using System.ComponentModel;
using System.Runtime.CompilerServices;
using CommanderApp.Services;

namespace CommanderApp;

public partial class MainPage : ContentPage, INotifyPropertyChanged
{
    private readonly IFileSystemService _fileService;
    private readonly IPanelManager _panelManager;
    private readonly IFileOperations _fileOperations;
    private readonly IKeyboardService _keyboardService;
    private readonly IPathHelper _pathHelper;

    // Для визуального выделения
    private readonly Color ActiveIndicatorColor = Color.FromArgb("#007ACC");
    private readonly Color InactiveIndicatorColor = Colors.Transparent;
    private readonly Color FocusedButtonColor = Color.FromArgb("#E3F2FD");
    private readonly Color NormalButtonColor = Colors.Transparent;

    // Для отслеживания двойного клика
    private DateTime _lastClickTime = DateTime.MinValue;
    private object _lastClickedButton = null;
    private bool _awaitingConfirmation = false;

    public string LeftPath
    {
        get => _panelManager.LeftPanelPath;
        set
        {
            if (_panelManager.LeftPanelPath != value)
            {
                _panelManager.UpdatePanelPaths(value, _panelManager.RightPanelPath);
                NotifyPropertyChanged();
            }
        }
    }

    public string RightPath
    {
        get => _panelManager.RightPanelPath;
        set
        {
            if (_panelManager.RightPanelPath != value)
            {
                _panelManager.UpdatePanelPaths(_panelManager.LeftPanelPath, value);
                NotifyPropertyChanged();
            }
        }
    }

    public MainPage(IFileSystemService fileService, 
                    IPanelManager panelManager,
                    IFileOperations fileOperations,
                    IKeyboardService keyboardService,
                    IPathHelper pathHelper)
    {
        InitializeComponent();
        
        _fileService = fileService;
        _panelManager = panelManager;
        _fileOperations = fileOperations;
        _keyboardService = keyboardService;
        _pathHelper = pathHelper;
        
        BindingContext = this;

        System.Diagnostics.Debug.WriteLine("=== MainPage constructor ===");

        // Подписываемся на события
        _panelManager.StateChanged += OnPanelStateChanged;
        _keyboardService.KeyPressed += OnKeyPressed;

        // Загружаем начальные директории
        var root = _fileService.GetRootPath();
        LoadDirectory(root, true);
        LoadDirectory(root, false);

        System.Diagnostics.Debug.WriteLine("=== MainPage constructor completed ===");
    }

    protected override void OnAppearing()
    {
        base.OnAppearing();
        System.Diagnostics.Debug.WriteLine("=== OnAppearing ===");
        
        Dispatcher.Dispatch(async () =>
        {
            await Task.Delay(300);
            SetInitialFocus();
        });
    }

    protected override void OnHandlerChanged()
    {
        base.OnHandlerChanged();
        System.Diagnostics.Debug.WriteLine($"=== OnHandlerChanged ===");
        
        _keyboardService.SetupKeyboardHandling(this);
    }

    private void OnKeyPressed(object sender, KeyPressedEventArgs e)
    {
        System.Diagnostics.Debug.WriteLine($"=== KEY PRESSED: {e.Key} on {e.Platform} ===");
        
        MainThread.BeginInvokeOnMainThread(() =>
        {
            // Сбрасываем флаг для всех клавиш навигации
            if (e.Key == "w" || e.Key == "s" || e.Key == "a" || e.Key == "d")
            {
                _awaitingConfirmation = true;
            }

            switch (e.Key)
            {
                case "w": // W - вверх
                    _panelManager.MoveSelection(-1);
                    break;
                case "s": // S - вниз
                    _panelManager.MoveSelection(1);
                    break;
                case "a": // A - левая панель
                    _panelManager.SwitchToLeftPanel();
                    break;
                case "d": // D - правая панель
                    _panelManager.SwitchToRightPanel();
                    break;
                case " ": // Space - вход/запуск
                case "enter": // Enter - вход/запуск
                    OpenSelectedItem();
                    break;
                case "f5": // F5 - Копирование
                    OnCopyClicked(this, EventArgs.Empty);
                    break;
                case "f6": // F6 - Перемещение
                    OnMoveClicked(this, EventArgs.Empty);
                    break;
                case "f7": // F7 - Создать папку
                    OnMkdirClicked(this, EventArgs.Empty);
                    break;
                case "f8": // F8 - Удаление
                    OnDeleteClicked(this, EventArgs.Empty);
                    break;
                case "f10": // F10 - Выход
                    OnExitClicked(this, EventArgs.Empty);
                    break;
                case "h": // H - Home
                    OnHomeClicked(this, EventArgs.Empty);
                    break;
            }
            
