/**
 * 设置一个任务
 * @param {Object} callback 回调函数
 * @param {Object} cronstr crontab表达式
 */
function setCronTak(callback, cronstr) {
	var bool = initCronTask(callback, cronstr);
	if(!bool) {
		alert("表达式有误");
	}
}

/**
 * 初始化一个任务
 * @param {Object} callback 回调函数
 * @param {Object} cronstr crontab表达式
 */
function initCronTask(callback, cronstr) {
	//用' '进行分割
	var contabs = cronstr.split(' ');
	var length = contabs.length;
	var cronArray = new Array();
	if(length == 7) {
		//获取秒
		var secondSelectedArray = getValueArray(contabs[0], "second");
		if(secondSelectedArray == null || secondSelectedArray.length == 0) {
			return false;
		}

		//获取分
		var minuteSelectedArray = getValueArray(contabs[1], "minute");
		if(minuteSelectedArray == null || minuteSelectedArray.length == 0) {
			return false;
		}

		//获取时
		var hourSelectedArray = getValueArray(contabs[2], "hour");
		if(hourSelectedArray == null || hourSelectedArray.length == 0) {
			return false;
		}

		//获取天
		var dayArray = getValueArray(contabs[3], "day");
		if(dayArray == null || dayArray.length == 0) {
			return false;
		}

		//获取周
		var weekArray = getValueArray(contabs[6], "week");
		if(weekArray == null || weekArray.length == 0) {
			return false;
		}

		//获取月
		var monthSelectedArray = getValueArray(contabs[4], "month");
		if(monthSelectedArray == null || monthSelectedArray.length == 0) {
			return false;
		}

		//获取年
		var yearArray = getValueArray(contabs[5], "year");
		if(yearArray == null || yearArray.length == 0) {
			return false;
		}
	} else {
		return false;
	}
	var cronObj = {};
	cronObj.secondSelectedArray = secondSelectedArray;
	cronObj.minuteSelectedArray = minuteSelectedArray;
	cronObj.hourSelectedArray = hourSelectedArray;
	cronObj.dayArray = dayArray;
	cronObj.weekArray = weekArray;
	cronObj.monthSelectedArray = monthSelectedArray;
	cronObj.yearArray = yearArray;
	//console.log(cronObj);

	//获取下一次执行时间
	var now = new Date();
	var nextTime = getCronNextTime(now, cronObj);
	if(nextTime != null) {
		//console.log(nextTime.toLocaleString());
		//触发下一次任务	
		now = new Date(); //再取一次时间会更精确些
		var subTime = nextTime.getTime() - now.getTime();
		if(subTime < 0) {
			subTime = 0;
		}
		//console.log("subTime=" + subTime);
		setTimeout(function() {
			callCronTask(callback, cronObj);
		}, subTime);
	}

	return true;
}
/**
 * 触发任务
 * @param {Object} callback 回调函数
 * @param {Object} cronObj  cron对象
 */
function callCronTask(callback, cronObj) {
	//触发任务
	setTimeout(callback, 0);
	//获取下一次执行时间
	var now = new Date();
	var nextTime = getCronNextTime(now, cronObj);
	if(nextTime != null) {
		//console.log(nextTime.toLocaleString());
		//触发下一次任务	
		now = new Date(); //再取一次时间会更精确些
		var subTime = nextTime.getTime() - now.getTime();
		if(subTime < 0) {
			subTime = 0;
		}
		//console.log("subTime=" + subTime);
		setTimeout(function() {
			callCronTask(callback, cronObj);
		}, subTime);
	}
}

