var util = require('../../util');
var Component = require('./Component');
var moment = require('../../module/moment');
var locales = require('../locales');

/**
 * A current time bar
 * @param {{range: Range, dom: Object, domProps: Object}} body
 * @param {Object} [options]        Available parameters:
 *                                  {Boolean} [showCurrentTime]
 * @constructor CurrentTime
 * @extends Component
 */
function CurrentTime (body, options) {
  this.body = body;

  // default options
  this.defaultOptions = {
    showCurrentTime: true,

    locales: locales,
    locale: 'en'
  };
  this.options = util.extend({}, this.defaultOptions);
  this.offset = 0;

  this._create();

  this.setOptions(options);
}

CurrentTime.prototype = new Component();

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

  this.bar = bar;
};

/**
 * Destroy the CurrentTime bar
 */
CurrentTime.prototype.destroy = function () {
  this.options.showCurrentTime = false;
  this.redraw(); // will remove the bar from the DOM and stop refreshing

  this.body = null;
};

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

/**
 * Repaint the component
 * @return {boolean} Returns true if the component is resized
 */
CurrentTime.prototype.redraw = function() {
  if (this.options.showCurrentTime) {
    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);

      this.start();
    }

    var now = new Date(new Date().valueOf() + this.offset);
    var x = this.body.util.toScreen(now);

    var locale = this.options.locales[this.options.locale];
    if (!locale) {
      if (!this.warned) {
        console.log('WARNING: locale "' + this.options.locale + '" not found in vis.js');
        this.warned = true;
      }
      locale = this.options.locales['en']; // fall back on english when not available
    }
    var title = locale.current + ' ' + locale.time + ': ' + moment(now).format('dddd, MMMM Do YYYY, H:mm:ss');
    title = title.charAt(0).toUpperCase() + title.substring(1);

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

  return false;
};

/**
 * Start auto refreshing the current time bar
 */
CurrentTime.prototype.start = function() {
  var me = this;

  function update () {
    me.stop();

    // determine interval to refresh
    var scale = me.body.range.conversion(me.body.domProps.center.width).scale;
    var interval = 1 / scale / 10;
    if (interval < 30)   interval = 30;
    if (interval > 1000) interval = 1000;

    me.redraw();

    // start a timer to adjust for the new time
    me.currentTimeTimer = setTimeout(update, interval);
  }

  update();
};

/**
 * Stop auto refreshing the current time bar
 */
CurrentTime.prototype.stop = function() {
  if (this.currentTimeTimer !== undefined) {
    clearTimeout(this.currentTimeTimer);
    delete this.currentTimeTimer;
  }
};

/**
 * Set a current time. This can be used for example to ensure that a client's
 * time is synchronized with a shared server time.
 * @param {Date | String | Number} time     A Date, unix timestamp, or
 *                                          ISO date string.
 */
CurrentTime.prototype.setCurrentTime = function(time) {
  var t = util.convert(time, 'Date').valueOf();
  var now = new Date().valueOf();
  this.offset = t - now;
  this.redraw();
};

/**
 * Get the current time.
 * @return {Date} Returns the current time.
 */
CurrentTime.prototype.getCurrentTime = function() {
  return new Date(new Date().valueOf() + this.offset);
};

module.exports = CurrentTime;