define(function(require, exports, module) {
'use strict';

var IntlHelper = require('shared/intl_helper');
var View = require('view');
var createDay = require('common/calc').createDay;
var timeObserver = require('time_observer');

var activeClass = View.ACTIVE;

IntlHelper.define('current-time', 'mozdatetime', {
  hour: 'numeric',
  minute: 'numeric',
  dayperiod: false,
});

function CurrentTime(options) {
  this._container = options.container;
  // timespan can be injected later! this is just a convenience
  this.timespan = options.timespan;
  this._sticky = options.sticky;
  this.activate = this.activate.bind(this);
  this._tick = this._tick.bind(this);
}
module.exports = CurrentTime;

CurrentTime.prototype = {
  _create: function() {
    if (this.element) {
      return;
    }

    this.element = document.createElement('div');
    this.element.setAttribute('aria-hidden', true);
    this.element.classList.add('md__current-time');
    this._container.appendChild(this.element);
  },

  refresh: function() {
    this._clearInterval();

    if (this._previousOverlap) {
      this._previousOverlap.classList.remove('is-hidden');
    }

    this._unmarkCurrentDay();
    this._hide();
    this.activate();
  },

  activate: function() {
    if (!this.timespan.containsNumeric(Date.now())) {
      this._maybeActivateInTheFuture();
      return;
    }

    this._create();
    this.element.classList.add(activeClass);
    this._tick();
  },

  _maybeActivateInTheFuture: function() {
    var now = Date.now();
    var diff = this.timespan.start - now;
    if (diff >= 0) {
      // if timespan is in the "future" we make sure it will start rendering
      // the current time as soon as it reaches 00:00:00 of the first day
      // inside timespan (eg. current time is 2014-05-22T23:59:50 and user is
      // viewing 2014-05-23 until past midnight)
      this._clearInterval();
      timeObserver.once('day', this.activate);
    }
  },

  deactivate: function() {
    this._clearInterval();
    this._hide();
  },

  _hide: function() {
    if (this.element) {
      this.element.classList.remove(activeClass);
    }
  },

  destroy: function() {
    this.deactivate();
    if (this.element) {
      this._container.removeChild(this.element);
    }
  },

  _clearInterval: function() {
    timeObserver.off('day', this.activate);
    timeObserver.off('minute', this._tick);
  },

  _tick: function() {
    this._clearInterval();
    if (!this.timespan.contains(new Date())) {
      this.deactivate();
      this._unmarkCurrentDay();
      return;
    }
    this._render();
    timeObserver.once('minute', this._tick);
  },

  _render: function() {
    var now = new Date();

    var formatter = IntlHelper.get('current-time');
    this.element.textContent = formatter.format(now);

    this.element.dataset.date = now;
    this.element.dataset.l10nDateFormat = 'current-time';
    this.element.id = 'current-time-indicator';

    var hour = now.getHours();
    var elapsedMinutes = (hour * 60) + now.getMinutes();
    var totalMinutes = 24 * 60;
    var percentage = ((elapsedMinutes / totalMinutes) * 100);
    // we limit the position between 0.5-99.5% to avoid cropping the text
    this.element.style.top = Math.max(Math.min(percentage, 99.5), 0.5) + '%';

    this._checkOverlap(hour);
    this._markCurrentDay(now);
  },

  _checkOverlap: function(hour) {
    // we only need to check the current hour (with current design there is
    // no way to overlap previous/next hours)
    var displayHour = this._container.querySelector(
      `.md__hour-${hour} .md__display-hour`
    );

    displayHour.classList.toggle('is-hidden', this._intersect(displayHour));

    // just in case last time it checked was against a different hour
    if (this._previousOverlap && this._previousOverlap !== displayHour) {
      this._previousOverlap.classList.remove('is-hidden');
    }

    this._previousOverlap = displayHour;
  },

  _intersect: function(displayHour) {
    var b1 = this.element.getBoundingClientRect();
    var b2 = displayHour.getBoundingClientRect();

    return (
      b1.left <= b2.right &&
      b2.left <= b1.right &&
      b1.top <= b2.bottom &&
      b2.top <= b1.bottom
    );
  },

  _markCurrentDay: function(date) {
    if (!this._sticky) {
      return;
    }

    var day = createDay(date);
    var selector = `.md__allday[data-date="${day}"] .md__day-name`;
    var header = this._sticky.querySelector(selector);

    if (header) {
      header.classList.add('is-today');
    }

    if (this._previousHeader !== header) {
      this._unmarkCurrentDay();
    }

    this._previousHeader = header;
  },

  _unmarkCurrentDay: function() {
    if (this._previousHeader) {
      this._previousHeader.classList.remove('is-today');
    }
  }
};

});