date.lua

JAN  = 31
daysFeb  = {28, 29}
MAR  = 31
APR  = 30
MAY  = 31
JUN  = 30
JUL  = 31
AUG  = 31
SEPT = 30
OCT  = 31
NOV  = 30
DEC  = 31
MONTH = {JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEPT, OCT, NOV, DEC}

SUN = 1
MON = 2
TUE = 3
WED = 4
THU = 5
FRI = 6
SAT = 7
WEEK = {SUN, MON, TUE, WED, THU, FRI, SAT}

EVEN = 1
LEAP = 2

EVENYEAR = 365
LEAPYEAR = 366
DAYSPERYEAR = {EVENYEAR, LEAPYEAR}

DAYSPERYEAR.isLeapYear = function(year)
	if ((((year % 4 ==0) and (year % 100~=0)) or (year % 400==0)))then
		daysOfYear = DAYSPERYEAR[LEAP]
		MONTH[2] = daysFeb[LEAP]
	else
		daysOfYear = DAYSPERYEAR[EVEN]
		MONTH[2] = daysFeb[EVEN]
	end
	return daysOfYear
end

function getDaysLeft(y,m,d)
	daysOfYear = DAYSPERYEAR.isLeapYear(y)
	monEnd = m-1
	monStart = 1
	local daysLeft = 0
	for i = monStart, monEnd do
		daysLeft = daysLeft + MONTH[i]
	end
	daysLeft = daysLeft + d
	daysLeft = daysOfYear - daysLeft
	
	return daysLeft, daysOfYear
end

function processInMonthLevel(day, y, m, d)
	local retDate = {}
	--print("day", day, "MONTH[", m,"]", MONTH[m], "d", d, "m - d",MONTH[m]-d)
	if ( day <= MONTH[m]-d) then
		--还在本月之内
		d = d + day
		retDate["year"] = y
		retDate["month"] = m
		retDate["day"] = d
	else
		--在本月之外
		day = day - MONTH[m] + d
		m = m + 1
		--print(MONTH[2])
		while(day > MONTH[m]) do
			day = day - MONTH[m]
			m = m + 1
		end
		d = day
		retDate["year"] = y
		retDate["month"] = m
		retDate["day"] = d
	end
	return retDate
end

function getDate(day, startDate)
	
	retDate = {}

	if (startDate == nil) then
		myDate = os.date("%Y/%m/%d")	
	else
		myDate = startDate
	end
	
	m = tonumber(string.sub(myDate, 6,7))
	d = tonumber(string.sub(myDate, 9,10))
	y = tonumber(string.sub(myDate, 1,4))
	daysLeft, daysOfYear = getDaysLeft(y,m,d)

	if(day <= daysLeft) then
		-- 还在y年之内
		retDate = processInMonthLevel(day,y, m, d)
		
	else
		-- 已经出了y年之外
		day = day - daysLeft
		y = y + 1
		daysOfYear = DAYSPERYEAR.isLeapYear(y)
		while( day > daysOfYear ) do		
			day = day - daysOfYear
			y = y + 1
			daysOfYear = DAYSPERYEAR.isLeapYear(y)
		end
		m = 1 
		d = 0
		retDate = processInMonthLevel(day, y, m, d)
	end	
	
	if(retDate.month < 10) then
		retDate.month = "0" .. tostring(retDate.month)
	end

	if(retDate.day < 10) then
		retDate.day = "0" .. tostring(retDate.day)
	end
	
	retdate = retDate.year .. "-" .. retDate.month .. "-" .. retDate.day
	
	return retdate
end

function date2time(luaDate)
	if (luaDate == nil or type(luaDate) ~= "string") then
		return;
	else		
		local year = string.match(luaDate, "%d+")
		year = tonumber(year)
		local month = string.match(luaDate, "-%d+")
		month = string.gsub(month, "-", "")
		month = tonumber(month)
		local day = string.match(luaDate, "%d+%s")
		day =  string.gsub(day, "%s", "")
		day = tonumber(day)
		local hour = string.match(luaDate, "%d+:")
		hour = string.gsub(hour, ":", "")
		hour = tonumber(hour)
		local minite = string.match(luaDate, ":%d+:")
		minite = string.gsub(minite, ":", "")
		minite = tonumber(minite)
		local second = string.match(luaDate, ":%d+:%d+")
		second = string.gsub(second, minite, "")
		second = string.gsub(second, ":", "")
		second = tonumber(second)
		print(year, month, day, hour, minite, second)
		print(type(year),type(month), type(day), type(hour), type(minite), type(second))
		if ( (type(month) == "number" and month>=1 and month<= 12) 
			and (type(day) == "number" and day>=1 and day <=31) 
			and (type(hour) == "number" and hour>=0 and hour <=23)
			and(type(minite) == "number" and minite>=0 and minite<=59) 
			and (type(second) == "number" and second >=0 and second <= 59)) then
			return os.time{year = year, month = month, day = day, hour = hour, min = minite, sec = second}
		else
			return;
		end
	end
end

function time2date(luaTime)
	if (luaTime == nil or type(luaTime) ~= "number") then
		return;
	else
		return os.date("%Y-%m-%d %H:%M:%S", luaTime)
	end
end