using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using Tango.Core.Commands;
using System.ComponentModel;
using System.Windows.Controls.Primitives;
using System.Windows.Threading;
using System.Diagnostics;

namespace Tango.SharedUI.Controls
{
    internal sealed class MultiSelectComboBoxTemplateSelector : DataTemplateSelector
    {
        public override DataTemplate SelectTemplate(object item, DependencyObject container)
        {
            FrameworkElement element = container as FrameworkElement;
            if (element != null && item != null && item is MultiSelectComboBoxItem)
                return element.FindResource("CheckItem") as DataTemplate;
           
            return element.FindResource("SearchItem") as DataTemplate; ;

        }
    }
    
    [TemplatePart(Name = MultiSelectComboBox.PartEditor, Type = typeof(TextBox))]
    [TemplatePart(Name = MultiSelectComboBox.PartPopup, Type = typeof(Popup))]
    public class MultiSelectComboBox : Control
    {
        #region Fields
        public const string PartEditor = "Edit_PART";
        public const string PartPopup = "MultiSel_Popup";
        private ItemsControl _items_control;
        private bool _isLoaded;
        #endregion
        #region "Constructors"  

        static MultiSelectComboBox()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(MultiSelectComboBox), new FrameworkPropertyMetadata(typeof(MultiSelectComboBox)));
            
        }
        public MultiSelectComboBox() : base()
        {
            SelectedItemsList = new ObservableCollection<object>();
            RemoveAllCommand = new RelayCommand(RemoveAllSelectedItems, CanRemoveAllSelectedItems);
            RemoveItemCommand = new RelayCommand<MultiSelectComboBoxItem>(RemoveSelectedItem);
            AddItemCommand = new RelayCommand<string>(AddSelectedItem);
            SearchText = new MultiSelectComboBoxSearchItem();
            Loaded += MultiSelectComboBox_Loaded;
            _isLoaded = false;


        }
        #endregion

        #region Properties

        private TextBox _editor;

        public TextBox Editor
        {
            get { return _editor; }
            set { _editor = value; }
        }

        private Popup _popup;

        public Popup Popup
        {
            get { return _popup; }
            set { _popup = value; }
        }

        private DispatcherTimer _fetchTimer;

        public DispatcherTimer FetchTimer
        {
            get { return _fetchTimer; }
            set { _fetchTimer = value; }
        }

        public ObservableCollection<object> SelectedItemsList
        {
            get { return (ObservableCollection<object>)GetValue(SelectedItemsListProperty); }
            set { SetValue(SelectedItemsListProperty, value); }
        }
        
        public static readonly DependencyProperty SelectedItemsListProperty =
            DependencyProperty.Register("SelectedItemsList", typeof(ObservableCollection<object>), typeof(MultiSelectComboBox), new PropertyMetadata(default(ObservableCollection<object>)));

 
        public ListCollectionView SearchItemsList
        {
            get { return (ListCollectionView)GetValue(SearchItemsListProperty); }
            set { SetValue(SearchItemsListProperty, value); }
        }
        /// <summary>
        /// The search items list property for popup items list
        /// </summary>
        public static readonly DependencyProperty SearchItemsListProperty =
            DependencyProperty.Register("SearchItemsList", typeof(ListCollectionView), typeof(MultiSelectComboBox), new PropertyMetadata(default(ObservableCollection<string>)));

        public ObservableCollection<string> Items
        {
            get { return (ObservableCollection<string>)GetValue(ItemsProperty); }
            set { SetValue(ItemsProperty, value); }
        }

        public static readonly DependencyProperty ItemsProperty =
            DependencyProperty.Register("Items", typeof(ObservableCollection<string>), typeof(MultiSelectComboBox), new PropertyMetadata(default(ObservableCollection<string>)));

        
        public bool IsToggleChecked
        {
            get { return (bool)GetValue(IsToggleCheckedProperty); }
            set { SetValue(IsToggleCheckedProperty, value); }
        }

        public static readonly DependencyProperty IsToggleCheckedProperty = 
            DependencyProperty.Register("IsToggleChecked", typeof(bool), typeof(MultiSelectComboBox), new FrameworkPropertyMetadata(false));

        private MultiSelectComboBoxSearchItem _searchText;
        /// <summary>
        /// Gets or sets the search text of TextBox.
        /// </summary>
        public MultiSelectComboBoxSearchItem SearchText
        {
            get { return _searchText; }
            set
            {
                _searchText = value;
                OnTextChanged();
            }
        }
        #endregion

        private void MultiSelectComboBox_Loaded(object sender, RoutedEventArgs e)
        {
            if (!_isLoaded)
            {
                ToggleButton b2 = GetTemplateChild("MultiSelToggleButton") as ToggleButton;
                if (b2 != null)
                {
                   // ct.LoadContent();
                    _items_control = b2.Template.FindName("SelectedItemsControl", b2) as ItemsControl;
                    if (_items_control != null)
                    {
                        var wrapPanel = _items_control.FindChild<WrapPanel>();
                        if (wrapPanel != null)
                        {
                            _items_control.Bind(ItemsControl.HeightProperty, wrapPanel, WrapPanel.ActualHeightProperty, BindingMode.OneWay);
                            _isLoaded = true;

