/* ex: set tabstop=2 softtabstop=2 shiftwidth=2 : */

/**
 * @param element
 * @param year
 * @param month
 */

/*jshint boss:true, plusplus:false */
function Qal(element) {
  /*global jQuery:true*/
  element = ("jQuery" in window && element instanceof jQuery) ? element[0] : element;

  this.element = element;
  this.year = 0;
  this.month = 0;
  this._event = null;

  var controls = this.element.getElementsByTagName("span");
  if (controls.length === 2 && controls[0].getAttribute("data-manipulation")  && controls[1].getAttribute("data-manipulation")) {
    // make it an ordinary array instead of DOMList
    this.controls = [controls[0], controls[1]];
  }
  else {
    throw new Error("Malformed controls in " + element + ".");
  }
}

Qal.prototype.toString = function() {
  return "" + this.year + "-" + this.month + "-1";
};

Qal.prototype.set = function(month, year) {
  var str, _now = new Date();
  var old_year = this.year;
  var old_month = this.month;
  this.year = year ? parseInt(year, 10) : _now.getFullYear();
  this.month = month ? parseInt(month, 10) : _now.getMonth() + 1;

  if (old_year !== this.year || old_month !== this.month) {
    // in case this.year is a Number, we prepend "" to convert it to a string
    str = "" + this.year + "-" + ("0" + this.month).slice(-2) + "-01";
    // cache value in DOM
    this.element.setAttribute("data-date", str);
  }

  var now = new Date(this.year, this.month - 1, 1);

  this.updateDOM(now);
  
  this.updateEvent();
  return this;
};

Qal.prototype.updateDOM = function(now) {
  var oneDayInMilliseconds = 86400000, arr = [], timeAt, i, item, str = "",
      lastMonthLastSunday, currentMonthEndTimeStamp, currentMonthEnd, lastMonthEnd;

  document.getElementById("ftc-calendar-description").innerHTML = "";

  function appendTo(arr, from, to) {
    to = to + 1;
    for (i = from; i < to; i++) {
      arr.push(i);
    }
    return arr;
  }


  lastMonthEnd = new Date(now - oneDayInMilliseconds).getDate();


  // month is actually pointed to next month
  currentMonthEndTimeStamp = new Date(now).setMonth(this.month) - oneDayInMilliseconds;
  currentMonthEnd = new Date(currentMonthEndTimeStamp).getDate();

  // find nearest Sunday in last month
  for (i = 0; i < 7; i++) {
    timeAt = new Date(now);
    if (timeAt.getDay() === 0) {
      lastMonthLastSunday = timeAt.getDate();
      break;
    }
    now = now - oneDayInMilliseconds;
  }


  // prepend last month
  // if the first day of this month is Sunday, then we do not prepend any
  if (lastMonthLastSunday > 1) {
    arr = appendTo(arr, lastMonthLastSunday, lastMonthEnd);
  }

  // append current month
  arr = appendTo(arr, 1, currentMonthEnd);
  
  // append next month
  var lengthToCurrentMonthEnd = arr.length - 1;
  var nextMonthFirstSaturday = 6 - (lengthToCurrentMonthEnd % 7);
  arr = appendTo(arr, 1, nextMonthFirstSaturday);

  var calendarLength = arr.length;

  function repeater(str, item, index) {
    var className = "", prefix;
    if (index < 7) {
      className += " first-row";
      if (item <= 7) {
        className += " this-month";
      }
    }
    else if (index <= lengthToCurrentMonthEnd) {
      className += " this-month";
    }

    if (index % 7 === 6) {
      className += " last-column";
    }

    if (className.charAt(0) === " ") {
      className = className.substring(1);
    }

    prefix = className ? "<span class='" + className + "'>" : "<span>";

    str += prefix + item + "</span>";
    return str;
  }
  
  for (i = 0; item = arr[i]; i++) {
    str = repeater(str, item, i);
  }

  var monthsInChinese = ["Error", "一", "二", "三", "四", "五", "六", "七", "八", "九", "十", "十一", "十二"];

  this.element.getElementsByTagName("div")[0].innerHTML = str;
  this.element.getElementsByTagName("h2")[0].innerHTML = this.year + "年" + this.month + "月";
};

Qal.prototype.change = function(manipulation, callback) {
  var year = this.year;
  var month = this.month;
  month = manipulation === "next" ? month + 1 : month - 1;
  if (month < 1) {
      month = 12;
      year -= 1;
  }
  else if (month > 12) {
      month = 1;
      year += 1;
  }
  this.set(month, year);
  if (callback) {
    callback.call(null, this.year, this.month);
  }
};

Qal.prototype.updateEvent = function(_event) {
  if (_event) {
    this._event = _event;
  }
  else {
    if (!this._event) {
      return;
    }
  }

  var i, _monthEvent = this._event[this.month], eventItem, _className, spans = [0], item, _spans = this.element.getElementsByTagName("span");

  for (i = 0; item = _spans[i]; i++) {
    if (/\bthis-month\b/.test(item.className)) {
      spans.push(item);
    }
  }
  item = null;

  function linkTo(item) {
    return function() {
      document.getElementById("ftc-calendar-description").innerHTML = "<a href='/m/events/recent.html?name="+ encodeURIComponent(item.name)+ "'>" + item._date + "日：" + item.name +"</a>";
    };
  }
  for (i = 0; item = _monthEvent[i]; i++) {
    if (!item._date || !spans[item._date]) {
      break;
    }
    _className = spans[item._date].className;
    _className += " hasEvent";
    if (_className.charAt(0) === " ") {
      _className = _className.substring(1);
    }
    spans[item._date].className = _className;
    spans[item._date].onclick = linkTo(item);

  }

};