Make stack amount var private

code/game/objects/items/apc_frame.dm

@@ -29,8 +29,7 @@
 			to_chat(user, "<span class='warning'>There is another network terminal here.</span>")
 			return
 		else
-			var/obj/item/stack/cable_coil/C = new /obj/item/stack/cable_coil(loc)
-			C.amount = 10
+			new /obj/item/stack/cable_coil(loc, 10)
 			to_chat(user, "You cut the cables and disassemble the unused power terminal.")
 			qdel(T)
 	new /obj/machinery/power/apc(loc, ndir, 1)

code/game/objects/items/stacks/marker_beacons.dm

@@ -127,7 +127,7 @@ var/list/marker_beacon_colors = list(
 	if(istype(I, /obj/item/stack/marker_beacon))
 		var/obj/item/stack/marker_beacon/M = I
 		to_chat(user, "<span class='notice'>You start picking [src] up...</span>")
-		if(do_after(user, remove_speed, target = src) && M.amount + 1 <= M.max_amount)
+		if(do_after(user, remove_speed, target = src) && M.get_amount() + 1 <= M.max_amount)
 			M.add(1)
 			playsound(src, 'sound/items/deconstruct.ogg', 50, 1)
 			qdel(src)

code/game/objects/items/stacks/stack.dm

@@ -17,7 +17,7 @@
 	center_of_mass = null
 	var/list/datum/stack_recipe/recipes
 	var/singular_name
-	var/amount = 1
+	VAR_PROTECTED/amount = 1
 	var/max_amount //also see stack recipes initialisation, param "max_res_amount" must be equal to this max_amount
 	var/stacktype //determines whether different stack types can merge
 	var/build_type = null //used when directly applied to a turf
@@ -33,8 +33,10 @@
 	. = ..()
 	if(!stacktype)
 		stacktype = type
-	if(amount)
-		src.amount = amount
+	if(!isnull(amount)) // Could be 0
+		if(amount < 0)
+			amount = max_amount
+		set_amount(amount, TRUE)
 	update_icon()
 
 /obj/item/stack/Destroy()
@@ -229,12 +231,15 @@
 //Return 1 if an immediate subsequent call to use() would succeed.
 //Ensures that code dealing with stacks uses the same logic
 /obj/item/stack/proc/can_use(var/used)
-	if (get_amount() < used)
+	if(used < 0 || used % 1)
+		stack_trace("Tried to use a bad stack amount: [used]")
+		return 0
+	if(get_amount() < used)
 		return 0
 	return 1
 
 /obj/item/stack/proc/use(var/used)
-	if (!can_use(used))
+	if(!can_use(used))
 		return 0
 	if(!uses_charge)
 		amount -= used
@@ -251,6 +256,9 @@
 		return 1
 
 /obj/item/stack/proc/add(var/extra)
+	if(extra < 0 || extra % 1)
+		stack_trace("Tried to add a bad stack amount: [extra]")
+		return 0
 	if(!uses_charge)
 		if(amount + extra > get_max_amount())
 			return 0
@@ -265,6 +273,27 @@
 			var/datum/matter_synth/S = synths[i]
 			S.add_charge(charge_costs[i] * extra)
 
+/obj/item/stack/proc/set_amount(var/new_amount, var/no_limits = FALSE)
+	if(new_amount < 0 || new_amount % 1)
+		stack_trace("Tried to set a bad stack amount: [new_amount]")
+		return 0
+	
+	// Clean up the new amount
+	new_amount = max(round(new_amount), 0)
+	
+	// Can exceed max if you really want
+	if(new_amount > max_amount && !no_limits)
+		new_amount = max_amount
+	
+	amount = new_amount
+	
+	// Can set it to 0 without qdel if you really want
+	if(amount == 0 && !no_limits)
+		qdel(src)
+		return FALSE
+
+	return TRUE
+
 /*
 	The transfer and split procs work differently than use() and add().
 	Whereas those procs take no action if the desired amount cannot be added or removed these procs will try to transfer whatever they can.
@@ -282,6 +311,10 @@
 
 	if (isnull(tamount))
 		tamount = src.get_amount()
+	
+	if(tamount < 0 || tamount % 1)
+		stack_trace("Tried to transfer a bad stack amount: [tamount]")
+		return 0
 
 	var/transfer = max(min(tamount, src.get_amount(), (S.get_max_amount() - S.get_amount())), 0)
 
