/*************************************************************************************
   
   Toolkit for WPF

   Copyright (C) 2007-2020 Xceed Software Inc.

   This program is provided to you under the terms of the XCEED SOFTWARE, INC.
   COMMUNITY LICENSE AGREEMENT (for non-commercial use) as published at 
   https://github.com/xceedsoftware/wpftoolkit/blob/master/license.md 

   For more features, controls, and fast professional support,
   pick up the Plus Edition at https://xceed.com/xceed-toolkit-plus-for-wpf/

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

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

using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using Xceed.Wpf.Toolkit.Core.Utilities;
using Xceed.Wpf.Toolkit.PropertyGrid;
using System.Windows.Threading;
using System.Reflection;

namespace Xceed.Wpf.Toolkit
{
  [TemplatePart( Name = PART_NewItemTypesComboBox, Type = typeof( ComboBox ) )]
  [TemplatePart( Name = PART_PropertyGrid, Type = typeof( PropertyGrid.PropertyGrid ) )]
  [TemplatePart( Name = PART_ListBox, Type = typeof( ListBox ) )]
  public class CollectionControl : Control
  {
    private const string PART_NewItemTypesComboBox = "PART_NewItemTypesComboBox";
    private const string PART_PropertyGrid = "PART_PropertyGrid";
    private const string PART_ListBox = "PART_ListBox";

    #region Private Members

    private ComboBox _newItemTypesComboBox;
    private PropertyGrid.PropertyGrid _propertyGrid;
    private ListBox _listBox;
    private bool _isCollectionUpdated;

    #endregion

    #region Properties

    #region IsReadOnly Property

    public static readonly DependencyProperty IsReadOnlyProperty = DependencyProperty.Register( "IsReadOnly", typeof( bool ), typeof( CollectionControl ), new UIPropertyMetadata( false ) );
    public bool IsReadOnly
    {
      get
      {
        return ( bool )GetValue( IsReadOnlyProperty );
      }
      set
      {
        SetValue( IsReadOnlyProperty, value );
      }
    }

    #endregion  //Items

    #region Items Property

    public static readonly DependencyProperty ItemsProperty = DependencyProperty.Register( "Items", typeof( ObservableCollection<object> ), typeof( CollectionControl ), new UIPropertyMetadata( null ) );
    public ObservableCollection<object> Items
    {
      get
      {
        return ( ObservableCollection<object> )GetValue( ItemsProperty );
      }
      set
      {
        SetValue( ItemsProperty, value );
      }
    }

    #endregion  //Items

    #region ItemsSource Property

    public static readonly DependencyProperty ItemsSourceProperty = DependencyProperty.Register( "ItemsSource", typeof( IEnumerable ), typeof( CollectionControl ), new UIPropertyMetadata( null, OnItemsSourceChanged ) );
    public IEnumerable ItemsSource
    {
      get
      {
        return (IEnumerable)GetValue( ItemsSourceProperty );
      }
      set
      {
        SetValue( ItemsSourceProperty, value );
      }
    }

    private static void OnItemsSourceChanged( DependencyObject d, DependencyPropertyChangedEventArgs e )
    {
      var CollectionControl = ( CollectionControl )d;
      if( CollectionControl != null )
        CollectionControl.OnItemSourceChanged( (IEnumerable)e.OldValue, (IEnumerable)e.NewValue );
    }

    public void OnItemSourceChanged( IEnumerable oldValue, IEnumerable newValue )
    {
      if( newValue != null )
      {
        var dict = newValue as IDictionary;
        if( dict != null )
        {
          // A Dictionary contains KeyValuePair that can't be edited.
          // We need to Add EditableKeyValuePairs from DictionaryEntries.
          foreach( DictionaryEntry item in dict )
          {
            var keyType = (item.Key != null) 
                          ? item.Key.GetType()
                          : (dict.GetType().GetGenericArguments().Count() > 0) ? dict.GetType().GetGenericArguments()[0] : typeof( object );
            var valueType = (item.Value != null)
                          ? item.Value.GetType()
                          : (dict.GetType().GetGenericArguments().Count() > 1) ? dict.GetType().GetGenericArguments()[ 1 ] : typeof( object );
            var editableKeyValuePair = ListUtilities.CreateEditableKeyValuePair( item.Key
                                                                                , keyType
                                                                                , item.Value
                                                                                , valueType );
            this.Items.Add( editableKeyValuePair );
          }
        }
        else
        {
          foreach( var item in newValue )
          {
            if( item != null )
            {
              Items.Add( item );
            }
          }
        }
      }
    }

