// MainPage.xaml.cs
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using Microsoft.Maui.Controls;

namespace CommanderApp;

public partial class MainPage : ContentPage, INotifyPropertyChanged
{
    private readonly IFileSystemService _fileService;

    public ObservableCollection<FileSystemItem> LeftItems { get; set; } = new();
    public ObservableCollection<FileSystemItem> RightItems { get; set; } = new();

    // --- Изменено: приватные поля + INotifyPropertyChanged ---
    private string _leftPath = string.Empty;
    private string _rightPath = string.Empty;

    private Grid? _currentSelectedGrid; // только один выделенный элемент в интерфейсе

    public string LeftPath
    {
        get => _leftPath;
        set
        {
            if (_leftPath != value)
            {
                _leftPath = value;
                NotifyPropertyChanged();
            }
        }
    }

    public string RightPath
    {
        get => _rightPath;
        set
        {
            if (_rightPath != value)
            {
                _rightPath = value;
                NotifyPropertyChanged();
            }
        }
    }

    private string _currentLeftPath = string.Empty;
    private string _currentRightPath = string.Empty;

    private FileSystemItem? _selectedLeftItem;
    private FileSystemItem? _selectedRightItem;

    public MainPage(IFileSystemService fileService)
    {
        InitializeComponent();
        _fileService = fileService;
        BindingContext = this;

        var root = _fileService.GetRootPath();
        LoadDirectory(root, true);
        LoadDirectory(root, false);
    }

    private void LoadDirectory(string path, bool isLeft)
    {
        var items = _fileService.GetDirectoryContents(path).ToList();

        if (isLeft)
        {
            LeftItems.Clear();
            foreach (var item in items) LeftItems.Add(item);
            _currentLeftPath = path;
            LeftPath = path; // Теперь это вызовет обновление UI
        }
        else
        {
            RightItems.Clear();
            foreach (var item in items) RightItems.Add(item);
            _currentRightPath = path;
            RightPath = path; // И это тоже
        }
    }

    private void OnLeftSelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        if (e.CurrentSelection.FirstOrDefault() is FileSystemItem item)
        {
            // Сохраняем выбор
            _selectedLeftItem = item;

            // Если это ".." или папка — переходим
            if (item.Name == ".." || item.IsDirectory)
            {
                LoadDirectory(item.FullName, true);
                // После перехода — сбрасываем выбор, чтобы не осталось выделения в новой папке
                _selectedLeftItem = null;
                LeftPanel.SelectedItem = null;
            }
            // Если это файл — ничего не делаем, оставляем его выделенным
        }
    }

    private void OnRightSelectionChanged(object sender, SelectionChangedEventArgs e)
    {
        if (e.CurrentSelection.FirstOrDefault() is FileSystemItem item)
        {
            _selectedRightItem = item;

            if (item.Name == ".." || item.IsDirectory)
            {
                LoadDirectory(item.FullName, false);
                _selectedRightItem = null;
                RightPanel.SelectedItem = null;
            }
        }
    }

    private async void OnCopyClicked(object sender, EventArgs e)
    {
        await ProcessFileOperation(async (src, destDir) =>
        {
            if (Directory.Exists(src))
                await CopyDirectory(src, Path.Combine(destDir, Path.GetFileName(src)));
            else
                File.Copy(src, Path.Combine(destDir, Path.GetFileName(src)), overwrite: true);
        }, "Copy");
    }

    private async void OnMoveClicked(object sender, EventArgs e)
    {
        await ProcessFileOperation((src, destDir) =>
        {
            var dest = Path.Combine(destDir, Path.GetFileName(src));
            if (Directory.Exists(src))
                Directory.Move(src, dest);
            else
                File.Move(src, dest, overwrite: true);
            return Task.CompletedTask;
        }, "Move");
    }

    private async void OnDeleteClicked(object sender, EventArgs e)
    {
        var item = _selectedLeftItem ?? _selectedRightItem;
        if (item == null) return;

        var confirm = await DisplayAlert("Delete", $"Delete '{item.Name}'?", "Yes", "No");
        if (confirm)
        {
            if (item.IsDirectory)
                Directory.Delete(item.FullName, recursive: true);
            else
                File.Delete(item.FullName);

            // Обновляем обе панели (или только ту, откуда удалили)
            LoadDirectory(_currentLeftPath, true);
            LoadDirectory(_currentRightPath, false);
        }
    }

    private async void OnMkdirClicked(object sender, EventArgs e)
    {
        var result = await DisplayPromptAsync("New Folder", "Folder name:", "Create", "Cancel");
        if (string.IsNullOrWhiteSpace(result)) return;

