dateinput = (function($) {
	function dateinput(el, opts) {
		if (typeof(opts) != "object") opts = {};
		$.extend(this, dateinput.default_opts, opts);
		this.input = $(el);
		this.bindmethodstoobj("show", "hide", "hideifclickoutside", "keydownhandler", "selectdate");
		this.build();
		this.selectdate();
		this.hide()
	};
	dateinput.default_opts = {
		month_names: ["一月份", "二月份", "三月份", "四月份", "五月份", "六月份", "七月份", "八月份", "九月份", "十月份", "十一月份", "十二月份"],
		short_month_names: ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12"],
		short_day_names: ["日", "一", "二", "三", "四", "五", "六"],
		start_of_week: 1
	};
	dateinput.prototype = {
		build: function() {
			var monthnav = $('<p class="month_nav">' + '<span class="button prev" title="[page-up]">&#171;</span>' + ' <span class="month_name"></span> ' + '<span class="button next" title="[page-down]">&#187;</span>' + '</p>');
			this.monthnamespan = $(".month_name", monthnav);
			$(".prev", monthnav).click(this.bindtoobj(function() {
				this.movemonthby( - 1)
			}));
			$(".next", monthnav).click(this.bindtoobj(function() {
				this.movemonthby(1)
			}));
			var yearnav = $('<p class="year_nav">' + '<span class="button prev" title="[ctrl+page-up]">&#171;</span>' + ' <span class="year_name"></span> ' + '<span class="button next" title="[ctrl+page-down]">&#187;</span>' + '</p>');
			this.yearnamespan = $(".year_name", yearnav);
			$(".prev", yearnav).click(this.bindtoobj(function() {
				this.movemonthby( - 12)
			}));
			$(".next", yearnav).click(this.bindtoobj(function() {
				this.movemonthby(12)
			}));
			var nav = $('<div class="nav"></div>').append(monthnav, yearnav);
			var tableshell = "<table><thead><tr>";
			$(this.adjustdays(this.short_day_names)).each(function() {
				tableshell += "<th>" + this + "</th>"
			});
			tableshell += "</tr></thead><tbody></tbody></table>";
			this.dateselector = this.rootlayers = $('<div class="date_selector"></div>').append(nav, tableshell).insertafter(this.input);
			if ($.browser.msie && $.browser.version < 7) {
				this.ieframe = $('<iframe class="date_selector_ieframe" frameborder="0" src="#"></iframe>').insertbefore(this.dateselector);
				this.rootlayers = this.rootlayers.add(this.ieframe);
				$(".button", nav).mouseover(function() {
					$(this).addclass("hover")
				});
				$(".button", nav).mouseout(function() {
					$(this).removeclass("hover")
				})
			};
			this.tbody = $("tbody", this.dateselector);
			this.input.change(this.bindtoobj(function() {
				this.selectdate()
			}));
			this.selectdate()
		},
		selectmonth: function(date) {
			var newmonth = new date(date.getfullyear(), date.getmonth(), 1);
			if (!this.currentmonth || !(this.currentmonth.getfullyear() == newmonth.getfullyear() && this.currentmonth.getmonth() == newmonth.getmonth())) {
				this.currentmonth = newmonth;
				var rangestart = this.rangestart(date),
				rangeend = this.rangeend(date);
				var numdays = this.daysbetween(rangestart, rangeend);
				var daycells = "";
				for (var i = 0; i <= numdays; i++) {
					var currentday = new date(rangestart.getfullyear(), rangestart.getmonth(), rangestart.getdate() + i, 12, 00);
					if (this.isfirstdayofweek(currentday)) daycells += "<tr>";
					if (currentday.getmonth() == date.getmonth()) {
						daycells += '<td class="selectable_day" date="' + this.datetostring(currentday) + '">' + currentday.getdate() + '</td>'
					} else {
						daycells += '<td class="unselected_month" date="' + this.datetostring(currentday) + '">' + currentday.getdate() + '</td>'
					};
					if (this.islastdayofweek(currentday)) daycells += "</tr>"
				};
				this.tbody.empty().append(daycells);
				this.monthnamespan.empty().append(this.monthname(date));
				this.yearnamespan.empty().append(this.currentmonth.getfullyear());
				$(".selectable_day", this.tbody).click(this.bindtoobj(function(event) {
					this.changeinput($(event.target).attr("date"))
				}));
				$("td[date=" + this.datetostring(new date()) + "]", this.tbody).addclass("today");
				$("td.selectable_day", this.tbody).mouseover(function() {
					$(this).addclass("hover")
				});
				$("td.selectable_day", this.tbody).mouseout(function() {
					$(this).removeclass("hover")
				})
			};
			$('.selected', this.tbody).removeclass("selected");
			$('td[date=' + this.selecteddatestring + ']', this.tbody).addclass("selected")
		},
		selectdate: function(date) {
			if (typeof(date) == "undefined") {
				date = this.stringtodate(this.input.val())
			};
			if (!date) date = new date();
			this.selecteddate = date;
			this.selecteddatestring = this.datetostring(this.selecteddate);
			this.selectmonth(this.selecteddate)
		},
		changeinput: function(datestring) {
			this.input.val(datestring).change();
			this.hide()
		},
		show: function() {
			this.rootlayers.css("display", "block");
			$([window, document.body]).click(this.hideifclickoutside);
			this.input.unbind("focus", this.show);
