context: #region Copyright & License Information
  /*
   * Copyright 2007-2014 The OpenRA Developers (see AUTHORS)
   * This file is part of OpenRA, which is free software. It is made
   * available to you under the terms of the GNU General Public License
   * as published by the Free Software Foundation. For more information,
   * see COPYING.
   */
  #endregion
  
  using System;
  using System.Collections.Generic;
  using System.Drawing;
  using System.IO;
  using System.Linq;
  using System.Reflection;
  using Eluant;
  using OpenRA.FileSystem;
  using OpenRA.Graphics;
  using OpenRA.Primitives;
  using OpenRA.Support;
  using OpenRA.Traits;
  
  namespace OpenRA.Scripting
  {
  	// Tag interfaces specifying the type of bindings to create
  	public interface IScriptBindable { }
  
  	// For objects that need the context to create their bindings
  	public interface IScriptNotifyBind
  	{
  		void OnScriptBind(ScriptContext context);
  	}
  
  	// For traitinfos that provide actor / player commands
  	public sealed class ScriptPropertyGroupAttribute : Attribute
  	{
  		public readonly string Category;
  		public ScriptPropertyGroupAttribute(string category) { Category = category; }
  	}
  
  	public sealed class ScriptActorPropertyActivityAttribute : Attribute { }
  
  	public abstract class ScriptActorProperties
  	{
  		protected readonly Actor self;
  		public ScriptActorProperties(Actor self) { this.self = self; }
  	}
  
  	public abstract class ScriptPlayerProperties
  	{
  		protected readonly Player player;
  		public ScriptPlayerProperties(Player player) { this.player = player; }
  	}
  
  	// For global-level bindings
  	public abstract class ScriptGlobal : ScriptObjectWrapper
  	{
  		protected override string DuplicateKeyError(string memberName) { return "Table '{0}' defines multiple members '{1}'".F(Name, memberName); }
  		protected override string MemberNotFoundError(string memberName) { return "Table '{0}' does not define a property '{1}'".F(Name, memberName); }
  
  		public readonly string Name;
  		public ScriptGlobal(ScriptContext context)
  			: base(context)
  		{
  			// The 'this.' resolves the actual (subclass) type
  			var type = this.GetType();
  			var names = type.GetCustomAttributes<ScriptGlobalAttribute>(true);
  			if (names.Count() != 1)
  				throw new InvalidOperationException("[LuaGlobal] attribute not found for global table '{0}'".F(type));
  
  			Name = names.First().Name;
  			Bind(new[] { this });
  		}
  	}
  
  	public sealed class ScriptGlobalAttribute : Attribute
  	{
  		public readonly string Name;
  		public ScriptGlobalAttribute(string name) { Name = name; }
  	}
  
  	public sealed class ScriptContext : IDisposable
  	{
  		public World World { get; private set; }
  		public WorldRenderer WorldRenderer { get; private set; }
  
  		readonly MemoryConstrainedLuaRuntime runtime;
  		readonly LuaFunction tick;
  
  		// Restrict user scripts (excluding system libraries) to 50 MB of memory use
  		const int MaxUserScriptMemory = 50 * 1024 * 1024;
  
  		// Restrict the number of instructions that will be run per map function call
  		const int MaxUserScriptInstructions = 1000000;
  
  		readonly Type[] knownActorCommands;
  		public readonly Cache<ActorInfo, Type[]> ActorCommands;
  		public readonly Type[] PlayerCommands;
  
  		bool disposed;
  
  		public ScriptContext(World world, WorldRenderer worldRenderer,
  			IEnumerable<string> scripts)
  		{
  			runtime = new MemoryConstrainedLuaRuntime();
  
  			World = world;
  			WorldRenderer = worldRenderer;
  			knownActorCommands = Game.modData.ObjectCreator
  				.GetTypesImplementing<ScriptActorProperties>()
  				.ToArray();
  
