From 09f3b5da1c84ab82f316d6e5ee9d2ef6be563a1a Mon Sep 17 00:00:00 2001
From: TheChosenEvilOne <34602646+TheChosenEvilOne@users.noreply.github.com>
Date: Wed, 29 Jan 2020 00:52:54 +0200
Subject: [PATCH] Correct atmos reaction priority. (#48871)
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Fixes atmospheric reaction priority by changing the approach of #40367. Instead of using an assoc list it saves the major gas in the reaction datum and uses that. It will of course be slightly slower but it is still better than before with reaction priority being messed.
Why It's Good For The Game

Fixes broken feature.
Changelog

🆑
fix: Atmospheric reaction priority works correctly now, this means hypernob will stop all reactions and reactions should generally be more consistent between rounds.
/🆑
---
 .../atmospherics/gasmixtures/gas_mixture.dm   |  9 ++++----
 .../atmospherics/gasmixtures/reactions.dm     | 22 +++++--------------
 2 files changed, 11 insertions(+), 20 deletions(-)

diff --git a/code/modules/atmospherics/gasmixtures/gas_mixture.dm b/code/modules/atmospherics/gasmixtures/gas_mixture.dm
index 44412a1a6f5..b0fb6f8cb68 100644
--- a/code/modules/atmospherics/gasmixtures/gas_mixture.dm
+++ b/code/modules/atmospherics/gasmixtures/gas_mixture.dm
@@ -373,8 +373,8 @@ GLOBAL_LIST_INIT(gaslist_cache, init_gaslist_cache())
 			sharer_temperature = max(sharer_temperature + heat/sharer_heat_capacity, TCMB)
 			if(sharer)
 				sharer.temperature = sharer_temperature
-				if (initial(sharer.gc_share)) 
-					sharer.garbage_collect() 
+				if (initial(sharer.gc_share))
+					sharer.garbage_collect()
 	return sharer_temperature
 	//thermal energy of the system (self and sharer) is unchanged
 
@@ -410,8 +410,9 @@ GLOBAL_LIST_INIT(gaslist_cache, init_gaslist_cache())
 	if(!length(cached_gases))
 		return
 	var/list/reactions = list()
-	for(var/I in cached_gases)
-		reactions += SSair.gas_reactions[I]
+	for(var/datum/gas_reaction/G in SSair.gas_reactions)
+		if(cached_gases[G.major_gas])
+			reactions += G
 	if(!length(reactions))
 		return
 	reaction_results = new
diff --git a/code/modules/atmospherics/gasmixtures/reactions.dm b/code/modules/atmospherics/gasmixtures/reactions.dm
index 43c9cd95735..185bddc9524 100644
--- a/code/modules/atmospherics/gasmixtures/reactions.dm
+++ b/code/modules/atmospherics/gasmixtures/reactions.dm
@@ -2,8 +2,6 @@
 
 /proc/init_gas_reactions()
 	. = list()
-	for(var/type in subtypesof(/datum/gas))
-		.[type] = list()
 
 	for(var/r in subtypesof(/datum/gas_reaction))
 		var/datum/gas_reaction/reaction = r
@@ -16,26 +14,18 @@
 				var/datum/gas/req_gas = req
 				if (!reaction_key || initial(reaction_key.rarity) > initial(req_gas.rarity))
 					reaction_key = req_gas
-		.[reaction_key] += list(reaction)
-		sortTim(., /proc/cmp_gas_reactions, TRUE)
+		reaction.major_gas = reaction_key
+		. += reaction
+	sortTim(., /proc/cmp_gas_reaction)
 
-/proc/cmp_gas_reactions(list/datum/gas_reaction/a, list/datum/gas_reaction/b) // compares lists of reactions by the maximum priority contained within the list
-	if (!length(a) || !length(b))
-		return length(b) - length(a)
-	var/maxa
-	var/maxb
-	for (var/datum/gas_reaction/R in a)
-		if (R.priority > maxa)
-			maxa = R.priority
-	for (var/datum/gas_reaction/R in b)
-		if (R.priority > maxb)
-			maxb = R.priority
-	return maxb - maxa
+/proc/cmp_gas_reaction(datum/gas_reaction/a, datum/gas_reaction/b) // compares lists of reactions by the maximum priority contained within the list
+	return b.priority - a.priority
 
 /datum/gas_reaction
 	//regarding the requirements lists: the minimum or maximum requirements must be non-zero.
 	//when in doubt, use MINIMUM_MOLE_COUNT.
 	var/list/min_requirements
+	var/major_gas //the highest rarity gas used in the reaction.
 	var/exclude = FALSE //do it this way to allow for addition/removal of reactions midmatch in the future
 	var/priority = 100 //lower numbers are checked/react later than higher numbers. if two reactions have the same priority they may happen in either order
 	var/name = "reaction"