Adds the antimatter engine (#1905)

* adds antimatter engine

* fixes some nullables

* fixes ALL OF THE NULLABLES

* adds explosions

* adds fancy lighting

* requested changes + license info

Co-authored-by: ancientpower <ancientpowerer@gmail.com>

Content.Server/GameObjects/Components/NodeContainer/NodeGroups/AMENodeGroup.cs

@@ -0,0 +1,152 @@
+using Content.Server.Explosions;
+using Content.Server.GameObjects.Components.NodeContainer.Nodes;
+using Content.Server.GameObjects.Components.Power.AME;
+using Robust.Shared.GameObjects.Components.Transform;
+using Robust.Shared.ViewVariables;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Content.Server.GameObjects.Components.NodeContainer.NodeGroups
+{
+    /// <summary>
+    /// Node group class for handling the Antimatter Engine's console and parts.
+    /// </summary>
+    [NodeGroup(NodeGroupID.AMEngine)]
+    public class AMENodeGroup : BaseNodeGroup
+    {
+        /// <summary>
+        /// The AME controller which is currently in control of this node group.
+        /// This could be tracked a few different ways, but this is most convenient,
+        /// since any part connected to the node group can easily find the master.
+        /// </summary>
+        [ViewVariables]
+        private AMEControllerComponent _masterController;
+
+        public AMEControllerComponent MasterController => _masterController;
+
+        private List<AMEShieldComponent> _cores = new List<AMEShieldComponent>();
+
+        public int CoreCount => _cores.Count;
+
+        protected override void OnAddNode(Node node)
+        {
+            base.OnAddNode(node);
+            if (_masterController == null)
+            {
+                node.Owner.TryGetComponent<AMEControllerComponent>(out var controller);
+                _masterController = controller;
+            }
+        }
+
+        protected override void OnRemoveNode(Node node)
+        {
+            base.OnRemoveNode(node);
+            RefreshAMENodes(_masterController);
+            if (_masterController != null && _masterController?.Owner == node.Owner) { _masterController = null; }
+        }
+
+        public void RefreshAMENodes(AMEControllerComponent controller)
+        {
+            if(_masterController == null && controller != null)
+            {
+                _masterController = controller;
+            }
+
+            if (_cores != null) {
+                foreach (AMEShieldComponent core in _cores)
+                {
+                    core.UnsetCore();
+                }
+                _cores.Clear();
+            }
+
+            //Check each shield node to see if it meets core criteria
+            foreach (Node node in Nodes)
+            {
+                if (!node.Owner.TryGetComponent<AMEShieldComponent>(out var shield)) { continue; }
+                var nodeNeighbors = node.Owner
+                    .GetComponent<SnapGridComponent>()
+                    .GetCellsInSquareArea()
+                    .Select(sgc => sgc.Owner)
+                    .Where(entity => entity != node.Owner)
+                    .Select(entity => entity.TryGetComponent<AMEShieldComponent>(out var adjshield) ? adjshield : null)
+                    .Where(adjshield => adjshield != null);
+
+                if (nodeNeighbors.Count() >= 8) { _cores.Add(shield); }
+            }
+
+            if (_cores == null) { return; }
+
+            foreach (AMEShieldComponent core in _cores)
+            {
+                core.SetCore();
+            }
+        }
+
+        public void UpdateCoreVisuals(int injectionAmount, bool injecting)
+        {
+
+            var injectionStrength = CoreCount > 0 ? injectionAmount / CoreCount : 0;
+
+            foreach (AMEShieldComponent core in _cores)
+            {
+                core.UpdateCoreVisuals(injectionStrength, injecting);
+            }
+        }
+
+        public int InjectFuel(int injectionAmount)
+        {
+            if(injectionAmount > 0 && CoreCount > 0)
+            {
+                var instability = 2 * (injectionAmount / CoreCount);
+                foreach(AMEShieldComponent core in _cores)
+                {
+                    core.CoreIntegrity -= instability;
+                }
+                return CoreCount * injectionAmount * 15000; //2 core engine injecting 2 fuel per core = 60kW(?)
+            }
+            return 0;
+        }
+
+        public int GetTotalStability()
+        {
+            if(CoreCount < 1) { return 100; }
+            var stability = 0;
+
+            foreach(AMEShieldComponent core in _cores)
+            {
+                stability += core.CoreIntegrity;
+            }
+
+            stability = stability / CoreCount;
+
+            return stability;
+        }
+
+        public void ExplodeCores()
+        {
+            if(_cores.Count < 1 || MasterController == null) { return; }
+
+            var intensity = 0;
+
+            /*
+             * todo: add an exact to the shielding and make this find the core closest to the controller
+             * so they chain explode, after helpers have been added to make it not cancer
+            */
+            var epicenter = _cores.First();
+
+            foreach (AMEShieldComponent core in _cores)
+            {
+                intensity += MasterController.InjectionAmount;
+            }
+
+            intensity = Math.Min(intensity, 8);
+
+            ExplosionHelper.SpawnExplosion(epicenter.Owner.Transform.GridPosition, intensity / 2, intensity, intensity * 2, intensity * 3);
+
+        }
+
+    }
+}