                            var searchItem =(_items_control.ItemContainerGenerator.ContainerFromItem(SearchText));
                            Editor = searchItem.FindVisualChildren< TextBox>().FirstOrDefault(x => x.Name == PartEditor);
                            if (Editor != null)
                            {
                                Editor.TextChanged += OnEditorTextChanged;
                                Editor.PreviewKeyDown += OnEditorKeyDown;
                                Editor.LostFocus += OnEditorLostFocus;
                                Editor.GotFocus += OnEditorGotFocus;
                            }
                        }
                    }
                    this.GotFocus += SelTextBox_GotFocus;
                }
            }
        }

        void OnTextChanged()
        {
            if(SearchItemsList != null)
            {
                if (String.IsNullOrEmpty(SearchText.Text))
                   SearchItemsList.Filter = null;
                else
                    SearchItemsList.Filter = new Predicate<object>(o => (((string)o).ToLower().Contains(SearchText.Text.ToLower())));
            }
        }
        /// <summary>
        /// When overridden in a derived class, is invoked whenever application code or internal processes call <see cref="M:System.Windows.FrameworkElement.ApplyTemplate" />.
        /// </summary>
        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();
            if (SelectedItemsList == null)
                SelectedItemsList = new ObservableCollection<object>();
            SelectedItemsList.Add(SearchText);
            
            SearchItemsList = new ListCollectionView(this.Items);
            Popup = Template.FindName(PartPopup, this) as Popup;
           

            if (Popup != null)
            {
                Popup.StaysOpen = false;
                Popup.Opened += OnPopupOpened;
                Popup.Closed += OnPopupClosed;
            }
        }

        private void OnEditorTextChanged(object sender, TextChangedEventArgs e)
        {
            if (FetchTimer == null)
            {
                FetchTimer = new DispatcherTimer();
                FetchTimer.Interval = TimeSpan.FromMilliseconds(500);
                FetchTimer.Tick += OnFetchTimerTick;
            }
            FetchTimer.IsEnabled = false;
            FetchTimer.Stop();
            IsToggleChecked = true;
               
            FetchTimer.IsEnabled = true;
            FetchTimer.Start();
           
        }

        private void OnFetchTimerTick(object sender, EventArgs e)
        {
            FetchTimer.IsEnabled = false;
            FetchTimer.Stop();
            SearchText.Text = Editor.Text;
            OnTextChanged();
        }

        private void OnEditorKeyDown(object sender, KeyEventArgs e)
        {
            IsToggleChecked = true;
        }

        private void OnEditorLostFocus(object sender, RoutedEventArgs e)
        {
            if (!IsKeyboardFocusWithin)
            {
                IsToggleChecked = false;
            }
        }

        private void SelTextBox_GotFocus(object sender, RoutedEventArgs e)
        {
            Editor?.Focus();
        }

        private void OnEditorGotFocus(object sender, RoutedEventArgs e)
        {
            IsToggleChecked = true;
        }

        private void OnPopupOpened(object sender, EventArgs e)
        {
            
        }
        private void OnPopupClosed(object sender, EventArgs e)
        {
            IsToggleChecked = false;

        }
        #region Commands
        /// <summary>
        /// The remove all command property for clear SelectedItemsList
        /// </summary>
        public static DependencyProperty RemoveAllCommandProperty = DependencyProperty.Register("RemoveAllCommand", typeof(RelayCommand), typeof(MultiSelectComboBox));
        public RelayCommand RemoveAllCommand
        {
            get { return (RelayCommand)GetValue(RemoveAllCommandProperty); }
            private set { SetValue(RemoveAllCommandProperty, value); }
        }

        /// <summary>
        /// The remove item from SelectedItemsList command property
        /// </summary>
        public static DependencyProperty RemoveItemCommandProperty = DependencyProperty.Register("RemoveItemCommand", typeof(RelayCommand<MultiSelectComboBoxItem>), typeof(MultiSelectComboBox));
        public RelayCommand<MultiSelectComboBoxItem> RemoveItemCommand
        {
            get { return (RelayCommand<MultiSelectComboBoxItem>)GetValue(RemoveItemCommandProperty); }
            private set { SetValue(RemoveItemCommandProperty, value); }
        }

        /// <summary>
        /// The add item to SelectedItemsList command property
        /// </summary>
        public static DependencyProperty AddItemCommandProperty = DependencyProperty.Register("AddItemCommand", typeof(RelayCommand<string>), typeof(MultiSelectComboBox));
        public RelayCommand<string> AddItemCommand
        {
            get { return (RelayCommand<string>)GetValue(AddItemCommandProperty); }
            private set { SetValue(AddItemCommandProperty, value); }
        }

        /// <summary>
        /// Removes the selected item.
        /// </summary>
        /// <param name="item">The item.</param>
        private void RemoveSelectedItem(IMultiSelectComboBoxItem item)
        {
            SelectedItemsList.Remove(item);
            RemoveAllCommand.RaiseCanExecuteChanged();
        }

        /// <summary>
        /// Adds the selected item.
        /// </summary>
        /// <param name="item">The item.</param>
        private void AddSelectedItem(string item)
        {
            if (SelectedItemsList.Any(x => (x as IMultiSelectComboBoxItem).Text == item))
                return;
            SelectedItemsList.Insert(SelectedItemsList.Count - 1, new MultiSelectComboBoxItem(item));
            RemoveAllCommand.RaiseCanExecuteChanged();
        }
        /// <summary>
        /// Removes all selected items.
        /// </summary>
        private void RemoveAllSelectedItems()
        {
            int index = SelectedItemsList.Count - 2;
            while (index >= 0)
            {
                SelectedItemsList.RemoveAt(index--);
             }
            RemoveAllCommand.RaiseCanExecuteChanged();
        }
        private bool CanRemoveAllSelectedItems()
        {
            return (SelectedItemsList != null && SelectedItemsList.Count > 1);
        }
        #endregion


    }
}