using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Controls;
using HeuristicLab.MainForm.WPF;
using System.Windows;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.Windows.Controls.Primitives;
using System.Collections;
using System.Diagnostics;
using System.ComponentModel;

namespace HeuristicLab.OKB.Cockpit.Admin {

  public partial class ItemSelector : UserControl, IOKBCockpitItem {

    class SelectionWrapper {

      public event EventHandler IsCheckedChanged;
      private bool isChecked;
      public bool IsChecked {
        get { return isChecked; }
        set {
          if (value == isChecked) return;
          isChecked = value;
          OnIsCheckedChanged();
        }
      }

      public object Obj { get; set; }

      public SelectionWrapper() {
      }

      public SelectionWrapper(object o) {
        Obj = o;
      }

      protected void OnIsCheckedChanged() {
        if (IsCheckedChanged != null)
          IsCheckedChanged(this, new EventArgs());
      }

      public override bool Equals(object obj) {
        return Obj.Equals(obj);
      }

      public override int GetHashCode() {
        if (Obj == null)
          return 0;
        return Obj.GetHashCode();
      }
    }

    public static DependencyProperty AvailableObjectsProperty = DependencyProperty.Register(
      "AvailableObjects", typeof(ObservableCollection<object>), typeof(ItemSelector),
      new PropertyMetadata(new ObservableCollection<object>()));

    public static DependencyProperty SelectedObjectsProperty = DependencyProperty.Register(
      "SelectedObjects", typeof(ObservableCollection<object>), typeof(ItemSelector),
      new PropertyMetadata(new ObservableCollection<object>()));

    public ObservableCollection<object> AvailableObjects {
      get { return (ObservableCollection<object>)GetValue(AvailableObjectsProperty); }
      set { SetValue(AvailableObjectsProperty, value); }
    }

    public ObservableCollection<object> SelectedObjects {
      get { return (ObservableCollection<object>)GetValue(SelectedObjectsProperty); }
      set { SetValue(SelectedObjectsProperty, value); }
    }

    private ObservableCollection<SelectionWrapper> DisplayedAvailableObjects;

    protected override void OnPropertyChanged(DependencyPropertyChangedEventArgs e) {
      base.OnPropertyChanged(e);
      if (e.Property == AvailableObjectsProperty) {
        ((ObservableCollection<object>)e.OldValue).CollectionChanged -= PropageAvailableObjectsChange;
        AvailableObjects.CollectionChanged += PropageAvailableObjectsChange;
        PropageAvailableObjectsChange(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
        ValidateSelection();
      } else if (e.Property == SelectedObjectsProperty) {
        ValidateSelection();
      }
    }

    private void ValidateSelection() {
      if (SelectedObjects == null)
        return;
      var selectedObjects = new HashSet<object>(SelectedObjects);
      SelectedObjects.Clear();
      if (AvailableObjects != null) {
        selectedObjects.IntersectWith(AvailableObjects);
        foreach (var wrapper in DisplayedAvailableObjects)
          wrapper.IsChecked = selectedObjects.Contains(wrapper.Obj);
        foreach (var o in selectedObjects)
          SelectedObjects.Add(o);
      }
    }

    private void PropageAvailableObjectsChange(object sender, NotifyCollectionChangedEventArgs args) {
      switch (args.Action) {
        case NotifyCollectionChangedAction.Add:
          foreach (var o in args.NewItems) DisplayedAvailableObjects.Add(new SelectionWrapper(o)); break;
        case NotifyCollectionChangedAction.Move:
          DisplayedAvailableObjects.Move(args.OldStartingIndex, args.NewStartingIndex); break;
        case NotifyCollectionChangedAction.Remove:
          foreach (var o in args.OldItems) DisplayedAvailableObjects.Remove(new SelectionWrapper(o)); break;
        case NotifyCollectionChangedAction.Replace:
          foreach (var o in args.OldItems) DisplayedAvailableObjects.Remove(new SelectionWrapper(o));
          foreach (var o in args.NewItems) DisplayedAvailableObjects.Insert(args.OldStartingIndex, new SelectionWrapper(o));
          break;
        case NotifyCollectionChangedAction.Reset:
          DisplayedAvailableObjects.Clear();
          foreach (var o in AvailableObjects) DisplayedAvailableObjects.Add(new SelectionWrapper(o));
          break;
      }
    }

    public ItemSelector() {
      InitializeComponent();
      DisplayedAvailableObjects = new ObservableCollection<SelectionWrapper>();
      AvailableObjectsList.ItemsSource = DisplayedAvailableObjects;
      SelectedObjectsList.DataContext = this;
      SelectedObjectsList.SetBinding(ListBox.ItemsSourceProperty, "SelectedObjects");
      AvailableObjects.CollectionChanged += PropageAvailableObjectsChange;
    }



    protected void OnAvailableClicked(object sender, RoutedEventArgs args) {
      ToggleButton button = args.OriginalSource as ToggleButton;
      if (button == null) return;
      SelectionWrapper wrapper = button.Tag as SelectionWrapper;
      if (wrapper == null) return;
      if (!SelectedObjects.Contains(wrapper.Obj)) {
        SelectedObjects.Add(wrapper.Obj);
        wrapper.IsChecked = true;
      } else {
        SelectedObjects.Remove(wrapper.Obj);
        wrapper.IsChecked = false;
      }
    }

    protected void OnSelectedClicked(object sender, RoutedEventArgs args) {
      Button button = args.OriginalSource as Button;
      if (button == null) return;
      object o = button.Tag;
      Debug.Assert(SelectedObjects.Contains(o));
      SelectedObjects.Remove(o);
      var wrappers = DisplayedAvailableObjects.Where(w => w.Obj == o);
      foreach (var w in wrappers)
        w.IsChecked = false;
    }
  }
}