add kill head objective (#17891)

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

Content.Server/Objectives/Conditions/KillRandomHeadCondition.cs

@@ -0,0 +1,47 @@
+using Content.Server.Mind.Components;
+using Content.Server.Objectives.Interfaces;
+using Content.Server.Roles;
+using Content.Shared.Mobs.Components;
+using Robust.Shared.Random;
+using System.Linq;
+
+namespace Content.Server.Objectives.Conditions;
+
+[DataDefinition]
+public sealed class KillRandomHeadCondition : KillPersonCondition
+{
+    public override IObjectiveCondition GetAssigned(Mind.Mind mind)
+    {
+        RequireDead = true;
+
+        var allHumans = EntityManager.EntityQuery<MindContainerComponent>(true).Where(mc =>
+        {
+            var entity = mc.Mind?.OwnedEntity;
+
+            if (entity == default)
+                return false;
+
+            return EntityManager.TryGetComponent(entity, out MobStateComponent? mobState) &&
+                  MobStateSystem.IsAlive(entity.Value, mobState) &&
+                   mc.Mind != mind;
+        }).Select(mc => mc.Mind).ToList();
+
+        if (allHumans.Count == 0)
+            return new DieCondition(); // I guess I'll die
+
+        var allHeads = allHumans.Where(mind => mind?.AllRoles.Any(role => {
+            if (role is not Job job)
+                return false;
+
+            // basically a command department check, pretty sussy but whatever
+            return job.Prototype.RequireAdminNotify;
+        }) ?? false).ToList();
+
+        if (allHeads.Count == 0)
+            allHeads = allHumans; // fallback to non-head target
+
+        return new KillRandomHeadCondition {Target = IoCManager.Resolve<IRobustRandom>().Pick(allHeads)};
+    }
+
+    public string Description => Loc.GetString("objective-condition-kill-head-description");
+}