Minor rework to how toxic chemicals work

code/__DEFINES/dcs/signals/signals_mob/signals_carbon.dm

@@ -60,6 +60,8 @@
 #define COMSIG_CARBON_GAIN_ORGAN "carbon_gain_organ"
 ///from /item/organ/proc/Remove() (/obj/item/organ/)
 #define COMSIG_CARBON_LOSE_ORGAN "carbon_lose_organ"
+///from on_mob_metabolize and mob_end_metabolize for the liver
+#define COMSIG_CARBON_UPDATE_TOXINS "carbon_update_toxins_cache"
 ///from /mob/living/carbon/doUnEquip(obj/item/I, force, newloc, no_move, invdrop, silent)
 #define COMSIG_CARBON_EQUIP_HAT "carbon_equip_hat"
 ///from /mob/living/carbon/doUnEquip(obj/item/I, force, newloc, no_move, invdrop, silent)

code/modules/mob/living/carbon/human/species_types/polysmorphs.dm

@@ -19,6 +19,7 @@
 	coldmod = 0.75
 	heatmod = 1.5
 	pressuremod = 0.75 //Xenos are completely pressure immune, they're bargain bin xenos
+	toxmod = 0.8 //their blood is acid, their liver is pretty used to fucked up things
 	acidmod = 0.2 //Their blood is literally acid
 	action_speed_coefficient = 1.1 //claws aren't dextrous like hands
 	speedmod = -0.1 //apex predator humanoid hybrid

code/modules/reagents/chemistry/reagents/toxin_reagents.dm

@@ -8,15 +8,18 @@
 	taste_description = "bitterness"
 	taste_mult = 1.2
 	evaporation_rate = 3 //6x faster than normal chems
+	/// Handled by the liver, does full damage for the highest toxpwr, and reduced for every following one
 	var/toxpwr = 1.5
 	var/silent_toxin = FALSE //won't produce a pain message when processed by liver/Life(seconds_per_tick = SSMOBS_DT, times_fired) if there isn't another non-silent toxin present.
 
-/datum/reagent/toxin/on_mob_life(mob/living/carbon/M)
-	if(toxpwr)
-		M.adjustToxLoss(toxpwr*REM, 0)
-		. = TRUE
-	..()
+/datum/reagent/toxin/on_mob_metabolize(mob/living/L)
+	. = ..()
+	SEND_SIGNAL(L, COMSIG_CARBON_UPDATE_TOXINS)
 
+/datum/reagent/toxin/on_mob_end_metabolize(mob/living/L)
+	. = ..()
+	SEND_SIGNAL(L, COMSIG_CARBON_UPDATE_TOXINS)
+
 /datum/reagent/toxin/amatoxin
 	name = "Amatoxin"
 	description = "A powerful poison derived from certain species of mushroom."
@@ -916,7 +919,7 @@
 /datum/reagent/toxin/delayed/on_mob_life(mob/living/carbon/M)
 	if(current_cycle > delay)
 		holder.remove_reagent(type, actual_metaboliztion_rate * M.metabolism_efficiency)
-		M.adjustToxLoss(actual_toxpwr*REM, 0)
+		toxpwr = actual_toxpwr
 		if(prob(10))
 			M.Paralyze(20, 0)
 		. = 1

code/modules/surgery/organs/liver.dm

@@ -1,5 +1,4 @@
-#define LIVER_DEFAULT_TOX_TOLERANCE 3 //amount of toxins the liver can filter out
-#define LIVER_DEFAULT_TOX_LETHALITY 0.01 //lower values lower how harmful toxins are to the liver
+#define LIVER_DEFAULT_TOX_LETHALITY 1 //lower values lower how harmful toxins are to the liver
 