    #endregion  //ItemsSource

    #region ItemsSourceType Property

    public static readonly DependencyProperty ItemsSourceTypeProperty = DependencyProperty.Register( "ItemsSourceType", typeof( Type ), typeof( CollectionControl ), new UIPropertyMetadata( null ) );
    public Type ItemsSourceType
    {
      get
      {
        return ( Type )GetValue( ItemsSourceTypeProperty );
      }
      set
      {
        SetValue( ItemsSourceTypeProperty, value );
      }
    }

    #endregion //ItemsSourceType

    #region NewItemType Property

    public static readonly DependencyProperty NewItemTypesProperty = DependencyProperty.Register( "NewItemTypes", typeof( IList ), typeof( CollectionControl ), new UIPropertyMetadata( null ) );
    public IList<Type> NewItemTypes
    {
      get
      {
        return ( IList<Type> )GetValue( NewItemTypesProperty );
      }
      set
      {
        SetValue( NewItemTypesProperty, value );
      }
    }

    #endregion  //NewItemType

    #region PropertiesLabel Property

    public static readonly DependencyProperty PropertiesLabelProperty = DependencyProperty.Register( "PropertiesLabel", typeof( object ), typeof( CollectionControl ), new UIPropertyMetadata( "Properties:" ) );
    public object PropertiesLabel
    {
      get
      {
        return ( object )GetValue( PropertiesLabelProperty );
      }
      set
      {
        SetValue( PropertiesLabelProperty, value );
      }
    }

    #endregion  //PropertiesLabel

    #region SelectedItem Property

    public static readonly DependencyProperty SelectedItemProperty = DependencyProperty.Register( "SelectedItem", typeof( object ), typeof( CollectionControl ), new UIPropertyMetadata( null ) );
    public object SelectedItem
    {
      get
      {
        return ( object )GetValue( SelectedItemProperty );
      }
      set
      {
        SetValue( SelectedItemProperty, value );
      }
    }

    #endregion  //EditorDefinitions

    #region TypeSelectionLabel Property

    public static readonly DependencyProperty TypeSelectionLabelProperty = DependencyProperty.Register( "TypeSelectionLabel", typeof( object ), typeof( CollectionControl ), new UIPropertyMetadata( "Select type:" ) );
    public object TypeSelectionLabel
    {
      get
      {
        return ( object )GetValue( TypeSelectionLabelProperty );
      }
      set
      {
        SetValue( TypeSelectionLabelProperty, value );
      }
    }

    #endregion  //TypeSelectionLabel

    #region EditorDefinitions Property

    public static readonly DependencyProperty EditorDefinitionsProperty = DependencyProperty.Register( "EditorDefinitions", typeof( EditorDefinitionCollection ), typeof( CollectionControl ), new UIPropertyMetadata( null ) );
    public EditorDefinitionCollection EditorDefinitions
    {
      get
      {
        return ( EditorDefinitionCollection )GetValue( EditorDefinitionsProperty );
      }
      set
      {
        SetValue( EditorDefinitionsProperty, value );
      }
    }

    #endregion  //EditorDefinitions

    #endregion //Properties

    #region Override Methods

    public override void OnApplyTemplate()
    {
      base.OnApplyTemplate();

      if( _newItemTypesComboBox != null )
      {
        _newItemTypesComboBox.Loaded -= new RoutedEventHandler( this.NewItemTypesComboBox_Loaded );
      }
      _newItemTypesComboBox = GetTemplateChild( PART_NewItemTypesComboBox ) as ComboBox;
      if( _newItemTypesComboBox != null )
      {
        _newItemTypesComboBox.Loaded += new RoutedEventHandler( this.NewItemTypesComboBox_Loaded );
      }

      _listBox = this.GetTemplateChild( PART_ListBox ) as ListBox;

      if( _propertyGrid != null )
      {
        _propertyGrid.PropertyValueChanged -= this.PropertyGrid_PropertyValueChanged;
      }
      _propertyGrid = GetTemplateChild( PART_PropertyGrid ) as PropertyGrid.PropertyGrid;
      if( _propertyGrid != null )
      {
        _propertyGrid.PropertyValueChanged += this.PropertyGrid_PropertyValueChanged;
      }
    }

    public PropertyGrid.PropertyGrid PropertyGrid
    {
      get
      {
        if( _propertyGrid == null )
        {
          this.ApplyTemplate();
        }
        return _propertyGrid;
      }
    }




