using System.ComponentModel;
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Windows.Input;
using CORP_MAUI.Models;
using CORP_MAUI.Pages;
using CORP_MAUI.Services;

namespace CORP_MAUI.ViewModels;

public class ProfileViewModel : INotifyPropertyChanged
{
    private User? _user;
    private bool _isLoading;
    private string? _localImagePath;
    private ImageSource? _imageSource;

    public ProfileViewModel()
    {
        LoadProfileCommand = new Command(async () => await LoadProfileAsync());
        LogoutCommand = new Command(async () => await LogoutAsync());
    }

    public User? User
    {
        get => _user;
        set
        {
            _user = value;
            OnPropertyChanged();
            OnPropertyChanged(nameof(FullName));
            OnPropertyChanged(nameof(Username));
            OnPropertyChanged(nameof(Email));
            OnPropertyChanged(nameof(Position));
            OnPropertyChanged(nameof(Department));
            OnPropertyChanged(nameof(StatusText));
            OnPropertyChanged(nameof(StatusColor));
            OnPropertyChanged(nameof(Skills));
            OnPropertyChanged(nameof(HasSkills));
        }
    }

    public bool IsLoading
    {
        get => _isLoading;
        set
        {
            _isLoading = value;
            OnPropertyChanged();
        }
    }

    // Wrappers for UI binding
    public string FullName => _user?.FullName ?? "Загрузка...";
    public string Username => _user != null ? $"@{_user.Username}" : "";
    public string Email => _user?.Email ?? "-";
    public string Position => _user?.PositionName ?? "-";
    public string Department => _user?.DepartmentName ?? "-";
    public bool IsOnline => _user?.IsOnline ?? false;
    public string StatusText => IsOnline ? "В сети" : "Не в сети";
    public Color StatusColor => IsOnline ? Colors.LimeGreen : Colors.Gray;
    public List<Skill> Skills => _user?.Skills ?? new List<Skill>();
    public bool HasSkills => Skills.Any();

    // Image Logic
    public ImageSource? DisplayImageSource
    {
        get
        {
            if (_imageSource != null) return _imageSource;
            
            if (!string.IsNullOrEmpty(_localImagePath) && File.Exists(_localImagePath)) 
            {
                try 
                {
                    if (new FileInfo(_localImagePath).Length == 0) return null;
                    return ImageSource.FromStream(() => 
                    {
                        try
                        {
                            return new FileStream(_localImagePath, FileMode.Open, FileAccess.Read, FileShare.Read);
                        }
                        catch
                        {
                            return null;
                        }
                    });
                }
                catch { return null; }
            }
            // Default placeholder if needed
            return ImageSource.FromFile("dotnet_bot.png"); 
        }
    }

    public ICommand LoadProfileCommand { get; }
    public ICommand LogoutCommand { get; }

    public async Task LoadProfileAsync()
    {
        if (IsLoading) return;
        IsLoading = true;

        try
        {
            User? loadedUser = await ServiceProvider.ApiService.GetCurrentUserAsync();
            if (loadedUser != null)
            {
                User = loadedUser;
                await LoadAvatarAsync();
            }
        }
        catch (Exception ex)
        {
            Trace.WriteLine($"Error loading profile: {ex.Message}");
            
            Page? mainPage = Application.Current?.Windows.FirstOrDefault()?.Page;
            if (mainPage != null)
                await mainPage.DisplayAlert("Ошибка", "Не удалось загрузить профиль", "OK");
        }
        finally
        {
            IsLoading = false;
        }
    }

    private async Task LoadAvatarAsync()
    {
        if (_user == null || string.IsNullOrEmpty(_user.DisplayAvatarUrl)) return;

        try
        {
            string url = _user.DisplayAvatarUrl;
            // Generate cache filename
            Uri uri = new Uri(url);
            string extension = Path.GetExtension(uri.LocalPath);
            if (string.IsNullOrEmpty(extension)) extension = ".jpg";
            
            string fileName = Path.GetFileNameWithoutExtension(uri.LocalPath);
            fileName = Path.GetInvalidFileNameChars().Aggregate(fileName, (current, c) => current.Replace(c, '_'));
            
            string cacheFileName = $"user_{_user.Id}_{fileName}{extension}";
            string cacheFilePath = Path.Combine(FileSystem.CacheDirectory, cacheFileName);
            
            // Check cache
            if (File.Exists(cacheFilePath))
            {
                 FileInfo fileInfo = new FileInfo(cacheFilePath);
                 if (fileInfo.Length > 0)
                 {
                    _localImagePath = cacheFilePath;
                    OnPropertyChanged(nameof(DisplayImageSource));
                    return;
                 }
            }

            // Download
            byte[]? bytes = await ServiceProvider.ApiService.GetImageBytesAsync(url);
            if (bytes is { Length: > 0 })
            {
                 // Simple signature check
                 bool isImage = false;
                 if (bytes.Length > 2)
                 {
                    if (bytes[0] == 0xFF && bytes[1] == 0xD8) isImage = true;
                    else if (bytes[0] == 0x89 && bytes[1] == 0x50) isImage = true;
                    else isImage = true; // Relaxed check
                    
                    if (bytes[0] == '<') isImage = false; // HTML check
                 }
                 
                 if (isImage) 
                 {
                     await File.WriteAllBytesAsync(cacheFilePath, bytes);
                     _localImagePath = cacheFilePath;
                     OnPropertyChanged(nameof(DisplayImageSource));
                 }
            }
        }
        catch (Exception ex)
        {
            Trace.WriteLine($"Avatar load error: {ex.Message}");
        }
    }

    private async Task LogoutAsync()
    {
        Page? mainPage = Application.Current?.Windows.FirstOrDefault()?.Page;
        if (mainPage == null) return;
        
        bool result = await mainPage.DisplayAlert("Выход", "Вы уверены, что хотите выйти?", "Да", "Нет");
        if (result)
        {
             try
             {
                 await ServiceProvider.ApiService.UpdateStatusAsync(false);
                 await ServiceProvider.WebSocketService.DisconnectAsync();
                 ServiceProvider.ApiService.Logout();
                 SecureStorage.Remove("user_id");
                 SecureStorage.Remove("username");
                 
                 if (Application.Current?.Windows.Count > 0)
                 {
                    Application.Current.Windows[0].Page = new NavigationPage(new LoginPage());
                 }
             }
             catch(Exception ex)
             {
                 await mainPage.DisplayAlert("Ошибка", $"Ошибка при выходе: {ex.Message}", "OK");
             }
        }
    }

    public event PropertyChangedEventHandler? PropertyChanged;
    protected void OnPropertyChanged([CallerMemberName] string? name = null) => 
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));
}