/**
 * 获取下一次执行时间
 * @param {Object} now 当前时间
 * @param {Object} cronObj cron对象
 */
function getCronNextTime(now, cronObj) {
	//预判时间是否可以取到(并不需要精确)
	var bool = preHandle(now, cronObj);
	if(!bool) {
		return null;
	}
	//获取下一时间
	var nextDateObj = {};
	var nextDate = getNextYear(now, cronObj, false, nextDateObj);
	if(nextDate != null) {
		//console.log(nextDate);
		return nextDate;
	} else {
		return null;
	}
}
/**
 * 取下一次时间先预处理
 * @param {Object} now 当前时间
 * @param {Object} cronObj cron对象
 */
function preHandle(now, cronObj) {
	var nowYear = now.getFullYear();
	var yearArray = cronObj.yearArray;
	//预判是润年否存在
	var hasLeapYear = preHandleYear(nowYear, yearArray);
	var maxSecMonthDay = 28;
	if(hasLeapYear) {
		maxSecMonthDay = 29;
	}
	var monthSelectedArray = cronObj.monthSelectedArray;
	//判断月中的最大天数
	var maxDays = getMaxDayInMonths(maxSecMonthDay, monthSelectedArray);
	//判断天中的最小天数是否比最大天数大
	var dayArray = cronObj.dayArray;
	var bool = getVaildDayCheck(maxDays, dayArray);
	if(bool) {
		return true;
	} else {
		return false;
	}
}

/**
 * 判断天数是否可能达到
 * @param {Object} maxDays 单月可能的最大天数
 * @param {Object} dayArray 天数cron数组
 */
function getVaildDayCheck(maxDays, dayArray) {
	for(var i = 0; i < dayArray.length; i++) {
		var ucron = dayArray[i];
		var min = ucron.min;
		var max = ucron.max;
		if(min <= maxDays || max <= maxDays) {
			return true;
		}
	}
	return false;
}

/**
 * 所有月中的最大单月天数
 * @param {Object} maxSecMonthDay 第二月最大天数
 * @param {Object} monthSelectedArray 月cron数组
 */
function getMaxDayInMonths(maxSecMonthDay, monthSelectedArray) {
	var maxDays = 0;
	for(var i = 0; i < monthSelectedArray.length; i++) {
		var month = monthSelectedArray[i];
		var days = getMaxDayWithMonth(maxSecMonthDay, month);
		if(maxDays < days) {
			maxDays = days;
		}
	}
	return maxDays;
}

/**
 * 使用月份获取最大天数
 * @param {Object} maxSecMonthDay 第二月最大天数
 * @param {Object} month 月份
 */
function getMaxDayWithMonth(maxSecMonthDay, month) {
	var day = 0;
	switch(month) {
		case 1:
		case 3:
		case 5:
		case 7:
		case 8:
		case 10:
		case 12:
			day = 31;
			break;
		case 2:
			day = maxSecMonthDay;
			break;
		default:
			day = 30;
	}
	return day;
}
/**
 * 判断是否可能存在闰年
 * @param {Object} nowYear 当前年
 * @param {Object} yearArray 年cron数组
 */
function preHandleYear(nowYear, yearArray) {
	for(var i = 0; i < yearArray.length; i++) {
		var ucron = yearArray[i];
		var min = ucron.min;
		var max = ucron.max;
		var divisor = ucron.divisor;
		if(min != null && max != null) {
			if(min < nowYear) {
				min = nowYear;
			}
			for(var j = min; j <= max; j++) {
				if(isLeapYear(j)) {
					return true;
				}
			}
		} else {
			return true;
		}
	}
	return false;
}
/**
 * 闰年判断
 * @param {Object} Year 年份
 */
function isLeapYear(Year) {
	if(((Year % 4) == 0) && ((Year % 100) != 0) || ((Year % 400) == 0)) {
		return(true);
	} else {
		return(false);
	}
}
/**
 * 确定下一次时间年份
 * @param {Object} now 当前时间
 * @param {Object} cronObj cron对象
 * @param {Object} gtFlag  是否大于当前时间、
 * @param {Object} nextDate 下一次时间对象
 */
function getNextYear(now, cronObj, gtFlag, nextDate) {
	var year = now.getFullYear(); //获取完整的年份(4位,1970-????)
	var yearArray = cronObj.yearArray;
	var maxYear = getMaxYear(yearArray);
	var min = getMinValue("year");
	if(min < year) {
		min = year;
	}
	for(var i = min; maxYear == null || i <= maxYear; i++) {
		if(isValidValue(yearArray, i)) {
			var gtFlag = i > min ? true : false;
			nextDate.nextYear = i;
			var dateTmp = getNextMonth(now, cronObj, gtFlag, nextDate);
			if(dateTmp != null) {
				return dateTmp;
			}
		}
	}
	return null;
}
/**
 * 获取可能的最大年份
 * @param {Object} yearArray 年cron数组
 */
function getMaxYear(yearArray) {
	var maxYear = getMinValue("year");
	for(var i = 0; i < yearArray.length; i++) {
		var ucron = yearArray[i];
		var min = ucron.min;
		var max = ucron.max;
		if(min != null && max != null) {
			if(maxYear < max) {
				maxYear = max;
			}
		} else {
			return null;
		}
	}
	return maxYear;
}

