Make it harder to decapitate people with rods and ammo boxes (#8561)

* changes

* Update stack.dm

* Update stack.dm

* Apply suggestions from code review

Co-authored-by: SirRichardFrancis <65828539+SirRichardFrancis@users.noreply.github.com>

* Update stack.dm

---------

Co-authored-by: Wrill <86113712+WrillWasTaken@users.noreply.github.com>
Co-authored-by: SirRichardFrancis <65828539+SirRichardFrancis@users.noreply.github.com>

Author: 3 people

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

@@ -15,6 +15,7 @@
 	max_amount = 60
 	attack_verb = list("hit", "bludgeoned", "whacked")
 	price_tag = 1
+	automerge = TRUE
 
 /obj/item/stack/rods/random
 	rand_min = 2
@@ -31,6 +32,7 @@
 	charge_costs = list(500)
 	stacktype = /obj/item/stack/rods
 	spawn_tags = null
+	automerge = FALSE
 
 /obj/item/stack/rods/attackby(obj/item/I, mob/living/user)
 	..()

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

@@ -26,29 +26,38 @@
 	var/consumable = TRUE	// Will the stack disappear entirely once the amount is used up?
 	var/splittable = TRUE	// Is the stack capable of being splitted?
 	var/novariants = TRUE //Determines whether the item should update it's sprites based on amount.
+	var/automerge = FALSE // Automatically merge with stacks on the same tile?
 
 	//If either of these two are set to nonzero values, the stack will have randomised quantity on spawn
 	//Used for the /random subtypes of material stacks. any stack works
 	var/rand_min = 0
 	var/rand_max = 0
-
-
-
+	//Damage dealt to something when falling on it, per amount in the stack.
+	//IE, if this is 0.2 a stack of 120 will deal 24 base damage when falling on a mob
+	var/fall_damage_per_amount = 0.2
 
 /obj/item/stack/New(var/loc, var/amount=null)
 	.=..()
 	if (amount)
 		src.amount = amount
 
 /obj/item/stack/Initialize()
-	.=..()
+	. = ..()
 	if (!stacktype)
 		stacktype = type
 
 	if (rand_min || rand_max)
 		amount = rand(rand_min, rand_max)
 		amount = round(amount, 1) //Just in case
 	update_icon()
+	if(automerge)
+		return INITIALIZE_HINT_LATELOAD
+
+//do this a little later because trying to merge with uninitialized stacks is an easy way to cause runtimes
+/obj/item/stack/LateInitialize()
+	. = ..()
+	if(automerge)
+		merge_loc_stacks()
 
 /obj/item/stack/update_icon()
 	if(novariants)
@@ -378,6 +387,9 @@
 	else
 		return ..()
 
+/obj/item/stack/get_fall_damage()
+	return amount * fall_damage_per_amount
+
 //Verb to split stacks
 /obj/item/stack/verb/split_verb()
 	set src in view(1)
@@ -413,6 +425,16 @@
 /obj/item/stack/get_item_cost(export)
 	return amount * ..()
 
+/obj/item/stack/Crossed(O)
+	. = ..()
+	if(automerge && (O != src) && istype(O, /obj/item/stack))
+		transfer_to(O)
+
+/obj/item/stack/proc/merge_loc_stacks()
+	for(var/obj/item/stack/material/loc_stack in loc)
+		if(loc_stack != src)
+			transfer_to(loc_stack)
+
 /*
  * Recipe datum
  */

code/modules/materials/material_sheets.dm

@@ -8,6 +8,7 @@
 	throw_range = 3
 	max_amount = 120
 	bad_type = /obj/item/stack/material
+	automerge = TRUE
 
 	var/default_type = MATERIAL_STEEL
 	var/material/material
@@ -90,7 +91,6 @@
 	..()
 	update_strings()
 
-
 /obj/item/stack/material/iron
 	name = "iron"
 	icon_state = "sheet-iron"
@@ -271,6 +271,7 @@
 	apply_colour = 1
 	price_tag = 50
 	novariants = FALSE
+	fall_damage_per_amount = 0.5
 
 /obj/item/stack/material/osmium/full
 	amount = 120

code/modules/projectiles/ammunition.dm

@@ -161,6 +161,9 @@
 		for(var/mattertype in .)
 			.[mattertype] *= amount // multiply matter appropriately
 
+/obj/item/ammo_casing/get_fall_damage()
+	return (amount >= min(maxamount, 10))
+
 //An item that holds casings and can be used to put them inside guns
 /obj/item/ammo_magazine
 	name = "magazine"
@@ -366,10 +369,25 @@
 		to_chat(usr, SPAN_NOTICE("[src] is already empty!"))
 		return
 	to_chat(usr, SPAN_NOTICE("You take out ammo from [src]."))
-	for(var/i=1 to stored_ammo.len)
-		var/obj/item/ammo_casing/C = removeCasing()
-		C.forceMove(target)
-		C.set_dir(pick(cardinal))
+
+	while(LAZYLEN(stored_ammo))
+
+		var/obj/item/ammo_casing/stack = removeCasing()
+		stack.forceMove(target)
+		stack.set_dir(pick(cardinal))
+
+		if(LAZYLEN(stored_ammo))
+			// We end on -1 since we already removed one
+			for(var/i = 1, i <= stack.maxamount - 1, i++)
+				if(!LAZYLEN(stored_ammo))
+					stack.update_icon()
+					break
+				var/obj/item/ammo_casing/AC = removeCasing()
+				if(!stack.mergeCasing(AC, null, null, TRUE, TRUE))
+					insertCasing(AC)
+					stack.update_icon()
+					break
+
 	update_icon()
 
 /obj/item/ammo_magazine/proc/get_label(value)