(function (root) {
  'use strict';

  var documentRef = root.document;
  var editors = {};
  var submitBound = false;
  var toolbarKeys = [
    'headerSelect', 'fontSize', 'color', 'bgColor', '|',
    'bold', 'italic', 'underline', 'through', '|',
    'justifyLeft', 'justifyCenter', 'justifyRight', 'justifyJustify', '|',
    'insertTable', 'clearStyle', 'insertLink', 'undo', 'redo'
  ];

  function findTextarea(target) {
    if (!target || !documentRef) return null;
    if (typeof target === 'string') return documentRef.querySelector(target);
    if (target.nodeType === 1) return target;
    return target[0] || null;
  }

  function ensureId(textarea) {
    if (!textarea.id) textarea.id = 'rich-editor-' + Math.floor(Math.random() * 1000000);
    return textarea.id;
  }

  function fieldValue(editor) {
    return String(editor.getText() || '').trim() ? editor.getHtml() : '';
  }

  function syncEditor(instance) {
    instance.textarea.value = fieldValue(instance.editor);
  }

  function createRichEditor(target, options) {
    var textarea = findTextarea(target);
    var settings = options || {};
    var id;
    var host;
    var toolbar;
    var content;
    var editor;
    var wangEditor = root.wangEditor;
    var instance;

    if (!textarea || !wangEditor || !wangEditor.createEditor || !wangEditor.createToolbar) return null;
    if (textarea.dataset.wangEditorInitialized === 'true') return editors[textarea.id] || null;

    id = ensureId(textarea);
    host = documentRef.createElement('div');
    host.className = 'rich-editor-host';
    toolbar = documentRef.createElement('div');
    toolbar.className = 'rich-editor-toolbar';
    toolbar.id = id + '-toolbar';
    content = documentRef.createElement('div');
    content.className = 'rich-editor-content';
    content.id = id + '-content';
    host.appendChild(toolbar);
    host.appendChild(content);
    textarea.insertAdjacentElement('afterend', host);

    try {
      editor = wangEditor.createEditor({
        selector: '#' + content.id,
        html: textarea.value || '',
        config: Object.assign({
          placeholder: textarea.getAttribute('placeholder') || '请输入内容',
          onChange: function (currentEditor) {
            textarea.value = fieldValue(currentEditor);
          },
          onBlur: function (currentEditor) {
            textarea.value = fieldValue(currentEditor);
          }
        }, settings.editorConfig || {}),
        mode: settings.mode || 'default'
      });
      wangEditor.createToolbar({
        editor: editor,
        selector: '#' + toolbar.id,
        config: Object.assign({ toolbarKeys: toolbarKeys }, settings.toolbarConfig || {}),
        mode: settings.mode || 'default'
      });
    } catch (error) {
      host.remove();
      return null;
    }

    textarea.hidden = true;
    textarea.setAttribute('aria-hidden', 'true');
    textarea.dataset.wangEditorInitialized = 'true';
    instance = {
      textarea: textarea,
      editor: editor,
      sync: function () { syncEditor(instance); },
      getHtml: function () { return fieldValue(editor); },
      getText: function () { return editor.getText(); }
    };
    editors[id] = instance;
    instance.sync();
    return instance;
  }

  function initRichEditors(rootNode, options) {
    var scope = rootNode || documentRef;
    var instances = {};

    if (!scope || !scope.querySelectorAll) return instances;
    Array.prototype.forEach.call(scope.querySelectorAll('.js-rich-editor'), function (textarea) {
      var instance = createRichEditor(textarea, options);

      if (instance) instances[textarea.id] = instance;
    });
    return instances;
  }

  function bindFormSync() {
    if (submitBound || !documentRef) return;
    submitBound = true;
    documentRef.addEventListener('submit', function (event) {
      Object.keys(editors).forEach(function (id) {
        var instance = editors[id];

        if (instance.textarea.form === event.target) instance.sync();
      });
    });
  }

  function initAll() {
    bindFormSync();
    return initRichEditors(documentRef);
  }

  root.AppRichEditor = {
    init: createRichEditor,
    initAll: initRichEditors,
    syncAll: function () {
      Object.keys(editors).forEach(function (id) { editors[id].sync(); });
    }
  };

  if (!documentRef) return;
  if (documentRef.readyState === 'loading') documentRef.addEventListener('DOMContentLoaded', initAll);
  else initAll();
})(window);