using System;
using System.Collections.Generic;
using System.Reflection;
using System.IO;

using org.hwo.contracts;

namespace org.budnhead.tools
{
	public static class ResourceLibrary
	{
		static Dictionary<Type,Dictionary<string,object>>
			resourceTypes = new Dictionary<Type, Dictionary<string, object>>();
		static List<string>
		resourcePaths = new List<string>(new string[]{"."});

		static Dictionary<Type,string>	prefixes = new Dictionary<Type, string>();
		static Dictionary<Type,string>	suffixes = new Dictionary<Type, string>();

		internal static bool initializeResourceType(Type t,string prefix,string suffix,bool initializeBases){
			ConstructorInfo ci = null;

			new BooleanConditional()
				.requiresValid(ref ci,delegate { return t.GetConstructor(new Type[]{ typeof(Stream) }); })
				.does( delegate { initializeResourceType(t,prefix,suffix); } );

			if (initializeBases && (t.BaseType != null)){
				initializeResourceType(t.BaseType,prefix,suffix,true);
			}


			return true;
		}
		internal static bool initializeResourceType(Type t,string prefix,string suffix){
			if (prefix != null)
				prefixes.Add(t,prefix);
			if (suffix != null)
				suffixes.Add(t,suffix);
			
			return true;
		}

		static T findLoadedInstance<T>(string name){
			if (resourceTypes.ContainsKey(typeof(T))){
				if (resourceTypes[typeof(T)].ContainsKey(name)){
					return (T)resourceTypes[typeof(T)][name];
				}
			}
			throw new KeyNotFoundException("");
		}

		public static void cacheInstance<T>(string name,T instance){
			if (!resourceTypes.ContainsKey(typeof(T))){
				resourceTypes.Add(typeof(T),new Dictionary<string, object>());
			}
			resourceTypes[typeof(T)].Add(name,instance);
		}

		public static T getResource<T>(string name){
			try {
				return findLoadedInstance<T>(name);
			} catch (KeyNotFoundException){
				string p="",s="";

				if (prefixes.ContainsKey(typeof(T))){
					p = prefixes[typeof(T)];
				}
				if (suffixes.ContainsKey(typeof(T))){
					s = suffixes[typeof(T)];
				}

				string resFileName = FileHelper.findFile(String.Format("{0}{1}{2}",p,name,s),resourcePaths.ToArray());
				if (resFileName != null){
					Stream resStream = new FileStream(resFileName,FileMode.Open);
					ConstructorInfo ci = typeof(T).GetConstructor(new Type[]{ typeof(Stream) });
					T o = (T)ci.Invoke(new object[]{ resStream });

					cacheInstance(name,o);

					return o;
				}
				throw new KeyNotFoundException(String.Format("ResourceLibrary[{0}:{1}]",typeof(T).ToString(),name));
			}
		}



	}
}