using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Aiwaz.Common
{
    public class ObjectFactory
    {
        private Dictionary<Type, Type> m_Patterns = new Dictionary<Type, Type>();
        private Dictionary<Type, Dictionary<string, object>> m_StoredObjects = new Dictionary<Type, Dictionary<string, object>>();

        public void RegisterPattern<O>()
        {
            var patternObject = typeof(O);
            var patternInterface = patternObject.GetInterface("I" + patternObject.Name);
            m_Patterns.Add(patternInterface, patternObject);
        }

        public void RegisterPattern<I, O>()
        {
            m_Patterns.Add(typeof(I), typeof(O));
        }

        public T CreateInstance<T>(params object[] args)
        {
            var creationType = m_Patterns.First(argPattern => argPattern.Key == typeof(T)).Value;
            Type[] creationArguments = null;
            if (args != null && args.Length > 0)
                creationArguments = args.Select(arg => arg.GetType()).ToArray();

            var constructor = creationType.GetConstructor(creationArguments == null ?
                                                            System.Type.EmptyTypes : creationArguments);

            var construct = (T)constructor.Invoke(args);
            return construct;
        }

        public T CreateNamedInstance<T>(string argName, params object[] args)
        {
            var construct = CreateInstance<T>(args);

            var storage = m_StoredObjects.FirstOrDefault(type => type.Key == typeof(T)).Value;
            if (storage == null)
            {
                m_StoredObjects.Add(typeof(T), new Dictionary<string, object>());
                storage = m_StoredObjects.FirstOrDefault(type => type.Key == typeof(T)).Value;
            }
            storage.Add(argName, construct);

            return construct;
        }

        public T FindNamedInstance<T>(string argName)
        {
            var storage = m_StoredObjects.FirstOrDefault(type => type.Key == typeof(T)).Value;
            if (storage == null || !storage.ContainsKey(argName))
                return default(T);
            return (T)storage[argName];
        }

        public void RemoveNamedInstance<T>(string argName)
        {
            var storage = m_StoredObjects.FirstOrDefault(type => type.Key == typeof(T)).Value;
            if (storage == null)
                return;
            storage.Remove(argName);
        }
    }
}