Framework for nerfing emags flexibly.

Tested locally.

code/controllers/configuration.dm

@@ -147,6 +147,11 @@
 	var/assistantlimit = 0 //enables assistant limiting
 	var/assistantratio = 2 //how many assistants to security members
 
+	var/emag_energy = -1
+	var/emag_starts_charged = 1
+	var/emag_recharge_rate = 0
+	var/emag_recharge_ticks = 0
+
 /datum/configuration/New()
 	. = ..()
 	var/list/L = typesof(/datum/game_mode) - /datum/game_mode
@@ -544,6 +549,14 @@
 					config.limbs_can_break = value
 				if("respawn_delay")
 					config.respawn_delay = value
+				if("emag_energy")
+					config.emag_energy = value
+				if("emag_starts_charged")
+					config.emag_starts_charged = value
+				if("emag_recharge_rate")
+					config.emag_recharge_rate = value
+				if("emag_recharge_ticks")
+					config.emag_recharge_ticks = value
 				else
 					diary << "Unknown setting in configuration: '[name]'"
 

code/game/machinery/doors/airlock.dm

@@ -49,6 +49,8 @@
 	autoclose = 1
 	var/busy = 0
 
+	emag_cost = 1 // in MJ
+
 /obj/machinery/door/airlock/Destroy()
 	if(wires)
 		wires.Destroy()
@@ -105,6 +107,7 @@
 	name = "Vault"
 	icon = 'icons/obj/doors/vault.dmi'
 	opacity = 1
+	emag_cost = 2 // in MJ
 	assembly_type = /obj/structure/door_assembly/door_assembly_highsecurity //Until somebody makes better sprites.
 
 /obj/machinery/door/airlock/freezer
@@ -284,6 +287,7 @@
 	name = "High Tech Security Airlock"
 	icon = 'icons/obj/doors/hightechsecurity.dmi'
 	assembly_type = /obj/structure/door_assembly/door_assembly_highsecurity
+	emag_cost = 2 // in MJ
 
 /*
 About the new airlock wires panel:

code/game/machinery/machinery.dm

@@ -116,7 +116,15 @@ Class Procs:
 	var/custom_aghost_alerts=0
 	var/panel_open = 0
 
-	var/machine_flags = 0//this is what you use for flags.
+	/**
+	 * Machine construction/destruction/emag flags.
+	 */
+	var/machine_flags = 0 // This is what you use for flags.
+
+	/**
+	 * Emag energy cost.
+	 */
+	var/emag_cost = 0     // Emag energy cost.
 
 	var/inMachineList = 1 // For debugging.
 
@@ -447,29 +455,49 @@ Class Procs:
 		return 1
 	return -1
 
+/**
+ * Handle emags.
+ * @param user /mob The mob that used the emag.
+ */
 /obj/machinery/proc/emag(mob/user as mob)
-	return
+	// Disable emaggability.
+	machine_flags &= ~EMAGGABLE
+
+/**
+ * Returns the cost of emagging this machine (emag_cost by default)
+ * @param user /mob The mob that used the emag.
+ * @param emag /obj/item/weapon/card/emag The emag used on this device.
+ * @return number Cost to emag.
+ */
+/obj/machinery/proc/getEmagCost(var/mob/user, var/obj/item/weapon/card/emag/emag)
+	return emag_cost
 
 /obj/machinery/attackby(var/obj/O, var/mob/user)
-	if(istype(O, /obj/item/weapon/card/emag) && machine_flags &EMAGGABLE)
-		emag(user)
-		return
-	if(istype(O, /obj/item/weapon/wrench) && machine_flags &WRENCHMOVE) //make sure this is BEFORE the fixed2work check
+	if(istype(O, /obj/item/weapon/card/emag) && machine_flags & EMAGGABLE)
+		var/obj/item/weapon/card/emag/E = O
+		if(E.canUse(user,src))
+			emag(user)
+			return
+
+	if(istype(O, /obj/item/weapon/wrench) && machine_flags & WRENCHMOVE) //make sure this is BEFORE the fixed2work check
 		if(!panel_open)
 			return wrenchAnchor(user)
 		else
 			user <<"<span class='warning'>\The [src]'s maintenance panel must be closed first!</span>"
 			return -1 //we return -1 rather than 0 for the if(..()) checks
-	if(istype(O, /obj/item/weapon/screwdriver) && machine_flags &SCREWTOGGLE)
+
+	if(istype(O, /obj/item/weapon/screwdriver) && machine_flags & SCREWTOGGLE)
 		return togglePanelOpen(O, user)
-	if(istype(O, /obj/item/weapon/crowbar) && machine_flags &CROWDESTROY)
+
+	if(istype(O, /obj/item/weapon/crowbar) && machine_flags & CROWDESTROY)
 		if(panel_open)
 			if(crowbarDestroy(user) == 1)
 				qdel(src)
 				return 1
 			else
 				return -1
-	if(!anchored && machine_flags &FIXED2WORK)
+
+	if(!anchored && machine_flags & FIXED2WORK)
 		return user << "<span class='warning'>\The [src] must be anchored first!</span>"
 
