using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Reflection;

namespace Caliburn.Metadata
{
    public class PresenterInfo : InfoBase
    {
        #region Fields

        private readonly Dictionary<string, ActionInfo> _actions = new Dictionary<string, ActionInfo>();

        #endregion

        #region Constructor

        private PresenterInfo() {}

        #endregion

        #region Properties

        public IList<ActionInfo> Actions
        {
            get
            {
                return new ReadOnlyCollection<ActionInfo>(
                    new List<ActionInfo>(_actions.Values)
                    );
            }
        }

        #endregion

        #region Methods

        public ActionInfo FindAction(string action)
        {
            ActionInfo info;
            _actions.TryGetValue(action, out info);
            return info;
        }

        #endregion

        #region Factory

        public static PresenterInfo Create(Type presenterType)
        {
            PresenterInfo info = new PresenterInfo();

            LoadMetadata(presenterType, info);
            CreateActions(presenterType, info);

            return info;
        }

        private static void LoadMetadata(Type presenterType, PresenterInfo info)
        {
            object[] attributes = presenterType.GetCustomAttributes(true);

            foreach(object att in attributes)
            {
                MetadataProvider provider = att as MetadataProvider;
                if(provider != null) info.AddMetadata(provider);
                else
                {
                    PresenterAttribute presenterAttribute = att as PresenterAttribute;
                    if(presenterAttribute != null)
                    {
                        if(!string.IsNullOrEmpty(presenterAttribute.Rescue))
                            info.InitializeRescue(presenterType, presenterAttribute.Rescue);
                    }
                }
            }
        }

        private static void CreateActions(Type presenterType, PresenterInfo info)
        {
            MethodInfo[] methodInfos = presenterType.GetMethods(BindingFlags.Instance | BindingFlags.Public);

            foreach(MethodInfo methodInfo in methodInfos)
            {
                ActionInfo actionInfo = ActionInfo.Create(info, methodInfo);

                if(actionInfo != null)
                    info._actions[actionInfo.Name] = actionInfo;
            }
        }

        #endregion
    }
}