Module:Time

require ('Module:No globals') local getArgs = require ('Module:Arguments').getArgs

local tz = {};																	-- holds local copy of the specified timezone table from tz_data{}

--[[--< I S _ S E T >--

Whether variable is set or not. A variable is set when it is not nil and not empty.

]]

local function is_set( var ) return not (var == nil or var == ''); end

--[[--< D E C O D E _ D S T _ E V E N T >--

extract ordinal, day-name, and month from daylight saving start/end definition string as digits: Second Sunday in March returns 2 0 3

Casing doesn't matter but the form of the string does: – all are separated by spaces

]]

local function decode_dst_event (dst_event_string) local ord, day, month; local ordinals = {['1st'] = 1, ['first'] = 1, ['2nd'] = 2, ['second'] = 2, ['3rd'] = 3, ['third'] = 3, ['4th'] = 4, ['fourth'] = 4, ['5th'] = 5, ['fifth'] = 5, ['last'] = -1}; local days = {['sunday'] = 0, ['monday'] = 1, ['tuesday'] = 2, ['wednesday'] = 3, ['thursday'] = 4, ['friday'] = 5, ['saturday'] = 6}; local months = {['january'] = 1, ['february'] = 2, ['march'] = 3, ['april'] = 4, ['may'] = 5, ['june'] = 6, ['july'] = 7, ['august'] = 8, ['september'] = 9, ['october'] = 10, ['november'] = 11, ['december'] = 12}; dst_event_string = dst_event_string:lower;								-- force the string to lower case because that is how the tables above are indexed ord, day, month = dst_event_string:match ('([%a%d]+)%s+(%a+)%s+%a+%s+(%a+)'); if not (is_set (ord) and is_set (day) and is_set (month)) then				-- if one or more of these not set, then pattern didn't match return nil; end return ordinals[ord], days[day], months[month]; end

--[[--< G E T _ D A Y S _ I N _ M O N T H >

Returns the number of days in the month where month is a number 1–12 and year is four-digit Gregorian calendar. Accounts for leap year.

]]

local function get_days_in_month (year, month) local days_in_month = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; year = tonumber (year);														-- force these to be numbers just in case month = tonumber (month);

if (2 == month) then														-- if February if (0 == (year%4) and (0 ~= (year%100) or 0 == (year%400))) then		-- is year a leap year? return 29;															-- if leap year then 29 days in February end end return days_in_month [month]; end

--[[--< G E T _ D S T _ M O N T H _ D A Y >

Return the date (month and day of the month) for the day that is the ordinal (nth) day-name in month (second Friday in June) of the current year

timestamp is today's date-time number from os.time; used to supply year timezone is the timezone parameter value from the template call

Equations used in this function taken from Template:Weekday_in_month

]]

local function get_dst_month_day (timestamp, start) local ord, weekday_num, month; local first_day_of_dst_month_num; local last_day_of_dst_month_num; local days_in_month; local year;

if true == start then ord, weekday_num, month = decode_dst_event (tz.dst_begins);				-- get start string and convert to digits else ord, weekday_num, month = decode_dst_event (tz.dst_ends);				-- get end string and convert to digits end if not (is_set (ord) and is_set (weekday_num) and is_set (month)) then return nil;																-- could not decode event string end year = os.date ('%Y', timestamp);

if -1 == ord then		-- j = t + 7×(n + 1) - (wt - w) mod 7				-- if event occurs on the last day-name of the month ('last Sunday of October') days_in_month = get_days_in_month (year, month); last_day_of_dst_month_num = os.date ('%w', os.time ({['year']=year, ['month']=month, ['day']=days_in_month})); return month, days_in_month + 7*(ord + 1) - ((last_day_of_dst_month_num - weekday_num) % 7); else	-- j = 7×n - 6 + (w - w1) mod 7 first_day_of_dst_month_num = os.date ('%w', os.time ({['year']=year, ['month']=month, ['day']=1})) return month, 7 * ord - 6 + (weekday_num - first_day_of_dst_month_num) % 7;		-- return month and calculated date end end

