using System;
using System.Collections.Generic;

namespace ln.http.rest
{

    public abstract partial class CRUDObjectContainer
    {
        class RegisteredType
        {
            public CRUDObjectContainer ObjectContainer { get; }
            public Type ObjectType { get; }

            Func<object,object> _idGetter;
            Dictionary<object, object> objectCache = new Dictionary<object, object>();

            public IEnumerable<FieldDescriptor> FieldDescriptors => fieldDescriptors;
            List<FieldDescriptor> fieldDescriptors = new List<FieldDescriptor>();

            public RegisteredType(CRUDObjectContainer objectContainer,Type objectType,Func<object,object> idGetter)
            {
                ObjectContainer = objectContainer;
                ObjectType = objectType;
                _idGetter = idGetter;
            }

            public bool TryGetObjectID(object objectInstance,out object objectIdentifier)
            {
                try
                {
                    objectIdentifier = _idGetter(objectInstance);
                } catch (Exception e)
                {
                    objectIdentifier = null;
                    return false;
                }
                return true;
            }

            public void AddCachedObject(object objectInstance)
            {
                Type objectType = objectInstance.GetType();
                if (!ObjectType.Equals(objectType))
                    throw new ArgumentException();

                if (!TryGetObjectID(objectInstance, out object objectIdentifier))
                    throw new ArgumentOutOfRangeException();

                objectCache.Add(objectIdentifier, objectInstance);
            }

            public void RemoveCachedObject(object objectInstance)
            {
                Type objectType = objectInstance.GetType();
                if (!ObjectType.Equals(objectType))
                    throw new ArgumentException();

                if (!TryGetObjectID(objectInstance, out object objectIdentifier))
                    throw new ArgumentOutOfRangeException();

                objectCache.Remove(objectIdentifier);
            }

        }
    }
}