      setupNavHighlighting() {
          // Check if support is present for IntersectionObserver
          if (!'IntersectionObserver' in window ||
              !'IntersectionObserverEntry' in window ||
              !'intersectionRatio' in window.IntersectionObserverEntry.prototype) {
              return;
          }
  
          let pageNav = document.querySelector('.sidebar-page-nav');
  
          // fetch all the headings.
          let headings = document.querySelector('.page-content').querySelectorAll('h1, h2, h3, h4, h5, h6');
          // if headings are present, add observers.
          if (headings.length > 0 && pageNav !== null) {
              addNavObserver(headings);
          }
  
          function addNavObserver(headings) {
              // Setup the intersection observer.
              let intersectOpts = {
                  rootMargin: '0px 0px 0px 0px',
                  threshold: 1.0
              };
              let pageNavObserver = new IntersectionObserver(headingVisibilityChange, intersectOpts);
  
              // observe each heading
              for (let i = 0; i !== headings.length; ++i) {
                  pageNavObserver.observe(headings[i]);
              }
          }
  
          function headingVisibilityChange(entries, observer) {
              for (let entry of entries) {
                  let isVisible = (entry.intersectionRatio === 1);
                  toggleAnchorHighlighting(entry.target.id, isVisible);
              }
          }
  
          function toggleAnchorHighlighting(elementId, shouldHighlight) {
              let anchorsToHighlight = pageNav.querySelectorAll('a[href="#' + elementId + '"]');
              for (let i = 0; i < anchorsToHighlight.length; i++) {
                  // Change below to use classList.toggle when IE support is dropped.
                  if (shouldHighlight) {
                      anchorsToHighlight[i].classList.add('current-heading');
                  } else {
                      anchorsToHighlight[i].classList.remove('current-heading');
                  }
              }
          }
      }
  
  }
  
  module.exports = PageDisplay;