Add puddles / reagent spills (#743)

Content.Server/GameObjects/Components/Fluids/SpillHelper.cs

@@ -0,0 +1,90 @@
+using Content.Shared.Chemistry;
+using Robust.Server.Interfaces.GameObjects;
+
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Map;
+using Robust.Shared.IoC;
+using Robust.Shared.Map;
+
+namespace Content.Server.GameObjects.Components.Fluids
+{
+    public static class SpillHelper
+    {
+
+        /// <summary>
+        /// Spills the specified solution at the entity's location if possible.
+        /// </summary>
+        /// <param name="entity">Entity location to spill at</param>
+        /// <param name="solution">Initial solution for the prototype</param>
+        /// <param name="prototype">Prototype to use</param>
+        internal static void SpillAt(IEntity entity, Solution solution, string prototype)
+        {
+            var entityLocation = entity.Transform.GridPosition;
+            SpillAt(entityLocation, solution, prototype);
+        }
+
+        // Other functions will be calling this one
+
+        /// <summary>
+        /// Spills solution at the specified grid co-ordinates
+        /// </summary>
+        /// <param name="gridCoordinates"></param>
+        /// <param name="solution">Initial solution for the prototype</param>
+        /// <param name="prototype">Prototype to use</param>
+        internal static void SpillAt(GridCoordinates gridCoordinates, Solution solution, string prototype)
+        {
+            if (solution.TotalVolume == 0)
+            {
+                return;
+            }
+
+            var mapManager = IoCManager.Resolve<IMapManager>();
+            var entityManager = IoCManager.Resolve<IEntityManager>();
+            var serverEntityManager = IoCManager.Resolve<IServerEntityManager>();
+
+            var mapGrid = mapManager.GetGrid(gridCoordinates.GridID);
+
+            // If space return early, let that spill go out into the void
+            var tileRef = mapGrid.GetTileRef(gridCoordinates);
+            if (tileRef.Tile.IsEmpty)
+            {
+                return;
+            }
+
+            // Get normalized co-ordinate for spill location and spill it in the centre
+            // TODO: Does SnapGrid or something else already do this?
+            var spillTileMapGrid = mapManager.GetGrid(gridCoordinates.GridID);
+            var spillTileRef = spillTileMapGrid.GetTileRef(gridCoordinates).GridIndices;
+            var spillGridCoords = spillTileMapGrid.GridTileToLocal(spillTileRef);
+
+            var spilt = false;
+
+            foreach (var spillEntity in entityManager.GetEntitiesAt(spillTileMapGrid.ParentMapId, spillGridCoords.Position))
+            {
+                if (!spillEntity.TryGetComponent(out PuddleComponent puddleComponent))
+                {
+                    continue;
+                }
+
+                if (!puddleComponent.TryAddSolution(solution))
+                {
+                    continue;
+                }
+
+                spilt = true;
+                break;
+            }
+
+            // Did we add to an existing puddle
+            if (spilt)
+            {
+                return;
+            }
+
+            var puddle = serverEntityManager.SpawnEntity(prototype, spillGridCoords);
+            puddle.GetComponent<PuddleComponent>().TryAddSolution(solution);
+        }
+
+    }
+
+}