initial

code/__HELPERS/_time.dm

@@ -111,3 +111,140 @@ GLOBAL_VAR_INIT(rollovercheck_last_timeofday, 0)
 	if(hour)
 		hourT = " and [hour] hour[(hour != 1)? "s":""]"
 	return "[day] day[(day != 1)? "s":""][hourT][minuteT][secondT]"
+
+/*
+
+Days of the week to make it easier to reference them.
+
+When using time2text(), please use "DDD" to find the weekday. Refrain from using "Day"
+
+*/
+#define MONDAY "Mon"
+#define TUESDAY "Tue"
+#define WEDNESDAY "Wed"
+#define THURSDAY "Thu"
+#define FRIDAY "Fri"
+#define SATURDAY "Sat"
+#define SUNDAY "Sun"
+
+//Months
+
+#define JANUARY 1
+#define FEBRUARY 2
+#define MARCH 3
+#define APRIL 4
+#define MAY 5
+#define JUNE 6
+#define JULY 7
+#define AUGUST 8
+#define SEPTEMBER 9
+#define OCTOBER 10
+#define NOVEMBER 11
+#define DECEMBER 12
+
+//Select holiday names -- If you test for a holiday in the code, make the holiday's name a define and test for that instead
+#define NEW_YEAR "New Year"
+#define VALENTINES "Valentine's Day"
+#define APRIL_FOOLS "April Fool's Day"
+#define ST_PATRICK "Saint Patrick's Day"
+
+#define EASTER "Easter"
+#define HALLOWEEN "Halloween"
+#define CHRISTMAS "Christmas"
+#define FESTIVE_SEASON "Festive Season"
+#define HOTDOG_DAY "National Hot Dog Day"
+
+/*Timezones*/
+
+/// Line Islands Time
+#define TIMEZONE_LINT 14
+
+// Chatham Daylight Time
+#define TIMEZONE_CHADT 13.75
+
+/// Tokelau Time
+#define TIMEZONE_TKT 13
+
+/// Tonga Time
+#define TIMEZONE_TOT 13
+
+/// New Zealand Daylight Time
+#define TIMEZONE_NZDT 13
+
+/// New Zealand Standard Time
+#define TIMEZONE_NZST 12
+
+/// Norfolk Time
+#define TIMEZONE_NFT 11
+
+/// Lord Howe Standard Time
+#define TIMEZONE_LHST 10.5
+
+/// Australian Eastern Standard Time
+#define TIMEZONE_AEST 10
+
+/// Australian Central Standard Time
+#define TIMEZONE_ACST 9.5
+
+/// Australian Central Western Standard Time
+#define TIMEZONE_ACWST 8.75
+
+/// Australian Western Standard Time
+#define TIMEZONE_AWST 8
+
+/// Christmas Island Time
+#define TIMEZONE_CXT 7
+
+/// Cocos Islands Time
+#define TIMEZONE_CCT 6.5
+
+/// Central European Summer Time
+#define TIMEZONE_CEST 2
+
+/// Coordinated Universal Time
+#define TIMEZONE_UTC 0
+
+/// Eastern Daylight Time
+#define TIMEZONE_EDT -4
+
+/// Eastern Standard Time
+#define TIMEZONE_EST -5
+
+/// Central Daylight Time
+#define TIMEZONE_CDT -5
+
+/// Central Standard Time
+#define TIMEZONE_CST -6
+
+/// Mountain Daylight Time
+#define TIMEZONE_MDT -6
+
+/// Mountain Standard Time
+#define TIMEZONE_MST -7
+
+/// Pacific Daylight Time
+#define TIMEZONE_PDT -7
+
+/// Pacific Standard Time
+#define TIMEZONE_PST -8
+
+/// Alaska Daylight Time
+#define TIMEZONE_AKDT -8
+
+/// Alaska Standard Time
+#define TIMEZONE_AKST -9
+
+/// Hawaii-Aleutian Daylight Time
+#define TIMEZONE_HDT -9
+
+/// Hawaii Standard Time
+#define TIMEZONE_HST -10
+
+/// Cook Island Time
+#define TIMEZONE_CKT -10
+
+/// Niue Time
+#define TIMEZONE_NUT -11
+
+/// Anywhere on Earth
+#define TIMEZONE_ANYWHERE_ON_EARTH -12

code/__HELPERS/dates.dm

@@ -0,0 +1,41 @@
+//Adapted from a free algorithm written in BASIC (https://www.assa.org.au/edm#Computer)
+/proc/EasterDate(y)
+	var/FirstDig, Remain19, temp //Intermediate Results
+	var/tA, tB, tC, tD, tE //Table A-E results
+	var/d, m //Day and Month returned
+
+	FirstDig = round((y / 100))
+	Remain19 = y % 19
+
+	temp = (round((FirstDig - 15) / 2)) + 202 - 11 * Remain19
+
+	switch(FirstDig)
+		if(21,24,25,27,28,29,30,31,32,34,35,38)
+			temp -= 1
+		if(33,36,37,39,40)
+			temp -= 2
+	temp %= 30
+
+	tA = temp + 21
+	if(temp == 29)
+		tA -= 1
+	if(temp == 28 && (Remain19 > 10))
+		tA -= 1
+	tB = (tA - 19) % 7
+
+	tC = (40 - FirstDig) % 4
+	if(tC == 3)
+		tC += 1
+	if(tC > 1)
+		tC += 1
+	temp = y % 100
+	tD = (temp + round((temp / 4))) % 7
+
+	tE = ((20 - tB - tC - tD) % 7) + 1
+	d = tA + tE
+	if(d > 31)
+		d -= 31
+		m = 4
+	else
+		m = 3
+	return list("day" = d, "month" = m)

