This module is intended for processing of date strings.

Please do not modify this code without applying the changes first at Module:Date/sandbox and testing 
at Module:Date/sandbox/testcases and Module talk:Date/sandbox/testcases.

Authors and maintainers:

]]

 
local p = {}

-- =======================================
-- === Dependencies ======================
-- =======================================
--local i18n = require('Module:I18n/date')		-- get localized translations of date formats
--local Fallback = require('Module:Fallback')			-- get fallback functions
local yesno = require('Module:Yesno')

local i18n = { -- 다른 언어는 굳이 필요하지 않으니 한국어만 설정
	DateLang = {
		['ko'] = 'ko-form'
	DateFormat = {
		['ko-form'] = {
		YMDHMS='Y년 F j일, H:i:s',	
		YMDHM ='Y년 F j일, H:i',		
		YMD ='Y년 F j일',		
		YM ='Y년 F',		
		MD ='F j일',		
		Y ='Y년',
		M ='F'
--[=[
ISOyear
 
This function returns year part of date string.
 
Usage:
 
Parameters
 1: The date string 
 
Error Handling:
 If the string does not look like it contain the year than the function will not return anything.
 That is the preferred treatment for the template:Creator which is the main (only?) template calling it.
]=]
function p.ISOyear( frame )
	local input = frame.args[1]
	if not input then
		input = frame.args["s"]
	end
	input = mw.text.trim( input )
 
	-- if empty string then return it
	if input == "" then
		return input
	end
 
	-- if number then return it
	if tonumber( input ) then
		return mw.ustring.format
	end
 
	-- otherwise use regular expression match
	input = mw.ustring.match( input, '^(-?%d%d?%d?%d?)-' )
	if input then
		return mw.ustring.format
	else
		return ''
	end
end

--[==[
Date
 
This function is the core part of the ISOdate template. 
 
Usage:
 
Parameters:
 year,month,day,hour,minute,second: broken down date-time component strings
 lang: The language to display it in
 case: Language format  for some languages
 class: CSS class for the  node, use "" for no metadata at all

 Error Handling:

]==]
function p.Date(frame)
	return p._Date	
end

function p._Date	
	-- if language is not provided than look up users language
	-- WARNING: This step should be done by the template as it does not seem to work as well here (cache issues?)
	if not lang or not mw.language.isValidCode( lang ) then
		lang = 'ko'
	end
	
	-- Just in case someone broke the internationalization code than fix the english defaults
	if i18n.DateLang['ko'] == nil then
		i18n.DateLang['ko'] = 'ko-form'
	end	
	if i18n.DateFormat['ko-form'] == nil then
		i18n.DateFormat['ko-form'] = {
		YMDHMS='Y년 F j일, H:i:s',	
		YMDHM ='Y년 F j일, H:i',		
		YMD ='Y년 F j일',		
		YM ='Y년 F',		
		MD ='F j일',		
		Y ='Y년',
		M ='F'
	end

	-- create datecode based on which variables are provided and check for out of bound values
	local maxval = {9999, 12, 31, 23, 59, 60} -- max values for year, month, ...
	local c = {'Y', 'M', 'D', 'H', 'M', 'S'}
	local datecode = '' -- a string signifying which combination of variables was provided
	local datenum = {} -- date-time encoded as a vector = [year, month, ... , second]
	for i, v in ipairs( datavec ) do
		if v~=nil and v~='' then
			datecode = datecode .. c[i]
			datenum[i] = tonumber(v)
			if datenum[i]==nil and i==2 then
				-- month is not a number -> check if it is a month name in English
				v = mw.language.new('en'):formatDate
				datenum[i] = tonumber(v)
			end
			if datenum[i]==nil or datenum[i]>maxval[i] then
				-- Some numbers are out of range -> abort and return the empty string
				return ''
			end
		end
	end
	