--[[--< G E T _ U T C _ O F F S E T >--

Get utc offset in hours and minutes, convert to seconds. If the offset can't be converted return nil. TODO: return error message? TODO: limit check this? +/-n hours? ]]

local function get_utc_offset local sign; local hours; local minutes; sign, hours, minutes = mw.ustring.match (tz.utc_offset, '([%+%-±−]?)(%d%d):(%d%d)');

if '-' == sign then sign = -1; else sign = 1; end if is_set (hours) and is_set (minutes) then return sign * ((hours * 3600) + (minutes * 60)); else return nil;																-- we require that all timezone table have what appears to be a valid offset end end

--[[--< M A K E _ D S T _ T I M E S T A M P S >

Return UTC timestamps for the date/time of daylight saving time events (beginning and ending). These timestamps will be compared to current UTC time. A dst timestamp is the date/time in seconds UTC for the timezone at the hour of the dst event.

For dst rules that specify local event times, the timestamp is the sum of: timestamp = current year + dst_month + dst_day + dst_time (all in seconds) local time Adjust local time to UTC by subtracting utc_offset: timestamp = timestamp - utc_offset (in seconds) For dst_end timestamp, subtract an hour for DST timestamp = timestamp - 3600 (in seconds)

For dst rules that specify utc event time the process is the same except that utc offset is not subtracted.

]]

local function make_dst_timestamps (timestamp) local dst_begin, dst_end;													-- dst begin and end time stamps local year;																	-- current year local dst_b_month, dst_e_month, dst_day;									-- month and date of dst event local dst_hour, dst_minute;													-- hour and minute of dst event on year-dst_month-dst_day local invert = false;														-- flag to pass on when dst_begin month is numerically larger than dst_end month (southern hemisphere) local utc_offset; local utc_flag;

year = os.date ('%Y', timestamp);											-- current year utc_offset = get_utc_offset ;												-- in seconds if not is_set (utc_offset) then												-- utc offset is a required timezone property return nil; end

dst_b_month, dst_day = get_dst_month_day (timestamp, true);					-- month and day that dst begins if not is_set (dst_b_month) then return nil; end dst_hour, dst_minute = tz.dst_time:match ('(%d%d):(%d%d)');					-- get dst time utc_flag = tz.dst_time:find ('[Uu][Tt][Cc]%s*$');							-- set flag when dst events occur at a specified utc time

dst_begin = os.time ({['year'] = year, ['month'] = dst_b_month, ['day'] = dst_day, ['hour'] = dst_hour, ['min'] = dst_minute});	-- form start timestamp if not is_set (utc_flag) then												-- if dst events are specified to occur at local time dst_begin = dst_begin - utc_offset;										-- adjust local time to utc by subtracting utc offset end

dst_e_month, dst_day = get_dst_month_day (timestamp, false);				-- month and day that dst ends if not is_set (dst_e_month) then return nil; end if is_set (tz.dst_e_time) then dst_hour, dst_minute = tz.dst_e_time:match ('(%d%d):(%d%d)');			-- get ending dst time; this one for those locales that use different start and end times utc_flag = tz.dst_e_time:find ('[Uu][Tt][Cc]%s*$');						-- set flag if dst is pegged to utc time end

dst_end = os.time ({['year'] = year, ['month'] = dst_e_month, ['day'] = dst_day, ['hour'] = dst_hour, ['min'] = dst_minute});	-- form end timestamp if not is_set (utc_flag) then												-- if dst events are specified to occur at local time dst_end = dst_end - 3600;												-- assume that local end time is DST so adjust to local ST		dst_end = dst_end - utc_offset;											-- adjust local time to utc by subtracting utc offset end

if dst_b_month > dst_e_month then invert = true;															-- true for southern hemisphere eg: start September YYYY end April YYYY+1 end

return dst_begin, dst_end, invert; end

--[[--< G E T _ T E S T _ T I M E >

decode ISO formatted date/time into a table suitable for os.time. For testing, this time is utc just as is returned by the os.time function.

