Crate Shelf Tweaks

code/game/objects/structures/crateshelf.dm

@@ -1,4 +1,5 @@
 #define DEFAULT_SHELF_CAPACITY 3 // Default capacity of the shelf
+#define DEFAULT_SHELF_MAX_CAPACITY 4
 #define DEFAULT_SHELF_USE_DELAY 1 SECONDS // Default interaction delay of the shelf
 #define DEFAULT_SHELF_VERTICAL_OFFSET 10 // Vertical pixel offset of shelving-related things. Set to 10 by default due to this leaving more of the crate on-screen to be clicked.
 
@@ -12,9 +13,13 @@
 	max_integrity = 50 // Not hard to break
 
 	var/capacity = DEFAULT_SHELF_CAPACITY
+	var/max_capacity = DEFAULT_SHELF_MAX_CAPACITY
 	var/use_delay = DEFAULT_SHELF_USE_DELAY
 	var/list/shelf_contents
 
+/obj/structure/crate_shelf/built
+	capacity = 1
+
 /obj/structure/crate_shelf/debug
 	capacity = 12
 
@@ -47,12 +52,40 @@
 		for(var/obj/structure/closet/crate/crate in shelf_contents)
 			. += "	[icon2html(crate, user)] [crate]"
 
+/obj/structure/crate_shelf/proc/add_shelf(num)
+	if(capacity + num > max_capacity)
+		return FALSE
+	var/stack_layer // This is used to generate the sprite layering of the shelf pieces.
+	var/stack_offset // This is used to generate the vertical offset of the shelf pieces.
+	var/prev_capacity = capacity
+	capacity += num
+	shelf_contents.len = capacity
+	for(var/i in prev_capacity to (capacity - 1))
+		if(i >= 3) // If we're at or above three, we'll be on the way to going off the tile we're on. This allows mobs to be below the shelf when this happens.
+			stack_layer = ABOVE_MOB_LAYER + (0.02 * i) - 0.01
+		else
+			stack_layer  = BELOW_OBJ_LAYER + (0.02 * i) - 0.01 // Make each shelf piece render above the last, but below the crate that should be on it.
+		stack_offset = DEFAULT_SHELF_VERTICAL_OFFSET * i // Make each shelf piece physically above the last.
+		overlays += image(icon = 'icons/obj/objects.dmi', icon_state = "shelf_stack", layer = stack_layer, pixel_y = stack_offset)
+
 /obj/structure/crate_shelf/attackby(obj/item/item, mob/living/user, params)
 	if (item.tool_behaviour == TOOL_WRENCH && !(flags_1&NODECONSTRUCT_1))
 		item.play_tool_sound(src)
-		if(do_after(user, 3 SECONDS, target = src))
+		if(do_after(user, 3 SECONDS, src))
 			deconstruct(TRUE)
 			return TRUE
+	if(istype(item, /obj/item/stack/sheet/metal))
+		if(capacity < max_capacity)
+			var/obj/item/stack/sheet/metal/our_sheet = item
+			if(our_sheet.get_amount() >= 2)
+				balloon_alert(user, "adding additional shelf to rack")
+				if(do_after(user, 3 SECONDS, src))
+					add_shelf(1)
+					our_sheet.add(-2)
+					return TRUE
+				to_chat(user, span_notice("Adding a shelf to [src] requires more metal."))
+				return FALSE
+		to_chat(user, span_notice("[src] cannot be built any higher!"))
 	return ..()
 
 /obj/structure/crate_shelf/relay_container_resist_act(mob/living/user, obj/structure/closet/crate)
@@ -143,4 +176,4 @@
 /obj/item/rack_parts/shelf
 	name = "crate shelf parts"
 	desc = "Parts of a shelf."
-	construction_type = /obj/structure/crate_shelf
+	construction_type = /obj/structure/crate_shelf/built