    #endregion

    #region Constructors

    static CollectionControl()
    {
      DefaultStyleKeyProperty.OverrideMetadata( typeof( CollectionControl ), new FrameworkPropertyMetadata( typeof( CollectionControl ) ) );
    }

    public CollectionControl()
    {
      Items = new ObservableCollection<object>();
      CommandBindings.Add( new CommandBinding( ApplicationCommands.New, this.AddNew, this.CanAddNew ) );
      CommandBindings.Add( new CommandBinding( ApplicationCommands.Delete, this.Delete, this.CanDelete ) );
      CommandBindings.Add( new CommandBinding( ApplicationCommands.Copy, this.Duplicate, this.CanDuplicate ) );
      CommandBindings.Add( new CommandBinding( ComponentCommands.MoveDown, this.MoveDown, this.CanMoveDown ) );
      CommandBindings.Add( new CommandBinding( ComponentCommands.MoveUp, this.MoveUp, this.CanMoveUp ) );
    }

    #endregion //Constructors

    #region Events

    #region ItemDeleting Event

    public delegate void ItemDeletingRoutedEventHandler( object sender, ItemDeletingEventArgs e );

    public static readonly RoutedEvent ItemDeletingEvent = EventManager.RegisterRoutedEvent( "ItemDeleting", RoutingStrategy.Bubble, typeof( ItemDeletingRoutedEventHandler ), typeof( CollectionControl ) );
    public event ItemDeletingRoutedEventHandler ItemDeleting
    {
      add
      {
        AddHandler( ItemDeletingEvent, value );
      }
      remove
      {
        RemoveHandler( ItemDeletingEvent, value );
      }
    }

    #endregion //ItemDeleting Event

    #region ItemDeleted Event

    public delegate void ItemDeletedRoutedEventHandler( object sender, ItemEventArgs e );

    public static readonly RoutedEvent ItemDeletedEvent = EventManager.RegisterRoutedEvent( "ItemDeleted", RoutingStrategy.Bubble, typeof( ItemDeletedRoutedEventHandler ), typeof( CollectionControl ) );
    public event ItemDeletedRoutedEventHandler ItemDeleted
    {
      add
      {
        AddHandler( ItemDeletedEvent, value );
      }
      remove
      {
        RemoveHandler( ItemDeletedEvent, value );
      }
    }

    #endregion //ItemDeleted Event

    #region ItemAdding Event

    public delegate void ItemAddingRoutedEventHandler( object sender, ItemAddingEventArgs e );

    public static readonly RoutedEvent ItemAddingEvent = EventManager.RegisterRoutedEvent( "ItemAdding", RoutingStrategy.Bubble, typeof( ItemAddingRoutedEventHandler ), typeof( CollectionControl ) );
    public event ItemAddingRoutedEventHandler ItemAdding
    {
      add
      {
        AddHandler( ItemAddingEvent, value );
      }
      remove
      {
        RemoveHandler( ItemAddingEvent, value );
      }
    }

    #endregion //ItemAdding Event

    #region ItemAdded Event

    public delegate void ItemAddedRoutedEventHandler( object sender, ItemEventArgs e );

    public static readonly RoutedEvent ItemAddedEvent = EventManager.RegisterRoutedEvent( "ItemAdded", RoutingStrategy.Bubble, typeof( ItemAddedRoutedEventHandler ), typeof( CollectionControl ) );
    public event ItemAddedRoutedEventHandler ItemAdded
    {
      add
      {
        AddHandler( ItemAddedEvent, value );
      }
      remove
      {
        RemoveHandler( ItemAddedEvent, value );
      }
    }

    #endregion //ItemAdded Event

    #region ItemMovedDown Event

    public delegate void ItemMovedDownRoutedEventHandler( object sender, ItemEventArgs e );

    public static readonly RoutedEvent ItemMovedDownEvent = EventManager.RegisterRoutedEvent( "ItemMovedDown", RoutingStrategy.Bubble, typeof( ItemMovedDownRoutedEventHandler ), typeof( CollectionControl ) );
    public event ItemMovedDownRoutedEventHandler ItemMovedDown
    {
      add
      {
        AddHandler( ItemMovedDownEvent, value );
      }
      remove
      {
        RemoveHandler( ItemMovedDownEvent, value );
      }
    }

