text: const MarkdownIt = require("markdown-it");
  const mdTasksLists = require('markdown-it-task-lists');
  const code = require('../libs/code');
  
  const DrawIO = require('../libs/drawio');
  
  class MarkdownEditor {
  
      constructor(elem) {
          this.elem = elem;
          this.markdown = new MarkdownIt({html: true});
          this.markdown.use(mdTasksLists, {label: true});
  
          this.display = this.elem.querySelector('.markdown-display');
          this.input = this.elem.querySelector('textarea');
          this.htmlInput = this.elem.querySelector('input[name=html]');
          this.cm = code.markdownEditor(this.input);
  
          this.onMarkdownScroll = this.onMarkdownScroll.bind(this);
          this.init();
      }
  
      init() {
  
          let lastClick = 0;
  
          // Prevent markdown display link click redirect
          this.display.addEventListener('click', event => {
              let isDblClick = Date.now() - lastClick < 300;
  
              let link = event.target.closest('a');
              if (link !== null) {
                  event.preventDefault();
                  window.open(link.getAttribute('href'));
                  return;
              }
  
              let drawing = event.target.closest('[drawio-diagram]');
              if (drawing !== null && isDblClick) {
                  this.actionEditDrawing(drawing);
                  return;
              }
  
              lastClick = Date.now();
          });
  
          // Button actions
          this.elem.addEventListener('click', event => {
              let button = event.target.closest('button[data-action]');
              if (button === null) return;
  
              let action = button.getAttribute('data-action');
              if (action === 'insertImage') this.actionInsertImage();
              if (action === 'insertLink') this.actionShowLinkSelector();
              if (action === 'insertDrawing') this.actionStartDrawing();
          });
  
          window.$events.listen('editor-markdown-update', value => {
              this.cm.setValue(value);
              this.updateAndRender();
          });
  
          this.codeMirrorSetup();
      }
  
      // Update the input content and render the display.
      updateAndRender() {
          let content = this.cm.getValue();
          this.input.value = content;
          let html = this.markdown.render(content);
          window.$events.emit('editor-html-change', html);
          window.$events.emit('editor-markdown-change', content);
          this.display.innerHTML = html;
          this.htmlInput.value = html;
      }
  
      onMarkdownScroll(lineCount) {
          let elems = this.display.children;
          if (elems.length <= lineCount) return;
  
          let topElem = (lineCount === -1) ? elems[elems.length-1] : elems[lineCount];
          // TODO - Replace jQuery
          $(this.display).animate({
              scrollTop: topElem.offsetTop
          }, {queue: false, duration: 200, easing: 'linear'});
      }
  
      codeMirrorSetup() {
          let cm = this.cm;
          // Custom key commands
          let metaKey = code.getMetaKey();
          const extraKeys = {};
          // Insert Image shortcut
          extraKeys[`${metaKey}-Alt-I`] = function(cm) {
              let selectedText = cm.getSelection();
              let newText = `![${selectedText}](http://)`;
              let cursorPos = cm.getCursor('from');
              cm.replaceSelection(newText);
              cm.setCursor(cursorPos.line, cursorPos.ch + newText.length -1);
          };
          // Save draft
          extraKeys[`${metaKey}-S`] = cm => {window.$events.emit('editor-save-draft')};
          // Save page
          extraKeys[`${metaKey}-Enter`] = cm => {window.$events.emit('editor-save-page')};
          // Show link selector
          extraKeys[`Shift-${metaKey}-K`] = cm => {this.actionShowLinkSelector()};
          // Insert Link
          extraKeys[`${metaKey}-K`] = cm => {insertLink()};
          // FormatShortcuts
          extraKeys[`${metaKey}-1`] = cm => {replaceLineStart('##');};
          extraKeys[`${metaKey}-2`] = cm => {replaceLineStart('###');};
          extraKeys[`${metaKey}-3`] = cm => {replaceLineStart('####');};
          extraKeys[`${metaKey}-4`] = cm => {replaceLineStart('#####');};
          extraKeys[`${metaKey}-5`] = cm => {replaceLineStart('');};
          extraKeys[`${metaKey}-d`] = cm => {replaceLineStart('');};
          extraKeys[`${metaKey}-6`] = cm => {replaceLineStart('>');};
          extraKeys[`${metaKey}-q`] = cm => {replaceLineStart('>');};
          extraKeys[`${metaKey}-7`] = cm => {wrapSelection('\n```\n', '\n```');};
          extraKeys[`${metaKey}-8`] = cm => {wrapSelection('`', '`');};
          extraKeys[`Shift-${metaKey}-E`] = cm => {wrapSelection('`', '`');};
          extraKeys[`${metaKey}-9`] = cm => {wrapSelection('<p class="callout info">', '</p>');};
          cm.setOption('extraKeys', extraKeys);
  
          // Update data on content change
          cm.on('change', (instance, changeObj) => {
              this.updateAndRender();
          });
  
