--[[ 



Display Gregorian date of a holiday that moves year to year. Date data can be obtained from multiple sources as configured in Module:Calendar date/events



  "localfile" = local data file (eg. /info/en/?search=Template:Calendar_date/localfiles/Hanukkah)

  "calculator" = user-supplied date calculator 

  "wikidata" = <tbd> for holidays with their own date entity page such as https://www.wikidata.org/wiki/Q51224536

               

 ]]



require('strict')



local p = {}

local cfg						-- Data structure from ~/events

local eventdata					-- Data structure from ~/localfiles/<holiday name>

local track = {}				-- Tracking category container



--[[--------------------------< inlineError >-----------------------



     Critical error. Render output completely in red. Add to tracking category.



 ]]



local function inlineError(arg, msg, tname)



	track"Category:Calendar date template errors" = 1

	return '<span style="font-size:100%" class="error citation-comment">Error in {{' .. tname .. '}} - Check <code style="color:inherit; border:inherit; padding:inherit;">&#124;' .. arg .. '=</code>  ' .. msg .. '</span>'



end



--[[--------------------------< trimArg >-----------------------



	 trimArg returns nil if arg is "" while trimArg2 returns 'true' if arg is "" 

	 trimArg2 is for args that might accept an empty value, as an on/off switch like nolink=



 ]]



local function trimArg(arg)

	if arg == "" or arg == nil then

		return nil

	else

		return mw.text.trim(arg)

	end

end

local function trimArg2(arg)

	if arg == nil then

		return nil

	else

		return mw.text.trim(arg)

	end

end



--[[--------------------------< tableLength >-----------------------



	Given a 1-D table, return number of elements



  ]]



local function tableLength(T)

	local count = 0

	for _ in pairs(T) do count = count + 1 end

	return count

end



--[[-------------------------< make_wikilink >----------------------------------------------------



	Makes a wikilink; when both link and display text is provided, returns a wikilink in the form [ [L|D] ]; if only

	link is provided, returns a wikilink in the form [ [L] ]; if neither are provided or link is omitted, returns an

	empty string.



  ]]



local function make_wikilink (link, display, no_link)

	if nil == no_link then

		if link and ('' ~= link) then

			if display and ('' ~= display) then

				return table.concat ({'[[', link, '|', display, ']]'});

			else

				return table.concat ({'[[', link, ']]'});

			end

		end

	else																		-- no_link

		if display and ('' ~= display) then										-- if there is display text

			return display;														-- return that

		else

			return link or '';													-- return the target article name or empty string

		end

	end

end



--[[--------------------------< createTracking >-----------------------



	Return data in track[] ie. tracking categories



  ]]



local function createTracking()



	local out = {};

	if tableLength(track) > 0 then

		for key, _ in pairs(track) do											-- loop through table

			table.insert (out, make_wikilink (key))								-- and convert category names to links

		end

	end

	return table.concat (out)													-- concat into one big string; empty string if table is empty

end



--[[--------------------------< isValidDate >----------------------------------------------------



	Returns true if date is after 31 December 1899 , not after 2100, and represents a valid date 

	(29 February 2017 is not a valid date).  Applies Gregorian leapyear rules. All arguments are required.



]]



local function isValidDate (year, month, day)



	local days_in_month = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}

	local month_length

	local y, m, d

	local today = os.date ('*')										-- fetch a table of current date parts



	if not year or year == '' or not month or month == '' or not day or day == '' then

		return false												-- something missing

	end



	y = tonumber (year)

	m = tonumber (month)

	d = tonumber (day)



	if 1900 > y or 2100 < y or 1 > m or 12 < m then					-- year and month are within bounds

		return false

	end



	if (2==m) then													-- if February

		month_length = 28											-- then 28 days unless

		if (0==(y%4) and (0~=(y%100) or 0==(y%400))) then			-- is a leap year?

			month_length = 29										-- if leap year then 29 days in February

		end

	else

		month_length=days_in_monthm];

	end



	if 1 > d or month_length < d then								-- day is within bounds

		return false

	end

	

	return true

end



--[[--------------------------< makeDate >-----------------------



	Given a zero-padded 4-digit year, 2-digit month and 2-digit day, return a full date in df format

	df = mdy, dmy, iso, ymd



 ]]



local function makeDate(year, month, day, df, format)

	local formatFull = {

		'dmy' = 'j F Y',

		'mdy' = 'F j, Y',

		'ymd' = 'Y F j',

		'iso' = 'Y-m-d'

	}

	local formatInfobox = {

		'dmy' = 'j F',

		'mdy' = 'F j',

		'ymd' = 'F j',

		'iso' = 'Y-m-d'