]]

local function get_test_time (iso_date) local year, month, day, hour, minute, second;

year, month, day, hour, minute, second = iso_date:match ('(%d%d%d%d)\-(%d%d)\-(%d%d)T(%d%d):(%d%d):(%d%d)'); if not year then return nil;																-- test time did not match the specified pattern end return {['year'] = year, ['month'] = month, ['day'] = day, ['hour'] = hour, ['min'] = minute, ['sec'] = second}; end

--[=[-< T I M E >--

This template takes several parameters; none are required: 1. the time zone abbreviation (positional, always the first unnamed parameter) 2. a date format flag; second positional parameter or |df=; can have one of several assigned values: y – display output time in dmy format dmy – same as 'y'		mdy – default; included for completeness iso – display output time in YYYY-MM-DDTHH:mm format 3. |dst= when set to 'no' disables dst calculations for locations that do not observe dst – Arizona in MST 4. |_TEST_TIME_= a specific utc time in ISO date time format used for testing this code TODO: convert _TEST_TIME_ to |time=?

Timezone abbreviations can be found here: List_of_time_zone_abbreviations

]=]

local function time (frame) local args = getArgs (frame); local utc_timestamp, timestamp;												-- current or _TEST_TIME_ timestamps; timestamp is local ST or DST time used in output local dst_begin_ts, dst_end_ts;												-- DST begin and end timestamps in UTC local tz_abbr;																-- select ST or DST timezone abbreviaion used in output local time_string;															-- holds output time/date in |df= format local utc_offset; local invert;																-- true when southern hemisphere local df;																	-- date format flag; the |df= parameter

local timeonly = 'yes' == args.timeonly;									-- boolean local dateonly = 'yes' == args.dateonly;									-- boolean local hide_refresh = 'yes' == args['hide-refresh'];							-- boolean local hide_tz = 'yes' == args['hide-tz'];									-- boolean local unlink_tz = 'yes' == args['unlink-tz'];								-- boolean

if timeonly and dateonly then												-- invalid condition when both are set timeonly, dateonly = false; end local tz_data = table.concat ({'Module:Time/data', frame:getTitle:find('sandbox', 1, true) and '/sandbox' or ''}); -- make a data module name; sandbox or live tz_data = mw.loadData (tz_data).tz_data;									-- load the data table

if args[1] then args[1] = args[1]:lower;												-- make lower case because tz table member indexes are lower case else args[1] = 'utc';														-- default to utc end if mw.ustring.match (args[1], 'utc[%+%-±−]?%d%d:%d%d') then					-- if rendering time for a UTC offset timezone tz.abbr = args[1]:upper:gsub('%-', '−');								-- set the link label to upper case and replace hyphen with a minus character (U+2212) tz.article = tz.abbr;													-- article title same as abbreviation tz.utc_offset = mw.ustring.match (args[1], 'utc([%+%-±−]?%d%d:%d%d)'):gsub('−', '%-');	-- extract the offset value; replace minus character with hyphen tz.df = 'iso'; args[1] = 'utc_offsets';												-- spoof to show that we recognize this timezone else tz = tz_data[args[1]];													-- make a local copy of the timezone table from tz_data{} end

if not is_set (tz_data[args[1]]) then return ' July 27, 2024 – unknown timezone (help) '; end df = args.df or args[2] or tz.df or 'mdy';									-- template |df= overrides typical df from tz properties TODO: error check these values? if is_set (df) then df = df:lower;														-- lower case because we will compare to lower case values later end

if is_set (args._TEST_TIME_) then											-- typically used to test the code at a specific utc time local test_time = get_test_time (args._TEST_TIME_); if not test_time then return ' July 27, 2024 – malformed or incomplete _TEST_TIME_ (help) '; end

