using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Controls.Primitives;
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;

namespace Tango.Console
{
    public class ConsoleTextBox : TextBox
    {
        private Border _caret;
        private ListBox _listSuggestions;
        private Popup _popup;
        private Popup _suggestionsPopup;

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

        public Brush CaretBottomBrush
        {
            get { return (Brush)GetValue(CaretBottomBrushProperty); }
            set { SetValue(CaretBottomBrushProperty, value); }
        }
        public static readonly DependencyProperty CaretBottomBrushProperty =
            DependencyProperty.Register("CaretBottomBrush", typeof(Brush), typeof(ConsoleTextBox), new PropertyMetadata(null));

        public double CaretPosition
        {
            get { return (double)GetValue(CaretPositionProperty); }
            set { SetValue(CaretPositionProperty, value); }
        }
        public static readonly DependencyProperty CaretPositionProperty =
            DependencyProperty.Register("CaretPosition", typeof(double), typeof(ConsoleTextBox), new PropertyMetadata(0.0));

        public bool IsSuggestionsOpened
        {
            get { return (bool)GetValue(IsSuggestionsOpenedProperty); }
            set { SetValue(IsSuggestionsOpenedProperty, value); }
        }
        public static readonly DependencyProperty IsSuggestionsOpenedProperty =
            DependencyProperty.Register("IsSuggestionsOpened", typeof(bool), typeof(ConsoleTextBox), new PropertyMetadata(false));

        public List<ConsoleSuggestion> FilteredSuggestions
        {
            get { return (List<ConsoleSuggestion>)GetValue(FilteredSuggestionsProperty); }
            set { SetValue(FilteredSuggestionsProperty, value); }
        }
        public static readonly DependencyProperty FilteredSuggestionsProperty =
            DependencyProperty.Register("FilteredSuggestions", typeof(List<ConsoleSuggestion>), typeof(ConsoleTextBox), new PropertyMetadata(null));

        public IEnumerable<ConsoleSuggestion> Suggestions
        {
            get { return (IEnumerable<ConsoleSuggestion>)GetValue(SuggestionsProperty); }
            set { SetValue(SuggestionsProperty, value); }
        }
        public static readonly DependencyProperty SuggestionsProperty =
            DependencyProperty.Register("Suggestions", typeof(IEnumerable<ConsoleSuggestion>), typeof(ConsoleTextBox), new PropertyMetadata(null));

        public ConsoleSuggestion SelectedSuggestion
        {
            get { return (ConsoleSuggestion)GetValue(SelectedSuggestionProperty); }
            set { SetValue(SelectedSuggestionProperty, value); }
        }
        public static readonly DependencyProperty SelectedSuggestionProperty =
            DependencyProperty.Register("SelectedSuggestion", typeof(ConsoleSuggestion), typeof(ConsoleTextBox), new PropertyMetadata(null));

        public int MaxSuggestions
        {
            get { return (int)GetValue(MaxSuggestionsProperty); }
            set { SetValue(MaxSuggestionsProperty, value); }
        }
        public static readonly DependencyProperty MaxSuggestionsProperty =
            DependencyProperty.Register("MaxSuggestions", typeof(int), typeof(ConsoleTextBox), new PropertyMetadata(1000));

        public Brush SuggestionsBorderBrush
        {
            get { return (Brush)GetValue(SuggestionsBorderBrushProperty); }
            set { SetValue(SuggestionsBorderBrushProperty, value); }
        }
        public static readonly DependencyProperty SuggestionsBorderBrushProperty =
            DependencyProperty.Register("SuggestionsBorderBrush", typeof(Brush), typeof(ConsoleTextBox), new PropertyMetadata(null));

        public Brush SuggestionsBackground
        {
            get { return (Brush)GetValue(SuggestionsBackgroundProperty); }
            set { SetValue(SuggestionsBackgroundProperty, value); }
        }
        public static readonly DependencyProperty SuggestionsBackgroundProperty =
            DependencyProperty.Register("SuggestionsBackground", typeof(Brush), typeof(ConsoleTextBox), new PropertyMetadata(null));

        public Brush SuggestionsForeground
        {
            get { return (Brush)GetValue(SuggestionsForegroundProperty); }
            set { SetValue(SuggestionsForegroundProperty, value); }
        }
        public static readonly DependencyProperty SuggestionsForegroundProperty =
            DependencyProperty.Register("SuggestionsForeground", typeof(Brush), typeof(ConsoleTextBox), new PropertyMetadata(null));


        public ConsoleTextBox()
        {
            SelectionChanged += (sender, e) => MoveCustomCaret();
            LostFocus += (sender, e) => _caret.Visibility = Visibility.Collapsed;
            GotKeyboardFocus += (sender, e) => _caret.Visibility = Visibility.Visible;
            LostKeyboardFocus += (sender, e) => _caret.Visibility = Visibility.Collapsed;

