// Copyright 2009 The Closure Library Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

/**
 * @fileoverview Locale independent date/time class.
 *
 */

goog.provide('goog.date.UtcDateTime');

goog.require('goog.date');
goog.require('goog.date.Date');
goog.require('goog.date.DateTime');
goog.require('goog.date.Interval');



/**
 * Class representing a date/time in GMT+0 time zone, without daylight saving.
 * Defaults to current date and time if none is specified. The get... and the
 * getUTC... methods are equivalent.
 *
 * @param {number|goog.date.DateLike=} opt_year Four digit UTC year or a
 *     date-like object.  If not set, the created object will contain the
 *     date determined by goog.now().
 * @param {number=} opt_month UTC month, 0 = Jan, 11 = Dec.
 * @param {number=} opt_date UTC date of month, 1 - 31.
 * @param {number=} opt_hours UTC hours, 0 - 23.
 * @param {number=} opt_minutes UTC minutes, 0 - 59.
 * @param {number=} opt_seconds UTC seconds, 0 - 59.
 * @param {number=} opt_milliseconds UTC milliseconds, 0 - 999.
 * @constructor
 * @struct
 * @extends {goog.date.DateTime}
 */
goog.date.UtcDateTime = function(
    opt_year, opt_month, opt_date, opt_hours, opt_minutes, opt_seconds,
    opt_milliseconds) {
  var timestamp;
  if (goog.isNumber(opt_year)) {
    timestamp = Date.UTC(
        opt_year, opt_month || 0, opt_date || 1, opt_hours || 0,
        opt_minutes || 0, opt_seconds || 0, opt_milliseconds || 0);
  } else {
    timestamp = opt_year ? opt_year.getTime() : goog.now();
  }
  /** @override */
  this.date = new Date(timestamp);
};
goog.inherits(goog.date.UtcDateTime, goog.date.DateTime);


/**
 * @param {number} timestamp Number of milliseconds since Epoch.
 * @return {!goog.date.UtcDateTime}
 */
goog.date.UtcDateTime.fromTimestamp = function(timestamp) {
  var date = new goog.date.UtcDateTime();
  date.setTime(timestamp);
  return date;
};


/**
 * Creates a DateTime from a UTC datetime string expressed in ISO 8601 format.
 *
 * @param {string} formatted A date or datetime expressed in ISO 8601 format.
 * @return {goog.date.UtcDateTime} Parsed date or null if parse fails.
 */
goog.date.UtcDateTime.fromIsoString = function(formatted) {
  var ret = new goog.date.UtcDateTime(2000);
  return goog.date.setIso8601DateTime(ret, formatted) ? ret : null;
};


/**
 * Clones the UtcDateTime object.
 *
 * @return {!goog.date.UtcDateTime} A clone of the datetime object.
 * @override
 */
goog.date.UtcDateTime.prototype.clone = function() {
  var date = new goog.date.UtcDateTime(this.date);
  date.setFirstDayOfWeek(this.getFirstDayOfWeek());
  date.setFirstWeekCutOffDay(this.getFirstWeekCutOffDay());
  return date;
};


/** @override */
goog.date.UtcDateTime.prototype.add = function(interval) {
  if (interval.years || interval.months) {
    var yearsMonths = new goog.date.Interval(interval.years, interval.months);
    goog.date.Date.prototype.add.call(this, yearsMonths);
  }
  var daysAndTimeMillis = 1000 *
      (interval.seconds +
       60 * (interval.minutes + 60 * (interval.hours + 24 * interval.days)));
  this.date = new Date(this.date.getTime() + daysAndTimeMillis);
};


/** @override */
goog.date.UtcDateTime.prototype.getTimezoneOffset = function() {
  return 0;
};


/** @override */
goog.date.UtcDateTime.prototype.getFullYear =
    goog.date.DateTime.prototype.getUTCFullYear;


/** @override */
goog.date.UtcDateTime.prototype.getMonth =
    goog.date.DateTime.prototype.getUTCMonth;


/** @override */
goog.date.UtcDateTime.prototype.getDate =
    goog.date.DateTime.prototype.getUTCDate;


/** @override */
goog.date.UtcDateTime.prototype.getHours =
    goog.date.DateTime.prototype.getUTCHours;


/** @override */
goog.date.UtcDateTime.prototype.getMinutes =
    goog.date.DateTime.prototype.getUTCMinutes;


/** @override */
goog.date.UtcDateTime.prototype.getSeconds =
    goog.date.DateTime.prototype.getUTCSeconds;


/** @override */
goog.date.UtcDateTime.prototype.getMilliseconds =
    goog.date.DateTime.prototype.getUTCMilliseconds;


/** @override */
goog.date.UtcDateTime.prototype.getDay = goog.date.DateTime.prototype.getUTCDay;


/** @override */
goog.date.UtcDateTime.prototype.setFullYear =
    goog.date.DateTime.prototype.setUTCFullYear;


/** @override */
goog.date.UtcDateTime.prototype.setMonth =
    goog.date.DateTime.prototype.setUTCMonth;


/** @override */
goog.date.UtcDateTime.prototype.setDate =
    goog.date.DateTime.prototype.setUTCDate;


/** @override */
goog.date.UtcDateTime.prototype.setHours =
    goog.date.DateTime.prototype.setUTCHours;


/** @override */
goog.date.UtcDateTime.prototype.setMinutes =
    goog.date.DateTime.prototype.setUTCMinutes;


/** @override */
goog.date.UtcDateTime.prototype.setSeconds =
    goog.date.DateTime.prototype.setUTCSeconds;


/** @override */
goog.date.UtcDateTime.prototype.setMilliseconds =
    goog.date.DateTime.prototype.setUTCMilliseconds;
