Adds a Join Queue if the server exceeds its hard population cap

Players can join a queue that will notify them with a message and sound when a slot becomes available. First come first serve.

Players have approximately 20 seconds to join after the notification. Failure to join in that window removes them from the queue, to remove AFKers.

I haven't tested the code yet but it's basically done.

code/controllers/subsystem/ticker.dm

@@ -41,6 +41,9 @@ var/datum/subsystem/ticker/ticker
 	var/totalPlayers = 0					//used for pregame stats on statpanel
 	var/totalPlayersReady = 0				//used for pregame stats on statpanel
 
+	var/queue_delay = 0
+	var/list/queued_players = list()		//used for join queues when the server exceeds the hard population cap
+
 	var/obj/screen/cinematic = null			//used for station explosion cinematic
 
 
@@ -97,6 +100,7 @@ var/datum/subsystem/ticker/ticker
 
 		if(GAME_STATE_PLAYING)
 			mode.process(wait * 0.1)
+			check_queue()
 
 			if(!mode.explosion_in_progress && mode.check_finished() || force_ending)
 				current_state = GAME_STATE_FINISHED
@@ -434,3 +438,23 @@ var/datum/subsystem/ticker/ticker
 	if(randomtips.len)
 		world << "<font color='purple'><b>Tip of the round: </b>[html_encode(pick(randomtips))]</font>"
 
+/datum/subsystem/ticker/proc/check_queue()
+	if(!queued_players.len || !config.hard_popcap)
+		return
+
+	queue_delay ++
+	var/mob/new_player/next_in_line = queued_players[1]
+
+	switch(queue_delay)
+		if(5) //every 5 ticks check if there is a slot available
+			if(living_player_count() < config.hard_popcap)
+				if(next_in_line && next_in_line.client)
+					next_in_line << "<span class='userdanger'>A slot has opened! You have approximately 20 seconds to join. <a href='?src=\ref[next_in_line];late_join=1'>\>\>Join Game\<\<</a>.</span>"
+					next_in_line << sound('sound/misc/notice1.ogg')
+					return
+				queued_players -= next_in_line //Client disconnected, remove he
+			queue_delay = 0 //No vacancy: restart timer
+		if(20 to INFINITY)  //No response from the next in line when a vacancy exists, remove he
+			next_in_line << "<span class='danger'>No response recieved. You have been removed from the line.</span>"
+			queued_players -= next_in_line
+			queue_delay = 0

code/modules/mob/new_player/new_player.dm

@@ -126,13 +126,28 @@
 		if(!ticker || ticker.current_state != GAME_STATE_PLAYING)
 			usr << "<span class='danger'>The round is either not ready, or has already finished...</span>"
 			return
+
 		var/relevant_cap
 		if(config.hard_popcap && config.extreme_popcap)
 			relevant_cap = min(config.hard_popcap, config.extreme_popcap)
 		else
 			relevant_cap = max(config.hard_popcap, config.extreme_popcap)
-		if(relevant_cap && living_player_count() >= relevant_cap && !(ckey(key) in admin_datums))
+
+		if(ticker.queued_players.len || (relevant_cap && living_player_count() >= relevant_cap && !(ckey(key) in admin_datums)))
+			var/queue_position = ticker.queued_players.Find(usr)
+
+			if(queue_position == 1 && living_player_count() < relevant_cap) //Let them join if there is a slot available and they are the next one in line
+				LateChoices()
+				return
+
 			usr << "<span class='danger'>[config.hard_popcap_message]</span>"
+			if(queue_position == 1)
+				usr << "<span class='notice'>You are next in line to join the game. You will be notified when a slot opens up.</span>"
+			else if(queue_position)
+				usr << "<span class='notice'>There are [queue_position-1] players in front of you in the queue to join the game.</span>"
+			else
+				ticker.queued_players += usr
+				usr << "<span class='notice'>You have been added to the queue to join the game. Your position in queue is [ticker.queued_players.len].</span>"
 			return
 		LateChoices()
 
@@ -234,6 +249,10 @@
 		src << alert("[rank] is not available. Please try another.")
 		return 0
 
+	//Remove the player from the join queue if he was in one and reset the timer
+	ticker.queued_players -= src
+	ticker.queue_delay = 4
+
 	SSjob.AssignRole(src, rank, 1)
 
 	var/mob/living/carbon/human/character = create_character()	//creates the human and transfers vars and mind