@@ -302,7 +335,10 @@
 	if(uses_charge)
 		return null
 
-	tamount = round(tamount)
+	if(tamount < 0 || tamount % 1)
+		stack_trace("Tried to split a bad stack amount: [tamount]")
+		return null
+	
 	var/transfer = max(min(tamount, src.amount, initial(max_amount)), 0)
 
 	var/orig_amount = src.amount

code/game/objects/items/weapons/id cards/cards.dm

@@ -130,10 +130,10 @@
 /obj/item/weapon/card/emag/attackby(obj/item/O as obj, mob/user as mob)
 	if(istype(O, /obj/item/stack/telecrystal))
 		var/obj/item/stack/telecrystal/T = O
-		if(T.amount < 1)
+		if(T.get_amount() < 1)
 			to_chat(usr, "<span class='notice'>You are not adding enough telecrystals to fuel \the [src].</span>")
 			return
-		uses += T.amount/2 //Gives 5 uses per 10 TC
+		uses += T.get_amount()*0.5 //Gives 5 uses per 10 TC
 		uses = CEILING(uses, 1) //Ensures no decimal uses nonsense, rounds up to be nice
 		to_chat(usr, "<span class='notice'>You add \the [O] to \the [src]. Increasing the uses of \the [src] to [uses].</span>")
 		qdel(O)

code/game/objects/items/weapons/material/whetstone.dm

@@ -13,7 +13,7 @@
 /obj/item/weapon/whetstone/attackby(obj/item/I, mob/user)
 	if(istype(I, /obj/item/stack/material))
 		var/obj/item/stack/material/M = I
-		if(M.amount >= 5)
+		if(M.get_amount() >= 5)
 			to_chat(user, "You begin to refine the [src] with [M]...")
 			if(do_after(user, 70))
 				M.use(5)

code/game/objects/items/weapons/storage/bags.dm

@@ -245,7 +245,7 @@
 		return 0
 	var/current = 0
 	for(var/obj/item/stack/material/S in contents)
-		current += S.amount
+		current += S.get_amount()
 	if(capacity == current)//If it's full, you're done
 		if(!stop_messages)
 			to_chat(usr, "<span class='warning'>The snatcher is full.</span>")
@@ -262,29 +262,27 @@
 	var/inserted = 0
 	var/current = 0
 	for(var/obj/item/stack/material/S2 in contents)
-		current += S2.amount
-	if(capacity < current + S.amount)//If the stack will fill it up
+		current += S2.get_amount()
+	if(capacity < current + S.get_amount())//If the stack will fill it up
 		amount = capacity - current
 	else
-		amount = S.amount
+		amount = S.get_amount()
 
 	for(var/obj/item/stack/material/sheet in contents)
-		if(S.type == sheet.type) // we are violating the amount limitation because these are not sane objects
-			sheet.amount += amount	// they should only be removed through procs in this file, which split them up.
-			S.amount -= amount
+		if(S.type == sheet.type)
+			// we are violating the amount limitation because these are not sane objects
+			sheet.set_amount(sheet.get_amount() + amount, TRUE)
+			S.use(amount) // will qdel() if we use it all
 			inserted = 1
 			break
 
-	if(!inserted || !S.amount)
+	if(!inserted)
 		usr.remove_from_mob(S)
 		usr.update_icons()	//update our overlays
 		if (usr.client && usr.s_active != src)
 			usr.client.screen -= S
 		S.dropped(usr)
-		if(!S.amount)
-			qdel(S)
-		else
-			S.loc = src
+		S.loc = src
 
 	orient2hud(usr)
 	if(usr.s_active)
@@ -305,7 +303,7 @@
 		for(var/obj/item/stack/material/I in contents)
 			adjusted_contents++
 			var/datum/numbered_display/D = new/datum/numbered_display(I)
-			D.number = I.amount
+			D.number = I.get_amount()
 			numbered_contents.Add( D )
 
