Pow3r: stage 1 (#4208)

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

Content.Server/Power/Components/ExaminableBatteryComponent.cs

@@ -0,0 +1,39 @@
+#nullable enable
+using Content.Shared.Examine;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Localization;
+using Robust.Shared.Utility;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Server.Power.Components
+{
+    [RegisterComponent]
+    public class ExaminableBatteryComponent : Component, IExamine
+    {
+        public override string Name => "ExaminableBattery";
+
+        [ViewVariables]
+        [ComponentDependency] private BatteryComponent? _battery = default!;
+
+        void IExamine.Examine(FormattedMessage message, bool inDetailsRange)
+        {
+            if (_battery == null)
+                return;
+            if (inDetailsRange)
+            {
+                var effectiveMax = _battery.MaxCharge;
+                if (effectiveMax == 0)
+                    effectiveMax = 1;
+                var chargeFraction = _battery.CurrentCharge / effectiveMax;
+                var chargePercentRounded = (int) (chargeFraction * 100);
+                message.AddMarkup(
+                    Loc.GetString(
+                        "examinable-battery-component-examine-detail",
+                        ("percent", chargePercentRounded),
+                        ("markupPercentColor", "green")
+                    )
+                );
+            }
+        }
+    }
+}