	}



	if not year or year == "" or not month or month == "" or not day or day == "" and formatdf then

		return nil

	end



	local date = table.concat ({year, month, day})               -- assemble iso format date

	if format ~= "infobox" then

		return mw.getContentLanguage():formatDate (formatFulldf], date)

	else

		return mw.getContentLanguage():formatDate (formatInfoboxdf], date)

	end

end



--[[--------------------------< dateOffset >-----------------------



	Given a 'origdate' in ISO format, return the date offset by number of days in 'offset' 

		eg. given "2018-02-01" and "-1" it will return "2018-01-30"

	On error, return origdate



  ]]



local function dateOffset(origdate, offset)



	local year, month, day = origdate:match ('(%d%d%d%d)-(%d%d)-(%d%d)')

	local now = os.time{year = year, month = month, day = day}

	local newdate = os.date("%Y-%m-%d", now + (tonumber(offset) * 24 * 3600))

	return newdate and newdate or origdate



  end



--[[--------------------------< renderHoli >-----------------------



	Render the data



  ]]

  

local function renderHoli(cfg,eventdata,calcdate,date,df,format,tname,cite)



	local hits = 0

	local matchdate = "^" .. date

	local startdate,enddate,outoffset,endoutoffset = nil

	local starttitle,endtitle = ""  



	-- user-supplied date calculator 

	if cfg.datatype == "calculator" then

		if cfg.datasource then

			startdate = calcdate

			enddate = dateOffset(startdate, cfg.days - 1)

		else

			return inlineError("holiday", 'invalid calculator result', tname )

		end



	-- read dates from localfile -- it assumes dates are in chrono order, need a more flexible method

	elseif cfg.datatype == "localfile" then                                              

		local numRecords = tableLength(eventdata) -- Get first and last date of holiday

		for i = 1, numRecords do

			if mw.ustring.find( eventdatai].date, matchdate ) then

				if hits == 0 then

					startdate = eventdatai].date

					hits = 1

				end

				if hits >= tonumber(cfg.days) then

					enddate = eventdatai].date

					break

				end

				hits = hits + 1

			end

		end

	end

     

	-- Verify data and special conditions

	if startdate == nil or enddate == nil then 

		if cfg.name == "Hanukkah" and startdate and not enddate then  -- Hanukkah bug, template doesn't support cross-year boundary

			enddate = dateOffset(startdate, 8)

		elseif cfg.datatype == "localfile" and cfg.days > "1" and startdate then

			enddate = dateOffset(startdate, cfg.days - 1)

		elseif startdate and not enddate then

			return inlineError("year", 'cannot find enddate', tname) .. createTracking()

		else

			return inlineError("holiday", 'cannot find startdate and enddate', tname) .. createTracking()

		end

	end

     

	-- Generate start-date offset (ie. holiday starts the evening before the given date)

	if cfg.startoffset then

		startdate = dateOffset(startdate, cfg.startoffset)

		if startdate ~= enddate then

			enddate = dateOffset(enddate, cfg.startoffset)

		else

			cfg.days = (cfg.days == "1") and "2"

		end

	end

 

	-- Generate end-date outside-Irael offset (ie. outside Israel the holiday ends +1 day later)

	endoutoffset = cfg.endoutoffset and dateOffset(enddate, cfg.endoutoffset)



	-- Format dates into df format 

	local year, month, day = startdate:match ('(%d%d%d%d)-(%d%d)-(%d%d)')

	startdate = makeDate(year, month, day, df, format)

	year, month, day = enddate:match ('(%d%d%d%d)-(%d%d)-(%d%d)')

	enddate = makeDate(year, month, day, df, format)

	if startdate == nil or enddate == nil then return nil end



	-- Add "outside of Israel" notices

	if endoutoffset then

		year, month, day = endoutoffset:match ('(%d%d%d%d)-(%d%d)-(%d%d)')

		local leader = ((format == "infobox") and "<br>") or " "

		endoutoffset = leader .. "(" .. makeDate(year, month, day, df, "infobox") .. " outside of Israel)"

	end

	if not endoutoffset then

		endoutoffset = ""

	end



	--- Determine format string

	format = ((format == "infobox") and " –<br>") or " – "



	--- Determine pre-pended text string eg. "sunset, <date>"

	local prepend1 = (cfg.prepend1 and (cfg.prepend1 .. ", ")) or ""

	local prepend2 = (cfg.prepend2 and (cfg.prepend2 .. ", ")) or ""



	-- return output

	if startdate == enddate or cfg.days == "1" then            -- single date

		return prepend1 .. startdate .. endoutoffset .. cite

	else

		return prepend1 .. startdate .. format .. prepend2 .. enddate .. endoutoffset .. cite

	end

end



--[[--------------------------< calendardate >-----------------------



     Main function



  ]]



function p.calendardate(frame)



	local pframe = frame:getParent()

	local args = pframe.args



	local tname = "Calendar date"					-- name of calling template. Change if template rename.

