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

namespace MauiApp1;

public partial class MainPage : ContentPage
{
    private readonly IFileSystemService _fileService;
    public ObservableCollection<FileSystemItem> LeftItems { get; set; } = new();
    public ObservableCollection<FileSystemItem> RightItems { get; set; } = new();
    public string LeftPath { get; set; } = string.Empty;
    public string RightPath { get; set; } = string.Empty;

    private string _currentLeftPath;
    private string _currentRightPath;

    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;
        }
        else
        {
            RightItems.Clear();
            foreach (var item in items) RightItems.Add(item);
            _currentRightPath = path;
            RightPath = path;
        }
    }

    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");
        }
    }
}