Merge pull request #9258 from mwerezak/charge

Updates instances of power cell usage

code/modules/clothing/spacesuits/rig/rig.dm

@@ -706,7 +706,7 @@
 	take_hit((100/severity_class), "electrical pulse", 1)
 
 /obj/item/weapon/rig/proc/shock(mob/user)
-	if (electrocute_mob(user, cell, src))
+	if (electrocute_mob(user, cell, src)) //electrocute_mob() handles removing charge from the cell, no need to do that here.
 		spark_system.start()
 		if(user.stunned)
 			return 1

code/modules/clothing/spacesuits/rig/rig_attackby.dm

@@ -3,9 +3,7 @@
 	if(!istype(user,/mob/living)) return 0
 
 	if(electrified != 0)
-		if(cell && cell.charge >= 100)
-			cell.use(100)
-		if(shock(user, 100))
+		if(shock(user)) //Handles removing charge from the cell, as well. No need to do that here.
 			return
 
 	// Pass repair items on to the chestpiece.
@@ -193,8 +191,6 @@
 /obj/item/weapon/rig/attack_hand(var/mob/user)
 
 	if(electrified != 0)
-		if(cell && cell.charge >= 100)
-			cell.use(100)
-		if(shock(user, 100))
+		if(shock(user)) //Handles removing charge from the cell, as well. No need to do that here.
 			return
 	..()

code/modules/mob/living/silicon/robot/robot.dm

@@ -1233,8 +1233,9 @@ var/list/robot_verbs_default = list(
 	if(cell.charge == 0)
 		return 0
 
-	if(cell.use(amount * CELLRATE * CYBORG_POWER_USAGE_MULTIPLIER))
-		used_power_this_tick += amount * CYBORG_POWER_USAGE_MULTIPLIER
+	var/power_use = amount * CYBORG_POWER_USAGE_MULTIPLIER
+	if(cell.checked_use(CELLRATE * power_use))
+		used_power_this_tick += power_use
 		return 1
 	return 0
 

code/modules/power/cell.dm

@@ -9,7 +9,7 @@
 	spawn(5)
 		updateicon()
 
-/obj/item/weapon/cell/drain_power(var/drain_check, var/surge, var/amount = 0)
+/obj/item/weapon/cell/drain_power(var/drain_check, var/surge, var/power = 0)
 
 	if(drain_check)
 		return 1
@@ -17,9 +17,9 @@
 	if(charge <= 0)
 		return 0
 
-	var/cell_amt = min((amount * CELLRATE), charge)
-	use(cell_amt)
-	return cell_amt / CELLRATE
+	var/cell_amt = power * CELLRATE
+
+	return use(cell_amt) / CELLRATE
 
 /obj/item/weapon/cell/proc/updateicon()
 	overlays.Cut()
@@ -37,13 +37,26 @@
 /obj/item/weapon/cell/proc/fully_charged()
 	return (charge == maxcharge)
 
-// use power from a cell
+// checks if the power cell is able to provide the specified amount of charge
+/obj/item/weapon/cell/proc/check_charge(var/amount)
+	return (charge >= amount)
+
+// use power from a cell, returns the amount actually used
 /obj/item/weapon/cell/proc/use(var/amount)
 	if(rigged && amount > 0)
 		explode()
 		return 0
-	charge = max(0, charge - amount)
-	return charge
+	var/used = min(charge, amount)
+	charge -= used
+	return used
+
+// Checks if the specified amount can be provided. If it can, it removes the amount
+// from the cell and returns 1. Otherwise does nothing and returns 0.
+/obj/item/weapon/cell/proc/checked_use(var/amount)
+	if(!check_charge(amount))
+		return 0
+	use(amount)
+	return 1
 
 // recharge the cell
 /obj/item/weapon/cell/proc/give(var/amount)

code/modules/power/power.dm

@@ -374,7 +374,7 @@
 	if (source_area)
 		source_area.use_power(drained_energy/CELLRATE)
 	else if (istype(power_source,/datum/powernet))
-		var/drained_power = drained_energy/CELLRATE //convert from "joules" to "watts"
+		var/drained_power = drained_energy/CELLRATE
 		drained_power = PN.draw_power(drained_power)
 	else if (istype(power_source, /obj/item/weapon/cell))
 		cell.use(drained_energy)

code/modules/projectiles/guns/energy.dm

@@ -57,7 +57,7 @@
 /obj/item/weapon/gun/energy/consume_next_projectile()
 	if(!power_supply) return null
 	if(!ispath(projectile_type)) return null
-	if(!power_supply.use(charge_cost)) return null
+	if(!power_supply.checked_use(charge_cost)) return null
 	return new projectile_type(src)
 
 /obj/item/weapon/gun/energy/proc/get_external_power_supply()