Player huggers now get second dibs if they hug a player (#3706)

# About the pull request

This PR makes it so the ckey of a player hugger is recorded in the
embryo so that they can get second dibs if/when that marine pops. The
marine player still has first dibs. If they manage to get a pop this
way, they forfeit any other hugs they currently have (kudos though if
someone is hugging multiple marines to put this measure into effect).

# Explain why it's good for the game

Another incentive for playable huggers!

# Testing Photographs and Procedure
<details>
<summary>Screenshots & Videos</summary>

Yes I test, you should too:

![image](https://github.com/cmss13-devs/cmss13/assets/76988376/7194169b-82a1-47ad-836d-42682f102b7a)

</details>


# Changelog
:cl: Drathek
add: Player facehugging gets 2nd dibs on the burst (the original marine
gets first dibs still)
/:cl:

code/_globalvars/lists/mobs.dm

@@ -23,6 +23,7 @@ GLOBAL_LIST_EMPTY_TYPED(alive_human_list, /mob/living/carbon/human) // list of a
 GLOBAL_LIST_EMPTY_TYPED(xeno_mob_list, /mob/living/carbon/xenomorph)
 GLOBAL_LIST_EMPTY_TYPED(living_xeno_list, /mob/living/carbon/xenomorph)
 GLOBAL_LIST_EMPTY_TYPED(xeno_cultists, /mob/living/carbon/human)
+GLOBAL_LIST_EMPTY_TYPED(player_embryo_list, /obj/item/alien_embryo)
 
 GLOBAL_LIST_EMPTY_TYPED(hellhound_list, /mob/living/carbon/xenomorph/hellhound)
 GLOBAL_LIST_EMPTY_TYPED(zombie_list, /mob/living/carbon/human)

code/modules/mob/living/carbon/xenomorph/Embryo.dm

@@ -12,6 +12,8 @@
 	var/hivenumber = XENO_HIVE_NORMAL
 	var/faction = FACTION_XENOMORPH
 	var/flags_embryo = FALSE // Used in /ciphering/predator property
+	/// The ckey of any player hugger that made this embryo
+	var/hugger_ckey
 
 /obj/item/alien_embryo/Initialize(mapload, ...)
 	. = ..()
@@ -33,6 +35,7 @@
 			C.med_hud_set_status()
 		STOP_PROCESSING(SSobj, src)
 		affected_mob = null
+	GLOB.player_embryo_list -= src
 	. = ..()
 
 /obj/item/alien_embryo/process()
@@ -145,20 +148,33 @@
 
 	var/mob/picked
 	// If the bursted person themselves has Xeno enabled, they get the honor of first dibs on the new larva.
-	if((!isyautja(affected_mob) || (isyautja(affected_mob) && prob(20))) && istype(affected_mob.buckled,  /obj/structure/bed/nest))
+	if((!isyautja(affected_mob) || (isyautja(affected_mob) && prob(20))) && istype(affected_mob.buckled, /obj/structure/bed/nest))
 		if(affected_mob.first_xeno || (affected_mob.client && affected_mob.client.prefs && (affected_mob.client.prefs.be_special & BE_ALIEN_AFTER_DEATH) && !jobban_isbanned(affected_mob, JOB_XENOMORPH)))
 			picked = affected_mob
 		else if(affected_mob.mind && affected_mob.mind.ghost_mob && affected_mob.client && affected_mob.client.prefs && (affected_mob.client.prefs.be_special & BE_ALIEN_AFTER_DEATH) && !jobban_isbanned(affected_mob, JOB_XENOMORPH))
 			picked = affected_mob.mind.ghost_mob
 
-
 	if(!picked)
 		// Get a candidate from observers
 		var/list/candidates = get_alien_candidates()
-
 		if(candidates && candidates.len)
-			picked = candidates[1]
-			message_alien_candidates(candidates, dequeued = 1)
+			// If they were facehugged by a player thats still in queue, they get second dibs on the new larva.
+			if(hugger_ckey)
+				for(var/mob/dead/observer/cur_obs as anything in candidates)
+					if(cur_obs.ckey == hugger_ckey)
+						picked = cur_obs
+						candidates -= cur_obs
+						message_alien_candidates(candidates, dequeued = 0)
+						for(var/obj/item/alien_embryo/embryo as anything in GLOB.player_embryo_list)
+							if(embryo.hugger_ckey == cur_obs.ckey && embryo != src)
+								// Skipping src just in case an admin wants to quickly check before this thing fully deletes
+								// If this nulls out any embryo, wow
+								embryo.hugger_ckey = null
+						break
+
+			if(!picked)
+				picked = candidates[1]
+				message_alien_candidates(candidates, dequeued = 1)
 
