Editing Module:One page calendar

require ('strict');
local getArgs = require ('Module:Arguments').getArgs

																				-- sequence to hold abbreviated month names where first-of-month is on day
local first_day_t = {															-- lang_object:formatDate ('L', 'YYYY-01-01') + 1 returns 1 (Sunday) to 7 (Saturday)
	{},																			-- table of months that begin on sunday
	{},																			-- table of months that begin on monday
	{},																			-- tuesday
	{},																			-- wednesday
	{},																			-- thursday
	{},																			-- friday
	{},																			-- saturday
	}

local subheader_rows_t = {														-- will get abbreviated month names for each of the days of the week
	{},																			-- these are the first three 'subheader' rows at the top of the wikitable; top
	{},																			-- middle
	{},																			-- bottom
	}

local week_day_names_t = {														-- for i18n though Help:Extension:ParserFunctions##time says day names rarely internationalized
	['sun_t'] = {},																-- holds calculated weekday names: [1]=<abbreviated>, [2]=<long>, [3]=<abbr title="<long>"><addreviated></abbr>
	['mon_t'] = {},																-- if your MediaWiki does not have weekday names for your language, these tables can be filled manually
	['tue_t'] = {},
	['wed_t'] = {},
	['thu_t'] = {},
	['fri_t'] = {},
	['sat_t'] = {},
	}


local row_format_str = '|| %s || %s || %s || %s || %s || %s || %s ';			-- format string for the three subheader rows

local weekday_rows_fmt_t = {													-- format strings for weekday wikitable rows
	'| 1 ||  8 || 15 || 22 || 29 || %s || %s || %s || %s || %s || %s || %s',
	'| 2 ||  9 || 16 || 23 || 30 || %s || %s || %s || %s || %s || %s || %s',
	'| 3 || 10 || 17 || 24 || 31 || %s || %s || %s || %s || %s || %s || %s',
	'| 4 || 11 || 18 || 25 ||    || %s || %s || %s || %s || %s || %s || %s',
	'| 5 || 12 || 19 || 26 ||    || %s || %s || %s || %s || %s || %s || %s',
	'| 6 || 13 || 20 || 27 ||    || %s || %s || %s || %s || %s || %s || %s',
	'| 7 || 14 || 21 || 28 ||    || %s || %s || %s || %s || %s || %s || %s',
	}

local caption_fmt = 'Calendar for year with 1 %s on a %s';						-- first %s is 'January' in local language; second %s is day name in local language


--[[--------------------------< M A I N >----------------------------------------------------------------------

	{{#invoke:Sandbox/trappist the monk/calendar|main|year=}}
supported parameters are:
	|year=			the year for which this calendar is rendered; defaults to current year
	|lang-tag=		language in which this calendar is rendered;  defaults to wiki's own language
	|table-style=	css style string suitable for use in an html style="" attribute; no quotes; defaults to empty string
	|caption=		a caption that replaces the default caption

]]

local function main (frame)
	local args_t = getArgs (frame);
	args_t['table-style'] = (args_t['table-style'] and ' style="' .. args_t['table-style'] .. '"') or '';	-- if not set, empty string for concatenation; applies to whole table

	local lang_object;
	
	if args_t['lang-tag'] then
		lang_object = mw.language.new (args_t['lang-tag']);						-- get a language object for the language specified by |lang-tag=
	else
		lang_object = mw.language.getContentLanguage();							-- get a language object for the local wiki language
	end
	
	if not week_day_names_t.sun_t[1] then										-- if empty auto fill; otherwise assume that tables have been filled manually at a local wiki
		for i, day in ipairs ({'sun_t', 'mon_t', 'tue_t', 'wed_t', 'thu_t', 'fri_t', 'sat_t'}) do	-- sequence values are used as indexes into week_day_names_t
			local long = lang_object:formatDate ('l', '2022-05-0' .. i);		-- 2022-05-01 is known to be a Sunday; calculate day names for the rest of the week
			local abbreviated = lang_object:formatDate ('D', '2022-05-0' .. i);	-- 2022-05-01 is known to be a Sun; calculate abbreviated day names for the rest of the week
		
			week_day_names_t[day][1] = abbreviated;								-- abbreviated day names: Sun, Mon, etc in local wiki language
			week_day_names_t[day][2] = long;									-- full day names: Sunday, Monday, etc in local wiki language
			week_day_names_t[day][3] = table.concat ({'<abbr title="', long, '">', abbreviated, '</abbr>'});
		end
	end
	
	local year = (args_t.year and args_t.year) or lang_object:formatDate ('Y');	-- get year from |year=; current year else	TODO: get year from article title?
	local jan_1_day = lang_object:formatDate ('l', year .. '-01-01');			-- get day name for day on which 1 January <year> occurs; for day name in table caption
	local jan_1_mon = lang_object:formatDate ('F', year .. '-01-01');			-- i18n: get month name for <year>-01-01; for month name in table caption