	-- create time stamp string (for example 2000-02-20 02:20:20) based on which variables were provided
	local timeStamp
	if datecode == 'YMDHMS' then
		timeStamp = string.format
	elseif datecode == 'YMDHM' then
		timeStamp = string.format
	elseif datecode:sub=='YMD' then
		timeStamp = string.format
		datecode = 'YMD' -- 'YMD', 'YMDHMS' and 'YMDHM' are the only supported format starting with 'YMD'. All others will be converted to 'YMD'
	elseif datecode == 'YM' then
		timeStamp = string.format
	elseif datecode:sub=='Y' then
		timeStamp = string.format
		datecode = 'Y' 
	elseif datecode == 'M' then
		timeStamp = string.format
		class = '' -- date not complete -> no html formating or micro-tagging of date string
	elseif datecode == 'MD' then
		timeStamp = string.format
		class = '' -- date not complete -> no html formating or micro-tagging of date string
	else
		return '' -- format not supported
	end

	-- ==========================================================
	-- === Create Date String using in chosen language
	-- ==========================================================
	
	-- which form should the date take? 
	-- Use Fallback module to handle rare languages which are more likely to use different for than default EN form
	local langDateForm = 'ko-form'
	
	-- special case of French and Gallic dates, which require different date format for the 1st day of the month
	if datenum[3]==1 and (langDateForm=='fr-form' or langDateForm=='ga-form') then
		langDateForm = langDateForm .. '1' -- ordinal form for the first day of the month
	end
	-- Look up country specific format input to function
	local dFormat = i18n.DateFormat[langDateForm][datecode]
	
	-- overwrite default grammatical case of the month (applies mostly to Slavic languages)
	if (case=='gen') then
		-- CAUTION: at the moment i18n.DateFormat uses "F" only as month name, but this might change and this operation does not check if 'F' is in "" brackets or not, so if some language starts using 'F' in "" than this will not work for that language
		dFormat = dFormat:gsub; 
	end
	if (case=='nom') then
		-- CAUTION: at the moment i18n.DateFormat uses "xg" only as month name, but this might change and this operation does not check if 'xg' is in "" brackets or not, so if some language starts using 'xg' in "" than this will not work for that language
		dFormat = dFormat:gsub;
	end
	if ((lang=='ru' or lang=='pl' or lang=='cs' or lang=='sl') and (case=='loc' or case=='ins')) or
		(lang=='fi' and (case=='ptv' or case=='ine'or case=='ela'or case=='ill') ) then
		local monthEn = mw.language.new('en'):formatDate -- month name in English
		-- month name using proper case and language. It relies on messages stored in MediaWiki namespace for some cases and languages
		-- That is why this IF statement uses "lang" not "langDateForm" variable to decide
		local monthMsg = mw.message.new( string.format ):inLanguage( lang )
		if not monthMsg:isDisabled then -- make sure it exists
			local month=monthMsg:plain
			dFormat = dFormat:gsub; -- replace default month with month name we already looked up
			dFormat = dFormat:gsub;
		end
	end
	-- Special case related to Quechua and Kichwa languages
	-- see https://commons.wikimedia.org/wiki/Template_talk:Date#Quechua from 2014
	if (lang=='qu' or lang=='qug') and case=='nom' then
		dFormat = dFormat:gsub;
	end	

	-- Lua only date formating using parser function (new)
		-- prefered call which gives "Lua error: too many language codes requested." on the Module talk:Date/sandbox/testcases page
		--local datestr = mw.language.new(lang):formatDate 
	local datestr = mw.getCurrentFrame:callParserFunction
	
	-- Another special case related to Thai solar calendar
	if lang=='th' and datenum[1]~= nil and datenum[1]<=1940 then
		-- As of 2014 parser function did not resolve those cases properly
		-- See https://en.wikipedia.org/wiki/Thai_solar_calendar#New_year for reference
		-- Disable once https://bugzilla.wikimedia.org/show_bug.cgi?id=66648 is fixed
		if datecode=='Y' then -- date is ambiguous
			datestr = string.format 
		elseif datenum[2]<=3 then -- year is wrong (one too many)
			datestr = datestr:gsub( string.format, string.format )
		end
	end
	
	-- If year<1000 than either keep it padded to the length of 4 digits or trim it
	-- decide if the year will stay padded with zeros (for years in 0-999 range)
	if datenum[1]~= nil and datenum[1]<1000 then
		local trim = yesno
		if trim == nil then
			local YMin, YMax = trim_year:match( '(%d+)-(%d+)' )
			trim = (YMin~=nil and datenum[1]>=tonumber(YMin) and datenum[1]<=tonumber(YMax)) 
		end
	
