/*************************************************************************************

   Extended WPF Toolkit

   Copyright (C) 2007-2013 Xceed Software Inc.

   This program is provided to you under the terms of the Microsoft Public
   License (Ms-PL) as published at http://wpftoolkit.codeplex.com/license 

   For more features, controls, and fast professional support,
   pick up the Plus Edition at http://xceed.com/wpf_toolkit

   Stay informed: follow @datagrid on Twitter or Like http://facebook.com/datagrids

  ***********************************************************************************/

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Data;
using System.Globalization;
using System.ComponentModel;
using System.Windows;
using System.Reflection;

namespace Xceed.Wpf.Toolkit.PropertyGrid.Converters
{
  public class SelectedObjectConverter : IValueConverter
  {
    private const string ValidParameterMessage = @"parameter must be one of the following strings: 'Type', 'TypeName', 'SelectedObjectName'";
    #region IValueConverter Members

    public object Convert( object value, Type targetType, object parameter, CultureInfo culture )
    {
      if( parameter == null )
        throw new ArgumentNullException( "parameter" );

      if( !( parameter is string ) )
        throw new ArgumentException( SelectedObjectConverter.ValidParameterMessage );

      if( this.CompareParam(parameter, "Type") )
      {
        return this.ConvertToType( value, culture );
      }
      else if( this.CompareParam( parameter, "TypeName" ) )
      {
        return this.ConvertToTypeName( value, culture );
      }
      else if( this.CompareParam( parameter, "SelectedObjectName" ) )
      {
        return this.ConvertToSelectedObjectName( value, culture );
      }
      else
      {
        throw new ArgumentException( SelectedObjectConverter.ValidParameterMessage );
      }
    }

    private bool CompareParam(object parameter, string parameterValue )
    {
      return string.Compare( ( string )parameter, parameterValue, true ) == 0;
    }

    private object ConvertToType( object value, CultureInfo culture )
    {
      return ( value != null )
        ? value.GetType()
        : null;
    }

    private object ConvertToTypeName( object value, CultureInfo culture )
    {
      if( value == null )
        return string.Empty;

      Type newType = value.GetType();

      //ICustomTypeProvider is only available in .net 4.5 and over. Use reflection so the .net 4.0 and .net 3.5 still works.
      if( newType.GetInterface( "ICustomTypeProvider", true ) != null )
      {
        var methodInfo = newType.GetMethod( "GetCustomType" );
        newType = methodInfo.Invoke( value, null ) as Type;
      }

      DisplayNameAttribute displayNameAttribute = newType.GetCustomAttributes( false ).OfType<DisplayNameAttribute>().FirstOrDefault();

      return (displayNameAttribute == null)
        ? newType.Name 
        : displayNameAttribute.DisplayName;
    }

    private object ConvertToSelectedObjectName( object value, CultureInfo culture )
    {
      if( value == null )
        return String.Empty;

      Type newType = value.GetType();
      PropertyInfo[] properties = newType.GetProperties();
      foreach( PropertyInfo property in properties )
      {
        if( property.Name == "Name" )
          return property.GetValue( value, null );
      }

      return String.Empty;
    }

    public object ConvertBack( object value, Type targetType, object parameter, CultureInfo culture )
    {
      throw new NotImplementedException();
    }

    #endregion
  }
}