 /obj/item/organ/liver
 	name = "liver"
@@ -12,55 +11,72 @@
 	maxHealth = STANDARD_ORGAN_THRESHOLD
 	healing_factor = STANDARD_ORGAN_HEALING
 	decay_factor = STANDARD_ORGAN_DECAY // smack in the middle of decay times
-	var/operated = FALSE	//whether we can still have our damages fixed through surgery
-	var/alcohol_tolerance = ALCOHOL_RATE//affects how much damage the liver takes from alcohol
-	var/toxTolerance = LIVER_DEFAULT_TOX_TOLERANCE//maximum amount of toxins the liver can just shrug off
-	var/toxLethality = LIVER_DEFAULT_TOX_LETHALITY//affects how much damage toxins do to the liver
-	var/filterToxins = TRUE //whether to filter toxins
+	/// whether we can still have our damages fixed through surgery
+	var/operated = FALSE	
+	/// affects how much damage the liver takes from alcohol
+	var/alcohol_tolerance = ALCOHOL_RATE
+	/// modifier to toxpwr for liver and toxin damage taken
+	var/toxLethality = LIVER_DEFAULT_TOX_LETHALITY 
+	/// cached list of the toxinpower of toxins
+	var/list/cached_toxpower = list()
+	/// whether or not the toxin process can provide a message
+	var/provide_pain_message = FALSE
+
+/obj/item/organ/liver/Insert(mob/living/carbon/M, special, drop_if_replaced, special_zone)
+	. = ..()
+	RegisterSignal(M, COMSIG_CARBON_UPDATE_TOXINS, PROC_REF(update_toxin_cache), override = TRUE)
+
+/obj/item/organ/liver/Remove(mob/living/carbon/M, special)
+	UnregisterSignal(M, COMSIG_CARBON_UPDATE_TOXINS)
+	return ..()
+
+/obj/item/organ/liver/proc/update_toxin_cache()
+	var/mob/living/carbon/C = owner
+	if(!istype(C))
+		return
 
-#define HAS_SILENT_TOXIN 0 //don't provide a feedback message if this is the only toxin present
-#define HAS_NO_TOXIN 1
-#define HAS_PAINFUL_TOXIN 2
+	provide_pain_message = FALSE
+	cached_toxpower = list()
+
+	for(var/datum/reagent/toxin/T in C.reagents.reagent_list)
+		cached_toxpower += T.toxpwr
+		provide_pain_message = provide_pain_message || !T.silent_toxin
+
+	sort_list(cached_toxpower,  cmp = /proc/cmp_numeric_dsc) //sort all toxpowers scaling from highest to lowest
 
 /obj/item/organ/liver/on_life()
 	var/mob/living/carbon/C = owner
 	..()	//perform general on_life()
 	if(istype(C))
-		if(!(organ_flags & ORGAN_FAILING))//can't process reagents with a failing liver
-
-			var/provide_pain_message = HAS_NO_TOXIN
-			if(filterToxins && !HAS_TRAIT(owner, TRAIT_TOXINLOVER))
-				//handle liver toxin filtration
-				for(var/datum/reagent/toxin/T in C.reagents.reagent_list)
-					var/thisamount = C.reagents.get_reagent_amount(T.type)
-					if (thisamount && thisamount <= toxTolerance)
-						C.reagents.remove_reagent(T.type, 1)
-					else
-						damage += (thisamount*toxLethality)
-						if(provide_pain_message != HAS_PAINFUL_TOXIN)
-							provide_pain_message = T.silent_toxin ? HAS_SILENT_TOXIN : HAS_PAINFUL_TOXIN
-
-			//metabolize reagents
-			C.reagents.metabolize(C, can_overdose=TRUE)
-
-			if(provide_pain_message && damage > 10 && prob(damage/3))//the higher the damage the higher the probability
-				to_chat(C, span_warning("You feel a dull pain in your abdomen."))
-		else	//for when our liver's failing
+		if(organ_flags & ORGAN_FAILING)//for when our liver's failing
 			C.reagents.end_metabolization(C, keep_liverless = TRUE) //Stops trait-based effects on reagents, to prevent permanent buffs
 			C.reagents.metabolize(C, can_overdose=FALSE, liverless = TRUE)
 			if(HAS_TRAIT(C, TRAIT_STABLELIVER))
 				return
 			C.adjustToxLoss(4, TRUE,  TRUE)
 			if(prob(30))
 				to_chat(C, span_warning("You feel a stabbing pain in your abdomen!"))
+
+		else 
+			if(length(cached_toxpower)) //deal with toxins
+				var/damage_multiplier = 1 //reduced for every subsequent toxin
+
+				for(var/dmg in cached_toxpower)
+					var/real_damage = dmg * toxLethality * damage_multiplier
+					damage_multiplier *= 0.5 //reduce the damage dealt for every subsequent toxin
+					C.adjustToxLoss(real_damage)
+					if(!HAS_TRAIT(owner, TRAIT_TOXINLOVER)) //don't hurt the liver if they like toxins
+						damage += (real_damage / 2)
+
+			//metabolize reagents
+			C.reagents.metabolize(C, can_overdose=TRUE)
+
+			if(provide_pain_message && damage > 10 && !HAS_TRAIT(owner, TRAIT_TOXINLOVER) && prob(damage/3))//the higher the damage the higher the probability
+				to_chat(C, span_warning("You feel a dull pain in your abdomen."))
 
