Adds hidden alarms, for air alarms, fire alarms, and APCs (#4816)

* Adds hidden alarms

* TRUE/FALSE defines

* Renames var to alarms_hidden

code/modules/alarm/alarm.dm

@@ -23,12 +23,13 @@
 	var/area/last_name				//The last acquired name, used should origin be lost
 	var/area/last_camera_area		//The last area in which cameras where fetched, used to see if the camera list should be updated.
 	var/end_time					//Used to set when this alarm should clear, in case the origin is lost.
+	var/hidden = FALSE				//If this alarm can be seen from consoles or other things.
 
-/datum/alarm/New(var/atom/origin, var/atom/source, var/duration, var/severity)
+/datum/alarm/New(var/atom/origin, var/atom/source, var/duration, var/severity, var/hidden)
 	src.origin = origin
 
 	cameras()	// Sets up both cameras and last alarm area.
-	set_source_data(source, duration, severity)
+	set_source_data(source, duration, severity, hidden)
 
 /datum/alarm/proc/process()
 	// Has origin gone missing?
@@ -43,17 +44,19 @@
 			AS.duration = 0
 			AS.end_time = world.time + ALARM_RESET_DELAY
 
-/datum/alarm/proc/set_source_data(var/atom/source, var/duration, var/severity)
+/datum/alarm/proc/set_source_data(var/atom/source, var/duration, var/severity, var/hidden)
 	var/datum/alarm_source/AS = sources_assoc[source]
 	if(!AS)
 		AS = new/datum/alarm_source(source)
 		sources += AS
 		sources_assoc[source] = AS
+		src.hidden = hidden
 	// Currently only non-0 durations can be altered (normal alarms VS EMP blasts)
 	if(AS.duration)
 		duration = SecondsToTicks(duration)
 		AS.duration = duration
 	AS.severity = severity
+	src.hidden = min(src.hidden, hidden)
 
 /datum/alarm/proc/clear(var/source)
 	var/datum/alarm_source/AS = sources_assoc[source]

code/modules/alarm/alarm_handler.dm

@@ -12,7 +12,7 @@
 		A.process()
 		check_alarm_cleared(A)
 
-/datum/alarm_handler/proc/triggerAlarm(var/atom/origin, var/atom/source, var/duration = 0, var/severity = 1)
+/datum/alarm_handler/proc/triggerAlarm(var/atom/origin, var/atom/source, var/duration = 0, var/severity = 1, var/hidden = 0)
 	var/new_alarm
 	//Proper origin and source mandatory
 	if(!(origin && source))
@@ -23,9 +23,9 @@
 	//see if there is already an alarm of this origin
 	var/datum/alarm/existing = alarms_assoc[origin]
 	if(existing)
-		existing.set_source_data(source, duration, severity)
+		existing.set_source_data(source, duration, severity, hidden)
 	else
-		existing = new/datum/alarm(origin, source, duration, severity)
+		existing = new/datum/alarm(origin, source, duration, severity, hidden)
 		new_alarm = 1
 
 	alarms |= existing
@@ -48,10 +48,10 @@
 		return check_alarm_cleared(existing)
 
 /datum/alarm_handler/proc/major_alarms()
-	return alarms
+	return visible_alarms()
 
 /datum/alarm_handler/proc/minor_alarms()
-	return alarms
+	return visible_alarms()
 
 /datum/alarm_handler/proc/check_alarm_cleared(var/datum/alarm/alarm)
 	if ((alarm.end_time && world.time > alarm.end_time) || !alarm.sources.len)
@@ -63,7 +63,7 @@
 
 /datum/alarm_handler/proc/on_alarm_change(var/datum/alarm/alarm, var/was_raised)
 	for(var/obj/machinery/camera/C in alarm.cameras())
-		if(was_raised)
+		if(was_raised && !alarm.hidden)
 			C.add_network(category)
 		else
 			C.remove_network(category)
@@ -95,3 +95,10 @@
 /datum/alarm_handler/proc/notify_listeners(var/alarm, var/was_raised)
 	for(var/listener in listeners)
 		call(listener, listeners[listener])(src, alarm, was_raised)
+
+/datum/alarm_handler/proc/visible_alarms()
+	var/list/visible_alarms = new()
+	for(var/datum/alarm/A in alarms)
+		if(!A.hidden)
+			visible_alarms.Add(A)
+	return visible_alarms

code/modules/alarm/atmosphere_alarm.dm

@@ -1,19 +1,16 @@
 /datum/alarm_handler/atmosphere
 	category = "Atmosphere Alarms"
 
-/datum/alarm_handler/atmosphere/triggerAlarm(var/atom/origin, var/atom/source, var/duration = 0, var/severity = 1)
-	..()
-
 /datum/alarm_handler/atmosphere/major_alarms()
 	var/list/major_alarms = new()
-	for(var/datum/alarm/A in alarms)
+	for(var/datum/alarm/A in visible_alarms())
 		if(A.max_severity() > 1)
 			major_alarms.Add(A)
 	return major_alarms
 
 /datum/alarm_handler/atmosphere/minor_alarms()
 	var/list/minor_alarms = new()
-	for(var/datum/alarm/A in alarms)
+	for(var/datum/alarm/A in visible_alarms())
 		if(A.max_severity() == 1)
 			minor_alarms.Add(A)
 	return minor_alarms