/**
 * 确定下一次时间的月份
 * @param {Object} now 当前时间
 * @param {Object} cronObj cron对象
 * @param {Object} gtFlag  是否大于当前时间
 * @param {Object} nextDate 下一次时间对象
 */
function getNextMonth(now, cronObj, gtFlag, nextDate) {
	var monthSelectedArray = cronObj.monthSelectedArray;
	var month = null;
	if(!gtFlag) {
		month = now.getMonth() + 1; //获取当前月份(1-12,1代表1月)
	}
	for(var i = 0; i < monthSelectedArray.length; i++) {
		if(gtFlag) {
			nextDate.nextMonth = monthSelectedArray[i];
			var dateTmp = getNextDay(now, cronObj, gtFlag, nextDate);
			if(dateTmp != null) {
				return dateTmp;
			}
		} else if(!gtFlag && month <= monthSelectedArray[i]) {
			nextDate.nextMonth = monthSelectedArray[i];
			var tmpGtFlag = monthSelectedArray[i] > month ? true : false;
			var dateTmp = getNextDay(now, cronObj, tmpGtFlag, nextDate);
			if(dateTmp != null) {
				return dateTmp;
			}
		}
	}
	return null;
}
/**
 * 确定下一次时间的天
 * @param {Object} now 当前时间
 * @param {Object} cronObj cron对象
 * @param {Object} gtFlag  是否大于当前时间
 * @param {Object} nextDate 下一次时间对象
 */
function getNextDay(now, cronObj, gtFlag, nextDate) {
	var dayArray = cronObj.dayArray;
	var weekArray = cronObj.weekArray;
	var min = getMinValue("day");
	if(!gtFlag) {
		day = now.getDate(); //获取当前日(1-31)
		if(min < day) {
			min = day;
		}
	}
	var max = getMonthDays(nextDate.nextYear, nextDate.nextMonth);
	var tmp = new Date(nextDate.nextYear, nextDate.nextMonth, min);
	var week = now.getDay(); //获取当前星期X(0-6,0代表星期天)
	var dayIgnore = isIgnore(dayArray);
	var weekIgnore = isIgnore(weekArray);
	for(var i = min; i <= max; i++) {
		if((dayIgnore && weekIgnore) || isValidValue(dayArray, i) || isValidValue(weekArray, (i - min + week) % 7)) {
			nextDate.nextDay = i;
			if(gtFlag) {
				var dateTmp = getNextHour(now, cronObj, gtFlag, nextDate);
				if(dateTmp != null) {
					return dateTmp;
				}
			} else {
				var tmpGtFlag = i > min ? true : false;
				var dateTmp = getNextHour(now, cronObj, tmpGtFlag, nextDate);
				if(dateTmp != null) {
					return dateTmp;
				}
			}
		}
	}
	return null;
}