          // Handle scroll to sync display view
          cm.on('scroll', instance => {
              // Thanks to http://liuhao.im/english/2015/11/10/the-sync-scroll-of-markdown-editor-in-javascript.html
              let scroll = instance.getScrollInfo();
              let atEnd = scroll.top + scroll.clientHeight === scroll.height;
              if (atEnd) {
                  this.onMarkdownScroll(-1);
                  return;
              }
  
              let lineNum = instance.lineAtHeight(scroll.top, 'local');
              let range = instance.getRange({line: 0, ch: null}, {line: lineNum, ch: null});
              let parser = new DOMParser();
              let doc = parser.parseFromString(this.markdown.render(range), 'text/html');
              let totalLines = doc.documentElement.querySelectorAll('body > *');
              this.onMarkdownScroll(totalLines.length);
          });
  
          // Handle image paste
          cm.on('paste', (cm, event) => {
              if (!event.clipboardData || !event.clipboardData.items) return;
              for (let i = 0; i < event.clipboardData.items.length; i++) {
                  uploadImage(event.clipboardData.items[i].getAsFile());
              }
          });
  
          // Handle images on drag-drop
          cm.on('drop', (cm, event) => {
              event.stopPropagation();
              event.preventDefault();
              let cursorPos = cm.coordsChar({left: event.pageX, top: event.pageY});
              cm.setCursor(cursorPos);
              if (!event.dataTransfer || !event.dataTransfer.files) return;
              for (let i = 0; i < event.dataTransfer.files.length; i++) {
                  uploadImage(event.dataTransfer.files[i]);
              }
          });
  
          // Helper to replace editor content
          function replaceContent(search, replace) {
              let text = cm.getValue();
              let cursor = cm.listSelections();
              cm.setValue(text.replace(search, replace));
              cm.setSelections(cursor);
          }
  
          // Helper to replace the start of the line
          function replaceLineStart(newStart) {
              let cursor = cm.getCursor();
              let lineContent = cm.getLine(cursor.line);
              let lineLen = lineContent.length;
              let lineStart = lineContent.split(' ')[0];
  
              // Remove symbol if already set
              if (lineStart === newStart) {
                  lineContent = lineContent.replace(`${newStart} `, '');
                  cm.replaceRange(lineContent, {line: cursor.line, ch: 0}, {line: cursor.line, ch: lineLen});
                  cm.setCursor({line: cursor.line, ch: cursor.ch - (newStart.length + 1)});
                  return;
              }
  
              let alreadySymbol = /^[#>`]/.test(lineStart);
              let posDif = 0;
              if (alreadySymbol) {
                  posDif = newStart.length - lineStart.length;
                  lineContent = lineContent.replace(lineStart, newStart).trim();
              } else if (newStart !== '') {
                  posDif = newStart.length + 1;
                  lineContent = newStart + ' ' + lineContent;
              }
              cm.replaceRange(lineContent, {line: cursor.line, ch: 0}, {line: cursor.line, ch: lineLen});
              cm.setCursor({line: cursor.line, ch: cursor.ch + posDif});
          }
  
          function wrapLine(start, end) {
              let cursor = cm.getCursor();
              let lineContent = cm.getLine(cursor.line);
              let lineLen = lineContent.length;
              let newLineContent = lineContent;
  
              if (lineContent.indexOf(start) === 0 && lineContent.slice(-end.length) === end) {
                  newLineContent = lineContent.slice(start.length, lineContent.length - end.length);
              } else {
                  newLineContent = `${start}${lineContent}${end}`;
              }
  
              cm.replaceRange(newLineContent, {line: cursor.line, ch: 0}, {line: cursor.line, ch: lineLen});
              cm.setCursor({line: cursor.line, ch: cursor.ch + start.length});
          }
  
          function wrapSelection(start, end) {
              let selection = cm.getSelection();
              if (selection === '') return wrapLine(start, end);
  
              let newSelection = selection;
              let frontDiff = 0;
              let endDiff = 0;
  
              if (selection.indexOf(start) === 0 && selection.slice(-end.length) === end) {
                  newSelection = selection.slice(start.length, selection.length - end.length);
                  endDiff = -(end.length + start.length);
              } else {
                  newSelection = `${start}${selection}${end}`;
                  endDiff = start.length + end.length;
              }
  
              let selections = cm.listSelections()[0];
              cm.replaceSelection(newSelection);
              let headFirst = selections.head.ch <= selections.anchor.ch;
              selections.head.ch += headFirst ? frontDiff : endDiff;
              selections.anchor.ch += headFirst ? endDiff : frontDiff;
              cm.setSelections([selections]);
          }
  
          // Handle image upload and add image into markdown content
          function uploadImage(file) {
              if (file === null || file.type.indexOf('image') !== 0) return;
              let ext = 'png';
  
              if (file.name) {
                  let fileNameMatches = file.name.match(/\.(.+)$/);
                  if (fileNameMatches.length > 1) ext = fileNameMatches[1];
              }
  
