using System;
using System.Windows;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using HC_APTBS.Services;
using HC_APTBS.ViewModels.Dialogs;
using HC_APTBS.Views.Dialogs;

namespace HC_APTBS.ViewModels
{
    /// <summary>
    /// ViewModel for the <c>AuthGateView</c> wrapper control that hides write-capable
    /// content behind an operator authentication dialog.
    ///
    /// <para>Used by the Pump page on the Adaptation and Unlock sub-sections per
    /// <c>docs/ui-structure.md</c> §3.d/§3.e (write actions require authentication).</para>
    /// </summary>
    public sealed partial class AuthGateViewModel : ObservableObject
    {
        private readonly IConfigurationService _config;
        private readonly ILocalizationService _loc;

        /// <summary>Initialises the gate; starts in the locked state.</summary>
        public AuthGateViewModel(IConfigurationService config, ILocalizationService loc)
        {
            _config = config;
            _loc    = loc;
        }

        // ── State ─────────────────────────────────────────────────────────────────

        /// <summary>True once the operator has successfully authenticated.</summary>
        [ObservableProperty]
        [NotifyCanExecuteChangedFor(nameof(AuthenticateCommand))]
        [NotifyCanExecuteChangedFor(nameof(LockCommand))]
        private bool _isAuthenticated;

        /// <summary>The currently authenticated username (empty when locked).</summary>
        [ObservableProperty] private string _authenticatedUser = string.Empty;

        // ── Commands ──────────────────────────────────────────────────────────────

        /// <summary>Opens the UserCheck dialog; flips to authenticated on success.</summary>
        [RelayCommand(CanExecute = nameof(CanAuthenticate))]
        private void Authenticate()
        {
            var vm  = new UserCheckViewModel(_config, _loc, AuthenticatedUser);
            var dlg = new UserCheckDialog(vm) { Owner = Application.Current.MainWindow };
            dlg.ShowDialog();
            if (!vm.Accepted) return;

            AuthenticatedUser = vm.AuthenticatedUser;
            IsAuthenticated   = true;
        }

        private bool CanAuthenticate() => !IsAuthenticated;

        /// <summary>Re-locks the gate (e.g. after finishing a sensitive operation).</summary>
        [RelayCommand(CanExecute = nameof(CanLock))]
        private void Lock()
        {
            IsAuthenticated   = false;
            AuthenticatedUser = string.Empty;
        }

        private bool CanLock() => IsAuthenticated;
    }
}