	for m=1, 12 do
		local month_abbr = lang_object:formatDate ('M', year .. '-' .. m);		-- get abbreviated month name
		local day_number = lang_object:formatDate ('w', year .. '-' .. m .. '-01') + 1;	-- returns a value 0-6; +1 offset makes 1-7 to index into first_day_t lua sequence
		table.insert (first_day_t[day_number], month_abbr);						-- add abbreviated month name to appropriate day number sequence
	end

	for row=1, 3 do																-- for each of the three 'month' subheader rows
		for day=1, 7 do															-- and for each day of the week in that row
			if first_day_t[day][row] then										-- if first of the month occurs on <day>
				table.insert (subheader_rows_t[row], first_day_t[day][row]);	-- insert abreviated month name
			else
				table.insert (subheader_rows_t[row], '');						-- insert empty string else
			end
		end
	end

	local out_t = {};															-- components of the output go here

	local caption = (args_t.caption and args_t.caption) or string.format (caption_fmt, jan_1_mon, jan_1_day);
	table.insert (out_t, '{| class="wikitable"' .. args_t['table-style'] .. '\n|+ ' .. caption);	-- open wikitable
	table.insert (out_t, table.concat ({'! colspan="12" | ', year}));			-- common column header holds year value from |year= or current year

	for i, row_t in ipairs (subheader_rows_t) do								-- for each of the three 'month' subheader rows
		if 1 == i then															-- first of these rows has rowspan and colspan styling
			table.insert (out_t, string.format ('| colspan="5" rowspan="3" |Date ' .. row_format_str, row_t[1], row_t[2], row_t[3], row_t[4], row_t[5], row_t[6], row_t[7]));
		else																	-- the others have no styling
			table.insert (out_t, string.format (row_format_str, row_t[1], row_t[2], row_t[3], row_t[4], row_t[5], row_t[6], row_t[7]));
		end
	end
																				-- append static day numbers and weekday rows
	table.insert (out_t, string.format (weekday_rows_fmt_t[1],
		week_day_names_t.sun_t[3], week_day_names_t.mon_t[3], week_day_names_t.tue_t[3], week_day_names_t.wed_t[3], week_day_names_t.thu_t[3], week_day_names_t.fri_t[3], week_day_names_t.sat_t[3]));
	table.insert (out_t, string.format (weekday_rows_fmt_t[2],
		week_day_names_t.mon_t[3], week_day_names_t.tue_t[1], week_day_names_t.wed_t[1], week_day_names_t.thu_t[1], week_day_names_t.fri_t[1], week_day_names_t.sat_t[1], week_day_names_t.sun_t[1]));
	table.insert (out_t, string.format (weekday_rows_fmt_t[3],
		week_day_names_t.tue_t[3], week_day_names_t.wed_t[1], week_day_names_t.thu_t[1], week_day_names_t.fri_t[1], week_day_names_t.sat_t[1], week_day_names_t.sun_t[1], week_day_names_t.mon_t[1]));
	table.insert (out_t, string.format (weekday_rows_fmt_t[4],
		week_day_names_t.wed_t[3], week_day_names_t.thu_t[1], week_day_names_t.fri_t[1], week_day_names_t.sat_t[1], week_day_names_t.sun_t[1], week_day_names_t.mon_t[1], week_day_names_t.tue_t[1]));
	table.insert (out_t, string.format (weekday_rows_fmt_t[5],
		week_day_names_t.thu_t[3], week_day_names_t.fri_t[1], week_day_names_t.sat_t[1], week_day_names_t.sun_t[1], week_day_names_t.mon_t[1], week_day_names_t.tue_t[1], week_day_names_t.wed_t[1]));
	table.insert (out_t, string.format (weekday_rows_fmt_t[6],
		week_day_names_t.fri_t[3], week_day_names_t.sat_t[1], week_day_names_t.sun_t[1], week_day_names_t.mon_t[1], week_day_names_t.tue_t[1], week_day_names_t.wed_t[1], week_day_names_t.thu_t[1]));
	table.insert (out_t, string.format (weekday_rows_fmt_t[7],
		week_day_names_t.sat_t[3], week_day_names_t.sun_t[1], week_day_names_t.mon_t[1], week_day_names_t.tue_t[1], week_day_names_t.wed_t[1], week_day_names_t.thu_t[1], week_day_names_t.fri_t[1]));

	table.insert (out_t, '|}');													-- close wikitable
	
	return table.concat (out_t, '\n|-\n');										-- make a big string and done

end


--[[--------------------------< E X P O R T S >----------------------------------------------------------------
]]

return	{
	main = main
	}