Pow3r: stage 1 (#4208)

Co-authored-by: 20kdc <asdd2808@gmail.com>

Content.Server/Power/EntitySystems/BatterySystem.cs

@@ -0,0 +1,42 @@
+#nullable enable
+using Content.Server.Power.Components;
+using JetBrains.Annotations;
+using Robust.Shared.GameObjects;
+
+namespace Content.Server.Power.EntitySystems
+{
+    [UsedImplicitly]
+    public class BatterySystem : EntitySystem
+    {
+        public override void Initialize()
+        {
+            base.Initialize();
+
+            SubscribeLocalEvent<BatteryComponent, NetworkBatteryPreSync>(PreSync);
+            SubscribeLocalEvent<BatteryComponent, NetworkBatteryPostSync>(PostSync);
+        }
+
+        private void PreSync(EntityUid uid, BatteryComponent component, NetworkBatteryPreSync args)
+        {
+            var networkBattery = ComponentManager.GetComponent<PowerNetworkBatteryComponent>(uid);
+
+            networkBattery.NetworkBattery.Capacity = component.MaxCharge;
+            networkBattery.NetworkBattery.CurrentStorage = component.CurrentCharge;
+        }
+
+        private void PostSync(EntityUid uid, BatteryComponent component, NetworkBatteryPostSync args)
+        {
+            var networkBattery = ComponentManager.GetComponent<PowerNetworkBatteryComponent>(uid);
+
+            component.CurrentCharge = networkBattery.NetworkBattery.CurrentStorage;
+        }
+
+        public override void Update(float frameTime)
+        {
+            foreach (var comp in ComponentManager.EntityQuery<BatteryComponent>())
+            {
+                comp.OnUpdate(frameTime);
+            }
+        }
+    }
+}