Data-oriented Construction System (#2152)

- Powerful
- Data-oriented
- Approved by PJB
- Powered by node graphs and AI pathfinding
- Coded by the same nerd who brought you atmos

Co-authored-by: Exp <theexp111@gmail.com>

Content.Server/Construction/Conditions/ComponentInTile.cs

@@ -0,0 +1,61 @@
+using System.Threading.Tasks;
+using Content.Shared.Construction;
+using Content.Shared.Maps;
+using JetBrains.Annotations;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Map;
+using Robust.Shared.IoC;
+using Robust.Shared.Serialization;
+
+namespace Content.Server.Construction.Conditions
+{
+    /// <summary>
+    ///     Makes the condition fail if any entities on a tile have (or not) a component.
+    /// </summary>
+    [UsedImplicitly]
+    public class ComponentInTile : IEdgeCondition
+    {
+        [Dependency] private readonly IComponentFactory _componentFactory = default!;
+        [Dependency] private readonly IMapManager _mapManager = default!;
+
+        public ComponentInTile()
+        {
+            IoCManager.InjectDependencies(this);
+        }
+
+        public void ExposeData(ObjectSerializer serializer)
+        {
+            serializer.DataField(this, x => x.Component, "component", string.Empty);
+            serializer.DataField(this, x => x.HasEntity, "hasEntity", true);
+        }
+
+        /// <summary>
+        ///     If true, any entity on the tile must have the component.
+        ///     If false, no entity on the tile must have the component.
+        /// </summary>
+        public bool HasEntity { get; private set; }
+
+        /// <summary>
+        ///     The component name in question.
+        /// </summary>
+        public string Component { get; private set; }
+
+        public async Task<bool> Condition(IEntity entity)
+        {
+            if (string.IsNullOrEmpty(Component)) return false;
+
+            var type = _componentFactory.GetRegistration(Component).Type;
+
+            var indices = entity.Transform.Coordinates.ToMapIndices(entity.EntityManager, _mapManager);
+            var entities = indices.GetEntitiesInTile(entity.Transform.GridID, true, entity.EntityManager);
+
+            foreach (var ent in entities)
+            {
+                if (ent.HasComponent(type))
+                    return HasEntity;
+            }
+
+            return !HasEntity;
+        }
+    }
+}