Fix m56d and m2c crushing, labeling, and damage retention (#5481)

# About the pull request

This PR addresses 5 things regarding the m56d and m2c:
1. Both now properly retain labeler labels (though technically the m56d
post can lose its label - gun takes priority)
2. The m56d now retains its damage when disassembled
3. The m56d's post now has an implementation for handle_charge_collision
so they can croosh not fully assembled guns
4. It appeared possible to duplicate the m56d when a charger crushed it
if it both was destroyed by the impact and the update_health resulted in
the gun being refunded; this is no longer possible since the charge
logic returns early if it is destroyed
5. Vehicles running over a m56d post now undeploys the m56d correctly if
it had a gun attached (it would downgrade to just a post)

# Explain why it's good for the game

Fixes #5477 but I don't think this *ever* worked. Rather the issue is
purely when the gun is in this state:

![image](https://github.com/cmss13-devs/cmss13/assets/76988376/c72209b5-07da-46ac-adaf-c202bff4489e)

Additionally, if we're going to have a mechanic to weld to fix the gun;
you shouldn't be able to circumvent this by simply disassembling it...
However, since the destruction of the m56d didn't have a guaranteed
chance to destroy the gun, technically this results in a fully repaired
gun again if you can make another post for it. It would need to work
more like the m2c if we wanted it to remain in a broken state in this
situation.

# Testing Photographs and Procedure
https://youtu.be/rg1mLFjhsEY (though I forgot to record crowbar
disassembly for the m56d too)

# Changelog
:cl: Drathek
fix: The M56D and the M2C now retain their labels when disassembled
fix: The M56D can now be charger crushed when not fully assembled
fix: The M56D being run over by a vehicle now undeploys the gun
correctly (so it retains the gun if it had a gun)
fix: Fix an edge case that could duplicate the M56D when charger crushed
balance: The M56D now retains the health of the gun through all of its
different disassembled states
/:cl:

code/modules/cm_marines/m2c.dm

@@ -131,20 +131,21 @@
 	if(!check_can_setup(user, rotate_check, OT, ACR))
 		return
 
-	var/obj/structure/machinery/m56d_hmg/auto/M =  new /obj/structure/machinery/m56d_hmg/auto(user.loc)
-	transfer_label_component(M)
-	M.setDir(user.dir) // Make sure we face the right direction
-	M.anchored = TRUE
-	playsound(M, 'sound/items/m56dauto_setup.ogg', 75, TRUE)
-	to_chat(user, SPAN_NOTICE("You deploy [M]."))
-	M.rounds = rounds
-	M.overheat_value = overheat_value
-	M.health = health
-	M.update_icon()
+	var/obj/structure/machinery/m56d_hmg/auto/HMG = new(user.loc)
+	transfer_label_component(HMG)
+	HMG.setDir(user.dir) // Make sure we face the right direction
+	HMG.anchored = TRUE
+	playsound(HMG, 'sound/items/m56dauto_setup.ogg', 75, TRUE)
+	to_chat(user, SPAN_NOTICE("You deploy [HMG]."))
+	HMG.rounds = rounds
+	HMG.overheat_value = overheat_value
+	HMG.health = health
+	HMG.update_damage_state()
+	HMG.update_icon()
 	qdel(src)
 
-	if(M.rounds > 0)
-		M.try_mount_gun(user)
+	if(HMG.rounds > 0)
+		HMG.try_mount_gun(user)
 
 /obj/item/device/m2c_gun/attackby(obj/item/O as obj, mob/user as mob)
 	if(!ishuman(user))
@@ -313,12 +314,13 @@
 	if(health <= 0)
 		playsound(src.loc, 'sound/items/Welder2.ogg', 25, 1)
 		visible_message(SPAN_WARNING("[src] has broken down completely!"))
-		var/obj/item/device/m2c_gun/HMG = new(src.loc)
+		var/obj/item/device/m2c_gun/HMG = new(loc)
 		HMG.rounds = rounds
 		HMG.broken_gun = TRUE
 		HMG.unacidable = FALSE
 		HMG.health = 0
 		HMG.update_icon()
+		transfer_label_component(HMG)
 		qdel(src)
 		return
 
@@ -475,10 +477,10 @@
 				return
 			user.visible_message(SPAN_NOTICE("[user] disassembles [src]."),SPAN_NOTICE("You fold up the tripod for [src], disassembling it."))
 			playsound(src.loc, 'sound/items/m56dauto_setup.ogg', 75, 1)
-			var/obj/item/device/m2c_gun/HMG = new(src.loc)
+			var/obj/item/device/m2c_gun/HMG = new(loc)
 			transfer_label_component(HMG)
-			HMG.rounds = src.rounds
-			HMG.overheat_value = round(0.5 * src.overheat_value)
+			HMG.rounds = rounds
+			HMG.overheat_value = round(0.5 * overheat_value)
 			if (HMG.overheat_value <= 10)
 				HMG.overheat_value = 0
 			HMG.update_icon()

code/modules/cm_marines/smartgun_mount.dm

@@ -137,14 +137,15 @@
 			to_chat(user, SPAN_WARNING("This is too close to [machine]!"))
 			return
 
