using System;
using System.ComponentModel;

using BLToolkit.Reflection;

namespace BLToolkit.ComponentModel
{
    public class ObjectHolder : ICustomTypeDescriptor
    {
        public ObjectHolder(object obj, ObjectBinder objectBinder)
        {
            _object             = obj;
            _originalProperties = ((ITypedList)objectBinder).GetItemProperties(null);
        }

        private readonly PropertyDescriptorCollection _originalProperties;
        private          PropertyDescriptorCollection _customProperties;

        private readonly object _object;
        public           object  Object
        {
            get { return _object; }
        }

        private ICustomTypeDescriptor _customTypeDescriptor;
        private ICustomTypeDescriptor  CustomTypeDescriptor
        {
            get
            {
                if (_customTypeDescriptor == null)
                {
                    _customTypeDescriptor = _object is ICustomTypeDescriptor?
                        (ICustomTypeDescriptor)_object:
                        TypeAccessor.GetCustomTypeDescriptor(_object.GetType());
                }

                return _customTypeDescriptor;
            }
        }

        #region ICustomTypeDescriptor Members

        AttributeCollection ICustomTypeDescriptor.GetAttributes()
        {
            return CustomTypeDescriptor.GetAttributes();
        }

        string ICustomTypeDescriptor.GetClassName()
        {
            return CustomTypeDescriptor.GetClassName();
        }

        string ICustomTypeDescriptor.GetComponentName()
        {
            return CustomTypeDescriptor.GetComponentName();
        }

        TypeConverter ICustomTypeDescriptor.GetConverter()
        {
            return CustomTypeDescriptor.GetConverter();
        }

        EventDescriptor ICustomTypeDescriptor.GetDefaultEvent()
        {
            return CustomTypeDescriptor.GetDefaultEvent();
        }

        PropertyDescriptor ICustomTypeDescriptor.GetDefaultProperty()
        {
            return CustomTypeDescriptor.GetDefaultProperty();
        }

        object ICustomTypeDescriptor.GetEditor(Type editorBaseType)
        {
            return CustomTypeDescriptor.GetEditor(editorBaseType);
        }

        EventDescriptorCollection ICustomTypeDescriptor.GetEvents(Attribute[] attributes)
        {
            return CustomTypeDescriptor.GetEvents(attributes);
        }

        EventDescriptorCollection ICustomTypeDescriptor.GetEvents()
        {
            return CustomTypeDescriptor.GetEvents();
        }

        PropertyDescriptorCollection ICustomTypeDescriptor.GetProperties(Attribute[] attributes)
        {
            if (_customProperties == null)
            {
                PropertyDescriptor[] properties = new PropertyDescriptor[_originalProperties.Count];

                for (int i = 0; i < properties.Length; i++)
                {
                    properties[i] = new ObjectPropertyDescriptor(_originalProperties[i]);
                }

                _customProperties = new PropertyDescriptorCollection(properties);
            }

            return _customProperties;
        }

        PropertyDescriptorCollection ICustomTypeDescriptor.GetProperties()
        {
            return ((ICustomTypeDescriptor)this).GetProperties(null);
        }

        object ICustomTypeDescriptor.GetPropertyOwner(PropertyDescriptor pd)
        {
            return CustomTypeDescriptor.GetPropertyOwner(pd);
        }

        #endregion

        #region ObjectPropertyDescriptor

        class ObjectPropertyDescriptor : PropertyDescriptorWrapper
        {
            public ObjectPropertyDescriptor(PropertyDescriptor pd)
                : base(pd)
            {
            }

            public override object GetValue(object component)
            {
                return base.GetValue(((ObjectHolder)component).Object);
            }

            public override void SetValue(object component, object value)
            {
                base.SetValue(((ObjectHolder)component).Object, value);
            }
        }

        #endregion
    }
}