Reaction fixes, refactoring, and flash powder retune (#7654)

# About the pull request

This PR refactors a bit of chemistry code (var cleanup, removal of
required_other, rework required_container to do path checking), disables
mob reaction for several reactions, and retunes the flash power effect.

Flash powder now creates a chemical light in the contents of its reagent
holder (allowing it to be destroyed), has some additional logging, and
has had its duration, range, and power retuned:

![image](https://github.com/user-attachments/assets/cd4cff2a-3b5c-4760-986f-d708c8ba58f3)

# Explain why it's good for the game
This hopefully gives a bit of experimentation to using this reaction,
tones down how excessive it can be, and introduces a bit of counterplay
now that it is now destroyable.

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

https://youtu.be/HSCVT3V1saQ

</details>


# Changelog
:cl: Drathek
balance: emp_pulse, flash_powder, and foam reactions are no longer
possible in mobs
balance: flash_powder has been reworked to attach to its holder (so it
can be destroyed), and values retuned/capped.
refactor: Refactored the metabolize proc for chemistry reactors (removed
required_other and changed required_container to use a path check
instead)
/:cl:

---------

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

code/game/objects/items/devices/flashlight.dm

@@ -524,11 +524,17 @@
 
 /obj/item/device/flashlight/flare/on/illumination/chemical/Initialize(mapload, amount)
 	. = ..()
-	light_range = floor(amount * 0.04)
-	if(!light_range)
+	if(amount < 1)
 		return INITIALIZE_HINT_QDEL
-	set_light(light_range)
-	fuel = amount * 5 SECONDS
+	var/square_amount = sqrt(amount)
+	// Fuel quickly ramps up to about 15.5 mins then tapers off the more volume there is (6s min)
+	fuel = max(((-150 / square_amount) - 2 * sqrt(amount + 2000) + 120), 0.1) MINUTES
+	// Range gradually ramps up from 1 to 15
+	light_range = max(min(square_amount - 3, 15), MINIMUM_USEFUL_LIGHT_RANGE)
+	// Power slowly ramps up from 1 to 5
+	light_power = min(0.1 * square_amount + 1, 5)
+	set_light(light_range, light_power)
+
 
 /obj/item/device/flashlight/slime
 	gender = PLURAL

code/modules/reagents/Chemistry-Holder.dm

@@ -222,99 +222,89 @@
 	return amount
 
 /datum/reagents/proc/metabolize(mob/M, alien, delta_time)
-	for(var/datum/reagent/R in reagent_list)
-		if(M && R && !QDELETED(R))
-			R.on_mob_life(M, alien, delta_time)
+	for(var/datum/reagent/reagent in reagent_list)
+		if(M && reagent && !QDELETED(reagent))
+			reagent.on_mob_life(M, alien, delta_time)
 	update_total()
 
 /datum/reagents/proc/handle_reactions()
-	if(!my_atom) return
-	if(my_atom.flags_atom & NOREACT) return //Yup, no reactions here. No siree.
+	if(!my_atom)
+		return
+	if(my_atom.flags_atom & NOREACT)
+		return //Yup, no reactions here. No siree.
 
-	var/reaction_occurred = 0
+	var/reaction_occurred = FALSE
 	do
-		reaction_occurred = 0
-		for(var/datum/reagent/R in reagent_list) // Usually a small list
-			if(R.original_id) //Prevent synthesised chem variants from being mixed
-				for(var/datum/reagent/O in reagent_list)
-					if(O.id == R.id)
+		reaction_occurred = FALSE
+		for(var/datum/reagent/reagent in reagent_list) // Usually a small list
+			if(reagent.original_id) //Prevent synthesised chem variants from being mixed
+				for(var/datum/reagent/current in reagent_list)
+					if(current.id == reagent.id)
 						continue
-					else if(O.original_id == R.original_id || O.id == R.original_id)
+					else if(current.original_id == reagent.original_id || current.id == reagent.original_id)
 						//Merge into the original
-						reagent_list -= R
-						O.volume += R.volume
-						qdel(R)
+						reagent_list -= reagent
+						current.volume += reagent.volume
+						qdel(reagent)
 						break
-			for(var/reaction in GLOB.chemical_reactions_filtered_list[R.id]) // Was a big list but now it should be smaller since we filtered it with our reagent id
-
-				if(!reaction)
-					continue
-
-				var/datum/chemical_reaction/C = reaction
-
-				var/total_required_reagents = length(C.required_reagents)
+			for(var/datum/chemical_reaction/reaction in GLOB.chemical_reactions_filtered_list[reagent.id]) // Was a big list but now it should be smaller since we filtered it with our reagent id
+				var/total_required_reagents = length(reaction.required_reagents)
 				var/total_matching_reagents = 0
 				var/total_required_catalysts = 0
-				if(C.required_catalysts)
-					total_required_catalysts = length(C.required_catalysts)
+				if(reaction.required_catalysts)
+					total_required_catalysts = length(reaction.required_catalysts)
 				var/total_matching_catalysts= 0
-				var/matching_container = 0
-				var/matching_other = 0
+				var/matching_container = FALSE
 				var/list/multipliers = new/list()
 
