define([
  'jquery',
  'summernote/base/core/func',
  'summernote/base/core/list',
  'summernote/base/core/dom'
], function ($, func, list, dom) {
  /**
   * @param {jQuery} $note
   * @param {Object} options
   * @return {Context}
   */
  var Context = function ($note, options) {
    var self = this;

    var ui = $.summernote.ui;
    this.memos = {};
    this.modules = {};
    this.layoutInfo = {};
    this.options = options;

    /**
     * create layout and initialize modules and other resources
     */
    this.initialize = function () {
      this.layoutInfo = ui.createLayout($note, options);
      this._initialize();
      $note.hide();
      return this;
    };

    /**
     * destroy modules and other resources and remove layout
     */
    this.destroy = function () {
      this._destroy();
      $note.removeData('summernote');
      ui.removeLayout($note, this.layoutInfo);
    };

    /**
     * destory modules and other resources and initialize it again
     */
    this.reset = function () {
      var disabled = self.isDisabled();
      this.code(dom.emptyPara);
      this._destroy();
      this._initialize();

      if (disabled) {
        self.disable();
      }
    };

    this._initialize = function () {
      // add optional buttons
      var buttons = $.extend({}, this.options.buttons);
      Object.keys(buttons).forEach(function (key) {
        self.memo('button.' + key, buttons[key]);
      });

      var modules = $.extend({}, this.options.modules, $.summernote.plugins || {});

      // add and initialize modules
      Object.keys(modules).forEach(function (key) {
        self.module(key, modules[key], true);
      });

      Object.keys(this.modules).forEach(function (key) {
        self.initializeModule(key);
      });
    };

    this._destroy = function () {
      // destroy modules with reversed order
      Object.keys(this.modules).reverse().forEach(function (key) {
        self.removeModule(key);
      });

      Object.keys(this.memos).forEach(function (key) {
        self.removeMemo(key);
      });
      // trigger custom onDestroy callback
      this.triggerEvent('destroy', this);
    };

    this.code = function (html) {
      var isActivated = this.invoke('codeview.isActivated');

      if (html === undefined) {
        this.invoke('codeview.sync');
        return isActivated ? this.layoutInfo.codable.val() : this.layoutInfo.editable.html();
      } else {
        if (isActivated) {
          this.layoutInfo.codable.val(html);
        } else {
          this.layoutInfo.editable.html(html);
        }
        $note.val(html);
        this.triggerEvent('change', html);
      }
    };

    this.isDisabled = function () {
      return this.layoutInfo.editable.attr('contenteditable') === 'false';
    };

    this.enable = function () {
      this.layoutInfo.editable.attr('contenteditable', true);
      this.invoke('toolbar.activate', true);
    };

    this.disable = function () {
      // close codeview if codeview is opend
      if (this.invoke('codeview.isActivated')) {
        this.invoke('codeview.deactivate');
      }
      this.layoutInfo.editable.attr('contenteditable', false);
      this.invoke('toolbar.deactivate', true);
    };

    this.triggerEvent = function () {
      var namespace = list.head(arguments);
      var args = list.tail(list.from(arguments));

      var callback = this.options.callbacks[func.namespaceToCamel(namespace, 'on')];
      if (callback) {
        callback.apply($note[0], args);
      }
      $note.trigger('summernote.' + namespace, args);
    };

    this.initializeModule = function (key) {
      var module = this.modules[key];
      module.shouldInitialize = module.shouldInitialize || func.ok;
      if (!module.shouldInitialize()) {
        return;
      }

      // initialize module
      if (module.initialize) {
        module.initialize();
      }

      // attach events
      if (module.events) {
        dom.attachEvents($note, module.events);
      }
    };

    this.module = function (key, ModuleClass, withoutIntialize) {
      if (arguments.length === 1) {
        return this.modules[key];
      }

      this.modules[key] = new ModuleClass(this);

      if (!withoutIntialize) {
        this.initializeModule(key);
      }
    };

    this.removeModule = function (key) {
      var module = this.modules[key];
      if (module.shouldInitialize()) {
        if (module.events) {
          dom.detachEvents($note, module.events);
        }

        if (module.destroy) {
          module.destroy();
        }
      }

      delete this.modules[key];
    };

    this.memo = function (key, obj) {
      if (arguments.length === 1) {
        return this.memos[key];
      }
      this.memos[key] = obj;
    };

    this.removeMemo = function (key) {
      if (this.memos[key] && this.memos[key].destroy) {
        this.memos[key].destroy();
      }

      delete this.memos[key];
    };

    /**
     *Some buttons need to change their visual style immediately once they get pressed
     */
    this.createInvokeHandlerAndUpdateState = function (namespace, value) {
      return function (event) {
        self.createInvokeHandler(namespace, value)(event);
        self.invoke('buttons.updateCurrentStyle');
      };
    };

    this.createInvokeHandler = function (namespace, value) {
      return function (event) {
        event.preventDefault();
        var $target = $(event.target);
        self.invoke(namespace, value || $target.closest('[data-value]').data('value'), $target);
      };
    };

    this.invoke = function () {
      var namespace = list.head(arguments);
      var args = list.tail(list.from(arguments));

      var splits = namespace.split('.');
      var hasSeparator = splits.length > 1;
      var moduleName = hasSeparator && list.head(splits);
      var methodName = hasSeparator ? list.last(splits) : list.head(splits);

      var module = this.modules[moduleName || 'editor'];
      if (!moduleName && this[methodName]) {
        return this[methodName].apply(this, args);
      } else if (module && module[methodName] && module.shouldInitialize()) {
        return module[methodName].apply(module, args);
      }
    };

    return this.initialize();
  };

  return Context;
});
