Objectives ecs rework (#19967)

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

Content.Server/Objectives/Systems/NumberObjectiveSystem.cs

@@ -0,0 +1,48 @@
+using Content.Server.Objectives.Components;
+using Content.Shared.Objectives.Components;
+using Robust.Shared.GameObjects;
+using Robust.Shared.Random;
+
+namespace Content.Server.Objectives.Systems;
+
+/// <summary>
+/// Provides API for other components, handles picking the count and setting the title and description.
+/// </summary>
+public sealed class NumberObjectiveSystem : EntitySystem
+{
+    [Dependency] private readonly IRobustRandom _random = default!;
+    [Dependency] private readonly MetaDataSystem _metaData = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeLocalEvent<NumberObjectiveComponent, ObjectiveAssignedEvent>(OnAssigned);
+        SubscribeLocalEvent<NumberObjectiveComponent, ObjectiveAfterAssignEvent>(OnAfterAssign);
+    }
+
+    private void OnAssigned(EntityUid uid, NumberObjectiveComponent comp, ref ObjectiveAssignedEvent args)
+    {
+        comp.Target = _random.Next(comp.Min, comp.Max);
+    }
+
+    private void OnAfterAssign(EntityUid uid, NumberObjectiveComponent comp, ref ObjectiveAfterAssignEvent args)
+    {
+        if (comp.Title != null)
+            _metaData.SetEntityName(uid, Loc.GetString(comp.Title, ("count", comp.Target)), args.Meta);
+
+        if (comp.Description != null)
+            _metaData.SetEntityDescription(uid, Loc.GetString(comp.Description, ("count", comp.Target)), args.Meta);
+    }
+
+    /// <summary>
+    /// Gets the objective's target count.
+    /// </summary>
+    public int GetTarget(EntityUid uid, NumberObjectiveComponent? comp = null)
+    {
+        if (!Resolve(uid, ref comp))
+            return 0;
+
+        return comp.Target;
+    }
+}