Fixes an exploit with stacking igniters. Refactors some assembly flag oddities. Limits assembly holders at 12 assemblies. (#71264)

## About The Pull Request

Soft revert of #71224 , Fixes #71222

Fixes an exploit involving attachment of multiple igniters to one
assembly.
- Multiple igniters or condensers can no longer be attached to the same
assembly holder
- Assembly holders have a limit of 12 assemblies maximum
- I'm not sure if this is too low or limited, I picked it arbitrarily.
Please inform me if it could be upped a smidge.
- This lag exploit was born because of limitless assembly holders, which
is a little silly even with the exploit aside. All that uncapped holders
can bring are exploits or bugs, which I feel confident limited can
prevent. What use is there even for having so many?
- Cleans up / refactors some aspects of assemblies and assembly holders.
- Assemblies had a weird wire type flag that was only ever used by
signallers, but also used wrong by signallers. I did some scanning of
the code and realized that ... a lot of this was just straight up
unused, and not even assigned anywhere.
- Now, there is a flag assembly flag var, which everything is read off
of. Tested it and still seemed to all work fine.

## Why It's Good For The Game

Lag exploits are bad. 

## Changelog

🆑 Melbert
fix: Fixed an exploit involving igniters attached to themselves.
Assembly holders are now limited to 12 assemblies maximum, and you
cannot attach multiple igniters to the same assembly.
refactor: Refactored some assembly jank, namely in how they pulse and
are pulsed.
/🆑

code/modules/assembly/assembly.dm

@@ -1,9 +1,3 @@
-#define WIRE_RECEIVE (1<<0)
-#define WIRE_PULSE (1<<1)
-#define WIRE_PULSE_SPECIAL (1<<2)
-#define WIRE_RADIO_RECEIVE (1<<3)
-#define WIRE_RADIO_PULSE (1<<4)
-#define ASSEMBLY_BEEP_VOLUME 5
 
 /obj/item/assembly
 	name = "assembly"
@@ -24,10 +18,11 @@
 	 * This will prevent things such as visible lasers from facing the incorrect direction when transformed by assembly_holder's update_appearance()
 	 */
 	var/is_position_sensitive = FALSE
+	/// Flags related to this assembly. See [assemblies.dm]
+	var/assembly_flags = NONE
 	var/secured = TRUE
 	var/list/attached_overlays = null
 	var/obj/item/assembly_holder/holder = null
-	var/wire_type = WIRE_RECEIVE | WIRE_PULSE
 	var/attachable = FALSE // can this be attached to wires
 	var/datum/wires/connected = null
 	var/next_activate = 0 //When we're next allowed to activate - for spam control
@@ -75,24 +70,26 @@
 		return FALSE
 	return TRUE
 
-///Called when another assembly acts on this one, var/radio will determine where it came from for wire calcs
-/obj/item/assembly/proc/pulsed(radio = FALSE, mob/pulser)
-	if(wire_type & WIRE_RECEIVE)
-		INVOKE_ASYNC(src, PROC_REF(activate), pulser)
-	if(radio && (wire_type & WIRE_RADIO_RECEIVE))
-		INVOKE_ASYNC(src, PROC_REF(activate), pulser)
+/**
+ * Pulsed: This device was pulsed by another device
+ *
+ * * pulser: Who triggered the pulse
+ */
+/obj/item/assembly/proc/pulsed(mob/pulser)
+	INVOKE_ASYNC(src, PROC_REF(activate), pulser)
 	SEND_SIGNAL(src, COMSIG_ASSEMBLY_PULSED)
 	return TRUE
 
-///Called when this device attempts to act on another device, var/radio determines if it was sent via radio or direct
-/obj/item/assembly/proc/pulse(radio = FALSE)
-	if(connected && wire_type)
+/**
+ * Pulse: This device is emitting a pulse to act on another device
+ */
+/obj/item/assembly/proc/pulse()
+	// if we have connected wires and are a pulsing assembly, pulse it
+	if(connected)
 		connected.pulse_assembly(src)
-		return TRUE
-	if(holder && (wire_type & WIRE_PULSE))
-		holder.process_activation(src, 1, 0)
-	if(holder && (wire_type & WIRE_PULSE_SPECIAL))
-		holder.process_activation(src, 0, 1)
+	// otherwise if we're attached to a holder, process the activation of it with our flags
+	else if(holder)
+		holder.process_activation(src)
 	return TRUE
 
 /// What the device does when turned on
@@ -116,21 +113,29 @@
 		return
 	. = ..()
 
-/obj/item/assembly/attackby(obj/item/W, mob/user, params)
-	if(isassembly(W))
-		var/obj/item/assembly/A = W
-		if((!A.secured) && (!secured))
-			holder = new/obj/item/assembly_holder(get_turf(src))
-			holder.assemble(src,A,user)
-			to_chat(user, span_notice("You attach and secure \the [A] to \the [src]!"))
-		else
-			to_chat(user, span_warning("Both devices must be in attachable mode to be attached together."))
+/obj/item/assembly/attackby(obj/item/attacking_item, mob/user, params)
+	if(isassembly(attacking_item))
+		var/obj/item/assembly/new_assembly = attacking_item
+		// Check both our's and their's assembly flags to see if either should not duplicate
+		// If so, and we match types, don't create a holder - block it
+		if(((new_assembly.assembly_flags|assembly_flags) & ASSEMBLY_NO_DUPLICATES) && istype(new_assembly, type))
+			balloon_alert(user, "can't attach another of that!")
+			return
+		if(new_assembly.secured || secured)
+			balloon_alert(user, "both devices not attachable!")
+			return
+
+		holder = new /obj/item/assembly_holder(drop_location())
+		holder.assemble(src, new_assembly, user)
+		holder.balloon_alert(user, "parts combined")
 		return
-	if(istype(W, /obj/item/assembly_holder))
-		if(!secured)
-			var/obj/item/assembly_holder/added_to_holder = W
-			added_to_holder.add_assembly(src, user)
-	..()
+
+	if(istype(attacking_item, /obj/item/assembly_holder))
+		var/obj/item/assembly_holder/added_to_holder = attacking_item
+		added_to_holder.try_add_assembly(src, user)
+		return
+
+	return ..()
 
 /obj/item/assembly/screwdriver_act(mob/living/user, obj/item/I)
 	if(..())