From defc4c1f94108e2cd9e99cfac5ca5a890a280793 Mon Sep 17 00:00:00 2001
From: mwerezak <mwerezak@gmail.com>
Date: Mon, 18 May 2015 20:09:09 -0400
Subject: [PATCH] Adds check_charge(), checked_use()

---
 .../game/objects/items/weapons/power_cells.dm |  5 +++-
 code/game/objects/items/weapons/stunbaton.dm  |  4 +--
 .../modules/mob/living/silicon/robot/robot.dm |  3 +--
 code/modules/power/cell.dm                    | 27 ++++++++++++++-----
 code/modules/power/power.dm                   |  2 +-
 code/modules/projectiles/guns/energy.dm       |  2 +-
 6 files changed, 29 insertions(+), 14 deletions(-)

diff --git a/code/game/objects/items/weapons/power_cells.dm b/code/game/objects/items/weapons/power_cells.dm
index 5cab6b24cb..bd344d2267 100644
--- a/code/game/objects/items/weapons/power_cells.dm
+++ b/code/game/objects/items/weapons/power_cells.dm
@@ -88,8 +88,11 @@
 	name = "infinite-capacity power cell!"
 	icon_state = "icell"
 	origin_tech =  null
-	maxcharge = 30000
+	maxcharge = 30000 //determines how badly mobs get shocked
 	matter = list("metal" = 700, "glass" = 80)
+	
+	check_charge()
+		return 1
 	use()
 		return 1
 
diff --git a/code/game/objects/items/weapons/stunbaton.dm b/code/game/objects/items/weapons/stunbaton.dm
index ca495ee263..811cd4f866 100644
--- a/code/game/objects/items/weapons/stunbaton.dm
+++ b/code/game/objects/items/weapons/stunbaton.dm
@@ -35,13 +35,13 @@
 
 /obj/item/weapon/melee/baton/proc/deductcharge(var/chrgdeductamt)
 	if(bcell)
-		if(bcell.charge >= chrgdeductamt)
-			bcell.use(chrgdeductamt)
+		if(bcell.checked_use(chrgdeductamt))
 			return 1
 		else
 			status = 0
 			update_icon()
 			return 0
+	return null
 
 /obj/item/weapon/melee/baton/update_icon()
 	if(status)
diff --git a/code/modules/mob/living/silicon/robot/robot.dm b/code/modules/mob/living/silicon/robot/robot.dm
index 71171212a2..542daeed5f 100644
--- a/code/modules/mob/living/silicon/robot/robot.dm
+++ b/code/modules/mob/living/silicon/robot/robot.dm
@@ -1234,8 +1234,7 @@ var/list/robot_verbs_default = list(
 		return 0
 
 	var/power_use = amount * CYBORG_POWER_USAGE_MULTIPLIER
-	if(cell.charge >= CELLRATE * power_use)
-		cell.use(CELLRATE * power_use)
+	if(cell.checked_use(CELLRATE * power_use))
 		used_power_this_tick += power_use
 		return 1
 	return 0
diff --git a/code/modules/power/cell.dm b/code/modules/power/cell.dm
index 553891565c..f664890be9 100644
--- a/code/modules/power/cell.dm
+++ b/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)
diff --git a/code/modules/power/power.dm b/code/modules/power/power.dm
index 7cfcc53246..4a172b361b 100644
--- a/code/modules/power/power.dm
+++ b/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)
diff --git a/code/modules/projectiles/guns/energy.dm b/code/modules/projectiles/guns/energy.dm
index f85f41276f..c167964f34 100644
--- a/code/modules/projectiles/guns/energy.dm
+++ b/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.charge < charge_cost || !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()