using System;
using System.Collections;
using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Globalization;
using System.Reflection;

namespace CPF.Drawing
{
    public class SizeConverter : TypeConverter
    {
        /// <include file='doc\PointConverter.uex' path='docs/doc[@for="PointConverter.CanConvertFrom"]/*' />
        /// <devdoc>
        ///      Determines if this converter can convert an object in the given source
        ///      type to the native type of the converter.
        /// </devdoc>
        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
        {
            if (sourceType == typeof(string))
            {
                return true;
            }
            return base.CanConvertFrom(context, sourceType);
        }

        /// <devdoc>
        ///    <para>Gets a value indicating whether this converter can
        ///       convert an object to the given destination type using the context.</para>
        /// </devdoc>
        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
        {
            if (destinationType == typeof(InstanceDescriptor))
            {
                return true;
            }
            return base.CanConvertTo(context, destinationType);
        }

        /// <devdoc>
        ///      Converts the given object to the converter's native type.
        /// </devdoc>        
        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
        {

            string strValue = value as string;

            if (strValue != null)
            {
                return Size.Parse(strValue);
            }

            return base.ConvertFrom(context, culture, value);
        }

        /// <devdoc>
        ///      Converts the given object to another type.  The most common types to convert
        ///      are to and from a string object.  The default implementation will make a call
        ///      to ToString on the object if the object is valid and if the destination
        ///      type is string.  If this cannot convert to the desitnation type, this will
        ///      throw a NotSupportedException.
        /// </devdoc>
        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
        {
            if (destinationType == null)
            {
                throw new ArgumentNullException("destinationType");
            }

            if (value is Size)
            {
                if (destinationType == typeof(string))
                {
                    Size pt = (Size)value;

                    return pt.ToString();
                }
                if (destinationType == typeof(InstanceDescriptor))
                {
                    Size pt = (Size)value;

                    ConstructorInfo ctor = typeof(Size).GetConstructor(new Type[] { typeof(float), typeof(float) });
                    if (ctor != null)
                    {
                        return new InstanceDescriptor(ctor, new object[] { pt.Width, pt.Height });
                    }
                }
            }

            return base.ConvertTo(context, culture, value, destinationType);
        }

        /// <include file='doc\PointConverter.uex' path='docs/doc[@for="PointConverter.CreateInstance"]/*' />
        /// <devdoc>
        ///      Creates an instance of this type given a set of property values
        ///      for the object.  This is useful for objects that are immutable, but still
        ///      want to provide changable properties.
        /// </devdoc>
        public override object CreateInstance(ITypeDescriptorContext context, IDictionary propertyValues)
        {
            if (propertyValues == null)
            {
                throw new ArgumentNullException("propertyValues");
            }

            object x = propertyValues["X"];
            object y = propertyValues["Y"];

            if (x == null || y == null ||
                (!(x is float) && !(x is int)) ||
                (!(y is float) && !(y is int)))
            {
                throw new ArgumentException("类型错误");
            }


            return new Size((float)x,
                              (float)y);

        }

        /// <include file='doc\PointConverter.uex' path='docs/doc[@for="PointConverter.GetCreateInstanceSupported"]/*' />
        /// <devdoc>
        ///      Determines if changing a value on this object should require a call to
        ///      CreateInstance to create a new value.
        /// </devdoc>
        public override bool GetCreateInstanceSupported(ITypeDescriptorContext context)
        {
            return true;
        }

        /// <include file='doc\PointConverter.uex' path='docs/doc[@for="PointConverter.GetProperties"]/*' />
        /// <devdoc>
        ///      Retrieves the set of properties for this type.  By default, a type has
        ///      does not return any properties.  An easy implementation of this method
        ///      can just call TypeDescriptor.GetProperties for the correct data type.
        /// </devdoc>
        public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext context, object value, Attribute[] attributes)
        {
            PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(Size), attributes);
            return props.Sort(new string[] { "X", "Y" });
        }


        /// <include file='doc\PointConverter.uex' path='docs/doc[@for="PointConverter.GetPropertiesSupported"]/*' />
        /// <devdoc>
        ///      Determines if this object supports properties.  By default, this
        ///      is false.
        /// </devdoc>
        public override bool GetPropertiesSupported(ITypeDescriptorContext context)
        {
            return true;
        }

    }
}
