New features, New wrappers for cell_slot system. (#6421)

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## About The Pull Request
Adds wrappers for cells to the cell_slot system for cleaner calling.
Adds a function to remove a cell and hand it directly to a mob for saner
handling outside the file. Adds a bunch of comments from what I've
divined in the hopes of granting others the same wisdom.
Swaps the single inducer line that can use the new wrapper procs.
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## Why It's Good For The Game
Will hopefully allow others to look upon silicons work and understand it
easier. Allows me to write prettier and safer code for the vehicle
refactor.
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## Changelog
-Comments a bunch of the functions because my brain is smooth
-Adds wrappers for cell.dm functions to allow for cleaner code lines
when dealing with this system
-Adds mob_remove_cell() for easier cell removal in vehicles update.
-"Updates" inducers to use the new wrappers (a single proc)
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:cl: Shadowcat
code: Adds cell.dm function wrappers to cell_slot.dm
code: Adds a function to remove a cell and hand it directly to a move in
cell_slot.dm
refactor: Comments a lot of the functions in cell_slot.dm
/:cl:

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your name to the right of the first :cl: if you want to overwrite your
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---------

Co-authored-by: LordME <[email protected]>

code/game/objects/items/inducer.dm

@@ -138,7 +138,7 @@
 				break
 			if(charged <= 0)
 				break
-			obj_cell_slot.cell.use(charged)
+			obj_cell_slot.use(charged)
 			used += charged
 
 	qdel(spark_system)

code/game/objects/systems/cell_slot.dm

@@ -36,9 +36,15 @@
 	// todo: kill this
 	var/legacy_use_device_cells = FALSE
 
+/**
+ * returns TRUE if slot accepts this type of cell
+ */
 /datum/object_system/cell_slot/proc/accepts_cell(obj/item/cell/cell)
 	return legacy_use_device_cells? istype(cell, /obj/item/cell/device) : TRUE
 
+/**
+ * removes cell from the system and drops it at new_loc
+ */
 /datum/object_system/cell_slot/proc/remove_cell(atom/new_loc)
 	if(isnull(cell))
 		return
@@ -48,6 +54,22 @@
 	cell = null
 	parent.object_cell_slot_removed(., src)
 
+/**
+ * helper to have a mob yank a cell
+ *
+ * * this does not check adjacency!
+ * * puts the cell in their hand if possible, otherwise drops it on them
+ */
+/datum/object_system/cell_slot/proc/mob_yank_cell(mob/user)
+	var/obj/item/cell/removed = remove_cell(user)
+	if(!removed)
+		return
+	user.put_in_hands_or_drop(removed)
+	return removed
+
+/**
+ * replaces the existing cell with the inserted cell, dropping the old cell
+ */
 /datum/object_system/cell_slot/proc/insert_cell(obj/item/cell/cell)
 	if(!isnull(cell))
 		. = remove_cell(parent.drop_location())
@@ -56,9 +78,18 @@
 		cell.forceMove(parent)
 	parent.object_cell_slot_inserted(cell, src)
 
+/**
+ * returns TRUE if the cell slot is mutable
+ */
 /datum/object_system/cell_slot/proc/interaction_active(mob/user)
 	return parent.object_cell_slot_mutable(user, src)
 
+/**
+ * returns TRUE if the slot has a cell
+ */
+/datum/object_system/cell_slot/proc/has_cell()
+	return !isnull(cell)
+
 //? Hooks
 
 /**
@@ -101,3 +132,91 @@
 	obj_cell_slot.remove_yank_time = 0
 	obj_cell_slot.legacy_use_device_cells = TRUE
 	return obj_cell_slot
+
+//? Wrappers for cell.dm functions
+//+ These exist to sanely perform cell functions through the obj_cell_slot system. These break safely if no cell exists.
+
+/**
+ * cell function wrapper - returns the rating of the cell inside or 0 if null
+ */
+/datum/object_system/cell_slot/proc/get_rating()
+	return cell?.get_rating() || 0
+
+/**
+ * cell function wrapper - returns the cell src or FALSE if null
+ */
+/datum/object_system/cell_slot/proc/get_cell(inducer)
+	return cell?.get_cell(inducer) || FALSE
+
+/**
+ * cell function passthrough - consumes energy using *universal units*
+ *
+ * *Uses universal units.*
+ *
+ * @params
+ * - actor - thing draining, can be null
+ * - amount - amount to drain in kilojoules
+ * - flags
+ *
+ * @return Amount drained
+ */
+/datum/object_system/cell_slot/proc/drain_energy(datum/actor, amount, flags)
+	return cell?.drain_energy(actor, amount, flags) || 0
+
+/**
+ * cell function wrapper - returns % charge of the cell or 0 if null
+ */
+/datum/object_system/cell_slot/proc/percent()
+	return cell?.percent() || 0
+
+/**
+ * cell function wrapper - checks if cell is fully charged
+ * returns TRUE or FALSE. returns FALSE if cell is null
+ */
+/datum/object_system/cell_slot/proc/fully_charged()
+	return cell?.fully_charged() ? TRUE : FALSE
+
+/**
+ * cell function wrapper - returns true if cell can provide specified amount
+ * returns 0 if null
+ */
+/datum/object_system/cell_slot/proc/check_charge(var/amount)
+	return cell?.check_charge(amount) || 0
+
+/**
+ * cell function wrapper - returns how much charge is missing from the cell or 0 if null
+ */
+/datum/object_system/cell_slot/proc/amount_missing()
+	return cell?.amount_missing() || 0
+
+/**
+ * cell function wrapper - attempts to use power from cell, returns the amount actually used or 0 if null
+ */
+/datum/object_system/cell_slot/proc/use(var/amount)
+	return cell?.use(amount) || 0
+
+/**
+ * cell function wrapper - checks if the specified amount can be provided. If it can, it removes the amount from the cell and returns TRUE otherwise does nothing and returns FALSE
+ * returns FALSE if cell is null
+ */
+/datum/object_system/cell_slot/proc/checked_use(var/amount)
+	return cell?.checked_use(amount) ? TRUE : FALSE
+
+/**
+ * cell function wrapper - use x cell units, affected by GLOB.cellefficiency, returns the amount actually used or 0 if null
+ */
+/datum/object_system/cell_slot/proc/use_scaled(var/amount)
+	return cell?.use_scaled(amount) || 0
+
+/**
+ * cell function wrapper - checked_use() but scaled by GLOB.cellefficiency
+ */
+/datum/object_system/cell_slot/proc/checked_use_scaled(var/amount)
+	return cell?.checked_use_scaled(amount) ? TRUE : FALSE
+
+/**
+ * cell function wrapper - recharge the cell by x amount returns the amount consumed or 0 if cell is null
+ */
+/datum/object_system/cell_slot/proc/give(var/amount)
+	return cell?.give(amount) || 0
+//? End wrappers for cell.dm functions