using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using Caliburn.Metadata;
using Caliburn.Services;

namespace Caliburn.Modules
{
    public class ModuleManager : IModuleManager
    {
        private readonly List<Module> _loadedModules = new List<Module>();
        private readonly IModuleLocator _moduleLocator;

        public ModuleManager(IModuleLocator moduleLocator)
        {
            _moduleLocator = moduleLocator;
            _moduleLocator.ModuleFound += LoadModule;
        }

        #region IModuleManager Members

        public virtual IList<Module> List
        {
            get { return new ReadOnlyCollection<Module>(_loadedModules); }
        }

        public virtual void LoadModule(Module module)
        {
            module.Load();
            _loadedModules.Add(module);
        }

        public virtual void RefreshModules()
        {
            foreach(Module module in _loadedModules)
            {
                module.Unload();
            }

            _loadedModules.Clear();
            _moduleLocator.Search();
        }

        public virtual Module CreateModule(Type moduleType)
        {
            Module module = new Module(
                (IModule) Activator.CreateInstance(moduleType)
                );

            object[] attributes = moduleType.GetCustomAttributes(true);

            foreach(object att in attributes)
            {
                MetadataProvider provider = att as MetadataProvider;
                if(provider != null) module.AddMetadata(provider);
            }

            return module;
        }

        #endregion
    }
}