-				for(var/B in C.required_reagents)
-					if(!has_reagent(B, C.required_reagents[B]))
+				for(var/required_reagent in reaction.required_reagents)
+					if(!has_reagent(required_reagent, reaction.required_reagents[required_reagent]))
 						break
 					total_matching_reagents++
-					multipliers += floor(get_reagent_amount(B) / C.required_reagents[B])
-				for(var/B in C.required_catalysts)
-					if(B == "silver" && istype(my_atom, /obj/item/reagent_container/glass/beaker/silver))
+					multipliers += floor(get_reagent_amount(required_reagent) / reaction.required_reagents[required_reagent])
+				for(var/catalyst in reaction.required_catalysts)
+					if(catalyst == "silver" && istype(my_atom, /obj/item/reagent_container/glass/beaker/silver))
 						total_matching_catalysts++
 						continue
-					if(!has_reagent(B, C.required_catalysts[B]))
+					if(!has_reagent(catalyst, reaction.required_catalysts[catalyst]))
 						break
 					total_matching_catalysts++
 
-				if(isliving(my_atom) && !C.mob_react) //Makes it so some chemical reactions don't occur in mobs
+				if(isliving(my_atom) && !reaction.mob_react) //Makes it so some chemical reactions don't occur in mobs
 					continue
 
-				if(!C.required_container)
-					matching_container = 1
-
-				else
-					if(my_atom.type == C.required_container)
-						matching_container = 1
-
-				if(!C.required_other)
-					matching_other = 1
+				if(!reaction.required_container)
+					matching_container = TRUE
+				else if(ispath(my_atom.type, reaction.required_container))
+					matching_container = TRUE
 
-				if(total_matching_reagents == total_required_reagents && total_matching_catalysts == total_required_catalysts && matching_container && matching_other)
+				if(total_matching_reagents == total_required_reagents && total_matching_catalysts == total_required_catalysts && matching_container)
 					var/multiplier = min(multipliers)
 					var/preserved_data = null
-					for(var/B in C.required_reagents)
+					for(var/required_reagent in reaction.required_reagents)
 						if(!preserved_data)
-							preserved_data = get_data(B)
-						remove_reagent(B, (multiplier * C.required_reagents[B]), safety = 1)
+							preserved_data = get_data(required_reagent)
+						remove_reagent(required_reagent, (multiplier * reaction.required_reagents[required_reagent]), safety = TRUE)
 
-					var/created_volume = C.result_amount*multiplier
-					if(C.result)
+					var/created_volume = reaction.result_amount*multiplier
+					if(reaction.result)
 
 						multiplier = max(multiplier, 1) //this shouldnt happen ...
-						add_reagent(C.result, C.result_amount*multiplier)
-						set_data(C.result, preserved_data)
+						add_reagent(reaction.result, reaction.result_amount*multiplier)
+						set_data(reaction.result, preserved_data)
 
 						//add secondary products
-						for(var/S in C.secondary_results)
-							add_reagent(S, C.result_amount * C.secondary_results[S] * multiplier)
+						for(var/secondary_result in reaction.secondary_results)
+							add_reagent(secondary_result, reaction.result_amount * reaction.secondary_results[secondary_result] * multiplier)
 
 					var/list/seen = viewers(4, get_turf(my_atom))
 					for(var/mob/M in seen)
 						to_chat(M, SPAN_NOTICE("[icon2html(my_atom, M)] The solution begins to bubble."))
 
