Crawling Part 1: The Knockdownening (#36881)

Co-authored-by: slarticodefast <161409025+slarticodefast@users.noreply.github.com>
Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>
Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
Co-authored-by: Princess Cheeseballs <66055347+Pronana@users.noreply.github.com>
Co-authored-by: ScarKy0 <scarky0@onet.eu>

Content.Shared/Movement/Systems/WormSystem.cs

@@ -0,0 +1,53 @@
+using Content.Shared.Alert;
+using Content.Shared.Movement.Components;
+using Content.Shared.Popups;
+using Content.Shared.Rejuvenate;
+using Content.Shared.Stunnable;
+
+namespace Content.Shared.Movement.Systems;
+
+/// <summary>
+/// This handles the worm component
+/// </summary>
+public sealed class WormSystem : EntitySystem
+{
+    [Dependency] private readonly AlertsSystem _alerts = default!;
+    [Dependency] private readonly SharedPopupSystem _popup = default!;
+    [Dependency] private readonly SharedStunSystem _stun = default!;
+
+    public override void Initialize()
+    {
+        SubscribeLocalEvent<WormComponent, StandUpAttemptEvent>(OnStandAttempt);
+        SubscribeLocalEvent<WormComponent, KnockedDownRefreshEvent>(OnKnockedDownRefresh);
+        SubscribeLocalEvent<WormComponent, RejuvenateEvent>(OnRejuvenate);
+        SubscribeLocalEvent<WormComponent, MapInitEvent>(OnMapInit);
+    }
+
+    private void OnMapInit(Entity<WormComponent> ent, ref MapInitEvent args)
+    {
+        EnsureComp<KnockedDownComponent>(ent, out var knocked);
+        _alerts.ShowAlert(ent, SharedStunSystem.KnockdownAlert);
+        _stun.SetAutoStand((ent, knocked));
+    }
+
+    private void OnRejuvenate(Entity<WormComponent> ent, ref RejuvenateEvent args)
+    {
+        RemComp<WormComponent>(ent);
+    }
+
+    private void OnStandAttempt(Entity<WormComponent> ent, ref StandUpAttemptEvent args)
+    {
+        if (args.Cancelled)
+            return;
+
+        args.Cancelled = true;
+        args.Message = (Loc.GetString("worm-component-stand-attempt"), PopupType.SmallCaution);
+        args.Autostand = false;
+    }
+
+    private void OnKnockedDownRefresh(Entity<WormComponent> ent, ref KnockedDownRefreshEvent args)
+    {
+        args.FrictionModifier *= ent.Comp.FrictionModifier;
+        args.SpeedModifier *= ent.Comp.SpeedModifier;
+    }
+}