            Suggestions = ConsoleDictionary.GetKnownCommands().Select(x => new ConsoleSuggestion()
            {
                Name = x.Name,
                Description = x.Description
            }).ToObservableCollection();
        }

        protected override void OnPreviewKeyDown(KeyEventArgs e)
        {
            if (IsSuggestionsOpened)
            {
                if (e.Key == Key.Down)
                {
                    if (_listSuggestions.SelectedIndex < _listSuggestions.Items.Count - 1)
                    {
                        _listSuggestions.SelectedIndex++;
                        _listSuggestions.ScrollIntoView(SelectedSuggestion);

                        _popup.IsOpen = false;

                        if (SelectedSuggestion != null && SelectedSuggestion.Description != null)
                        {
                            _popup.IsOpen = FilteredSuggestions.Count > 0;
                        }
                    }

                    e.Handled = true;
                    return;
                }
                else if (e.Key == Key.Up)
                {
                    if (_listSuggestions.SelectedIndex > 0)
                    {
                        _listSuggestions.SelectedIndex--;
                        _listSuggestions.ScrollIntoView(SelectedSuggestion);

                        _popup.IsOpen = false;
                        if (SelectedSuggestion != null && SelectedSuggestion.Description != null)
                        {
                            _popup.IsOpen = FilteredSuggestions.Count > 0;
                        }
                    }

                    e.Handled = true;
                    return;
                }
                else if (e.Key == Key.Enter)
                {
                    var selectedItem = (_listSuggestions.SelectedItem as ConsoleSuggestion);
                    if (selectedItem != null)
                    {
                        var words = Text.Split(' ').ToList();

                        if (words.Count > 1)
                        {
                            words = words.Take(words.Count - 1).ToList();
                            Text = String.Join(" ", words) + " " + selectedItem.Name;
                        }
                        else
                        {
                            Text = selectedItem.Name;
                        }

                        IsSuggestionsOpened = false;
                        CaretIndex = Text.Length;
                        e.Handled = true;
                        return;
                    }

                    IsSuggestionsOpened = false;
                }
            }

            base.OnPreviewKeyDown(e);
        }

        protected override void OnTextChanged(TextChangedEventArgs e)
        {
            base.OnTextChanged(e);

            try
            {
                if (CaretIndex == Text.Length)
                {
                    String lastWord = Text.Split(' ').LastOrDefault();
                    lastWord?.Trim();

                    if (Suggestions != null)
                    {
                        FilteredSuggestions = Suggestions.Where(x => (lastWord.IsNotNullOrEmpty() && x.Name.ToLower().StartsWith(lastWord.ToLower())) || Text.EndsWith(" ")).OrderBy(x => x.Name).Take(MaxSuggestions).ToList();

                        if (Text.Contains(" "))
                        {
                            FilteredSuggestions = FilteredSuggestions.Where(x => x.Type != ConsoleSuggestionType.Command).ToList();
                        }

                        IsSuggestionsOpened = FilteredSuggestions.Count > 0;
                        _popup.IsOpen = false;
                        _popup.IsOpen = FilteredSuggestions.Count > 0 && SelectedSuggestion != null;
                    }
                }
                else
                {
                    IsSuggestionsOpened = false;
                    _popup.IsOpen = false;
                }
            }
            catch (Exception ex)
            {
                Debug.WriteLine(ex);
                Debugger.Break();
            }
        }

        protected override void OnSelectionChanged(RoutedEventArgs e)
        {
            base.OnSelectionChanged(e);

            if (CaretIndex < Text.Length)
            {
                IsSuggestionsOpened = false;
                _popup.IsOpen = false;
            }
        }

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

            _caret = GetTemplateChild("PART_Caret") as Border;
            _listSuggestions = GetTemplateChild("PART_listSuggestions") as ListBox;
            _popup = GetTemplateChild("PART_popup") as Popup;
            _suggestionsPopup = GetTemplateChild("PART_SuggestionsPopup") as Popup;
        }

        private void MoveCustomCaret()
        {
            var caretLocation = GetRectFromCharacterIndex(CaretIndex).Location;

            if (!double.IsInfinity(caretLocation.X))
            {
                Canvas.SetLeft(_caret, caretLocation.X);
                CaretPosition = caretLocation.X;

                _suggestionsPopup.PlacementRectangle = new Rect(CaretPosition + 10, 20, 0, 0);
            }
        }
    }
}