/**
 * 确定下一次时间的小时
 * @param {Object} now 当前时间
 * @param {Object} cronObj cron对象
 * @param {Object} gtFlag  是否大于当前时间
 * @param {Object} nextDate 下一次时间对象
 */
function getNextHour(now, cronObj, gtFlag, nextDate) {
	var hourSelectedArray = cronObj.hourSelectedArray;
	var hour = null;
	if(!gtFlag) {
		hour = now.getHours();
	}
	for(var i = 0; i < hourSelectedArray.length; i++) {
		if(gtFlag) {
			nextDate.nextHour = hourSelectedArray[i];
			var dateTmp = getNextMinute(now, cronObj, gtFlag, nextDate);
			if(dateTmp != null) {
				return dateTmp;
			}
		} else if(!gtFlag && hour <= hourSelectedArray[i]) {
			nextDate.nextHour = hourSelectedArray[i];
			var tmpGtFlag = hourSelectedArray[i] > hour ? true : false;
			var dateTmp = getNextMinute(now, cronObj, tmpGtFlag, nextDate);
			if(dateTmp != null) {
				return dateTmp;
			}
		}
	}
	return null;
}

/**
 * 确定下一次时间的分钟
 * @param {Object} now 当前时间
 * @param {Object} cronObj cron对象
 * @param {Object} gtFlag  是否大于当前时间
 * @param {Object} nextDate 下一次时间对象
 */
function getNextMinute(now, cronObj, gtFlag, nextDate) {
	var minuteSelectedArray = cronObj.minuteSelectedArray;
	var minute = null;
	if(!gtFlag) {
		minute = now.getMinutes();
	}
	for(var i = 0; i < minuteSelectedArray.length; i++) {
		if(gtFlag) {
			nextDate.nextMinute = minuteSelectedArray[i];
			var dateTmp = getNextSencond(now, cronObj, gtFlag, nextDate);
			if(dateTmp != null) {
				return dateTmp;
			}
		} else if(!gtFlag && minute <= minuteSelectedArray[i]) {
			nextDate.nextMinute = minuteSelectedArray[i];
			var tmpGtFlag = minuteSelectedArray[i] > minute ? true : false;
			var dateTmp = getNextSencond(now, cronObj, tmpGtFlag, nextDate);
			if(dateTmp != null) {
				return dateTmp;
			}
		}
	}
	return null;
}

/**
 * 确定下一次时间的秒
 * @param {Object} now 当前时间
 * @param {Object} cronObj cron对象
 * @param {Object} gtFlag  是否大于当前时间
 * @param {Object} nextDate 下一次时间对象
 */
function getNextSencond(now, cronObj, gtFlag, nextDate) {
	var secondSelectedArray = cronObj.secondSelectedArray;
	var second = null;
	if(!gtFlag) {
		second = now.getSeconds();
	}
	for(var i = 0; i < secondSelectedArray.length; i++) {
		if(gtFlag) {
			nextDate.nextSecond = secondSelectedArray[i];
			var dateTmp = new Date(nextDate.nextYear, nextDate.nextMonth - 1, nextDate.nextDay, nextDate.nextHour, nextDate.nextMinute, nextDate.nextSecond);
			return dateTmp;
		} else if(!gtFlag && second < secondSelectedArray[i]) {
			nextDate.nextSecond = secondSelectedArray[i];
			var dateTmp = new Date(nextDate.nextYear, nextDate.nextMonth - 1, nextDate.nextDay, nextDate.nextHour, nextDate.nextMinute, nextDate.nextSecond);
			return dateTmp;
		}
	}
	return null;
}

