emag refactor (#15181)

* limitedcharges stuff from emag

* changes except broken

* fix

* the

* move recharging to server, emag namespace -> charges

* the

* use resolve

* pro

webedit gaming

* the

* the

---------

Co-authored-by: deltanedas <@deltanedas:kde.org>

Content.Shared/Charges/Systems/SharedChargesSystem.cs

@@ -0,0 +1,62 @@
+using Content.Shared.Charges.Components;
+using Content.Shared.Examine;
+
+namespace Content.Shared.Charges.Systems;
+
+public abstract class SharedChargesSystem : EntitySystem
+{
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<LimitedChargesComponent, ExaminedEvent>(OnExamine);
+    }
+
+    protected virtual void OnExamine(EntityUid uid, LimitedChargesComponent comp, ExaminedEvent args)
+    {
+        if (!args.IsInDetailsRange)
+            return;
+
+        args.PushMarkup(Loc.GetString("limited-charges-charges-remaining", ("charges", comp.Charges)));
+        if (comp.Charges == comp.MaxCharges)
+        {
+            args.PushMarkup(Loc.GetString("limited-charges-max-charges"));
+            return;
+        }
+    }
+
+    /// <summary>
+    /// Tries to add a number of charges. If it over or underflows it will be clamped, wasting the extra charges.
+    /// </summary>
+    public void AddCharges(EntityUid uid, int change, LimitedChargesComponent? comp = null)
+    {
+        if (!Resolve(uid, ref comp, false))
+            return;
+
+        var old = comp.Charges;
+        comp.Charges = Math.Clamp(comp.Charges + change, 0, comp.MaxCharges);
+        if (comp.Charges != old)
+            Dirty(comp);
+    }
+
+    /// <summary>
+    /// Gets the limited charges component and returns true if there are no charges. Will return false if there is no limited charges component.
+    /// </summary>
+    public bool IsEmpty(EntityUid uid, LimitedChargesComponent? comp = null)
+    {
+        // can't be empty if there are no limited charges
+        if (!Resolve(uid, ref comp, false))
+            return false;
+
+        return comp.Charges <= 0;
+    }
+
+    /// <summary>
+    /// Uses a single charge. Must check IsEmpty beforehand to prevent using with 0 charge.
+    /// </summary>
+    public virtual void UseCharge(EntityUid uid, LimitedChargesComponent? comp = null)
+    {
+        if (Resolve(uid, ref comp, false))
+            AddCharges(uid, -1, comp);
+    }
+}