Power switchable refactor (#20419)

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

Content.Shared/Power/Generator/SharedPowerSwitchableSystem.cs

@@ -0,0 +1,72 @@
+using Content.Shared.Examine;
+
+namespace Content.Shared.Power.Generator;
+
+/// <summary>
+/// Shared logic for power-switchable devices.
+/// </summary>
+/// <seealso cref="PowerSwitchableComponent"/>
+public abstract class SharedPowerSwitchableSystem : EntitySystem
+{
+    public override void Initialize()
+    {
+        SubscribeLocalEvent<PowerSwitchableComponent, ExaminedEvent>(OnExamined);
+    }
+
+    private void OnExamined(EntityUid uid, PowerSwitchableComponent comp, ExaminedEvent args)
+    {
+        // Show which voltage is currently selected.
+        var voltage = VoltageColor(GetVoltage(uid, comp));
+        args.PushMarkup(Loc.GetString(comp.ExamineText, ("voltage", voltage)));
+    }
+
+    /// <summary>
+    /// Helper to get the colored markup string for a voltage type.
+    /// </summary>
+    public string VoltageColor(SwitchableVoltage voltage)
+    {
+        return Loc.GetString("power-switchable-voltage", ("voltage", VoltageString(voltage)));
+    }
+
+    /// <summary>
+    /// Converts from "hv" to "HV" since for some reason the enum gets made lowercase???
+    /// </summary>
+    public string VoltageString(SwitchableVoltage voltage)
+    {
+        return voltage.ToString().ToUpper();
+    }
+
+    /// <summary>
+    /// Returns index of the next cable type index to cycle to.
+    /// </summary>
+    public int NextIndex(EntityUid uid, PowerSwitchableComponent? comp = null)
+    {
+        if (!Resolve(uid, ref comp))
+            return 0;
+
+        // loop back at the end
+        return (comp.ActiveIndex + 1) % comp.Cables.Count;
+    }
+
+    /// <summary>
+    /// Returns the current cable voltage being used by a power-switchable device.
+    /// </summary>
+    public SwitchableVoltage GetVoltage(EntityUid uid, PowerSwitchableComponent? comp = null)
+    {
+        if (!Resolve(uid, ref comp))
+            return default;
+
+        return comp.Cables[comp.ActiveIndex].Voltage;
+    }
+
+    /// <summary>
+    /// Returns the cable's next voltage to cycle to being used by a power-switchable device.
+    /// </summary>
+    public SwitchableVoltage GetNextVoltage(EntityUid uid, PowerSwitchableComponent? comp = null)
+    {
+        if (!Resolve(uid, ref comp))
+            return default;
+
+        return comp.Cables[NextIndex(uid, comp)].Voltage;
+    }
+}