using System;
using System.Reflection;
using System.Xml;
using oodb.attributes;

namespace oodb.mapping.collections
{
    public class ISetExtendedHandling : ExtendedFieldHandling
    {
        public Type ReferencedType { get; }
        public FieldInfo ReferencedField { get; protected set; }

        public Type ImplementationType { get; }

        public ISetExtendedHandling(OODB oodb,FieldInfo fieldInfo)
            :base(oodb,fieldInfo)
        {
            ReferencedType = fieldInfo.FieldType.GetGenericArguments()[0];
            ImplementationType = typeof(ISetImplementation<>).MakeGenericType(ReferencedType);
        }

        public override void Initialize()
        {
            ReferencedFieldAttribute referencedFieldAttribute = FieldInfo.GetCustomAttribute<ReferencedFieldAttribute>();
            string refFieldName = referencedFieldAttribute != null ? referencedFieldAttribute.FieldName : FieldInfo.DeclaringType.Name;
            ReferencedField = ReferencedType.GetField(refFieldName, BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public);

            OODB.StorageAdapter.GetSearchIndex(ReferencedField);
        }

        public override void Attach(Persistent persistent)
        {
            object iset = FieldInfo.GetValue(persistent);

            if (ImplementationType != iset.GetType())
            {
                object impl = Activator.CreateInstance(ImplementationType,OODB,FieldInfo,persistent);
                FieldInfo.SetValue(persistent, impl);
            }

        }

        public override void Detach(Persistent persistent)
        {
        }

        public override void Load(XmlElement persistenceElement, Persistent persistent)
        {
            Attach(persistent);
        }

        public override void Save(XmlElement persistenceElement, Persistent persistent)
        {
        }
    }
}