-	var/obj/structure/machinery/m56d_post/M = new /obj/structure/machinery/m56d_post(user.loc)
-	M.setDir(user.dir) // Make sure we face the right direction
-	M.gun_rounds = src.rounds //Inherit the amount of ammo we had.
-	M.gun_mounted = TRUE
-	M.anchored = TRUE
-	M.update_icon()
-	transfer_label_component(M)
-	to_chat(user, SPAN_NOTICE("You deploy \the [src]."))
+	var/obj/structure/machinery/m56d_post/post = new(user.loc)
+	post.setDir(user.dir) // Make sure we face the right direction
+	post.gun_rounds = rounds
+	post.gun_mounted = TRUE
+	post.gun_health = health // retain damage
+	post.anchored = TRUE
+	post.update_icon()
+	transfer_label_component(post)
+	to_chat(user, SPAN_NOTICE("You deploy [src]."))
 	qdel(src)
 
 
@@ -223,8 +224,8 @@
 		return
 
 	to_chat(user, SPAN_NOTICE("You deploy \the [src]."))
-	var/obj/structure/machinery/m56d_post/M = new /obj/structure/machinery/m56d_post(user.loc)
-	transfer_label_component(M)
+	var/obj/structure/machinery/m56d_post/post = new(user.loc)
+	transfer_label_component(post)
 	qdel(src)
 
 
@@ -238,8 +239,12 @@
 	density = TRUE
 	layer = ABOVE_MOB_LAYER
 	projectile_coverage = PROJECTILE_COVERAGE_LOW
-	var/gun_mounted = FALSE //Has the gun been mounted?
-	var/gun_rounds = 0 //Did the gun come with any ammo?
+	///Whether a gun is mounted
+	var/gun_mounted = FALSE
+	///Ammo amount of the mounted gun
+	var/gun_rounds = 0
+	///Health of the mounted gun
+	var/gun_health = 0
 	health = 50
 
 /obj/structure/machinery/m56d_post/initialize_pass_flags(datum/pass_flags_container/PF)
@@ -302,8 +307,9 @@
 			to_chat(user, SPAN_WARNING("\The [src] can't be folded while screwed to the floor. Unscrew it first."))
 			return
 		to_chat(user, SPAN_NOTICE("You fold [src]."))
-		var/obj/item/device/m56d_post/P = new(loc)
-		user.put_in_hands(P)
+		var/obj/item/device/m56d_post/post = new(loc)
+		transfer_label_component(post)
+		user.put_in_hands(post)
 		qdel(src)
 
 /obj/structure/machinery/m56d_post/attackby(obj/item/O, mob/user)
@@ -331,6 +337,8 @@
 			user.visible_message(SPAN_NOTICE("[user] installs [MG] into place."),SPAN_NOTICE("You install [MG] into place."))
 			gun_mounted = 1
 			gun_rounds = MG.rounds
+			gun_health = MG.health
+			MG.transfer_label_component(src)
 			update_icon()
 			user.temp_drop_inv_item(MG)
 			qdel(MG)
@@ -343,12 +351,19 @@
 		to_chat(user, "You begin dismounting [src]'s gun...")
 		if(do_after(user, 30 * user.get_skill_duration_multiplier(SKILL_ENGINEER), INTERRUPT_ALL|BEHAVIOR_IMMOBILE, BUSY_ICON_BUILD) && gun_mounted)
 			playsound(src.loc, 'sound/items/Crowbar.ogg', 25, 1)
-			user.visible_message(SPAN_NOTICE("[user] removes [src]'s gun."),SPAN_NOTICE("You remove [src]'s gun."))
-			var/obj/item/device/m56d_gun/G = new(loc)
-			G.rounds = gun_rounds
-			G.update_icon()
+			user.visible_message(SPAN_NOTICE("[user] removes [src]'s gun."), SPAN_NOTICE("You remove [src]'s gun."))
+			var/obj/item/device/m56d_gun/HMG = new(loc)
+			HMG.rounds = gun_rounds
+			if(gun_health)
+				HMG.health = gun_health
+			HMG.update_icon()
+			transfer_label_component(HMG)
+			var/datum/component/label/label = GetComponent(/datum/component/label)
+			if(label)
+				label.remove_label()
 			gun_mounted = FALSE
 			gun_rounds = 0
+			gun_health = 0
 			update_icon()
 		return
 