              // Insert image into markdown
              let id = "image-" + Math.random().toString(16).slice(2);
              let placeholderImage = window.baseUrl(`/loading.gif#upload${id}`);
              let selectedText = cm.getSelection();
              let placeHolderText = `![${selectedText}](${placeholderImage})`;
              cm.replaceSelection(placeHolderText);
  
              let remoteFilename = "image-" + Date.now() + "." + ext;
              let formData = new FormData();
              formData.append('file', file, remoteFilename);
  
              window.$http.post('/images/gallery/upload', formData).then(resp => {
                  replaceContent(placeholderImage, resp.data.thumbs.display);
              }).catch(err => {
                  events.emit('error', trans('errors.image_upload_error'));
                  replaceContent(placeHolderText, selectedText);
                  console.log(err);
              });
          }
  
          function insertLink() {
              let cursorPos = cm.getCursor('from');
              let selectedText = cm.getSelection() || '';
              let newText = `[${selectedText}]()`;
              cm.focus();
              cm.replaceSelection(newText);
              let cursorPosDiff = (selectedText === '') ? -3 : -1;
              cm.setCursor(cursorPos.line, cursorPos.ch + newText.length+cursorPosDiff);
          }
  
         this.updateAndRender();
      }
  
      actionInsertImage() {
          let cursorPos = this.cm.getCursor('from');
          window.ImageManager.show(image => {
              let selectedText = this.cm.getSelection();
              let newText = "![" + (selectedText || image.name) + "](" + image.thumbs.display + ")";
              this.cm.focus();
              this.cm.replaceSelection(newText);
              this.cm.setCursor(cursorPos.line, cursorPos.ch + newText.length);
          });
      }
  
      // Show the popup link selector and insert a link when finished
      actionShowLinkSelector() {
          let cursorPos = this.cm.getCursor('from');
          window.EntitySelectorPopup.show(entity => {
              let selectedText = this.cm.getSelection() || entity.name;
              let newText = `[${selectedText}](${entity.link})`;
              this.cm.focus();
              this.cm.replaceSelection(newText);
              this.cm.setCursor(cursorPos.line, cursorPos.ch + newText.length);
          });
      }
  
      // Show draw.io if enabled and handle save.
      actionStartDrawing() {
          if (document.querySelector('[drawio-enabled]').getAttribute('drawio-enabled') !== 'true') return;
          let cursorPos = this.cm.getCursor('from');
  
          DrawIO.show(() => {
              return Promise.resolve('');
          }, (pngData) => {
              // let id = "image-" + Math.random().toString(16).slice(2);
              // let loadingImage = window.baseUrl('/loading.gif');
              let data = {
                  image: pngData,
                  uploaded_to: Number(document.getElementById('page-editor').getAttribute('page-id'))
              };
  
              window.$http.post(window.baseUrl('/images/drawing/upload'), data).then(resp => {
                  let newText = `<div drawio-diagram="${resp.data.id}"><img src="${resp.data.url}"></div>`;
                  this.cm.focus();
                  this.cm.replaceSelection(newText);
                  this.cm.setCursor(cursorPos.line, cursorPos.ch + newText.length);
                  DrawIO.close();
              }).catch(err => {
                  window.$events.emit('error', trans('errors.image_upload_error'));
                  console.log(err);
              });
          });
      }
  
      // Show draw.io if enabled and handle save.
      actionEditDrawing(imgContainer) {
          if (document.querySelector('[drawio-enabled]').getAttribute('drawio-enabled') !== 'true') return;
          let cursorPos = this.cm.getCursor('from');
          let drawingId = imgContainer.getAttribute('drawio-diagram');
  
          DrawIO.show(() => {
              return window.$http.get(window.baseUrl(`/images/base64/${drawingId}`)).then(resp => {
                  return `data:image/png;base64,${resp.data.content}`;
              });
          }, (pngData) => {
  
              let data = {
                  image: pngData,
                  uploaded_to: Number(document.getElementById('page-editor').getAttribute('page-id'))
              };
  
              window.$http.put(window.baseUrl(`/images/drawing/upload/${drawingId}`), data).then(resp => {
                  let newText = `<div drawio-diagram="${resp.data.id}"><img src="${resp.data.url + `?updated=${Date.now()}`}"></div>`;
                  let newContent = this.cm.getValue().split('\n').map(line => {
                      if (line.indexOf(`drawio-diagram="${drawingId}"`) !== -1) {
                          return newText;
                      }
                      return line;
                  }).join('\n');
                  this.cm.setValue(newContent);
                  this.cm.setCursor(cursorPos);
                  this.cm.focus();
                  DrawIO.close();
              }).catch(err => {
                  window.$events.emit('error', trans('errors.image_upload_error'));
                  console.log(err);
              });
          });
      }
  
  }
  
  module.exports = MarkdownEditor ;