 	var/row_num = 0
@@ -319,14 +317,14 @@
 /obj/item/weapon/storage/bag/sheetsnatcher/quick_empty()
 	var/location = get_turf(src)
 	for(var/obj/item/stack/material/S in contents)
-		while(S.amount)
-			var/obj/item/stack/material/N = new S.type(location)
-			var/stacksize = min(S.amount,N.max_amount)
-			N.amount = stacksize
-			S.amount -= stacksize
-			N.update_icon()
-		if(!S.amount)
-			qdel(S) // todo: there's probably something missing here
+		var/cur_amount = S.get_amount()
+		var/full_stacks = round(cur_amount / S.max_amount) // Floor of current/max is amount of full stacks we make
+		var/remainder = cur_amount % S.max_amount // Current mod max is remainder after full sheets removed
+		for(var/i = 1 to full_stacks)
+			new S.type(location, S.max_amount)
+		if(remainder)
+			new S.type(location, remainder)
+		S.set_amount(0)
 	orient2hud(usr)
 	if(usr.s_active)
 		usr.s_active.show_to(usr)
@@ -342,10 +340,10 @@
 	//Therefore, make a new stack internally that has the remainder.
 	// -Sayu
 
-	if(S.amount > S.max_amount)
-		var/obj/item/stack/material/temp = new S.type(src)
-		temp.amount = S.amount - S.max_amount
-		S.amount = S.max_amount
+	if(S.get_amount() > S.max_amount)
+		var/newstack_amt = S.get_amount() - S.max_amount
+		new S.type(src, newstack_amt) // The one we'll keep to replace the one we give
+		S.set_amount(S.max_amount) // The one we hand to the clicker
 
 	return ..(S,new_location)
 

code/game/objects/structures/crates_lockers/closets/syndicate.dm

@@ -116,7 +116,6 @@
 
 	for(var/i = 0, i<2, i++)
 		for(var/res in resources)
-			var/obj/item/stack/R = new res(src)
-			R.amount = R.max_amount
+			new res(src, -1)
 
 	return ..()

code/game/objects/structures/curtains.dm

@@ -43,8 +43,7 @@
 		to_chat(user, "<span class='notice'>You start to cut the shower curtains.</span>")
 		if(do_after(user, 10))
 			to_chat(user, "<span class='notice'>You cut the shower curtains.</span>")
-			var/obj/item/stack/material/plastic/A = new /obj/item/stack/material/plastic( src.loc )
-			A.amount = 3
+			new /obj/item/stack/material/plastic(src.loc, 3)
 			qdel(src)
 		return
 	else

code/game/objects/structures/droppod.dm

@@ -113,8 +113,7 @@
 		if(finished)
 			to_chat(user, "<span class='notice'>You start breaking down \the [src].</span>")
 			if(do_after(user, 10 SECONDS, src, exclusive = TASK_ALL_EXCLUSIVE))
-				var/obj/item/stack/S = new /obj/item/stack/material/plasteel(loc)
-				S.amount = 10
+				new /obj/item/stack/material/plasteel(loc, 10)
 				playsound(user, O.usesound, 50, 1)
 				qdel(src)
 		else

code/game/objects/structures/flora/trees.dm

@@ -101,8 +101,7 @@
 		return
 
 	if(product && product_amount) // Make wooden logs.
-		var/obj/item/stack/material/M = new product(get_turf(src))
-		M.amount = product_amount
+		var/obj/item/stack/material/M = new product(get_turf(src), product_amount)
 		M.update_icon()
 	visible_message("<span class='danger'>\The [src] is felled!</span>")
 	stump()

code/game/objects/structures/plasticflaps.dm

@@ -22,8 +22,7 @@
 		to_chat(user, "<span class='notice'>You start to cut the plastic flaps.</span>")
 		if(do_after(user, 10 * P.toolspeed))
 			to_chat(user, "<span class='notice'>You cut the plastic flaps.</span>")
-			var/obj/item/stack/material/plastic/A = new /obj/item/stack/material/plastic( src.loc )
-			A.amount = 4
+			new /obj/item/stack/material/plastic(src.loc, 4)
 			qdel(src)
 		return
 	else

code/game/objects/structures/window.dm

@@ -297,7 +297,7 @@
 			visible_message("<span class='notice'>[user] dismantles \the [src].</span>")
 			var/obj/item/stack/material/mats = new glasstype(loc)
 			if(is_fulltile())
-				mats.amount = 4
+				mats.set_amount(4)
 			qdel(src)
 	else if(istype(W, /obj/item/stack/cable_coil) && reinf && state == 0 && !istype(src, /obj/structure/window/reinforced/polarized))
 		var/obj/item/stack/cable_coil/C = W