Add completions to addobjective and localize it (#30456)

* Add completions to addobjective and localise it

* Cleanup

* Fix

* Make a manager to handle subscribtion completion options

This is so we can unsubscribe to prototype reloads properly

* Convert the manager into a system

* Move the system into the systems folder

I forgor

* Merge CompletionsSystem into ObjectivesSystem

Content.Server/Objectives/ObjectivesSystem.cs

@@ -11,6 +11,8 @@ using Robust.Shared.Prototypes;
 using Robust.Shared.Random;
 using System.Linq;
 using System.Text;
+using Content.Server.Objectives.Commands;
+using Content.Shared.Prototypes;
 using Robust.Server.Player;
 using Robust.Shared.Utility;
 
@@ -24,11 +26,22 @@ public sealed class ObjectivesSystem : SharedObjectivesSystem
     [Dependency] private readonly IRobustRandom _random = default!;
     [Dependency] private readonly EmergencyShuttleSystem _emergencyShuttle = default!;
 
+    private IEnumerable<string>? _objectives;
+
     public override void Initialize()
     {
         base.Initialize();
 
         SubscribeLocalEvent<RoundEndTextAppendEvent>(OnRoundEndText);
+
+        _prototypeManager.PrototypesReloaded += CreateCompletions;
+    }
+
+    public override void Shutdown()
+    {
+        base.Shutdown();
+
+        _prototypeManager.PrototypesReloaded -= CreateCompletions;
     }
 
     /// <summary>
@@ -249,6 +262,32 @@ public sealed class ObjectivesSystem : SharedObjectivesSystem
 
         return Loc.GetString("objectives-player-named", ("name", name));
     }
+
+
+    private void CreateCompletions(PrototypesReloadedEventArgs unused)
+    {
+        CreateCompletions();
+    }
+
+    /// <summary>
+    /// Get all objective prototypes by their IDs.
+    /// This is used for completions in <see cref="AddObjectiveCommand"/>
+    /// </summary>
+    public IEnumerable<string> Objectives()
+    {
+        if (_objectives == null)
+            CreateCompletions();
+
+        return _objectives!;
+    }
+
+    private void CreateCompletions()
+    {
+        _objectives = _prototypeManager.EnumeratePrototypes<EntityPrototype>()
+            .Where(p => p.HasComponent<ObjectiveComponent>())
+            .Select(p => p.ID)
+            .Order();
+    }
 }
 
 /// <summary>