@@ -389,13 +404,16 @@
 			var/disassemble_time = 30
 			if(do_after(user, disassemble_time * user.get_skill_duration_multiplier(SKILL_ENGINEER), INTERRUPT_ALL|BEHAVIOR_IMMOBILE, BUSY_ICON_BUILD))
 				playsound(src.loc, 'sound/items/Deconstruct.ogg', 25, 1)
-				user.visible_message(SPAN_NOTICE("[user] screws the M56D into the mount."),SPAN_NOTICE("You finalize the M56D heavy machine gun."))
-				var/obj/structure/machinery/m56d_hmg/G = new(src.loc) //Here comes our new turret.
-				transfer_label_component(G)
-				G.visible_message("[icon2html(G, viewers(src))] <B>\The [G] is now complete!</B>") //finished it for everyone to
-				G.setDir(dir) //make sure we face the right direction
-				G.rounds = src.gun_rounds //Inherent the amount of ammo we had.
-				G.update_icon()
+				user.visible_message(SPAN_NOTICE("[user] screws the M56D into the mount."), SPAN_NOTICE("You finalize the M56D heavy machine gun."))
+				var/obj/structure/machinery/m56d_hmg/HMG = new(loc)
+				transfer_label_component(HMG)
+				HMG.visible_message("[icon2html(HMG, viewers(src))] <B>\The [HMG] is now complete!</B>")
+				HMG.setDir(dir)
+				HMG.rounds = gun_rounds
+				if(gun_health)
+					HMG.health = gun_health
+					HMG.update_damage_state()
+				HMG.update_icon()
 				qdel(src)
 		else
 			if(anchored)
@@ -562,7 +580,7 @@
 			return
 		else
 			playsound(src.loc, 'sound/items/Ratchet.ogg', 25, 1)
-			user.visible_message("[user] rotates \the [src].","You rotate \the [src].")
+			user.visible_message("[user] rotates [src].", "You rotate [src].")
 			setDir(turn(dir, -90))
 			if(operator)
 				update_pixels(operator)
@@ -576,14 +594,15 @@
 
 			var/disassemble_time = 30
 			if(do_after(user, disassemble_time * user.get_skill_duration_multiplier(SKILL_ENGINEER), INTERRUPT_ALL|BEHAVIOR_IMMOBILE, BUSY_ICON_BUILD))
-				user.visible_message(SPAN_NOTICE(" [user] disassembles [src]! "),SPAN_NOTICE(" You disassemble [src]!"))
+				user.visible_message(SPAN_NOTICE("[user] disassembles [src]!"), SPAN_NOTICE("You disassemble [src]!"))
 				playsound(src.loc, 'sound/items/Screwdriver.ogg', 25, 1)
-				var/obj/item/device/m56d_gun/HMG = new(src.loc) //Here we generate our disassembled mg.
+				var/obj/item/device/m56d_gun/HMG = new(loc)
 				transfer_label_component(HMG)
-				HMG.rounds = src.rounds //Inherent the amount of ammo we had.
+				HMG.rounds = rounds
 				HMG.has_mount = TRUE
+				HMG.health = health
 				HMG.update_icon()
-				qdel(src) //Now we clean up the constructed gun.
+				qdel(src)
 				return
 
 	if(istype(O, /obj/item/ammo_magazine/m56d)) // RELOADING DOCTOR FREEMAN.
@@ -595,7 +614,7 @@
 			if(user.action_busy) return
 			if(!do_after(user, 25 * user.get_skill_duration_multiplier(SKILL_ENGINEER), INTERRUPT_ALL, BUSY_ICON_FRIENDLY))
 				return
-		user.visible_message(SPAN_NOTICE("[user] loads [src]! "),SPAN_NOTICE("You load [src]!"))
+		user.visible_message(SPAN_NOTICE("[user] loads [src]!"), SPAN_NOTICE("You load [src]!"))
 		playsound(loc, 'sound/weapons/gun_minigun_cocked.ogg', 25, 1)
 		if(rounds)
 			var/obj/item/ammo_magazine/m56d/D = new(user.loc)
@@ -638,10 +657,10 @@
 	if(health <= 0)
 		var/destroyed = rand(0,1) //Ammo cooks off or something. Who knows.
 		playsound(src.loc, 'sound/items/Welder2.ogg', 25, 1)
-		if(!destroyed) new /obj/structure/machinery/m56d_post(loc)
-		else
+		if(!destroyed)
 			var/obj/item/device/m56d_gun/HMG = new(loc)
-			HMG.rounds = src.rounds //Inherent the amount of ammo we had.
+			transfer_label_component(HMG)
+			HMG.rounds = rounds
 		qdel(src)
 		return
 
@@ -981,6 +1000,7 @@
 		to_chat(operator, SPAN_HIGHDANGER("You are knocked off the gun by the sheer force of the ram!"))
 		operator.unset_interaction()
 		operator.apply_effect(3, WEAKEN)
+		operator.emote("pain")
 
 /// Getter for burst_firing
 /obj/structure/machinery/m56d_hmg/proc/get_burst_firing()