Nightshifts & Randomized Station Time

This commit adds the Nightshift lighting mode from /tg/. From 19:00 to
07:00 in station time, the station will go into a reduced-lighting mode,
with dimmed lights across the station.

In conjunction with this, there is a new configuration option to start
the shift time at a random time other than 12:00, so that players are
more likely to experience a night shift (as opposed to having to have a
7 hour round).

code/modules/power/apc.dm

@@ -104,6 +104,10 @@
 
 	var/shock_proof = 0 //if set to 1, this APC will not arc bolts of electricity if it's overloaded.
 
+	// Nightshift
+	var/nightshift_lights = FALSE
+	var/last_nightshift_switch = 0
+
 /obj/machinery/power/apc/worn_out
 	name = "\improper Worn out APC"
 	keep_preset_name = 1
@@ -773,6 +777,7 @@
 	data["siliconUser"] = istype(user, /mob/living/silicon)
 	data["siliconLock"] = locked
 	data["malfStatus"] = get_malf_status(user)
+	data["nightshiftLights"] = nightshift_lights
 
 	var/powerChannels[0]
 	powerChannels[++powerChannels.len] = list(
@@ -904,6 +909,16 @@
 
 		toggle_breaker()
 
+	else if(href_list["toggle_nightshift"])
+		if(!is_authenticated(usr))
+			return
+
+		if(last_nightshift_switch < world.time + 100) // don't spam...
+			to_chat(usr, "<span class='warning'>[src]'s night lighting circuit breaker is still cycling!</span>")
+			return
+		last_nightshift_switch = world.time
+		set_nightshift(!nightshift_lights)
+
 	else if(href_list["cmode"])
 		if(!is_authenticated(usr))
 			return
@@ -1353,4 +1368,13 @@
 	else
 		return 0
 
+/obj/machinery/power/apc/proc/set_nightshift(on)
+	set waitfor = FALSE
+	nightshift_lights = on
+	for(var/obj/machinery/light/L in area)
+		if(L.nightshift_allowed)
+			L.nightshift_enabled = nightshift_lights
+			L.update(FALSE)
+		CHECK_TICK
+
 #undef APC_UPDATE_ICON_COOLDOWN

code/modules/power/lighting.dm

@@ -153,6 +153,13 @@
 	var/rigged = 0				// true if rigged to explode
 	var/lightmaterials = list(MAT_GLASS=100)	//stores the materials the light is made of to stop infinite glass exploit
 
+	var/nightshift_enabled = FALSE	//Currently in night shift mode?
+	var/nightshift_allowed = TRUE	//Set to FALSE to never let this light get switched to night mode.
+	var/nightshift_light_range = 8
+	var/nightshift_light_power = 0.45
+	var/nightshift_light_color = "#FFDDCC"
+
+
 // the smaller bulb light fixture
 
 /obj/machinery/light/small
@@ -161,6 +168,7 @@
 	fitting = "bulb"
 	brightness_range = 4
 	brightness_color = "#a0a080"
+	nightshift_light_range = 4
 	desc = "A small lighting fixture."
 	light_type = /obj/item/weapon/light/bulb
 
@@ -226,18 +234,24 @@
 	return
 
 // update the icon_state and luminosity of the light depending on its state
-/obj/machinery/light/proc/update(var/trigger = 1)
-
+/obj/machinery/light/proc/update(var/trigger = TRUE)
+	switch(status)
+		if(LIGHT_BROKEN, LIGHT_BURNED, LIGHT_EMPTY)
+			on = FALSE
 	update_icon()
 	if(on)
-		if(light_range != brightness_range || light_power != brightness_power || light_color != brightness_color)
+		var/BR = nightshift_enabled ? nightshift_light_range : brightness_range
+		var/PO = nightshift_enabled ? nightshift_light_power : brightness_power
+		var/CO = nightshift_enabled ? nightshift_light_color : brightness_color
+		var/matching = light_range == BR && light_power == PO && light_color == CO
+		if(!matching)
 			switchcount++
 			if(rigged)
 				if(status == LIGHT_OK && trigger)
 					log_admin("LOG: Rigged light explosion, last touched by [fingerprintslast]")
 					message_admins("LOG: Rigged light explosion, last touched by [fingerprintslast]")
 					explode()
-			else if( prob( min(60, switchcount*switchcount*0.01) ) )
+			else if(prob(min(60, switchcount * switchcount * 0.01)))
 				if(status == LIGHT_OK && trigger)
 					status = LIGHT_BURNED
 					icon_state = "[base_state]-burned"
@@ -245,7 +259,7 @@
 					set_light(0)
 			else
 				use_power = 2
-				set_light(brightness_range, brightness_power, brightness_color)
+				set_light(BR, PO, CO)
 	else
 		use_power = 1
 		set_light(0)