 	// Spawn the larva
 	var/mob/living/carbon/xenomorph/larva/new_xeno

code/modules/mob/living/carbon/xenomorph/Facehuggers.dm

@@ -241,46 +241,46 @@
 	throw_atom(target, 3, SPEED_FAST)
 	return TRUE
 
-/obj/item/clothing/mask/facehugger/proc/attach(mob/living/M, silent = FALSE, knockout_mod = 1)
-	if(attached || !can_hug(M, hivenumber))
+/obj/item/clothing/mask/facehugger/proc/attach(mob/living/living_mob, silent = FALSE, knockout_mod = 1, hugger_ckey = null)
+	if(attached || !can_hug(living_mob, hivenumber))
 		return FALSE
 
 	// This is always going to be valid because of the can_hug check above
-	var/mob/living/carbon/human/H = M
+	var/mob/living/carbon/human/human = living_mob
 	if(!silent)
-		H.visible_message(SPAN_DANGER("[src] leaps at [H]'s face!"))
+		human.visible_message(SPAN_DANGER("[src] leaps at [human]'s face!"))
 
 	if(isxeno(loc)) //Being carried? Drop it
 		var/mob/living/carbon/xenomorph/X = loc
 		X.drop_inv_item_on_ground(src)
 
-	if(isturf(H.loc))
-		forceMove(H.loc)//Just checkin
+	if(isturf(human.loc))
+		forceMove(human.loc)//Just checkin
 
-	if(!H.handle_hugger_attachment(src))
+	if(!human.handle_hugger_attachment(src))
 		return FALSE
 
 	attached = TRUE
 
-	forceMove(H)
+	forceMove(human)
 	icon_state = initial(icon_state)
-	H.equip_to_slot(src, WEAR_FACE)
-	H.update_inv_wear_mask()
-	H.disable_lights()
-	H.disable_special_items()
-	if(ishuman_strict(H))
-		playsound(loc, H.gender == "male" ? 'sound/misc/facehugged_male.ogg' : 'sound/misc/facehugged_female.ogg' , 25, 0)
-	else if(isyautja(H))
+	human.equip_to_slot(src, WEAR_FACE)
+	human.update_inv_wear_mask()
+	human.disable_lights()
+	human.disable_special_items()
+	if(ishuman_strict(human))
+		playsound(loc, human.gender == "male" ? 'sound/misc/facehugged_male.ogg' : 'sound/misc/facehugged_female.ogg' , 25, 0)
+	else if(isyautja(human))
 		playsound(loc, 'sound/voice/pred_facehugged.ogg', 65, FALSE)
 	if(!sterile)
-		if(!H.species || !(H.species.flags & IS_SYNTHETIC)) //synthetics aren't paralyzed
-			H.apply_effect(MIN_IMPREGNATION_TIME * 0.5 * knockout_mod, PARALYZE) //THIS MIGHT NEED TWEAKS
+		if(!human.species || !(human.species.flags & IS_SYNTHETIC)) //synthetics aren't paralyzed
+			human.apply_effect(MIN_IMPREGNATION_TIME * 0.5 * knockout_mod, PARALYZE) //THIS MIGHT NEED TWEAKS
 
-	addtimer(CALLBACK(src, PROC_REF(impregnate), H), rand(MIN_IMPREGNATION_TIME, MAX_IMPREGNATION_TIME))
+	addtimer(CALLBACK(src, PROC_REF(impregnate), human, hugger_ckey), rand(MIN_IMPREGNATION_TIME, MAX_IMPREGNATION_TIME))
 
 	return TRUE
 
-/obj/item/clothing/mask/facehugger/proc/impregnate(mob/living/carbon/human/target)
+/obj/item/clothing/mask/facehugger/proc/impregnate(mob/living/carbon/human/target, hugger_ckey = null)
 	if(!target || target.wear_mask != src) //Was taken off or something
 		return
 	if(SEND_SIGNAL(target, COMSIG_HUMAN_IMPREGNATE, src) & COMPONENT_NO_IMPREGNATE)
@@ -295,6 +295,8 @@
 		if(!embryos)
 			var/obj/item/alien_embryo/embryo = new /obj/item/alien_embryo(target)
 			embryo.hivenumber = hivenumber
+			embryo.hugger_ckey = hugger_ckey
+			GLOB.player_embryo_list += embryo
 
 			embryo.flags_embryo = flags_embryo
 			flags_embryo = NO_FLAGS

code/modules/mob/living/carbon/xenomorph/castes/Facehugger.dm

@@ -143,9 +143,9 @@
 
 /mob/living/carbon/xenomorph/facehugger/proc/handle_hug(mob/living/carbon/human/human)
 	var/obj/item/clothing/mask/facehugger/hugger = new /obj/item/clothing/mask/facehugger(loc, hivenumber)
-	var/did_hug = hugger.attach(human, TRUE, 0.5)
+	var/did_hug = hugger.attach(human, TRUE, 0.5, client?.ckey)
 	if(client)
-		client?.player_data?.adjust_stat(PLAYER_STAT_FACEHUGS, STAT_CATEGORY_XENO, 1)
+		client.player_data?.adjust_stat(PLAYER_STAT_FACEHUGS, STAT_CATEGORY_XENO, 1)
 	var/area/hug_area = get_area(src)
 	if(hug_area)
 		for(var/mob/dead/observer/observer as anything in GLOB.observer_list)