using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using UtopiaCanteenSystem.Services;

namespace UtopiaCanteenSystem.ViewModels;

public partial class AdminLoginViewModel : ObservableObject
{
    private readonly IAuthService _authService;
    private readonly AppSession _session;
    private readonly INavigationService _navigation;
    private readonly IConfigService _config;

    [ObservableProperty]
    private string _username = string.Empty;

    // Updated from code-behind (PasswordBox doesn't support binding cleanly).
    [ObservableProperty]
    private string _password = string.Empty;

    [ObservableProperty]
    private string _errorMessage = string.Empty;

    [ObservableProperty]
    private bool _isBusy;

    [ObservableProperty]
    private bool _rememberCredentials;

    public AdminLoginViewModel(IAuthService authService, AppSession session, INavigationService navigation, IConfigService config)
    {
        _authService = authService;
        _session = session;
        _navigation = navigation;
        _config = config;

        RememberCredentials = _config.GetRememberAdminCredentials();
        if (RememberCredentials)
        {
            Username = _config.GetSavedAdminUsername();
            Password = _config.GetSavedAdminPassword();
        }
    }

    [RelayCommand]
    private async Task AdminLoginAsync()
    {
        if (IsBusy)
            return;

        ErrorMessage = string.Empty;

        var user = Username?.Trim() ?? string.Empty;
        var pass = Password ?? string.Empty;

        // Requirement: always clear fields after clicking LOGIN (success or failure).
        // Keep local copies for the ongoing request.
        Username = string.Empty;
        Password = string.Empty;

        if (string.IsNullOrWhiteSpace(user) || string.IsNullOrEmpty(pass))
        {
            ErrorMessage = "Username and password are required.";
            return;
        }

        IsBusy = true;
        try
        {
            var result = await _authService.LoginAsync(user, pass).ConfigureAwait(true);
            if (!result.Success)
            {
                ErrorMessage = "Invalid username or password.";
                return;
            }

            _session.SetAdminAuthenticated(user, result.EmployeeId);

            // Persist credentials only if user opted in.
            _config.SetRememberAdminCredentials(RememberCredentials);
            if (RememberCredentials)
            {
                _config.SetSavedAdminUsername(user);
                _config.SetSavedAdminPassword(pass);
            }
            else
            {
                _config.SetSavedAdminUsername(string.Empty);
                _config.SetSavedAdminPassword(string.Empty);
            }

            _navigation.NavigateToScanner();
        }
        finally
        {
            IsBusy = false;
        }
    }
}