 	if(damage > maxHealth)//cap liver damage
 		damage = maxHealth
 
-#undef HAS_SILENT_TOXIN
-#undef HAS_NO_TOXIN
-#undef HAS_PAINFUL_TOXIN
-
 /obj/item/organ/liver/prepare_eat()
 	var/obj/S = ..()
 	S.reagents.add_reagent(/datum/reagent/iron, 5)
@@ -84,8 +100,7 @@
 	name = "alien liver" // doesnt matter for actual aliens because they dont take toxin damage
 	icon_state = "liver-x" // Same sprite as fly-person liver.
 	desc = "A liver that used to belong to a killer alien, who knows what it used to eat."
-	toxLethality = LIVER_DEFAULT_TOX_LETHALITY * 2.5 // rejects its owner early after too much punishment
-	toxTolerance = 15 // complete toxin immunity like xenos have would be too powerful
+	toxLethality = LIVER_DEFAULT_TOX_LETHALITY * 0.5
 
 /obj/item/organ/liver/cybernetic
 	name = "cybernetic liver"
@@ -94,8 +109,7 @@
 	organ_flags = ORGAN_SYNTHETIC
 	alcohol_tolerance = 0.001
 	maxHealth = 2 * STANDARD_ORGAN_THRESHOLD
-	toxTolerance = 3.3
-	toxLethality = 0.009
+	toxLethality = LIVER_DEFAULT_TOX_LETHALITY * 0.9
 
 /obj/item/organ/liver/cybernetic/upgraded
 	name = "upgraded cybernetic liver"
@@ -104,8 +118,7 @@
 	alcohol_tolerance = 0.0005
 	maxHealth = 3 * STANDARD_ORGAN_THRESHOLD //300% health of a normal liver
 	healing_factor = 2 * STANDARD_ORGAN_HEALING //Can regenerate from damage quicker
-	toxTolerance = 20
-	toxLethality = 0.007
+	toxLethality = LIVER_DEFAULT_TOX_LETHALITY * 0.7
 
 /obj/item/organ/liver/cybernetic/upgraded/on_life()
 	. = ..()
@@ -125,7 +138,6 @@
 	attack_verb = list("processed")
 	desc = "A machine component, installed in the chest. This grants the machine the ability to process chemicals that enter its systems."
 	alcohol_tolerance = 0
-	toxTolerance = -1
 	toxLethality = 0
 	status = ORGAN_ROBOTIC
 	compatible_biotypes = ALL_BIOTYPES