    #endregion //ItemMovedDown Event

    #region ItemMovedUp Event

    public delegate void ItemMovedUpRoutedEventHandler( object sender, ItemEventArgs e );

    public static readonly RoutedEvent ItemMovedUpEvent = EventManager.RegisterRoutedEvent( "ItemMovedUp", RoutingStrategy.Bubble, typeof( ItemMovedUpRoutedEventHandler ), typeof( CollectionControl ) );
    public event ItemMovedUpRoutedEventHandler ItemMovedUp
    {
      add
      {
        AddHandler( ItemMovedUpEvent, value );
      }
      remove
      {
        RemoveHandler( ItemMovedUpEvent, value );
      }
    }

    #endregion //ItemMovedUp Event

    #endregion

    #region EventHandlers

    void NewItemTypesComboBox_Loaded( object sender, RoutedEventArgs e )
    {
      if( _newItemTypesComboBox != null )
        _newItemTypesComboBox.SelectedIndex = 0;
    }

    private void PropertyGrid_PropertyValueChanged( object sender, PropertyGrid.PropertyValueChangedEventArgs e )
    {
      if( _listBox != null )
      {
        _isCollectionUpdated = true;
        _listBox.Dispatcher.BeginInvoke( DispatcherPriority.Input, new Action( () =>
        {
          _listBox.Items.Refresh();
        }
        ) );
      }
    }

    #endregion

    #region Commands

    private void AddNew( object sender, ExecutedRoutedEventArgs e )
    {
      var newItem = this.CreateNewItem( ( Type )e.Parameter );

      this.AddNewCore( newItem );
    }

    private void CanAddNew( object sender, CanExecuteRoutedEventArgs e )
    {
      var t = e.Parameter as Type;
      this.CanAddNewCore( t, e );
    }

    private void CanAddNewCore( Type t, CanExecuteRoutedEventArgs e )
    {
      if( ( t != null ) && !this.IsReadOnly )
      {
        var isComplexStruct = t.IsValueType && !t.IsEnum && !t.IsPrimitive;

        if( isComplexStruct || ( t.GetConstructor( Type.EmptyTypes ) != null ) )
        {
          e.CanExecute = true;
        }
      }
    }

    private void AddNewCore( object newItem )
    {
      if( newItem == null )
        throw new ArgumentNullException( "newItem" );

      var eventArgs = new ItemAddingEventArgs( ItemAddingEvent, newItem );
      this.RaiseEvent( eventArgs );
      if( eventArgs.Cancel )
        return;
      newItem = eventArgs.Item;

      this.Items.Add( newItem );

      this.RaiseEvent( new ItemEventArgs( ItemAddedEvent, newItem ) );
      _isCollectionUpdated = true;

      this.SelectedItem = newItem;
    }

    private void Delete( object sender, ExecutedRoutedEventArgs e )
    {
      var eventArgs = new ItemDeletingEventArgs( ItemDeletingEvent, e.Parameter );
      this.RaiseEvent( eventArgs );
      if( eventArgs.Cancel )
        return;

      this.Items.Remove( e.Parameter );

      this.RaiseEvent( new ItemEventArgs( ItemDeletedEvent, e.Parameter ) );
      _isCollectionUpdated = true;
    }

    private void CanDelete( object sender, CanExecuteRoutedEventArgs e )
    {
      e.CanExecute = e.Parameter != null && !this.IsReadOnly;
    }

    private void Duplicate( object sender, ExecutedRoutedEventArgs e )
    {
      var newItem = this.DuplicateItem( e );
      this.AddNewCore( newItem );
    }

    private void CanDuplicate( object sender, CanExecuteRoutedEventArgs e )
    {
      var t = (e.Parameter != null) ? e.Parameter.GetType() : null;
      this.CanAddNewCore( t, e );
    }

    private object DuplicateItem( ExecutedRoutedEventArgs e )
    {
      if( e == null )
        throw new ArgumentNullException( "e" );

      var baseItem = e.Parameter;
      var newItemType = baseItem.GetType();
      var newItem = this.CreateNewItem( newItemType );

      var type = newItemType;
      while( type != null )
      {
        var baseProperties = type.GetFields( BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance );
        foreach( var prop in baseProperties )
        {
          prop.SetValue( newItem, prop.GetValue( baseItem ) );
        }
        type = type.BaseType;
      }

      return newItem;
    }

    private void MoveDown( object sender, ExecutedRoutedEventArgs e )
    {
      var selectedItem = e.Parameter;
      var index = Items.IndexOf( selectedItem );
      Items.RemoveAt( index );
      Items.Insert( ++index, selectedItem );