code/controllers/subsystem/events.dm

@@ -24,6 +24,8 @@ SUBSYSTEM_DEF(events)
 		if(!E.typepath)
 			continue //don't want this one! leave it for the garbage collector
 		control += E //add it to the list of all events (controls)
+	if(isnull(GLOB.holidays))
+		fill_holidays()
 	reschedule()
 	return SS_INIT_SUCCESS
 
@@ -128,3 +130,41 @@ SUBSYSTEM_DEF(events)
 	SSevents.can_fire = !SSevents.can_fire
 	message_admins("[usr.client] has toggled the events subsystem [SSevents.can_fire == 1 ? "on" : "off"]")
 	log_admin("[usr.client] has toggled the events subsystem [SSevents.can_fire == 1 ? "on" : "off"]")
+
+GLOBAL_LIST(holidays)
+
+/**
+ * Checks that the passed holiday is located in the global holidays list.
+ *
+ * Returns a holiday datum, or null if it's not that holiday.
+ */
+/proc/check_holidays(holiday_to_find)
+	if(isnull(GLOB.holidays) && !fill_holidays())
+		return // Failed to generate holidays, for some reason
+
+	return GLOB.holidays[holiday_to_find]
+
+/**
+ * Fills the holidays list if applicable, or leaves it an empty list.
+ */
+/proc/fill_holidays()
+	GLOB.holidays = list()
+	for(var/holiday_type in subtypesof(/datum/holiday))
+		var/datum/holiday/holiday = new holiday_type()
+		var/delete_holiday = TRUE
+		for(var/timezone in holiday.timezones)
+			var/time_in_timezone = world.realtime + timezone HOURS
+
+			var/YYYY = text2num(time2text(time_in_timezone, "YYYY")) // get the current year
+			var/MM = text2num(time2text(time_in_timezone, "MM")) // get the current month
+			var/DD = text2num(time2text(time_in_timezone, "DD")) // get the current day
+			var/DDD = time2text(time_in_timezone, "DDD") // get the current weekday
+
+			if(holiday.shouldCelebrate(DD, MM, YYYY, DDD))
+				GLOB.holidays[holiday.name] = holiday
+				delete_holiday = FALSE
+				break
+		if(delete_holiday)
+			qdel(holiday)
+
+	return TRUE

code/game/objects/structures/signs.dm

@@ -599,3 +599,46 @@
 	desc = "An unbelievably creepy cat clock that surveys the room with every tick and every tock."
 	icon = 'icons/obj/structures/props/catclock.dmi'
 	icon_state = "cat_clock_motion"
+
+//===================//
+//      Calendar     //
+//=================//
+
+/obj/structure/sign/calendar
+	name = "wall calendar"
+	desc = "Classic office decoration and a place to stare at maniacally."
+	icon_state = "calendar_civ"
+	var/calendar_faction
+
+/obj/structure/sign/calendar/get_examine_text(mob/user)
+	. = ..()
+	. += SPAN_INFO("The current date is: [time2text(world.realtime, "DDD, MMM DD")], [GLOB.game_year].")
+	if(length(GLOB.holidays))
+		. += SPAN_INFO("Events:")
+		for(var/holidayname in GLOB.holidays)
+			var/datum/holiday/holiday = GLOB.holidays[holidayname]
+			if(holiday.holiday_faction)
+				if(holiday.holiday_faction != calendar_faction)
+					continue
+			. += SPAN_INFO("[holiday.name]")
+			. += SPAN_BOLDNOTICE("[holiday.greet_text]")
+
+/obj/structure/sign/calendar/upp
+	icon_state = "calendar_upp"
+	desc = "Classic office decoration and a place to stare at maniacally, has a UPP logo on it, also all text is in Russian."
+	calendar_faction = FACTION_UPP
+
+/obj/structure/sign/calendar/wy
+	icon_state = "calendar_wy"
+	desc = "Classic office decoration and a place to stare at maniacally, produced by Weyland-Yutani."
+	calendar_faction = FACTION_WY
+
+/obj/structure/sign/calendar/twe
+	icon_state = "calendar_twe"
+	desc = "Classic office decoration and a place to stare at maniacally, has a pattern resembling a Union Jack on it."
+	calendar_faction = FACTION_TWE
+
+/obj/structure/sign/calendar/ua
+	icon_state = "calendar_ua"
+	desc = "Classic office decoration and a place to stare at maniacally, has a vertically placed UA flag and some army symbolics."
+	calendar_faction = FACTION_MARINE