  			ActorCommands = new Cache<ActorInfo, Type[]>(FilterActorCommands);
  			PlayerCommands = Game.modData.ObjectCreator
  				.GetTypesImplementing<ScriptPlayerProperties>()
  				.ToArray();
  
  			runtime.DoBuffer(GlobalFileSystem.Open(Path.Combine("lua", "scriptwrapper.lua")).ReadAllText(), "scriptwrapper.lua").Dispose();
  			tick = (LuaFunction)runtime.Globals["Tick"];
  
  			// Register globals
  			using (var fn = runtime.CreateFunctionFromDelegate((Action<string>)FatalError))
  				runtime.Globals["FatalError"] = fn;
  
  			runtime.Globals["MaxUserScriptInstructions"] = MaxUserScriptInstructions;
  
  			using (var registerGlobal = (LuaFunction)runtime.Globals["RegisterSandboxedGlobal"])
  			{
  				using (var fn = runtime.CreateFunctionFromDelegate((Action<string>)Console.WriteLine))
  					registerGlobal.Call("print", fn).Dispose();
  
  				// Register global tables
  				var bindings = Game.modData.ObjectCreator.GetTypesImplementing<ScriptGlobal>();
  				foreach (var b in bindings)
  				{
  					var ctor = b.GetConstructors(BindingFlags.Public | BindingFlags.Instance).FirstOrDefault(c =>
  					{
  						var p = c.GetParameters();
  						return p.Length == 1 && p.First().ParameterType == typeof(ScriptContext);
  					});
  
  					if (ctor == null)
  						throw new InvalidOperationException("{0} must define a constructor that takes a ScriptContext context parameter".F(b.Name));
  
  					var binding = (ScriptGlobal)ctor.Invoke(new[] { this });
  					using (var obj = binding.ToLuaValue(this))
  						registerGlobal.Call(binding.Name, obj).Dispose();
  				}
  			}
  
  			// System functions do not count towards the memory limit
  			runtime.MaxMemoryUse = runtime.MemoryUse + MaxUserScriptMemory;
  
  			using (var loadScript = (LuaFunction)runtime.Globals["ExecuteSandboxedScript"])
  			{
  				foreach (var s in scripts)
  					loadScript.Call(s, GlobalFileSystem.Open(s).ReadAllText()).Dispose();
  			}
  		}
  
  		bool error;
  		public void FatalError(string message)
  		{
  			Console.WriteLine("Fatal Lua Error: {0}", message);
  			Game.AddChatLine(Color.White, "Fatal Lua Error", message);
  			error = true;
  		}
  
  		public void RegisterMapActor(string name, Actor a)
  		{
  			using (var registerGlobal = (LuaFunction)runtime.Globals["RegisterSandboxedGlobal"])
  			{
  				if (runtime.Globals.ContainsKey(name))
  					throw new LuaException("The global name '{0}' is reserved, and may not be used by a map actor".F(name));
  
  				using (var obj = a.ToLuaValue(this))
  					registerGlobal.Call(name, obj).Dispose();
  			}
  		}
  
  		public void WorldLoaded()
  		{
  			if (error)
  				return;
  
  			using (var worldLoaded = (LuaFunction)runtime.Globals["WorldLoaded"])
  				worldLoaded.Call().Dispose();
  		}
  
  		public void Tick(Actor self)
  		{
  			if (error || disposed)
  				return;
  
  			using (new PerfSample("tick_lua"))
  				tick.Call().Dispose();
  		}
  
  		public void Dispose()
  		{
  			if (disposed)
  				return;
  			disposed = true;
  			if (runtime != null)
  				runtime.Dispose();
  		}
  
  		static Type[] ExtractRequiredTypes(Type t)
  		{
  			// Returns the inner types of all the Requires<T> interfaces on this type
  			var outer = t.GetInterfaces()
  				.Where(i => i.IsGenericType && i.GetGenericTypeDefinition() == typeof(Requires<>));
  
  			return outer.SelectMany(i => i.GetGenericArguments()).ToArray();
  		}
  
  		static readonly object[] NoArguments = new object[0];
  		Type[] FilterActorCommands(ActorInfo ai)
  		{
  			var method = typeof(TypeDictionary).GetMethod("Contains");
  
gt: 			return knownActorCommands.Where(c => ExtractRequiredTypes(c)