			$(document.body).keydown(this.keydownhandler);
			this.setposition()
		},
		hide: function() {
			this.rootlayers.css("display", "none");
			$([window, document.body]).unbind("click", this.hideifclickoutside);
			this.input.focus(this.show);
			$(document.body).unbind("keydown", this.keydownhandler)
		},
		hideifclickoutside: function(event) {
			if (event.target != this.input[0] && !this.insideselector(event)) {
				this.hide()
			}
		},
		insideselector: function(event) {
			var offset = this.dateselector.position();
			offset.right = offset.left + this.dateselector.outerwidth();
			offset.bottom = offset.top + this.dateselector.outerheight();
			return event.pagey < offset.bottom && event.pagey > offset.top && event.pagex < offset.right && event.pagex > offset.left
		},
		keydownhandler: function(event) {
			switch (event.keycode) {
			case 9:
			case 27:
				this.hide();
				return;
				break;
			case 13:
				this.changeinput(this.selecteddatestring);
				break;
			case 33:
				this.movedatemonthby(event.ctrlkey ? -12 : -1);
				break;
			case 34:
				this.movedatemonthby(event.ctrlkey ? 12 : 1);
				break;
			case 38:
				this.movedateby( - 7);
				break;
			case 40:
				this.movedateby(7);
				break;
			case 37:
				this.movedateby( - 1);
				break;
			case 39:
				this.movedateby(1);
				break;
			default:
				return
			}
			event.preventdefault()
		},
		stringtodate: function(string) {
			var matches;
			if (matches = string.match(/^(\d{1,2}) ([^\s]+) (\d{4,4})$/)) {
				return new date(matches[3], this.shortmonthnum(matches[2]), matches[1], 12, 00)
			} else {
				return null
			}
		},
		datetostring: function(date) {
			return date.getfullyear()+"-"+this.short_month_names[date.getmonth()]+"-" +date.getdate()
		},
		setposition: function() {
			var offset = this.input.offset();
			this.rootlayers.css({
				top: offset.top + this.input.outerheight(),
				left: offset.left
			});
			if (this.ieframe) {
				this.ieframe.css({
					width: this.dateselector.outerwidth(),
					height: this.dateselector.outerheight()
				})
			}
		},
		movedateby: function(amount) {
			var newdate = new date(this.selecteddate.getfullyear(), this.selecteddate.getmonth(), this.selecteddate.getdate() + amount);
			this.selectdate(newdate)
		},
		movedatemonthby: function(amount) {
			var newdate = new date(this.selecteddate.getfullyear(), this.selecteddate.getmonth() + amount, this.selecteddate.getdate());
			if (newdate.getmonth() == this.selecteddate.getmonth() + amount + 1) {
				newdate.setdate(0)
			};
			this.selectdate(newdate)
		},
		movemonthby: function(amount) {
			var newmonth = new date(this.currentmonth.getfullyear(), this.currentmonth.getmonth() + amount, this.currentmonth.getdate());
			this.selectmonth(newmonth)
		},
		monthname: function(date) {
			return this.month_names[date.getmonth()]
		},
		bindtoobj: function(fn) {
			var self = this;
			return function() {
				return fn.apply(self, arguments)
			}
		},
		bindmethodstoobj: function() {
			for (var i = 0; i < arguments.length; i++) {
				this[arguments[i]] = this.bindtoobj(this[arguments[i]])
			}
		},
		indexfor: function(array, value) {
			for (var i = 0; i < array.length; i++) {
				if (value == array[i]) return i
			}
		},
		monthnum: function(month_name) {
			return this.indexfor(this.month_names, month_name)
		},
		shortmonthnum: function(month_name) {
			return this.indexfor(this.short_month_names, month_name)
		},
		shortdaynum: function(day_name) {
			return this.indexfor(this.short_day_names, day_name)
		},
		daysbetween: function(start, end) {
			start = date.utc(start.getfullyear(), start.getmonth(), start.getdate());
			end = date.utc(end.getfullyear(), end.getmonth(), end.getdate());
			return (end - start) / 86400000
		},
		changedayto: function(dayofweek, date, direction) {
			var difference = direction * (math.abs(date.getday() - dayofweek - (direction * 7)) % 7);
			return new date(date.getfullyear(), date.getmonth(), date.getdate() + difference)
		},
		rangestart: function(date) {
			return this.changedayto(this.start_of_week, new date(date.getfullyear(), date.getmonth()), -1)
		},
		rangeend: function(date) {
			return this.changedayto((this.start_of_week - 1) % 7, new date(date.getfullyear(), date.getmonth() + 1, 0), 1)
		},
		isfirstdayofweek: function(date) {
			return date.getday() == this.start_of_week
		},
		islastdayofweek: function(date) {
			return date.getday() == (this.start_of_week - 1) % 7
		},
		adjustdays: function(days) {
			var newdays = [];
			for (var i = 0; i < days.length; i++) {
				newdays[i] = days[(i + this.start_of_week) % 7]
			};
			return newdays
		}
	};
	$.fn.date_input = function(opts) {
		return this.each(function() {
			new dateinput(this, opts)
		})
	};
	$.date_input = {
		initialize: function(opts) {
			$("input.date_input").date_input(opts)
		}
	};
	return dateinput
})(jquery);