Add utility AI (#806)

Co-authored-by: Pieter-Jan Briers <pieterjan.briers@gmail.com>
Co-authored-by: Metal Gear Sloth <metalgearsloth@gmail.com>
Co-authored-by: Pieter-Jan Briers <pieterjan.briers+git@gmail.com>

Content.Server/AI/WorldState/Blackboard.cs

@@ -0,0 +1,70 @@
+using System;
+using System.Collections.Generic;
+using Robust.Shared.Interfaces.GameObjects;
+using Robust.Shared.Interfaces.Reflection;
+using Robust.Shared.IoC;
+using Robust.Shared.Utility;
+
+namespace Content.Server.AI.WorldState
+{
+    /// <summary>
+    /// The blackboard functions as an AI's repository of knowledge in a common format.
+    /// </summary>
+    public sealed class Blackboard
+    {
+        // Some stuff like "My Health" is easy to represent as components but abstract stuff like "How much food is nearby"
+        // is harder. This also allows data to be cached if it's being hit frequently.
+        
+        // This also stops you from re-writing the same boilerplate everywhere of stuff like "Do I have OuterClothing on?"
+
+        private readonly Dictionary<Type, IAiState> _states = new Dictionary<Type, IAiState>();
+        private readonly List<IPlanningState> _planningStates = new List<IPlanningState>();
+
+        public Blackboard(IEntity owner)
+        {
+            Setup(owner);
+        }
+
+        private void Setup(IEntity owner)
+        {
+            var typeFactory = IoCManager.Resolve<IDynamicTypeFactory>();
+            var blackboardManager = IoCManager.Resolve<BlackboardManager>();
+
+            foreach (var state in blackboardManager.AiStates)
+            {
+                var newState = (IAiState) typeFactory.CreateInstance(state);
+                newState.Setup(owner);
+                _states.Add(newState.GetType(), newState);
+
+                switch (newState)
+                {
+                    case IPlanningState planningState:
+                        _planningStates.Add(planningState);
+                        break;
+                }
+            }
+        }
+
+        /// <summary>
+        /// All planning states will have their values reset
+        /// </summary>
+        public void ResetPlanning()
+        {
+            foreach (var state in _planningStates)
+            {
+                state.Reset();
+            }
+        }
+
+        /// <summary>
+        /// Get the AI state class
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <returns></returns>
+        /// <exception cref="InvalidOperationException"></exception>
+        public T GetState<T>() where T : IAiState
+        {
+            return (T) _states[typeof(T)];
+        }
+    }
+}