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

namespace HC_APTBS.ViewModels
{
    /// <summary>
    /// A single row in the Tests-page preconditions checklist.
    /// <para>Labels and remediation hints are localised strings resolved by the parent
    /// <see cref="TestPreconditionsViewModel"/> and refreshed whenever
    /// <see cref="ILocalizationService.LanguageChanged"/> fires. The item itself only
    /// carries the currently-resolved text plus a navigation hook so the view can offer
    /// a "fix-it" link when the check fails.</para>
    /// </summary>
    public sealed partial class PreconditionItemViewModel : ObservableObject
    {
        /// <summary>Stable identifier used by the parent VM to look items up when refreshing.</summary>
        public string Id { get; }

        /// <summary>Localised human-readable check label (e.g. "Oil pump ON").</summary>
        [ObservableProperty] private string _label = string.Empty;

        /// <summary>True when the associated runtime check currently passes.</summary>
        [ObservableProperty] private bool _isSatisfied;

        /// <summary>When false, this check is advisory only and does not block Start.</summary>
        [ObservableProperty] private bool _isRequired = true;

        /// <summary>Localised fix-it hint shown when the check fails (e.g. "Go to Bench → start oil pump").</summary>
        [ObservableProperty] private string _remediationText = string.Empty;

        /// <summary>When non-null, the remediation button navigates to this page.</summary>
        public AppPage? RemediationTargetPage { get; }

        /// <summary>True when the remediation action should be offered (failing + has a target page).</summary>
        public bool HasRemediation => !IsSatisfied && RemediationTargetPage.HasValue;

        private readonly MainViewModel _root;

        /// <param name="id">Stable identifier (used by the parent VM to patch state).</param>
        /// <param name="root">Root view-model used to drive page navigation.</param>
        /// <param name="remediationTargetPage">Destination page when the fix-it link is clicked, or null when no page applies.</param>
        /// <param name="isRequired">When false this item is advisory only.</param>
        public PreconditionItemViewModel(
            string id,
            MainViewModel root,
            AppPage? remediationTargetPage = null,
            bool isRequired = true)
        {
            Id = id;
            _root = root;
            RemediationTargetPage = remediationTargetPage;
            _isRequired = isRequired;
        }

        /// <summary>Navigates the shell to the remediation target page.</summary>
        [RelayCommand]
        private void NavigateToFix()
        {
            if (RemediationTargetPage.HasValue)
                _root.SelectedPage = RemediationTargetPage.Value;
        }

        partial void OnIsSatisfiedChanged(bool value) => OnPropertyChanged(nameof(HasRemediation));
    }
}