[MIRROR] Reaction & holder tweaks (#1055)

* Reaction & holder tweaks (#81545)

## About The Pull Request
- Fixes #81537. For competing reactions where reaction B consumes the
results formed from reaction A `total_step_added` yields values higher
than the actual volume of products formed causing the reaction to end
early leading to less volume of product formed as explained in the
comment
- Removes `update_total()` from instant reactions as it already does
that for us making it a little faster
- merges `remove_all_direct()` with `remove_all()` to reduce code as
their functionalities are very similar

## Changelog
:cl:
fix: multiple reactions occuring in the same holder like mixing drinks
will yield correct reagent result volumes
code: Removes `update_total()` from instant reactions improving
performance slightly
code: merges `remove_all_direct()` with `remove_all()` to reduce code
size
/:cl:

* Reaction & holder tweaks

---------

Co-authored-by: SyncIt21 <[email protected]>

code/modules/antagonists/wizard/equipment/teleport_rod.dm

@@ -107,8 +107,8 @@
 	// (Primarily a way to prevent cheese with damage healing chem mixes,
 	// but also serves as a counter-counter to stuff like mute toxin.)
 	var/obj/item/organ/user_stomach = user.get_organ_slot(ORGAN_SLOT_STOMACH)
-	user.reagents?.remove_all_direct(0.33)
-	user_stomach?.reagents?.remove_all_direct(0.33)
+	user.reagents?.remove_all(0.33, relative = TRUE)
+	user_stomach?.reagents?.remove_all(0.33, relative = TRUE)
 	if(user.has_status_effect(/datum/status_effect/teleport_flux/perma))
 		return
 

code/modules/reagents/chemistry/equilibrium.dm

@@ -390,11 +390,15 @@
 	reaction_quality = purity
 
 	//post reaction checks
-	if(!(check_fail_states(total_step_added)))
+	if(!check_fail_states(total_step_added))
 		to_delete = TRUE
 		return
 
 	//If the volume of reagents created(total_step_added) >= volume of reagents still to be created(step_target_vol) then end
 	//i.e. we have created all the reagents needed for this reaction
-	if(total_step_added >= step_target_vol)
+	//This is only accurate when a single reaction is present and we don't have multiple reactions where
+	//reaction B consumes the products formed from reaction A(which can happen in add_reagent() as it also triggers handle_reactions() which can consume the reagent just added)
+	//because total_step_added will be higher than the actual volume that was created leading to the reaction ending early
+	//and yielding less products than intended
+	if(total_step_added >= step_target_vol && length(holder.reaction_list) == 1)
 		to_delete = TRUE

code/modules/reagents/chemistry/holder/holder.dm

@@ -304,54 +304,42 @@
 	return total_removed //this should be amount unless the loop is prematurely broken, in which case it'll be lower. It shouldn't ever go OVER amount.
 
 /**
- * Removes all reagents by an amount equal to
- * [amount specified] / total volume present in this holder
+ * Removes all reagents either proportionally(amount is the direct volume to remove)
+ * when proportional the total volume of all reagents removed will equal to amount
+ * or relatively(amount is a percentile between 0->1) when relative amount is the %
+ * of each reagent to be removed
+ *
  * Arguments
  *
- * * amount - the volume of each reagent
+ * * amount - the amount to remove
+ * * relative - if TRUE amount is treated as an percentage between 0->1. If FALSE amount is the direct volume to remove
  */
-
-/datum/reagents/proc/remove_all(amount = 1)
+/datum/reagents/proc/remove_all(amount = 1, relative = FALSE)
 	if(!total_volume)
 		return FALSE
 
 	if(!IS_FINITE(amount))
 		stack_trace("non finite amount passed to remove all reagents [amount]")
 		return FALSE
+	if(relative && (amount < 0 || amount > 1))
+		stack_trace("illegal percentage value passed to remove all reagents [amount]")
+		return FALSE
 
 	amount = round(amount, CHEMICAL_QUANTISATION_LEVEL)
 	if(amount <= 0)
 		return FALSE
 
 	var/list/cached_reagents = reagent_list
-	var/part = amount / total_volume
 	var/total_removed_amount = 0
-
+	var/part = amount
+	if(!relative)
+		part /= total_volume
 	for(var/datum/reagent/reagent as anything in cached_reagents)
 		total_removed_amount += remove_reagent(reagent.type, reagent.volume * part)
 
 	handle_reactions()
 	return round(total_removed_amount, CHEMICAL_VOLUME_ROUNDING)
 
-/**
- * Like remove_all but removes a percentage of every reagent directly rather than by volume
- *
- * Arguments
- * * percentage - the percentage of each reagent to remove
- */
-/datum/reagents/proc/remove_all_direct(percentage = 0.5)
-	if(!total_volume)
-		return 0
-	if(percentage <= 0)
-		stack_trace("non positive percentage passed to remove all reagents direct [percentage]")
-		return 0
-	var/total_removed_amount = 0
-	for(var/datum/reagent/reagent as anything in reagent_list)
-		total_removed_amount += remove_reagent(reagent.type, reagent.volume * percentage)
-
-	handle_reactions()
-	return round(total_removed_amount, CHEMICAL_VOLUME_ROUNDING)
-
 /**
  * Removes an specific reagent from this holder
  * Arguments

code/modules/reagents/chemistry/holder/reactions.dm

@@ -97,8 +97,6 @@
 		if((selected_reaction.reaction_flags & REACTION_INSTANT) || (flags & REAGENT_HOLDER_INSTANT_REACT)) //If we have instant reactions, we process them here
 			instant_react(selected_reaction)
 			.++
-			update_total()
-			continue
 		else
 			var/exists = FALSE
 			for(var/datum/equilibrium/E_exist as anything in reaction_list)