using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Input;
using JD.Filters;
using Xceed.Wpf.DataGrid;

namespace JD.Pickers.PickerControls
{
    /// <summary>
    /// http://stackoverflow.com/questions/1329362/c-sharp-generics-usercontrol
    /// The C# compiler does not support Generics inheriting from UserControl, so we need to "hide" the generic in an intermediate class.
    /// </summary>
    public partial class MultiPicker : UserControl
    {
    }

    /// <summary>
    /// Interaction logic for MultiPicker.xaml
    /// </summary>
    public class MultiPicker<T> : MultiPicker
    {
        private readonly ICollectionView _collectionViewDataList;
        private readonly ICollectionView _collectionViewSelectionList;

        // keyboard keys you can use to select/deselect a map
        private readonly List<Key> _selectKeys = new List<Key> { Key.Space, Key.Right };
        private readonly List<Key> _deselectKeys = new List<Key> { Key.Space, Key.Delete, Key.Left };

        private ObservableCollection<T> DataList { get; }

        public ObservableCollection<T> Selection { get; }

        public Filter Filter { get; set; }

        public MultiPicker(IEnumerable<T> items)
        {
            InitializeComponent();

            DataList = new ObservableCollection<T>();
            Selection = new ObservableCollection<T>();

            // populate
            foreach (var item in items)
            {
                DataList.Add(item);
            }

            // configure filter
            Filter = new Filter(typeof(T))
            {
                HasQuickFilter = true,
                RefreshAction = () => { _collectionViewDataList.Refresh(); }
            };

            _collectionViewDataList = CollectionViewSource.GetDefaultView(DataList);
            _collectionViewDataList.Filter = Filter.Apply;

            _collectionViewSelectionList = CollectionViewSource.GetDefaultView(Selection);

            filterControl.Filter = Filter;

            // databinding
            dataGridControl.DataContext = DataList;
            dataGridControl.ItemsSource = DataList;

            selectedListControl.ItemsSource = Selection;

            // link events
            buttonSelect.Click += SelectEvent;
            buttonDeselect.Click += DeselectEvent;

            selectedListControl.KeyUp += DeselectKeyEvent;
            dataGridControl.KeyUp += SelectKeyEvent;

            // events for listbox items
            var style = new Style(typeof(ListBoxItem));
            style.Setters.Add(new EventSetter(MouseDoubleClickEvent,
                new MouseButtonEventHandler(DeselectEvent)));
            selectedListControl.ItemContainerStyle = style;

            // events for datarow items
            style = new Style(typeof(DataRow));
            style.Setters.Add(new EventSetter(MouseDoubleClickEvent,
                new MouseButtonEventHandler(SelectEvent)));
            dataGridControl.ItemContainerStyle = style;

            /* disable listbox spacebar selection (so that the spacebar can be used as we want) */
            selectedListControl.PreviewKeyDown += (sender, e) =>
            {
                if (e.Key == Key.Space)
                {
                    e.Handled = true;
                }
            };

            dataGridControl.Loaded += SetColumnWidth;
        }

        private void SetColumnWidth(object sender, RoutedEventArgs e)
        {
            const int minWidth = 150;

            var totalControlWidth = dataGridControl.ActualWidth;

            var numberOfColumns = dataGridControl.Columns.Count;
            foreach (var column in dataGridControl.Columns)
            {
                column.Width = Math.Max(totalControlWidth / numberOfColumns, minWidth);
            }
        }

        private void DeselectEvent(object sender, RoutedEventArgs e)
        {
            RemoveSelectedViewFromSelection();
        }

        private void DeselectKeyEvent(object sender, KeyEventArgs e)
        {
            if (_deselectKeys.Contains(e.Key))
            {
                RemoveSelectedViewFromSelection();
            }
        }

        private void SelectEvent(object sender, RoutedEventArgs e)
        {
            AddSelectedRowsToSelection();
        }

        private void SelectKeyEvent(object sender, KeyEventArgs e)
        {
            if (_selectKeys.Contains(e.Key))
            {
                AddSelectedRowsToSelection();
            }
        }

        private void AddSelectedRowsToSelection()
        {
            var selectedItems = dataGridControl.SelectedItems;
            foreach (T member in selectedItems)
            {
                if (!Selection.Contains(member))
                {
                    Selection.Add(member);
                }
            }

            dataGridControl.SelectedItems.Clear();
        }

        private void RemoveSelectedViewFromSelection()
        {
            while (selectedListControl.SelectedIndex != -1)
            {
                var element = selectedListControl.SelectedItem;
                Selection.Remove((T)element);
            }

            _collectionViewSelectionList.Refresh();
        }

        public bool? ShowDialog(Window owner = null)
        {
            var dialogWindow = new Window
            {
                Content = this,
                WindowStyle = WindowStyle.ToolWindow,
                HorizontalContentAlignment = HorizontalAlignment.Stretch,
                VerticalContentAlignment = VerticalAlignment.Stretch,
                WindowStartupLocation = WindowStartupLocation.CenterScreen,
                Width = 750,
                Owner = owner,
                Topmost = true
            };

            dialogWindow.Loaded += (sender, e) => filterControl.SearchBox.Focus();
            buttonOk.Click += (sender, e) => { dialogWindow.DialogResult = true; };
            buttonCancel.Click += (sender, e) => { dialogWindow.DialogResult = false; };

            // keyboard shortcuts
            dialogWindow.KeyUp += (sender, e) =>
            {
                if (e.Key == Key.Return)
                {
                    dialogWindow.DialogResult = true;
                }
                else if (e.Key == Key.Escape)
                {
                    dialogWindow.DialogResult = false;
                }
            };

            return dialogWindow.ShowDialog();
        }
    }
}