Carp wave spawner and dragons as an actual event (#10254)

Content.Server/Dragon/DragonSystem.Rule.cs

@@ -0,0 +1,67 @@
+using System.Linq;
+using Content.Server.GameTicking;
+using Content.Server.StationEvents.Components;
+using Content.Shared.Dragon;
+using Robust.Server.GameObjects;
+using Robust.Shared.Random;
+
+namespace Content.Server.Dragon;
+
+public sealed partial class DragonSystem
+{
+    public override string Prototype => "Dragon";
+
+    private int RiftsMet(DragonComponent component)
+    {
+        var finished = 0;
+
+        foreach (var rift in component.Rifts)
+        {
+            if (!TryComp<DragonRiftComponent>(rift, out var drift) ||
+                drift.State != DragonRiftState.Finished)
+                continue;
+
+            finished++;
+        }
+
+        return finished;
+    }
+
+    public override void Started()
+    {
+        var spawnLocations = EntityManager.EntityQuery<IMapGridComponent, TransformComponent>().ToList();
+
+        if (spawnLocations.Count == 0)
+            return;
+
+        var location = _random.Pick(spawnLocations);
+        Spawn("MobDragon", location.Item2.MapPosition);
+    }
+
+    public override void Ended()
+    {
+        return;
+    }
+
+    private void OnRiftRoundEnd(RoundEndTextAppendEvent args)
+    {
+        if (!RuleAdded)
+            return;
+
+        args.AddLine(Loc.GetString("dragon-round-end-summary"));
+
+        foreach (var dragon in EntityQuery<DragonComponent>(true))
+        {
+            var met = RiftsMet(dragon);
+
+            if (TryComp<ActorComponent>(dragon.Owner, out var actor))
+            {
+                args.AddLine(Loc.GetString("dragon-round-end-dragon-player", ("name", dragon.Owner), ("rifts", met), ("player", actor.PlayerSession)));
+            }
+            else
+            {
+                args.AddLine(Loc.GetString("dragon-round-end-dragon", ("name", dragon.Owner), ("rifts", met)));
+            }
+        }
+    }
+}