 /obj/machinery/proc/shock(mob/user, prb, var/siemenspassed = -1)

code/game/objects/items/weapons/cards_ids.dm

@@ -60,7 +60,99 @@
 	icon_state = "emag"
 	item_state = "card-id"
 	origin_tech = "magnets=2;syndicate=2"
-	var/uses = 10
+
+	/**
+	 * Number of uses left.  -1 = infinite
+	 * (Note: Some devices can use more than 1 use, so this is just called "energy")
+	 * @since 10-28-2014
+	 */
+	var/energy = -1
+
+	/**
+	 * Max energy per emag.  -1 = infinite
+	 * @since 10-28-2014
+	 */
+	var/max_energy = -1
+
+	/**
+	 * Every X ticks, add [recharge_rate] energy.
+	 * @since 10-28-2014
+	 */
+	var/recharge_ticks = 0
+
+	/**
+	 * Every [recharge_ticks] ticks, add X energy.
+	 * @since 10-28-2014
+	 */
+	var/recharge_rate = 0
+
+	var/nticks=0
+
+/obj/item/weapon/card/emag/New(var/loc, var/disable_tuning=0)
+	..(loc)
+
+	// For standardized subtypes, once they're established.
+	if(disable_tuning)
+		return
+
+	// Tuning tools.
+	//////////////////
+	if(config.emag_energy != -1)
+		max_energy = config.emag_energy
+
+		if(config.emag_starts_charged)
+			energy = max_energy
+
+	if(config.emag_recharge_rate != 0)
+		recharge_rate = config.emag_recharge_rate
+
+	if(config.emag_recharge_ticks > 0)
+		recharge_ticks = config.emag_recharge_ticks
+
+/obj/item/weapon/card/emag/process()
+	if(energy < max_energy)
+		// Specified number of ticks has passed?  Add charge.
+		if(nticks >= recharge_ticks)
+			nticks = 0
+			energy = min(energy + recharge_rate, max_energy)
+		nticks ++
+	else
+		nticks = 0
+		processing_objects.Remove(src)
+
+/obj/item/weapon/card/emag/proc/canUse(var/mob/user, var/obj/machinery/M)
+	// We've already checked for emaggability.  All we do here is check cost.
+
+	// Infinite uses?  Just return true.
+	if(energy < 0)
+		return 1
+
+	var/cost=M.getEmagCost(user,src)
+
+	// Free to emag?  Return true every time.
+	if(cost == 0)
+		return 1
+
+	if(energy >= cost)
+		energy -= cost
+
+		// Start recharging, if we're supposed to.
+		if(energy < max_energy && recharge_rate && recharge_ticks)
+			if(!(src in processing_objects))
+				processing_objects.Add(src)
+
+		return 1
+
+	return 0
+
+/obj/item/weapon/card/emag/examine()
+	..()
+	if(energy==-1)
+		usr << "\The [name] has a tiny fusion generator for power."
+	else
+		usr << "This [name] has [energy]MJ left in its capacitor ([max_energy]MJ capacity)."
+	if(recharge_rate && recharge_ticks)
+		usr << "A small label on a thermocouple notes that it recharges at a rate of [recharge_rate]MJ for every [recharge_ticks>1?"":recharge_ticks] oscillator tick[recharge_ticks>1?"s":""]."
 
 /obj/item/weapon/card/id
 	name = "identification card"

config-example/game_options.txt

@@ -59,3 +59,23 @@ ANIMAL_DELAY 0
 # Define how large an explosion can be.
 ## DEFAULT: 14
 MAX_EXPLOSION_RANGE 14
+
+#################
+### EMAG SHIT ###
+#################
+
+# Max energy an emag can hold.
+## DEFAULT: -1 (infinite)
+EMAG_ENERGY -1
+
+# Whether an emag starts charged (1), or uncharged (0).
+## DEFAULT: 1 (charged)
+EMAG_STARTS_CHARGED 1
+
+# Amount of energy to add per recharge cycle.
+## DEFAULT: 0
+EMAG_RECHARGE_RATE 0
+
+# Number of ticks per recharge cycle
+## DEFAULT: 0 (no recharging)
+EMAG_RECHARGE_TICKS 0