Adds required jobs support to gamemodes (#44026)

* Adds required_jobs support to gamemodes

* alos needs to be checked with no players present

* early return

code/controllers/subsystem/job.dm

@@ -228,7 +228,7 @@ SUBSYSTEM_DEF(job)
  *  fills var "assigned_role" for all ready players.
  *  This proc must not have any side effect besides of modifying "assigned_role".
  **/
-/datum/controller/subsystem/job/proc/DivideOccupations()
+/datum/controller/subsystem/job/proc/DivideOccupations(list/required_jobs)
 	//Setup new player list and get the jobs list
 	JobDebug("Running DO")
 
@@ -248,7 +248,7 @@ SUBSYSTEM_DEF(job)
 
 	JobDebug("DO, Len: [unassigned.len]")
 	if(unassigned.len == 0)
-		return TRUE
+		return validate_required_jobs(required_jobs)
 
 	//Scale number of open security officer slots to population
 	setup_officer_positions()
@@ -354,7 +354,26 @@ SUBSYSTEM_DEF(job)
 		if(!GiveRandomJob(player))
 			if(!AssignRole(player, SSjob.overflow_role)) //If everything is already filled, make them an assistant
 				return FALSE //Living on the edge, the forced antagonist couldn't be assigned to overflow role (bans, client age) - just reroll
-	return TRUE
+	
+	return validate_required_jobs(required_jobs)
+
+/datum/controller/subsystem/job/proc/validate_required_jobs(list/required_jobs)
+	if(!required_jobs.len)
+		return TRUE
+	for(var/required_group in required_jobs)
+		var/group_ok = TRUE
+		for(var/rank in required_group)
+			var/datum/job/J = GetJob(rank)
+			if(!J)
+				SSticker.mode.setup_error = "Invalid job [rank] in gamemode required jobs."
+				return FALSE
+			if(J.current_positions < required_group[rank])
+				group_ok = FALSE
+				break
+		if(group_ok)
+			return TRUE
+	SSticker.mode.setup_error = "Required jobs not present."
+	return FALSE
 
 //We couldn't find a job from prefs for this guy.
 /datum/controller/subsystem/job/proc/HandleUnassigned(mob/dead/new_player/player)

code/controllers/subsystem/ticker.dm

@@ -230,7 +230,7 @@ SUBSYSTEM_DEF(ticker)
 	var/can_continue = 0
 	can_continue = src.mode.pre_setup()		//Choose antagonists
 	CHECK_TICK
-	can_continue = can_continue && SSjob.DivideOccupations() 				//Distribute jobs
+	can_continue = can_continue && SSjob.DivideOccupations(mode.required_jobs) 				//Distribute jobs
 	CHECK_TICK
 
 	if(!GLOB.Debug2)

code/game/gamemodes/game_mode.dm

@@ -25,6 +25,7 @@
 	var/list/datum/mind/antag_candidates = list()	// List of possible starting antags goes here
 	var/list/restricted_jobs = list()	// Jobs it doesn't make sense to be.  I.E chaplain or AI cultist
 	var/list/protected_jobs = list()	// Jobs that can't be traitors because
+	var/list/required_jobs = list()		// alternative required job groups eg list(list(cap=1),list(hos=1,sec=2)) translates to one captain OR one hos and two secmans
 	var/required_players = 0
 	var/maximum_players = -1 // -1 is no maximum, positive numbers limit the selection of a mode on overstaffed stations
 	var/required_enemies = 0

code/game/gamemodes/revolution/revolution.dm

@@ -14,6 +14,7 @@
 	antag_flag = ROLE_REV
 	false_report_weight = 10
 	restricted_jobs = list("Security Officer", "Warden", "Detective", "AI", "Cyborg","Captain", "Head of Personnel", "Head of Security", "Chief Engineer", "Research Director", "Chief Medical Officer")
+	required_jobs = list(list("Captain"=1),list("Head of Personnel"=1),list("Head of Security"=1),list("Chief Engineer"=1),list("Research Director"=1),list("Chief Medical Officer"=1)) //Any head present
 	required_players = 30
 	required_enemies = 2
 	recommended_enemies = 3