 					playsound(get_turf(my_atom), 'sound/effects/bubbles.ogg', 15, 1)
 
-					C.on_reaction(src, created_volume)
-					reaction_occurred = 1
+					reaction.on_reaction(src, created_volume)
+					reaction_occurred = TRUE
 					break
 
 	while(reaction_occurred)

code/modules/reagents/Chemistry-Reactions.dm

@@ -6,15 +6,17 @@
 	var/list/required_reagents = new/list()
 	var/list/required_catalysts = new/list()
 
-	var/mob_react = TRUE //Determines if a chemical reaction can occur inside a mob
+	/// Determines if a chemical reaction can occur inside a mob
+	var/mob_react = TRUE
+	/// The container path required for the reaction to happen
+	var/required_container = null
 
-	// both vars below are currently unused
-	var/atom/required_container = null // the container required for the reaction to happen
-	var/required_other = 0 // an integer required for the reaction to happen
-
-	var/result_amount = 0 //I recommend you set the result amount to the total volume of all components.
-	var/secondary = 0 // set to nonzero if secondary reaction
-	var/list/secondary_results = list() //additional reagents produced by the reaction
+	/// The resulting amount: Recommended to be set to the total volume of all components
+	var/result_amount = 0
+	/// set to nonzero if secondary reaction
+	var/secondary = 0
+	/// additional reagents produced by the reaction
+	var/list/secondary_results = list()
 	var/requires_heating = 0
 
 /datum/chemical_reaction/proc/on_reaction(datum/reagents/holder, created_volume)

code/modules/reagents/chemistry_reactions/other.dm

@@ -33,6 +33,7 @@
 	result = null
 	required_reagents = list("uranium" = 1, "iron" = 1) // Yes, laugh, it's the best recipe I could think of that makes a little bit of sense
 	result_amount = 2
+	mob_react = FALSE
 
 /datum/chemical_reaction/emp_pulse/on_reaction(datum/reagents/holder, created_volume)
 	var/location = get_turf(holder.my_atom)
@@ -155,13 +156,27 @@
 	result = null
 	required_reagents = list("aluminum" = 1, "potassium" = 1, "sulfur" = 1 )
 	result_amount = 3
+	mob_react = FALSE
 
 /datum/chemical_reaction/flash_powder/on_reaction(datum/reagents/holder, created_volume)
-	var/location = get_turf(holder.my_atom)
-	var/datum/effect_system/spark_spread/s = new /datum/effect_system/spark_spread
-	s.set_up(2, 1, location)
-	s.start()
-	new /obj/item/device/flashlight/flare/on/illumination/chemical(location, created_volume)
+	var/turf/location = get_turf(holder.my_atom)
+	var/datum/effect_system/spark_spread/sparker = new
+	sparker.set_up(2, 1, location)
+	sparker.start()
+	var/obj/item/device/flashlight/flare/on/illumination/chemical/light = new(holder.my_atom, created_volume)
+
+	//Admin messaging
+	var/area/area = get_area(location)
+	var/where = "[area.name]|[location.x], [location.y]"
+	var/whereLink = "<A HREF='?_src_=admin_holder;[HrefToken(forceGlobal = TRUE)];adminplayerobservecoodjump=1;X=[location.x];Y=[location.y];Z=[location.z]'>[where]</a>"
+	var/data = " [created_volume] volume -> fuel: [light.fuel] range: [light.light_range] power: [light.light_power]"
+
+	if(holder.my_atom.fingerprintslast)
+		msg_admin_niche("[src] reaction has taken place in ([whereLink])[data]. Last associated key is [holder.my_atom.fingerprintslast].")
+		log_game("[src] reaction has taken place in ([where])[data]. Last associated key is [holder.my_atom.fingerprintslast].")
+	else
+		msg_admin_niche("[src] reaction has taken place in ([whereLink])[data]. No associated key.")
+		log_game("[src] reaction has taken place in ([where])[data]. No associated key.")
 
 /datum/chemical_reaction/chemfire
 	name = "Napalm"
@@ -373,6 +388,7 @@
 	result = null
 	required_reagents = list("fluorosurfactant" = 1, "water" = 1)
 	result_amount = 2
+	mob_react = FALSE
 
 /datum/chemical_reaction/foam/on_reaction(datum/reagents/holder, created_volume)
 	var/location = get_turf(holder.my_atom)