Gun refactor (#8301)

Co-authored-by: Kara <lunarautomaton6@gmail.com>
Co-authored-by: T-Stalker <le0nel_1van@hotmail.com>
Co-authored-by: T-Stalker <43253663+DogZeroX@users.noreply.github.com>
Co-authored-by: ElectroJr <leonsfriedrich@gmail.com>
Co-authored-by: metalgearsloth <metalgearsloth@gmail.com>

Content.Client/Weapons/Ranged/Systems/GunSystem.SpentAmmo.cs

@@ -0,0 +1,34 @@
+using Content.Client.Weapons.Ranged.Components;
+using Content.Shared.Weapons.Ranged.Systems;
+using Robust.Client.GameObjects;
+
+namespace Content.Client.Weapons.Ranged.Systems;
+
+public sealed partial class GunSystem
+{
+    private void InitializeSpentAmmo()
+    {
+        SubscribeLocalEvent<SpentAmmoVisualsComponent, AppearanceChangeEvent>(OnSpentAmmoAppearance);
+    }
+
+    private void OnSpentAmmoAppearance(EntityUid uid, SpentAmmoVisualsComponent component, ref AppearanceChangeEvent args)
+    {
+        var sprite = args.Sprite;
+        if (sprite == null) return;
+
+        if (!args.AppearanceData.TryGetValue(AmmoVisuals.Spent, out var varSpent))
+        {
+            return;
+        }
+
+        var spent = (bool) varSpent;
+        string state;
+
+        if (spent)
+            state = component.Suffix ? $"{component.State}-spent" : "spent";
+        else
+            state = component.State;
+
+        sprite.LayerSetState(AmmoVisualLayers.Base, state);
+    }
+}