Mobstate Refactor (#13389)

Refactors mobstate and moves mob health thresholds to their own component

Co-authored-by: DrSmugleaf <drsmugleaf@gmail.com>

Content.Client/DamageState/DamageStateVisualizerSystem.cs

@@ -0,0 +1,65 @@
+using Content.Shared.Mobs;
+using Robust.Client.GameObjects;
+using DrawDepth = Content.Shared.DrawDepth.DrawDepth;
+
+namespace Content.Client.DamageState;
+
+public sealed class DamageStateVisualizerSystem : VisualizerSystem<DamageStateVisualsComponent>
+{
+    protected override void OnAppearanceChange(EntityUid uid, DamageStateVisualsComponent component, ref AppearanceChangeEvent args)
+    {
+        var sprite = args.Sprite;
+
+        if (sprite == null || !args.Component.TryGetData(MobStateVisuals.State, out MobState data))
+        {
+            return;
+        }
+
+        if (!component.States.TryGetValue(data, out var layers))
+        {
+            return;
+        }
+
+        if (component.Rotate)
+        {
+            sprite.NoRotation = data switch
+            {
+                MobState.Critical => false,
+                MobState.Dead => false,
+                _ => true
+            };
+        }
+
+        // Brain no worky rn so this was just easier.
+        foreach (var key in new []{ DamageStateVisualLayers.Base, DamageStateVisualLayers.BaseUnshaded })
+        {
+            if (!sprite.LayerMapTryGet(key, out _)) continue;
+
+            sprite.LayerSetVisible(key, false);
+        }
+
+        foreach (var (key, state) in layers)
+        {
+            // Inheritance moment.
+            if (!sprite.LayerMapTryGet(key, out _)) continue;
+
+            sprite.LayerSetVisible(key, true);
+            sprite.LayerSetState(key, state);
+        }
+
+        // So they don't draw over mobs anymore
+        if (data == MobState.Dead)
+        {
+            if (sprite.DrawDepth > (int) DrawDepth.FloorObjects)
+            {
+                component.OriginalDrawDepth = sprite.DrawDepth;
+                sprite.DrawDepth = (int) DrawDepth.FloorObjects;
+            }
+        }
+        else if (component.OriginalDrawDepth != null)
+        {
+            sprite.DrawDepth = component.OriginalDrawDepth.Value;
+            component.OriginalDrawDepth = null;
+        }
+    }
+}