        // Создаём в активной панели (выберем левую, если выделение слева, иначе правую)
        string targetPath = (_selectedLeftItem != null || LeftItems.Count > 0) ? _currentLeftPath : _currentRightPath;
        string newPath = Path.Combine(targetPath, result.Trim());

        if (!Directory.Exists(newPath))
        {
            Directory.CreateDirectory(newPath);
            LoadDirectory(_currentLeftPath, true);
            LoadDirectory(_currentRightPath, false);
        }
        else
        {
            await DisplayAlert("Error", "Folder already exists.", "OK");
        }
    }

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

    private async Task CopyDirectory(string sourceDir, string targetDir)
    {
        Directory.CreateDirectory(targetDir);

        foreach (var file in Directory.GetFiles(sourceDir))
        {
            await Task.Run(() => File.Copy(file, Path.Combine(targetDir, Path.GetFileName(file)), overwrite: true));
        }

        foreach (var dir in Directory.GetDirectories(sourceDir))
        {
            await CopyDirectory(dir, Path.Combine(targetDir, Path.GetFileName(dir)));
        }
    }

    private async Task ProcessFileOperation(Func<string, string, Task> operation, string actionName)
    {
        var srcItem = _selectedLeftItem ?? _selectedRightItem;
        if (srcItem == null)
        {
            await DisplayAlert("Error", "Select a file or folder first.", "OK");
            return;
        }

        // Определяем целевую директорию: противоположная панель
        string destDir = (srcItem == _selectedLeftItem) ? _currentRightPath : _currentLeftPath;

        try
        {
            await operation(srcItem.FullName, destDir);
            // Обновляем обе панели
            LoadDirectory(_currentLeftPath, true);
            LoadDirectory(_currentRightPath, false);
        }
        catch (Exception ex)
        {
            await DisplayAlert("Error", $"{actionName} failed: {ex.Message}", "OK");
        }
    }

    private void OnLeftItemTapped(object sender, TappedEventArgs e)
    {
        var grid = (Grid)sender;
        var item = (FileSystemItem)grid.BindingContext;

        // Сбрасываем выделение у предыдущего элемента (где бы он ни был)
        if (_currentSelectedGrid != null)
        {
            _currentSelectedGrid.BackgroundColor = Colors.Transparent;
        }

        // Выделяем новый элемент
        grid.BackgroundColor = Color.FromArgb("#d0e0ff");
        _currentSelectedGrid = grid;

        // Обновляем активный выбор
        _selectedLeftItem = item;
        _selectedRightItem = null; // сбрасываем выбор в правой панели
    }

    private void OnLeftItemDoubleTapped(object sender, TappedEventArgs e)
    {
        var grid = (Grid)sender;
        var item = (FileSystemItem)grid.BindingContext;

        if (item.IsDirectory)
        {
            LoadDirectory(item.FullName, isLeft: true);
            // Сбрасываем выделение, так как панель обновляется
            if (_currentSelectedGrid != null)
            {
                _currentSelectedGrid.BackgroundColor = Colors.Transparent;
                _currentSelectedGrid = null;
            }
            _selectedLeftItem = null;
            _selectedRightItem = null;
        }
    }

    private void OnRightItemTapped(object sender, TappedEventArgs e)
    {
        var grid = (Grid)sender;
        var item = (FileSystemItem)grid.BindingContext;

        if (_currentSelectedGrid != null)
        {
            _currentSelectedGrid.BackgroundColor = Colors.Transparent;
        }

        grid.BackgroundColor = Color.FromArgb("#d0e0ff");
        _currentSelectedGrid = grid;

        _selectedRightItem = item;
        _selectedLeftItem = null; // сбрасываем выбор в левой панели
    }

    private void OnRightItemDoubleTapped(object sender, TappedEventArgs e)
    {
        var grid = (Grid)sender;
        var item = (FileSystemItem)grid.BindingContext;

        if (item.IsDirectory)
        {
            LoadDirectory(item.FullName, isLeft: false);
            if (_currentSelectedGrid != null)
            {
                _currentSelectedGrid.BackgroundColor = Colors.Transparent;
                _currentSelectedGrid = null;
            }
            _selectedLeftItem = null;
            _selectedRightItem = null;
        }
    }

    // --- Реализация INotifyPropertyChanged ---
    public new event PropertyChangedEventHandler? PropertyChanged;

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