var Hammer = require('hammerjs');
var util = require('../../util');
var Component = require('./Component');

/**
 * A custom time bar
 * @param {{range: Range, dom: Object}} body
 * @param {Object} [options]        Available parameters:
 *                                  {Boolean} [showCustomTime]
 * @constructor CustomTime
 * @extends Component
 */

function CustomTime (body, options) {
  this.body = body;

  // default options
  this.defaultOptions = {
    showCustomTime: false
  };
  this.options = util.extend({}, this.defaultOptions);

  this.customTime = new Date();
  this.eventParams = {}; // stores state parameters while dragging the bar

  // create the DOM
  this._create();

  this.setOptions(options);
}

CustomTime.prototype = new Component();

/**
 * Set options for the component. Options will be merged in current options.
 * @param {Object} options  Available parameters:
 *                          {boolean} [showCustomTime]
 */
CustomTime.prototype.setOptions = function(options) {
  if (options) {
    // copy all options that we know
    util.selectiveExtend(['showCustomTime'], this.options, options);
  }
};

/**
 * Create the DOM for the custom time
 * @private
 */
CustomTime.prototype._create = function() {
  var bar = document.createElement('div');
  bar.className = 'customtime';
  bar.style.position = 'absolute';
  bar.style.top = '0px';
  bar.style.height = '100%';
  this.bar = bar;

  var drag = document.createElement('div');
  drag.style.position = 'relative';
  drag.style.top = '0px';
  drag.style.left = '-10px';
  drag.style.height = '100%';
  drag.style.width = '20px';
  bar.appendChild(drag);

  // attach event listeners
  this.hammer = Hammer(bar, {
    prevent_default: true
  });
  this.hammer.on('dragstart', this._onDragStart.bind(this));
  this.hammer.on('drag',      this._onDrag.bind(this));
  this.hammer.on('dragend',   this._onDragEnd.bind(this));
};

/**
 * Destroy the CustomTime bar
 */
CustomTime.prototype.destroy = function () {
  this.options.showCustomTime = false;
  this.redraw(); // will remove the bar from the DOM

  this.hammer.enable(false);
  this.hammer = null;

  this.body = null;
};

/**
 * Repaint the component
 * @return {boolean} Returns true if the component is resized
 */
CustomTime.prototype.redraw = function () {
  if (this.options.showCustomTime) {
    var parent = this.body.dom.backgroundVertical;
    if (this.bar.parentNode != parent) {
      // attach to the dom
      if (this.bar.parentNode) {
        this.bar.parentNode.removeChild(this.bar);
      }
      parent.appendChild(this.bar);
    }

    var x = this.body.util.toScreen(this.customTime);

    this.bar.style.left = x + 'px';
    this.bar.title = 'Time: ' + this.customTime;
  }
  else {
    // remove the line from the DOM
    if (this.bar.parentNode) {
      this.bar.parentNode.removeChild(this.bar);
    }
  }

  return false;
};

/**
 * Set custom time.
 * @param {Date} time
 */
CustomTime.prototype.setCustomTime = function(time) {
  this.customTime = new Date(time.valueOf());
  this.redraw();
};

/**
 * Retrieve the current custom time.
 * @return {Date} customTime
 */
CustomTime.prototype.getCustomTime = function() {
  return new Date(this.customTime.valueOf());
};

/**
 * Start moving horizontally
 * @param {Event} event
 * @private
 */
CustomTime.prototype._onDragStart = function(event) {
  this.eventParams.dragging = true;
  this.eventParams.customTime = this.customTime;

  event.stopPropagation();
  event.preventDefault();
};

/**
 * Perform moving operating.
 * @param {Event} event
 * @private
 */
CustomTime.prototype._onDrag = function (event) {
  if (!this.eventParams.dragging) return;

  var deltaX = event.gesture.deltaX,
      x = this.body.util.toScreen(this.eventParams.customTime) + deltaX,
      time = this.body.util.toTime(x);

  this.setCustomTime(time);

  // fire a timechange event
  this.body.emitter.emit('timechange', {
    time: new Date(this.customTime.valueOf())
  });

  event.stopPropagation();
  event.preventDefault();
};

/**
 * Stop moving operating.
 * @param {event} event
 * @private
 */
CustomTime.prototype._onDragEnd = function (event) {
  if (!this.eventParams.dragging) return;

  // fire a timechanged event
  this.body.emitter.emit('timechanged', {
    time: new Date(this.customTime.valueOf())
  });

  event.stopPropagation();
  event.preventDefault();
};

module.exports = CustomTime;