            // Всегда скроллим после любого действия с клавиатуры
            ScrollToSelectedItem();
        });
    }

    private void OnPanelStateChanged(object sender, PanelStateChangedEventArgs e)
    {
        UpdateVisualState();
        
        // Устанавливаем фокус на выбранный элемент
        if (e.IsLeftPanelActive && e.LeftSelectedIndex >= 0 && e.LeftSelectedIndex < LeftPanel.Children.Count)
        {
            var button = LeftPanel.Children[e.LeftSelectedIndex] as Button;
            button?.Focus();
        }
        else if (!e.IsLeftPanelActive && e.RightSelectedIndex >= 0 && e.RightSelectedIndex < RightPanel.Children.Count)
        {
            var button = RightPanel.Children[e.RightSelectedIndex] as Button;
            button?.Focus();
        }
        
        // Скроллим при изменении состояния
        ScrollToSelectedItem();
    }

    private void SetInitialFocus()
    {
        try
        {
            System.Diagnostics.Debug.WriteLine("=== Setting initial focus ===");
            
            if (LeftPanel.Children.Count > 0)
            {
                var firstButton = LeftPanel.Children[0] as Button;
                if (firstButton != null)
                {
                    var focused = firstButton.Focus();
                    System.Diagnostics.Debug.WriteLine($"First button focus result: {focused}");
                    
                    if (focused)
                    {
                        _panelManager.SetSelection(0, true);
                        ScrollToSelectedItem();
                    }
                }
            }
        }
        catch (Exception ex)
        {
            System.Diagnostics.Debug.WriteLine($"Error setting initial focus: {ex.Message}");
        }
    }

    // Простой и надежный метод скролла
    private async void ScrollToSelectedItem()
    {
        try
        {
            await Task.Delay(50); // Небольшая задержка для стабильности
            
            if (_panelManager.IsLeftPanelActive)
            {
                if (_panelManager.LeftSelectedIndex >= 0 && _panelManager.LeftSelectedIndex < LeftPanel.Children.Count)
                {
                    // Вычисляем позицию для скролла
                    var itemHeight = 40; // Высота одного элемента
                    var scrollViewHeight = LeftScrollView.Height; // Высота видимой области
                    var visibleItems = (int)(scrollViewHeight / itemHeight); // Сколько элементов видно
                    
                    // Вычисляем целевой скролл, чтобы элемент был в середине видимой области
                    var targetScrollY = Math.Max(0, (_panelManager.LeftSelectedIndex - visibleItems / 2) * itemHeight);
                    
                    await LeftScrollView.ScrollToAsync(0, targetScrollY, true);
                    
                    System.Diagnostics.Debug.WriteLine($"Left scroll: index={_panelManager.LeftSelectedIndex}, targetY={targetScrollY}");
                }
            }
            else
            {
                if (_panelManager.RightSelectedIndex >= 0 && _panelManager.RightSelectedIndex < RightPanel.Children.Count)
                {
                    // Вычисляем позицию для скролла
                    var itemHeight = 40; // Высота одного элемента
                    var scrollViewHeight = RightScrollView.Height; // Высота видимой области
                    var visibleItems = (int)(scrollViewHeight / itemHeight); // Сколько элементов видно
                    
                    // Вычисляем целевой скролл, чтобы элемент был в середине видимой области
                    var targetScrollY = Math.Max(0, (_panelManager.RightSelectedIndex - visibleItems / 2) * itemHeight);
                    
                    await RightScrollView.ScrollToAsync(0, targetScrollY, true);
                    
                    System.Diagnostics.Debug.WriteLine($"Right scroll: index={_panelManager.RightSelectedIndex}, targetY={targetScrollY}");
                }
            }
        }
        catch (Exception ex)
        {
            System.Diagnostics.Debug.WriteLine($"Scroll error: {ex.Message}");
        }
    }

