Add ammo consumption and item pickup systems

GameCore/Combat/Effects/ConsumeAmmoCost.cs

@@ -0,0 +1,19 @@
+using GameCore.Combat.Interfaces;
+using GameCore.Inventory;
+
+namespace GameCore.Combat.Effects;
+
+public class ConsumeAmmoCost(string ammoId, int amount) : ICostEffect
+{
+    public void Execute(EffectContext context)
+    {
+        var inventory = context.World.GetComponent<InventoryComponent>(context.Owner);
+        inventory?.RemoveItem(ammoId, amount);
+    }
+
+    public bool CanAfford(EffectContext context)
+    {
+        var inventory = context.World.GetComponent<InventoryComponent>(context.Owner);
+        return inventory != null && inventory.HasItem(ammoId, amount);
+    }
+}

GameCore/Combat/Interfaces/ICostEffect.cs

@@ -0,0 +1,8 @@
+using GameCore.Combat.Effects;
+
+namespace GameCore.Combat.Interfaces;
+
+public interface ICostEffect : IEffect
+{
+    bool CanAfford(EffectContext context);
+}

GameCore/Combat/WeaponComponent.cs

@@ -7,6 +7,7 @@ public class WeaponComponent : IComponent
 {
     public float FireRate { get; set; } = 1f;
 
+    public List<ICostEffect> FireCosts { get; set; } = [];
     public List<IEffect> OnFireEffects { get; set; } = [];
     public List<IEffect> OnHitEffects { get; set; } = [];
 

GameCore/Combat/WeaponSystem.cs

@@ -27,12 +27,21 @@ public class WeaponSystem : ISystem
 
             if (input.IsFiring && weapon.CooldownTimer <= 0f)
             {
-                // Check for ammo if applicable
-                
                 var context = new EffectContext { World = world, Owner = entity };
 
-                foreach (var effect in weapon.OnFireEffects) effect.Execute(context);
+                var canFire = true;
+                foreach (var cost in weapon.FireCosts)
+                    if (!cost.CanAfford(context))
+                    {
+                        canFire = false;
+                        //TODO: Publish an event or notify the player they can't fire
+                        break;
+                    }
 
+                if (!canFire) continue;
+
+                foreach (var cost in weapon.FireCosts) cost.Execute(context);
+                foreach (var effect in weapon.OnFireEffects) effect.Execute(context);
                 world.PublishEvent(new WeaponFiredEvent(entity, input.MuzzlePosition));
                 weapon.CooldownTimer = 1f / weapon.FireRate;
             }