/**
 * 获取cron分割数组
 * @param {Object} indexCron cron子字符串
 * @param {Object} type 类型
 */
function getValueArray(indexCron, type) {
	//console.log(type);
	//按逗号分割表达式
	var subcrons = indexCron.split(',');
	var subcronArray = new Array();
	for(var i = 0; i < subcrons.length; i++) {
		var ucron = {};
		//按/进行分割
		var parts = subcrons[i].split('/');
		if(parts.length == 0 || parts.length >= 3) {
			return null;
		}
		if(parts.length == 1) {
			ucron.divisor = 1;
		} else {
			if(isValidNumber(parts[1]) && parts[1] > 0) {
				ucron.divisor = parts[1];
			} else {
				return null;
			}
		}
		//按-进行分割
		var timeRange = parts[0].split('-');
		if(timeRange.length == 1 && timeRange[0] == "*") {
			ucron.min = getMinValue(type);
			ucron.max = getMaxValue(type);
		} else if(timeRange.length == 1 && timeRange[0] == "?" && (type == "day" || type == "week")) { //只能天和周配置问号
			ucron.min = null; //只有问号时min值才会为空
			ucron.max = null;
		} else if(timeRange.length == 1 && isValidNumber(timeRange[0])) {
			ucron.min = timeRange[0];
			ucron.max = timeRange[0];
		} else if(timeRange.length == 2 && isValidNumber(timeRange[0]) && isValidNumber(timeRange[1])) {
			ucron.min = timeRange[0];
			ucron.max = timeRange[1];
		} else {
			return null;
		}
		subcronArray[i] = ucron;
	}
	if(type == "day" || type == "week" || type == "year") {
		return subcronArray;
	} else {
		return getSelectedValue(subcronArray, type);
	}
}
/**
 * 获取符合要求数据
 * @param {Object} subcronArray cron子表达式数组
 * @param {Object} type 类型
 */
function getSelectedValue(subcronArray, type) {
	var min = getMinValue(type);
	var max = getMaxValue(type);
	var selectedArray = new Array();
	var j = 0;
	for(var i = min; i <= max; i++) {
		if(isValidValue(subcronArray, i)) {
			selectedArray[j] = i;
			j++;
		}
	}
	return selectedArray;
}

/**
 * 是否是有效的数据
 * @param {Object} subcronArray cron子表达式数组
 * @param {Object} value 类型
 */
function isValidValue(subcronArray, value) {
	for(var i = 0; i < subcronArray.length; i++) {
		var ucron = subcronArray[i];
		var min = ucron.min;
		var max = ucron.max;
		var divisor = ucron.divisor;
		if(min != null && value >= min && (max == null || value <= max) && value % divisor == 0) {
			return true;
		}
	}
	return false;
}

/**
 * 是否忽略该项
 * @param {Object} subcronArray cron子表达式数组
 */
function isIgnore(subcronArray) {
	for(var i = 0; i < subcronArray.length; i++) {
		var ucron = subcronArray[i];
		var min = ucron.min;
		if(min == null) {
			return true;
		}
	}
	return false;
}

/**
 * 获取当月天数
 * @param {Object} year 年份
 * @param {Object} month 月份
 */
function getMonthDays(year, month) {
	var d = new Date(year, month, 0);
	return d.getDate();
}
/**
 * 根据类型获取最小值
 * @param {Object} type 类型
 */
function getMinValue(type) {
	if(type == "second" || type == "minute" || type == "hour" || type == "week") { //秒分时周
		return 0;
	}
	if(type == "day" || type == "month") { //天月
		return 1;
	}
	return 1970; //年
}
/**
 * 根据类型获取最大值
 * @param {Object} type 类型
 */
function getMaxValue(type) {
	if(type == "second" || type == "minute") { //秒分
		return 59;
	}
	if(type == "hour") { //时
		return 23;
	}
	if(type == "day") { //天
		return 31;
	}
	if(type == "month") { //月
		return 12;
	}
	if(type == "week") { //周
		return 6;
	}
	return null; //年
}
/**
 * 判断是否为有效数字
 * @param {Object} str 字符串
 */
function isValidNumber(str) {
	if(/^\d+$/.test(str)) {
		return true;
	} else {
		return false;
	}
}