using Caliburn.MemoryManagement;
using Caliburn.Metadata;
using Caliburn.Services;

namespace Caliburn.Composition
{
    public class CompositeManager : ICompositeManager
    {
        protected readonly WeakDictionary<string, object> _composites =
            new WeakDictionary<string, object>();

        #region ICompositeManager Members

        public virtual void RegisterComposite(string name, object composite)
        {
            _composites[name] = composite;
        }

        public virtual T GetComposite<T>(string name)
            where T : IComposite
        {
            object composite;
            _composites.TryGetValue(name, out composite);

            if(composite != null)
            {
                IViewManager viewManager = DI.Resolve<IViewManager>();
                ElementDefaults defaults = viewManager.GetDefaults(composite.GetType());

                if(defaults != null)
                    return (T)defaults.CreateCompositeProxy(composite);

                return default(T);
            }

            return default(T);
        }

        #endregion
    }
}