      this.RaiseEvent( new ItemEventArgs( ItemMovedDownEvent, selectedItem ) );
      _isCollectionUpdated = true;

      this.SelectedItem = selectedItem;
    }

    private void CanMoveDown( object sender, CanExecuteRoutedEventArgs e )
    {
      if( e.Parameter != null && Items.IndexOf( e.Parameter ) < ( Items.Count - 1 ) && !this.IsReadOnly )
        e.CanExecute = true;
    }

    private void MoveUp( object sender, ExecutedRoutedEventArgs e )
    {
      var selectedItem = e.Parameter;
      var index = Items.IndexOf( selectedItem );
      this.Items.RemoveAt( index );
      this.Items.Insert( --index, selectedItem );

      this.RaiseEvent( new ItemEventArgs( ItemMovedUpEvent, selectedItem ) );
      _isCollectionUpdated = true;

      this.SelectedItem = selectedItem;
    }

    private void CanMoveUp( object sender, CanExecuteRoutedEventArgs e )
    {
      if( e.Parameter != null && Items.IndexOf( e.Parameter ) > 0 && !this.IsReadOnly )
        e.CanExecute = true;
    }

    #endregion //Commands

    #region Methods

    public bool PersistChanges()
    {
      this.PersistChanges( this.Items );
      return _isCollectionUpdated;
    }

    internal void PersistChanges( IList sourceList )
    {
      var collection = ComputeItemsSource();
      if( collection == null )
        return;

      //IDictionary<T> and IDictionary
      if( collection is IDictionary )
      {
        //For a Dictionary, we need to parse the list of EditableKeyValuePair and add KeyValuePair to the Dictionary.
        var dict = (IDictionary)collection;
        //the easiest way to persist changes to the source is to just clear the source list and then add all items to it.
        dict.Clear();

        foreach( var item in sourceList )
        {
          var propInfoKey = item.GetType().GetProperty( "Key" );
          var propInfoValue = item.GetType().GetProperty( "Value" );
          if( (propInfoKey != null) && (propInfoValue != null) )
          {
            dict.Add( propInfoKey.GetValue( item, null ), propInfoValue.GetValue( item, null ) );
          }
        }
      }
      //IList
      else if( collection is IList )
      {
        var list = (IList)collection;

        //the easiest way to persist changes to the source is to just clear the source list and then add all items to it.
        list.Clear();

        if( list.IsFixedSize )
        {
          if( sourceList.Count > list.Count )
            throw new IndexOutOfRangeException("Exceeding array size.");

          for( int i = 0; i < sourceList.Count; ++i )
            list[ i ] = sourceList[ i ];
        }
        else
        {
          foreach( var item in sourceList )
          {
            list.Add( item );
          }
        }
      }
      else
      {
        //ICollection<T> (or IList<T>)
        var collectionType = collection.GetType();
        var iCollectionOfTInterface = collectionType.GetInterfaces().FirstOrDefault( x => x.IsGenericType && (x.GetGenericTypeDefinition() == typeof( ICollection<> )) );
        if( iCollectionOfTInterface != null )
        {
          var argumentType = iCollectionOfTInterface.GetGenericArguments().FirstOrDefault();
          if( argumentType != null )
          {
            var iCollectionOfTType = typeof( ICollection<> ).MakeGenericType( argumentType );

            //the easiest way to persist changes to the source is to just clear the source list and then add all items to it.
            iCollectionOfTType.GetMethod( "Clear" ).Invoke( collection, null );

            foreach( var item in sourceList )
            {
              iCollectionOfTType.GetMethod( "Add" ).Invoke( collection, new object[] { item } );
            }
          }
        }
      }
    }

    private IEnumerable CreateItemsSource()
    {
      IEnumerable collection = null;

      if( ItemsSourceType != null )
      {
        var constructor = ItemsSourceType.GetConstructor( Type.EmptyTypes );
        if( constructor != null )
        {
          collection = ( IEnumerable )constructor.Invoke( null );
        }
        else if( ItemsSourceType.IsArray )
        {
          collection = Array.CreateInstance( ItemsSourceType.GetElementType(), Items.Count );
        }
      }

      return collection;
    }

    private object CreateNewItem( Type type )
    {
      return Activator.CreateInstance( type );
    }

    private IEnumerable ComputeItemsSource()
    {
      if( ItemsSource == null )
        ItemsSource = CreateItemsSource();

      return ItemsSource;
    }

    #endregion //Methods
  }
}