experimental welder fuel regeneration (#15475)

* solution regeneration system

* experimental welding tool regenerates 1u of fuel every second

* pro

* use a solution

* added -> generated

---------

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

Content.Server/Chemistry/Components/SolutionRegenerationComponent.cs

@@ -0,0 +1,39 @@
+using Content.Server.Chemistry.EntitySystems;
+using Content.Shared.Chemistry.Components;
+using Content.Shared.FixedPoint;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom.Prototype;
+
+namespace Content.Server.Chemistry.Components;
+
+/// <summary>
+/// Passively increases a solution's quantity of a reagent.
+/// </summary>
+[RegisterComponent]
+[Access(typeof(SolutionRegenerationSystem))]
+public sealed class SolutionRegenerationComponent : Component
+{
+    /// <summary>
+    /// The name of the solution to add to.
+    /// </summary>
+    [DataField("solution", required: true), ViewVariables(VVAccess.ReadWrite)]
+    public string Solution = string.Empty;
+
+    /// <summary>
+    /// The reagent(s) to be regenerated in the solution.
+    /// </summary>
+    [DataField("generated", required: true), ViewVariables(VVAccess.ReadWrite)]
+    public Solution Generated = default!;
+
+    /// <summary>
+    /// How long it takes to regenerate once.
+    /// </summary>
+    [DataField("duration"), ViewVariables(VVAccess.ReadWrite)]
+    public TimeSpan Duration = TimeSpan.FromSeconds(1);
+
+    /// <summary>
+    /// The time when the next regeneration will occur.
+    /// </summary>
+    [DataField("nextChargeTime", customTypeSerializer: typeof(TimeOffsetSerializer)), ViewVariables(VVAccess.ReadWrite)]
+    public TimeSpan NextRegenTime = TimeSpan.FromSeconds(0);
+}

Content.Server/Chemistry/EntitySystems/SolutionRegenerationSystem.cs

@@ -0,0 +1,40 @@
+using Content.Server.Chemistry.Components;
+using Content.Server.Chemistry.Components.SolutionManager;
+using Robust.Shared.Timing;
+
+namespace Content.Server.Chemistry.EntitySystems;
+
+public sealed class SolutionRegenerationSystem : EntitySystem
+{
+    [Dependency] private readonly SolutionContainerSystem _solutionContainer = default!;
+    [Dependency] private readonly IGameTiming _timing = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<SolutionRegenerationComponent, EntityUnpausedEvent>(OnUnpaused);
+    }
+
+    public override void Update(float frameTime)
+    {
+        base.Update(frameTime);
+
+        var query = EntityQueryEnumerator<SolutionRegenerationComponent, SolutionContainerManagerComponent>();
+        while (query.MoveNext(out var uid, out var regen, out var manager))
+        {
+            if (_timing.CurTime < regen.NextRegenTime)
+                continue;
+
+            // timer ignores if its full, it's just a fixed cycle
+            regen.NextRegenTime = _timing.CurTime + regen.Duration;
+            if (_solutionContainer.TryGetSolution(uid, regen.Solution, out var solution, manager))
+                _solutionContainer.TryAddSolution(uid, solution, regen.Generated);
+        }
+    }
+
+    private void OnUnpaused(EntityUid uid, SolutionRegenerationComponent comp, ref EntityUnpausedEvent args)
+    {
+        comp.NextRegenTime += args.PausedTime;
+    }
+}

Resources/Prototypes/Entities/Objects/Tools/welders.yml

@@ -127,6 +127,12 @@
     enabled: false
     radius: 1.5
     color: lightblue
+  - type: SolutionRegeneration
+    solution: Welder
+    generated:
+      reagents:
+      - ReagentId: WeldingFuel
+        Quantity: 1
 
 - type: entity
   name: emergency welding tool