    // Остальные методы без изменений...
    private void OpenSelectedItem()
    {
        var item = _panelManager.SelectedItem;
            
        if (item != null)
        {
            System.Diagnostics.Debug.WriteLine($"Opening: {item.Name} (IsDirectory: {item.IsDirectory})");
            
            if (item.IsDirectory)
            {
                LoadDirectory(item.FullName, _panelManager.IsLeftPanelActive);
            }
            else
            {
                _ = _fileOperations.OpenFileAsync(item.FullName);
            }
        }
        else
        {
            System.Diagnostics.Debug.WriteLine("No item selected");
        }
    }

    private void UpdateVisualState()
    {
        // Визуальное выделение активной панели
        if (_panelManager.IsLeftPanelActive)
        {
            LeftPanelIndicator.BackgroundColor = ActiveIndicatorColor;
            RightPanelIndicator.BackgroundColor = InactiveIndicatorColor;
        }
        else
        {
            LeftPanelIndicator.BackgroundColor = InactiveIndicatorColor;
            RightPanelIndicator.BackgroundColor = ActiveIndicatorColor;
        }

        UpdateButtonSelection();
    }

    private void UpdateButtonSelection()
    {
        // Сбрасываем выделение всех кнопок
        foreach (var child in LeftPanel.Children)
        {
            if (child is Button button)
            {
                button.BackgroundColor = NormalButtonColor;
            }
        }
        
        foreach (var child in RightPanel.Children)
        {
            if (child is Button button)
            {
                button.BackgroundColor = NormalButtonColor;
            }
        }

        // Выделяем активную кнопку
        if (_panelManager.IsLeftPanelActive && _panelManager.LeftSelectedIndex >= 0 && _panelManager.LeftSelectedIndex < LeftPanel.Children.Count)
        {
            if (LeftPanel.Children[_panelManager.LeftSelectedIndex] is Button leftButton)
            {
                leftButton.BackgroundColor = FocusedButtonColor;
            }
        }
        else if (!_panelManager.IsLeftPanelActive && _panelManager.RightSelectedIndex >= 0 && _panelManager.RightSelectedIndex < RightPanel.Children.Count)
        {
            if (RightPanel.Children[_panelManager.RightSelectedIndex] is Button rightButton)
            {
                rightButton.BackgroundColor = FocusedButtonColor;
            }
        }
    }

    private void LoadDirectory(string path, bool isLeft)
    {
        try
        {
            var items = _fileService.GetDirectoryContents(path).ToList();
            var panel = isLeft ? LeftPanel : RightPanel;
            var collection = isLeft ? _panelManager.LeftItems : _panelManager.RightItems;

            panel.Children.Clear();
            collection.Clear();

            foreach (var item in items)
            {
                collection.Add(item);
                AddItemToPanel(item, panel, isLeft);
            }

            if (isLeft)
            {
                LeftPath = path;
                _panelManager.SetSelection(items.Count > 0 ? 0 : -1, true);
            }
            else
            {
                RightPath = path;
                _panelManager.SetSelection(items.Count > 0 ? 0 : -1, false);
            }

            System.Diagnostics.Debug.WriteLine($"Loaded {items.Count} items to {(isLeft ? "LEFT" : "RIGHT")} panel");
            UpdateVisualState();

            _awaitingConfirmation = false;

            // Устанавливаем фокус на первый элемент
            if (items.Count > 0)
            {
                Dispatcher.Dispatch(() =>
                {
                    var firstButton = panel.Children[0] as Button;
                    firstButton?.Focus();
                    ScrollToSelectedItem();
                });
            }
        }
        catch (Exception ex)
        {
            System.Diagnostics.Debug.WriteLine($"Error loading directory: {ex.Message}");
            DisplayAlert("Error", $"Cannot load directory: {ex.Message}", "OK");
        }
    }

    private void AddItemToPanel(FileSystemItem item, VerticalStackLayout panel, bool isLeft)
    {
        var button = new Button
        {
            Text = item.DisplayText,
            Padding = new Thickness(15, 8),
            HeightRequest = 40,
            BackgroundColor = NormalButtonColor,
            HorizontalOptions = LayoutOptions.FillAndExpand,
            TextColor = Colors.Black,
            FontSize = 14,
            BorderColor = Colors.Transparent,
            CornerRadius = 0
        };