	local holiday = nil								-- name of holiday

	local date = nil								-- date of holiday (year) 

	local df = nil									-- date format (mdy, dmy, iso - default: iso)

	local format = nil								-- template display format options

	local cite = nil								-- leave a citation at end 

	local calcdate = ""             



	--- Determine holiday

	holiday = trimArg(args.holiday)					-- required

	if not holiday then

		holiday = trimArg(args.event)				-- event alias

		if not holiday then

			return inlineError("holiday", 'missing holiday argument', tname) .. createTracking()

		end

	end



	--- Determine date

	date = trimArg(args.year)						-- required

	if not date then

		return inlineError("year", 'missing year argument', tname) .. createTracking()

	elseif not isValidDate(date, "01", "01") then

		return inlineError("year", 'invalid year', tname) .. createTracking()

	end



	--- Determine format type

	format = trimArg(args.format)

	if not format then

		format = "none"

	elseif format ~= "infobox" then

		format = "none"

	end 



	-- Load configuration file

	local eventsfile = mw.loadData ('Module:Calendar date/events')

	if eventsfile.hebrew_calendarmw.ustring.upper(holiday)] then

		cfg = eventsfile.hebrew_calendarmw.ustring.upper(holiday)]

	elseif eventsfile.christian_eventsmw.ustring.upper(holiday)] then

		cfg = eventsfile.christian_eventsmw.ustring.upper(holiday)]

	elseif eventsfile.carnivalsmw.ustring.upper(holiday)] then

		cfg = eventsfile.carnivalsmw.ustring.upper(holiday)]

	elseif eventsfile.chinese_eventsmw.ustring.upper(holiday)] then

		cfg = eventsfile.chinese_eventsmw.ustring.upper(holiday)]

	elseif eventsfile.misc_eventsmw.ustring.upper(holiday)] then

		cfg = eventsfile.misc_eventsmw.ustring.upper(holiday)]

	else

		return inlineError("holiday", 'unknown holiday ' .. holiday, tname) .. createTracking()

	end



	-- If datatype = localfile 

	if cfg.datatype == "localfile" then

		local eventfile = nil

		eventfile = mw.loadData(cfg.datasource)

		if eventfile.event then

			eventdata = eventfile.event

		else

			return inlineError("holiday", 'unknown holiday file ' .. cfg.datasource .. '</span>', tname) .. createTracking()

		end



	-- If datatype = calculator

	elseif cfg.datatype == "calculator" then

		calcdate = frame:preprocess(cfg.datasource:gsub("YYYY", date))

		local year, month, day = calcdate:match ('(%d%d%d%d)-(%d%d)-(%d%d)')

		if not isValidDate(year, month, day) then

			return inlineError("holiday", 'invalid calculated date ' .. calcdate, tname) .. createTracking()

		end

	else

		return inlineError("holiday", 'unknown "datatype" in configuration', tname) .. createTracking()

	end



	--- Determine df - priority to |df in template, otherwise df in datafile, otherwise default to dmy

	df = trimArg(args.df)

	if not df then

		df = (cfg.df and cfg.df) or "dmy"

	end

	if df ~= "mdy" and df ~= "dmy" and df ~= "iso" then

		df = "dmy"

	end



	-- Determine citation

	cite = trimArg2(args.cite)

	if cite then

		if (cite ~= "no") then

			cite = ""

			if cfg.citeurl and cfg.accessdate and cfg.source and cfg.name then

				local citetitle = cfg.citetitle

				if citetitle == nil then

					citetitle = 'Dates for ' .. cfg.name

				end

				cite = frame:preprocess('<ref name="' .. holiday .. ' dates">{{cite web |url=' .. cfg.citeurl .. ' |title=' .. citetitle .. ' |publisher=' .. cfg.source .. '|accessdate=' .. cfg.accessdate .. '}}</ref>')

			elseif cfg.source then

				cite = frame:preprocess('<ref name="' .. holiday .. ' dates">' .. cfg.source:gsub("YYYY", date) .. '</ref>')

			else

				cite = ""

			end

		else

			cite = ""

		end

	else

		cite = ""

	end



	-- Render 

	local rend = renderHoli( cfg,eventdata,calcdate,date,df,format,tname,cite)

	if not rend then

		rend = '<span style="font-size:100%" class="error citation-comment">Error in [[:Template:' .. tname .. ']]: Unknown problem. Please report on template talk page.</span>'

		track"Category:Webarchive template errors" = 1 

	end



	return rend .. createTracking()



end



return p