#region Copyright & License Information
/*
 * Copyright 2007-2015 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;
using System.Collections.Generic;
using System.Linq;

namespace OpenRA.Primitives
{
	public class TypeDictionary : IEnumerable
	{
		Dictionary<Type, object> dataSingular = new Dictionary<Type, object>();
		Dictionary<Type, List<object>> dataMultiple = new Dictionary<Type, List<object>>();

		public void Add(object val)
		{
			var t = val.GetType();

			foreach (var i in t.GetInterfaces())
				InnerAdd(i, val);
			foreach (var tt in t.BaseTypes())
				InnerAdd(tt, val);
		}

		void InnerAdd(Type t, object val)
		{
			List<object> objs;
			object obj;

			if (dataMultiple.TryGetValue(t, out objs))
				objs.Add(val);
			else if (dataSingular.TryGetValue(t, out obj))
			{
				dataSingular.Remove(t);
				dataMultiple.Add(t, new List<object> { obj, val });
			}
			else
				dataSingular.Add(t, val);
		}

		public bool Contains<T>()
		{
			return dataSingular.ContainsKey(typeof(T)) || dataMultiple.ContainsKey(typeof(T));
		}

		public T Get<T>()
		{
			if (dataMultiple.ContainsKey(typeof(T)))
				throw new InvalidOperationException("TypeDictionary contains multiple instance of type `{0}`".F(typeof(T)));

			object ret;
			if (!dataSingular.TryGetValue(typeof(T), out ret))
				throw new InvalidOperationException("TypeDictionary does not contain instance of type `{0}`".F(typeof(T)));
			return (T)ret;
		}

		public T GetOrDefault<T>()
		{
			return (T)GetOrDefault(typeof(T));
		}

		public object GetOrDefault(Type t)
		{
			if (dataMultiple.ContainsKey(t))
				throw new InvalidOperationException("TypeDictionary contains multiple instances of type `{0}`".F(t));

			object ret;
			if (!dataSingular.TryGetValue(t, out ret))
				return null;
			return ret;
		}

		public IEnumerable<T> WithInterface<T>()
		{
			List<object> objs;
			object obj;

			if (dataMultiple.TryGetValue(typeof(T), out objs))
				return objs.Cast<T>();
			else if (dataSingular.TryGetValue(typeof(T), out obj))
				return new T[] { (T)obj };
			else
				return new T[0];
		}

		public IEnumerator GetEnumerator()
		{
			return WithInterface<object>().GetEnumerator();
		}
	}

	public static class TypeExts
	{
		public static IEnumerable<Type> BaseTypes(this Type t)
		{
			while (t != null)
			{
				yield return t;
				t = t.BaseType;
			}
		}
	}
}