        // Обработчик клика - выделение при клике, открытие при двойном клике
        button.Clicked += (s, e) => HandleItemClick(button, item, isLeft);

        // Обработчик фокуса
        button.Focused += (s, e) => 
        {
            var index = panel.Children.IndexOf(button);
            if (index >= 0)
            {
                _panelManager.SetSelection(index, isLeft);
            }
        };

        panel.Children.Add(button);
    }

    private void HandleItemClick(Button button, FileSystemItem item, bool isLeft)
    {
        var currentTime = DateTime.Now;
        var isDoubleClick = (currentTime - _lastClickTime).TotalMilliseconds < 500
                          && _lastClickedButton == button;

        _lastClickTime = currentTime;
        _lastClickedButton = button;

        System.Diagnostics.Debug.WriteLine($"=== CLICK: {item.Name} in {(isLeft ? "LEFT" : "RIGHT")} panel, Double: {isDoubleClick}, AwaitingConfirm: {_awaitingConfirmation} ===");

        // ВСЕГДА выделяем элемент при клике
        var panel = isLeft ? LeftPanel : RightPanel;
        var index = panel.Children.IndexOf(button);

        if (index >= 0)
        {
            _panelManager.SetSelection(index, isLeft);
            button.Focus();
            ScrollToSelectedItem();
        }

        // Открываем, если:
        // - двойной клик (мышь), ИЛИ
        // - одиночный клик, но мы только что навигировались клавишами (Enter/Space имитация)
        if (isDoubleClick || _awaitingConfirmation)
        {
            // Сбрасываем флаг ПЕРЕД открытием
            _awaitingConfirmation = false;

            if (item.IsDirectory)
            {
                LoadDirectory(item.FullName, isLeft);
            }
            else
            {
                _ = _fileOperations.OpenFileAsync(item.FullName);
            }
        }
    }

    // Команды тулбара (без изменений)
    private async void OnCopyClicked(object sender, EventArgs e)
    {
        System.Diagnostics.Debug.WriteLine("=== BUTTON: F5 Copy ===");
        
        var sourceItem = _panelManager.SelectedItem;
        var targetPath = _panelManager.IsLeftPanelActive ? RightPath : LeftPath;
        
        if (sourceItem != null)
        {
            try
            {
                var targetFullPath = _pathHelper.CombinePaths(targetPath, sourceItem.Name);
                
                bool success;
                if (sourceItem.IsDirectory)
                {
                    success = await _fileOperations.CopyDirectoryAsync(sourceItem.FullName, targetFullPath);
                    if (success)
                        await DisplayAlert("Success", $"Directory '{sourceItem.Name}' copied successfully", "OK");
                }
                else
                {
                    success = await _fileOperations.CopyAsync(sourceItem.FullName, targetFullPath);
                    if (success)
                        await DisplayAlert("Success", $"File '{sourceItem.Name}' copied successfully", "OK");
                }
                
                if (success)
                {
                    // Обновляем целевую панель
                    LoadDirectory(targetPath, !_panelManager.IsLeftPanelActive);
                }
                else
                {
                    await DisplayAlert("Error", "Copy operation failed", "OK");
                }
            }
            catch (Exception ex)
            {
                await DisplayAlert("Error", $"Copy failed: {ex.Message}", "OK");
            }
        }
        else
        {
            await DisplayAlert("Info", "Please select an item to copy", "OK");
        }
    }

    private async void OnMoveClicked(object sender, EventArgs e)
    {
        System.Diagnostics.Debug.WriteLine("=== BUTTON: F6 Move ===");
        
        var sourceItem = _panelManager.SelectedItem;
        var targetPath = _panelManager.IsLeftPanelActive ? RightPath : LeftPath;
        
        if (sourceItem != null)
        {
            try
            {
                var targetFullPath = _pathHelper.CombinePaths(targetPath, sourceItem.Name);
                
                bool success;
                if (sourceItem.IsDirectory)
                {
                    success = await _fileOperations.CopyDirectoryAsync(sourceItem.FullName, targetFullPath);
                    if (success)
                        success = await _fileOperations.DeleteAsync(sourceItem.FullName);
                }
                else
                {
                    success = await _fileOperations.MoveAsync(sourceItem.FullName, targetFullPath);
                }
                
                if (success)
                {
                    await DisplayAlert("Success", $"Item '{sourceItem.Name}' moved successfully", "OK");
                    
