Fixes math for chiral inversion buffer & reagent display messages (#93946)

## About The Pull Request
- Chiral inversion buffer now converts multiple reagents with 1u being
able to convert 10u of the entire solution & not just one reagent in the
target. This means if we have say 5u of reagent A & 5u of reagent B
where both can be inverted, then 1u of the inversing buffer can convert
both reagents
- Chiral inversion buffer can now be transferred to another reagent
holder if no conversion occurred instead of just disappearing into the
wind
- Fixes some objects displaying 0u of reagent transferred which happens
when reagent intercept occurs

## Changelog
🆑
fix: Chiral inversion buffer now converts multiple reagents
fix: Chiral inversion buffer can now be transferred into another reagent
holder if no conversion took place instead of just evaporating
fix: dropper, bottles & syringes now won't display messages like 0u of
reagent transferred
/🆑

code/modules/reagents/chemistry/reagents/reaction_agents_reagents.dm

@@ -156,19 +156,35 @@
 	if(!.)
 		return
 
-	for(var/_reagent in target.reagent_list)
-		var/datum/reagent/reaction_agent/reagent = _reagent
+	var/conversion_buffer = amount * 10 //Converts up to 10 units of reagent per 1 unit of inversing buffer.
+	var/converted = 0
+	var/list/cached_reagents = target.reagent_list.Copy()
+	for(var/datum/reagent/reagent as anything in cached_reagents)
+		if(!conversion_buffer)
+			return
 		if(reagent.purity <= reagent.inverse_chem_val)
-			target.my_atom.audible_message(span_warning("The beaker goes into a rolling boil as the contents begin inversing!"))
-			playsound(target.my_atom, 'sound/effects/chemistry/catalyst.ogg', 50, TRUE)
-			var/converted = min(reagent.volume, amount * 10)//Converts up to 10 units of reagent per 1 unit of inversing buffer.
-			if(converted > 0)
-				target.remove_reagent(reagent.type, converted, safety = FALSE)
-				target.add_reagent(reagent.inverse_chem, converted, FALSE, added_purity = reagent.get_inverse_purity(reagent.purity))
-				volume -= amount
-				holder.update_total()
-				break
-		else
-			target.my_atom.audible_message(span_warning("The buffer quietly fizzles away with no effect."))
-			volume -= amount
-			holder.update_total()
+			//compute volume of reagent to be converted
+			converted = min(reagent.volume, conversion_buffer)
+			//remove original reagent from target
+			reagent.volume -= converted
+			target.update_total()
+			//add new inverse reagent to target
+			target.add_reagent(reagent.inverse_chem, converted, FALSE, added_purity = reagent.get_inverse_purity(reagent.purity))
+			//remove from buffer remaining
+			conversion_buffer -= converted
+
+	//audible feedback
+	if(conversion_buffer < amount * 10)
+		target.my_atom.audible_message(span_warning("The beaker goes into a rolling boil as the contents begin inversing!"))
+		playsound(target.my_atom, 'sound/effects/chemistry/catalyst.ogg', 50, TRUE)
+	else
+		target.my_atom.audible_message(span_warning("The buffer fizzles with no effect."))
+
+	//remove inversening reagent based on total buffer removed
+	var/volume_to_transfer = amount - (amount * (1 - (conversion_buffer / (amount * 10))))
+	if(volume_to_transfer)
+		target.add_reagent(type, volume_to_transfer, reagtemp = holder.chem_temp, added_purity = purity, added_ph = ph)
+	if(!copy_only)
+		volume -= amount
+		holder.update_total()
+

code/modules/reagents/reagent_containers.dm

@@ -404,7 +404,8 @@
 
 	var/trans = round(reagents.trans_to(target, amount_per_transfer_from_this, transferred_by = user), CHEMICAL_VOLUME_ROUNDING)
 	playsound(target.loc, SFX_LIQUID_POUR, 50, TRUE)
-	to_chat(user, span_notice("You transfer [trans] unit\s of the solution to [target]."))
+	if(trans)
+		to_chat(user, span_notice("You transfer [trans] unit\s of the solution to [target]."))
 	SEND_SIGNAL(src, COMSIG_REAGENTS_CUP_TRANSFER_TO, target)
 	target.update_appearance()
 	return ITEM_INTERACT_SUCCESS

code/modules/reagents/reagent_containers/cups/bottle.dm

@@ -548,7 +548,8 @@
 		return ITEM_INTERACT_BLOCKING
 
 	var/transfer_amount = round(reagents.trans_to(tool, amount_per_transfer_from_this, transferred_by = user), CHEMICAL_VOLUME_ROUNDING)
-	balloon_alert(user, "transferred [transfer_amount] unit\s")
+	if(transfer_amount)
+		balloon_alert(user, "transferred [transfer_amount] unit\s")
 	flick("syrup_anim",src)
 	tool.update_appearance()
 	update_appearance()

code/modules/reagents/reagent_containers/dropper.dm

@@ -60,7 +60,8 @@
 			log_combat(user, M, "squirted", reagents.get_reagent_log_string())
 
 		trans = round(reagents.trans_to(target, amount_per_transfer_from_this, transferred_by = user), CHEMICAL_VOLUME_ROUNDING)
-		to_chat(user, span_notice("You transfer [trans] unit\s of the solution."))
+		if(trans)
+			to_chat(user, span_notice("You transfer [trans] unit\s of the solution."))
 		update_appearance()
 		target.update_appearance()
 		return ITEM_INTERACT_SUCCESS
@@ -74,8 +75,8 @@
 		return ITEM_INTERACT_BLOCKING
 
 	var/trans = round(target.reagents.trans_to(src, amount_per_transfer_from_this, transferred_by = user), CHEMICAL_VOLUME_ROUNDING)
-
-	to_chat(user, span_notice("You fill [src] with [trans] unit\s of the solution."))
+	if(trans)
+		to_chat(user, span_notice("You fill [src] with [trans] unit\s of the solution."))
 
 	update_appearance()
 	target.update_appearance()

code/modules/reagents/reagent_containers/syringes.dm

@@ -137,8 +137,8 @@
 		return ITEM_INTERACT_BLOCKING
 
 	var/trans = target.reagents.trans_to(src, amount_per_transfer_from_this, transferred_by = user) // transfer from, transfer to - who cares?
-
-	to_chat(user, span_notice("You fill [src] with [trans] units of the solution. It now contains [reagents.total_volume] units."))
+	if(trans)
+		to_chat(user, span_notice("You fill [src] with [trans] units of the solution. It now contains [reagents.total_volume] units."))
 	target.update_appearance()
 	return ITEM_INTERACT_SUCCESS