		-- If the date form isn't the Thai solar calendar, don't zero pad years in the range of 100-999. 
		-- If at some point support for Islamic/Hebrew/Japanese years is added, they may need to be skipped as well. 
		if trim then
			--local yearStr1 = mw.language.new(lang):formatDate
			local yearStr1 = mw.getCurrentFrame:callParserFunction
			--local yearStr1 = datestr:match( '%d%d%d%d' ) -- 4 digits in a row (in any language) - that must be a year
			local yearStr2 = yearStr1
			local zeroStr = mw.ustring.sub
			for i=1,3 do -- trim leading zeros
				if mw.ustring.sub==zeroStr then
					yearStr2 = mw.ustring.sub
				else
					break
				end
			end
			datestr = datestr:gsub
			--datestr = string.format('%s ', datestr, yearStr1, yearStr2 )
		end
	end
	
	-- html formating and tagging of date string
	if class ~= '' then
		local DateHtmlTags = ''
		datestr = DateHtmlTags:format
	end
	return datestr
end

--[===[
ISOdate
 
This function is the core part of the ISOdate template. 
 
Usage:
 
Parameters:
 1: The date string 
 lang: The language to display it in
 form: Language format  for some languages
 class: CSS class for the  node

 Error Handling:
 If the string does not look like it contain the proper ISO date than the function will return the original string.
 
 That is the preferred treatment for the template:Information (and similar templates) which calling it.
]===]
function p.ISOdate(frame)

	local datevec = p._ISOdate( frame.args[1] )
	-- call p._Date function to format date string
	local succeded, datestr
	succeded, datestr = pcall
	if succeded and datestr~='' then
		tail = mw.ustring.gsub
		return mw.text.trim( datestr .. tail)
	else
		-- in case of errors return the original string
		return input
	end	
end

function p._ISOdate(d) -- Returns the vector for the date
	-- pattern: regexp - regular expresion to test; dlen - number of date elements; tail = which element is a "tail" if any
	-- regexp hints:
	-- 1) Strings starting with "^" and ending with "$" indicate whole string match
	-- 2) optional tail part copied as-is and following the main parsed part of the date have to be separated from the date by a whitespace, so "(\s.+)?"
	local pattern = {
		-- strings starting with YYYY-MM-DD HH:MM:SS. Year 4 digits (if we know seconds than it was within the last 100 years), the rest 1-2
		-- date and time can be separated by space or "T" and there could be a "Z" on the end indicating "Zulu" time zone
		-- strings starting with YYYY-MM-DD HH:MM. Year 4 digits, the rest 1-2
		-- strings starting with YYYY-MM-DD. Year 3-4 digits, the rest 1-2
		-- strings starting with YYYY-MM. Year 3-4 digits, month 1-2 digits
		-- string starts with a number -> it has to be 3 or 4 digit long to be a year
		 -- if whole string is a number (1-4 digit long) than it will be interpreted as a year
	
	-- create datevec based on which variables are provided
	local input = mw.text.trim( d )
	local datevec = {'','','','','',''}
	local tail = ''
	local vec, pat
	local debugStr = ''
	for i, pat in ipairs( pattern ) do
		vec = {input:match( pat.regexp )}
		if vec and vec[1]~=nil then
			for j=1,pat.dlen do
				datevec[j] = vec[j]
			end
			if pat.tail>0 and vec[pat.tail]~=nil then
				tail = vec[pat.tail]
			end
			debugStr = string.format(' (%i)', i)
			break
		end
	end	
	if datevec[1]=='' or datevec[1]==nil then
		-- quickly return if input does not look like date (it could be a template)
		return input
	else
		return datevec
	end
end

function p._isLeapYear( year )
 if year % 400 == 0 then
 return 1
 elseif year % 100 == 0 and year % 400 ~= 0 then
 return 0
 elseif year % 4 == 0 and year % 100 ~= 0 then
 return 1
 else
 return 0
 end
end