                    // Обновляем обе панели
                    LoadDirectory(_panelManager.IsLeftPanelActive ? LeftPath : RightPath, _panelManager.IsLeftPanelActive);
                    LoadDirectory(targetPath, !_panelManager.IsLeftPanelActive);
                }
                else
                {
                    await DisplayAlert("Error", "Move operation failed", "OK");
                }
            }
            catch (Exception ex)
            {
                await DisplayAlert("Error", $"Move failed: {ex.Message}", "OK");
            }
        }
        else
        {
            await DisplayAlert("Info", "Please select an item to move", "OK");
        }
    }

    private async void OnMkdirClicked(object sender, EventArgs e)
    {
        System.Diagnostics.Debug.WriteLine("=== BUTTON: F7 Mkdir ===");
        
        var currentPath = _panelManager.IsLeftPanelActive ? LeftPath : RightPath;
        
        // Запрашиваем имя новой папки
        var folderName = await DisplayPromptAsync("Create Folder", "Enter folder name:", "Create", "Cancel", "New Folder");
        
        if (!string.IsNullOrWhiteSpace(folderName))
        {
            try
            {
                var newFolderPath = _pathHelper.CombinePaths(currentPath, folderName);
                var success = await _fileOperations.CreateDirectoryAsync(newFolderPath);
                
                if (success)
                {
                    await DisplayAlert("Success", $"Folder '{folderName}' created successfully", "OK");
                    
                    // Обновляем текущую панель
                    LoadDirectory(currentPath, _panelManager.IsLeftPanelActive);
                }
                else
                {
                    await DisplayAlert("Error", "Failed to create folder", "OK");
                }
            }
            catch (Exception ex)
            {
                await DisplayAlert("Error", $"Cannot create folder: {ex.Message}", "OK");
            }
        }
    }

    private async void OnDeleteClicked(object sender, EventArgs e)
    {
        System.Diagnostics.Debug.WriteLine("=== BUTTON: F8 Delete ===");
        
        var item = _panelManager.SelectedItem;
        
        if (item != null)
        {
            // Подтверждение удаления
            var result = await DisplayAlert("Confirm Delete", 
                $"Are you sure you want to delete '{item.Name}'?", 
                "Delete", "Cancel");
            
            if (result)
            {
                try
                {
                    var success = await _fileOperations.DeleteAsync(item.FullName);
                    
                    if (success)
                    {
                        await DisplayAlert("Success", $"Item '{item.Name}' deleted successfully", "OK");
                        
                        // Обновляем текущую панель
                        LoadDirectory(_panelManager.IsLeftPanelActive ? LeftPath : RightPath, _panelManager.IsLeftPanelActive);
                    }
                    else
                    {
                        await DisplayAlert("Error", "Delete operation failed", "OK");
                    }
                }
                catch (Exception ex)
                {
                    await DisplayAlert("Error", $"Delete failed: {ex.Message}", "OK");
                }
            }
        }
        else
        {
            await DisplayAlert("Info", "Please select an item to delete", "OK");
        }
    }

    private void OnHomeClicked(object sender, EventArgs e)
    {
        System.Diagnostics.Debug.WriteLine("=== BUTTON: Home ===");
        
        try
        {
            // Получаем домашнюю директорию пользователя
            var homePath = _pathHelper.GetUserHomePath();
            
            // Переходим в домашнюю директорию на активной панели
            LoadDirectory(homePath, _panelManager.IsLeftPanelActive);
            
            System.Diagnostics.Debug.WriteLine($"Navigated to home directory: {homePath}");
        }
        catch (Exception ex)
        {
            DisplayAlert("Error", $"Cannot navigate to home directory: {ex.Message}", "OK");
        }
    }

    private void OnExitClicked(object sender, EventArgs e) => Application.Current?.Quit();

    // INotifyPropertyChanged
    public new event PropertyChangedEventHandler? PropertyChanged;

    protected virtual void NotifyPropertyChanged([CallerMemberName] string? propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}