--		utc_timestamp = os.time(get_test_time (args._TEST_TIME_)); utc_timestamp = os.time(test_time); else utc_timestamp = os.time ;												-- get current server time (UTC) end utc_offset = get_utc_offset ;												-- utc offset for specified timezone in seconds timestamp = utc_timestamp + utc_offset;										-- make local time timestamp

if 'no' == args.dst then													-- for timezones that DO observe dst but for this location ... tz_abbr = tz.abbr;														-- ... dst is not observed (|dst=no) show time as standard time else if is_set (tz.dst_begins) and is_set (tz.dst_ends) and is_set (tz.dst_time) then	-- make sure we have all of the parts dst_begin_ts, dst_end_ts, invert = make_dst_timestamps (timestamp);	-- get begin and end dst timestamps and invert flag

if nil == dst_begin_ts or nil == dst_end_ts then return ' July 27, 2024 – error calculating dst timestamps (help) '; end if invert then														-- southern hemisphere; use beginning and ending of standard time in the comparison if utc_timestamp >= dst_end_ts and utc_timestamp < dst_begin_ts then	-- is current date time standard time? tz_abbr = tz.abbr;											-- standard time abbreviation else timestamp = timestamp + 3600;								-- add an hour tz_abbr = tz.dst_abbr;										-- dst abbreviation end else																-- northern hemisphere if utc_timestamp >= dst_begin_ts and utc_timestamp < dst_end_ts then	-- all timestamps are UTC timestamp = timestamp + 3600;								-- add an hour tz_abbr = tz.dst_abbr; else tz_abbr = tz.abbr; end end elseif is_set (tz.dst_begins) or is_set (tz.dst_ends) or is_set (tz.dst_time) then	-- if some but not all not all parts then emit error message return table.concat ({' July 27, 2024 – incomplete definition for ', args[1]:upper, ' (help) '}); else tz_abbr = tz.abbr;													-- dst not observed for this timezone end end if dateonly then if 'iso' == df then														-- |df=iso df = 'iso_date'; elseif df:find ('^dmy') or 'y' == df then								-- |df=dmy, |df=dmy12, |df=dmy24, |df=y df = 'dmy_date'; else df = 'mdy_date';													-- default end

elseif timeonly or df:match ('^%d+$') then									-- time only of |df= is just digits df = table.concat ({'t', df:match ('%l*(12)') or '24'});				-- |df=12, |df=24, |df=dmy12, |df=dmy24, |df=mdy12, |df=mdy24; default to t24 elseif 'y' == df or 'dmy24' == df then df = 'dmy';

elseif 'mdy24' == df then df = 'mdy'; end local format = { t12 = '%l:%M %p',														-- time only t24 = '%R', iso_date ='%F',															-- date only dmy_date = '%e %B %Y', mdy_date = '%B %e, %Y', dmy12 = '%l:%M %p, %e %B %Y',											-- 12hr time and date mdy12 = '%l:%M %p, %B %e, %Y', dmy = '%R, %e %B %Y',													-- 24hr time and date mdy = '%R, %B %e, %Y', iso = '%FT%R' }	if format[df] then time_string = mw.text.trim (os.date (format[df], timestamp)); else return table.concat ({' July 27, 2024 – invalid date format ', df, ' (help) '}); end if not is_set (tz.article) then												-- if some but not all not all parts then emit error message return table.concat ({' July 27, 2024 – incomplete definition for ', args[1]:upper, ' (help) '}); end local refresh_link = (hide_refresh and '') or		table.concat ({			' ',				-- open span			mw.title.getCurrentTitle:fullUrl({action = 'purge'}),				-- add the a refresh link url			' refresh ',												-- close the span			});

local tz_tag = (hide_tz and ) or		((unlink_tz and table.concat ({' ', tz_abbr})) or						-- unlinked			table.concat ({' ', tz_abbr, }));			-- linked return table.concat ({time_string, tz_tag, refresh_link});

end

----< E X P O R T E D  F U N C T I O N S >--

return {time = time}