var mousetrap = require('mousetrap');
var Hammer = require('../module/hammer');
var util = require('../util');

/**
 * Turn an element into an activatable element.
 * When not active, the element has a transparent overlay. When the overlay is
 * clicked, the mode is changed to active.
 * When active, the element is displayed with a blue border around it, and
 * the interactive contents of the element can be used. When clicked outside
 * the element, the elements mode is changed to inactive.
 * @param {Element} container
 * @constructor
 */
function Activator(container) {
  this.active = false;

  this.dom = {
    container: container
  };

  this.dom.overlay = document.createElement('div');
  this.dom.overlay.className = 'overlay';

  this.dom.container.appendChild(this.dom.overlay);

  this.hammer = Hammer(this.dom.overlay, {prevent_default: false});
  this.hammer.on('tap', this._onTapOverlay.bind(this));

  // attach a tap event to the window, in order to deactivate when clicking outside the timeline
  this.windowHammer = Hammer(window, {prevent_default: false});
  this.windowHammer.on('tap', this.deactivate.bind(this));

  // mousetrap listener only bounded when active)
  this.escListener = this.deactivate.bind(this);
}

// The currently active activator
Activator.current = null;

/**
 * Destroy the activator. Cleans up all created DOM and event listeners
 */
Activator.prototype.destroy = function () {
  this.deactivate();

  // remove dom
  this.dom.overlay.parentNode.removeChild(this.dom.overlay);

  // cleanup hammer instances
  this.hammer = null;
  this.windowHammer = null;
};

/**
 * Activate the element
 * Overlay is hidden, element is decorated with a blue shadow border
 */
Activator.prototype.activate = function () {
  // we allow only one active activator at a time
  if (Activator.current) {
    Activator.current.deactivate();
  }
  Activator.current = this;

  this.active = true;
  this.dom.overlay.style.display = 'none';
  util.addClassName(this.dom.container, 'vis-active');
  mousetrap.bind('esc', this.escListener);
};

/**
 * Deactivate the element
 * Overlay is displayed on top of the element
 */
Activator.prototype.deactivate = function () {
  this.active = false;
  this.dom.overlay.style.display = '';
  util.removeClassName(this.dom.container, 'vis-active');
  mousetrap.unbind('esc', this.escListener);
};

Activator.prototype._onTapOverlay = function (event) {
  // activate the container
  this.activate();
  event.stopPropagation();
};

module.exports = Activator;