Power cell slot QOL (#15373)

Content.Server/PowerCell/PowerCellDrawComponent.cs

@@ -0,0 +1,25 @@
+namespace Content.Server.PowerCell;
+
+/// <summary>
+/// Indicates that the entity's ActivatableUI requires power or else it closes.
+/// </summary>
+[RegisterComponent]
+public sealed class PowerCellDrawComponent : Component
+{
+    [ViewVariables(VVAccess.ReadWrite), DataField("enabled")]
+    public bool Enabled = false;
+
+    /// <summary>
+    /// How much the entity draws while the UI is open.
+    /// Set to 0 if you just wish to check for power upon opening the UI.
+    /// </summary>
+    [ViewVariables(VVAccess.ReadWrite), DataField("drawRate")]
+    public float DrawRate = 1f;
+
+    /// <summary>
+    /// How much power is used whenever the entity is "used".
+    /// This is used to ensure the UI won't open again without a minimum use power.
+    /// </summary>
+    [ViewVariables(VVAccess.ReadWrite), DataField("useRate")]
+    public float UseRate = 0f;
+}

Content.Server/PowerCell/PowerCellSlotEmptyEvent.cs

@@ -0,0 +1,7 @@
+namespace Content.Server.PowerCell;
+
+/// <summary>
+/// Raised directed on an entity when its active power cell has no more charge to supply.
+/// </summary>
+[ByRefEvent]
+public readonly record struct PowerCellSlotEmptyEvent;

Content.Server/PowerCell/PowerCellSystem.cs

@@ -10,19 +10,25 @@ using Content.Shared.Rounding;
 using Robust.Shared.Containers;
 using System.Diagnostics.CodeAnalysis;
 using Content.Server.Kitchen.Components;
+using Content.Server.UserInterface;
 using Content.Shared.Containers.ItemSlots;
+using Content.Shared.Popups;
 using Content.Shared.Rejuvenate;
+using Content.Shared.UserInterface;
+using Robust.Server.GameObjects;
 
 namespace Content.Server.PowerCell;
 
 public sealed class PowerCellSystem : SharedPowerCellSystem
 {
+    [Dependency] private readonly ActivatableUISystem _activatable = default!;
     [Dependency] private readonly SolutionContainerSystem _solutionsSystem = default!;
     [Dependency] private readonly ExplosionSystem _explosionSystem = default!;
     [Dependency] private readonly IAdminLogManager _adminLogger = default!;
     [Dependency] private readonly SharedContainerSystem _containerSystem = default!;
     [Dependency] private readonly ItemSlotsSystem _itemSlotsSystem = default!;
     [Dependency] private readonly SharedAppearanceSystem _sharedAppearanceSystem = default!;
+    [Dependency] private readonly SharedPopupSystem _popup = default!;
 
     public override void Initialize()
     {
@@ -39,6 +45,28 @@ public sealed class PowerCellSystem : SharedPowerCellSystem
         SubscribeLocalEvent<BatteryComponent, BeingMicrowavedEvent>(OnMicrowaved);
     }
 
+    public override void Update(float frameTime)
+    {
+        base.Update(frameTime);
+        var query = EntityQueryEnumerator<PowerCellDrawComponent, PowerCellSlotComponent>();
+
+        while (query.MoveNext(out var uid, out var comp, out var slot))
+        {
+            if (!comp.Enabled)
+                continue;
+
+            if (!TryGetBatteryFromSlot(uid, out var battery, slot))
+                continue;
+
+            if (battery.TryUseCharge(comp.DrawRate * frameTime))
+                continue;
+
+            comp.Enabled = false;
+            var ev = new PowerCellSlotEmptyEvent();
+            RaiseLocalEvent(uid, ref ev);
+        }
+    }
+
     private void OnRejuvenate(EntityUid uid, PowerCellComponent component, RejuvenateEvent args)
     {
         component.IsRigged = false;
@@ -102,6 +130,89 @@ public sealed class PowerCellSystem : SharedPowerCellSystem
         QueueDel(uid);
     }
 
+    #region Activatable
+
+    /// <summary>
+    /// Returns whether the entity has a slotted battery and <see cref="PowerCellDrawComponent.UseRate"/> charge.
+    /// </summary>
+    /// <param name="user">Popup to this user with the relevant detail if specified.</param>
+    public bool HasActivatableCharge(EntityUid uid, PowerCellDrawComponent? battery = null, PowerCellSlotComponent? cell = null, EntityUid? user = null)
+    {
+        if (!Resolve(uid, ref battery, ref cell, false))
+            return false;
+
+        return HasCharge(uid, battery.UseRate, cell, user);
+    }
+
+    /// <summary>
+    /// Tries to use the <see cref="PowerCellDrawComponent.UseRate"/> for this entity.
+    /// </summary>
+    /// <param name="user">Popup to this user with the relevant detail if specified.</param>
+    public bool TryUseActivatableCharge(EntityUid uid, PowerCellDrawComponent? battery = null, PowerCellSlotComponent? cell = null, EntityUid? user = null)
+    {
+        if (!Resolve(uid, ref battery, ref cell, false))
+            return false;
+
+        if (TryUseCharge(uid, battery.UseRate, cell, user))
+        {
+            _activatable.CheckUsage(uid);
+            return true;
+        }
+
+        return false;
+    }
+
+    #endregion
+
+    /// <summary>
+    /// Returns whether the entity has a slotted battery and charge for the requested action.
+    /// </summary>
+    /// <param name="user">Popup to this user with the relevant detail if specified.</param>
+    public bool HasCharge(EntityUid uid, float charge, PowerCellSlotComponent? component = null, EntityUid? user = null)
+    {
+        if (!TryGetBatteryFromSlot(uid, out var battery, component))
+        {
+            if (user != null)
+                _popup.PopupEntity(Loc.GetString("power-cell-no-battery"), uid, user.Value);
+
+            return false;
+        }
+
+        if (battery.CurrentCharge < charge)
+        {
+            if (user != null)
+                _popup.PopupEntity(Loc.GetString("power-cell-insufficient"), uid, user.Value);
+
+            return false;
+        }
+
+        return true;
+    }
+
+    /// <summary>
+    /// Tries to use charge from a slotted battery.
+    /// </summary>
+    public bool TryUseCharge(EntityUid uid, float charge, PowerCellSlotComponent? component = null, EntityUid? user = null)
+    {
+        if (!TryGetBatteryFromSlot(uid, out var battery, component))
+        {
+            if (user != null)
+                _popup.PopupEntity(Loc.GetString("power-cell-no-battery"), uid, user.Value);
+
+            return false;
+        }
+
+        if (!battery.TryUseCharge(charge))
+        {
+            if (user != null)
+                _popup.PopupEntity(Loc.GetString("power-cell-insufficient"), uid, user.Value);
+
+            return false;
+        }
+
+        return true;
+    }
+
     public bool TryGetBatteryFromSlot(EntityUid uid, [NotNullWhen(true)] out BatteryComponent? battery, PowerCellSlotComponent? component = null)
     {
         if (!Resolve(uid, ref component, false))