using System.Collections.ObjectModel;
using System.Windows;
using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using EngineeringSync.Setup.Services;
using EngineeringSync.Setup.Views.Pages;

namespace EngineeringSync.Setup.ViewModels;

public partial class WizardViewModel : ObservableObject
{
    public WizardState State { get; } = new();

    [ObservableProperty] private WizardPageBase _currentPage = null!;
    [ObservableProperty] private int _currentStepIndex;
    [ObservableProperty] private bool _canGoBack;
    [ObservableProperty] private bool _canGoNext = true;
    [ObservableProperty] private bool _isLastStep;
    [ObservableProperty]
    [NotifyPropertyChangedFor(nameof(ShowNextButton))]
    private bool _isInstalling;

    [ObservableProperty]
    [NotifyPropertyChangedFor(nameof(ShowNextButton))]
    private bool _isCompleted;

    public bool ShowNextButton => !IsCompleted && !IsInstalling;

    public ObservableCollection<WizardStep> Steps { get; } =
    [
        new("Willkommen",    "\uE80F"),   // Home icon
        new("Installation",  "\uE7B7"),   // Folder icon
        new("Erstes Projekt","\uE8B7"),   // Link icon
        new("Backup",        "\uE72E"),   // Save icon (NEU)
        new("Optionen",      "\uE713"),   // Settings icon
        new("Zusammenfassung","\uE8A9"),  // List icon
        new("Installation",  "\uE896"),   // Download icon
        new("Fertig",        "\uE930"),   // Completed icon
    ];

    private readonly List<Func<WizardPageBase>> _pageFactories;
    private readonly InstallerService _installer;

    public WizardViewModel()
    {
        _installer = new InstallerService(State);

        _pageFactories =
        [
            () => new WelcomePage(this),
            () => new InstallPathPage(this),
            () => new FirstProjectPage(this),
            () => new BackupOptionsPage(this),    // NEU – Index 3
            () => new ServiceOptionsPage(this),
            () => new SummaryPage(this),
            () => new InstallingPage(this, _installer),
            () => new CompletionPage(this),
        ];

        NavigateTo(0);
    }

    public void NavigateTo(int index)
    {
        CurrentStepIndex = index;
        CurrentPage = _pageFactories[index]();
        Steps[index].IsActive = true;

        for (int i = 0; i < Steps.Count; i++)
        {
            Steps[i].IsCompleted = i < index;
            Steps[i].IsActive    = i == index;
        }

        CanGoBack   = index > 0 && index < Steps.Count - 1 && !IsInstalling;
        IsLastStep  = index == Steps.Count - 2; // "Zusammenfassung" ist letzter normaler Schritt
        // IsInstalling wird NICHT hier gesetzt – wird von InstallingPage kontrolliert
        IsCompleted  = index == Steps.Count - 1;
        CanGoNext   = !IsInstalling && !IsCompleted;
    }

    public void SetInstallingState(bool installing)
    {
        IsInstalling = installing;
        // CanGoNext wird durch die Bedingung !IsInstalling && !IsCompleted neu evaluiert
        CanGoNext = !IsInstalling && !IsCompleted;
        // GoBackCommand und CancelCommand CanExecute Bedingungen neu evaluieren
        GoBackCommand.NotifyCanExecuteChanged();
        CancelCommand.NotifyCanExecuteChanged();
    }

    [RelayCommand(CanExecute = nameof(CanExecuteGoBack))]
    private void GoBack() => NavigateTo(CurrentStepIndex - 1);

    private bool CanExecuteGoBack => CanGoBack && !IsInstalling;

    [RelayCommand]
    private void GoNext()
    {
        if (!CurrentPage.Validate()) return;
        if (CurrentStepIndex < _pageFactories.Count - 1)
            NavigateTo(CurrentStepIndex + 1);
    }

    [RelayCommand(CanExecute = nameof(CanExecuteCancel))]
    private void Cancel()
    {
        if (IsCompleted) return;
        var result = MessageBox.Show(
            "Setup wirklich abbrechen?",
            "EngineeringSync Setup",
            MessageBoxButton.YesNo,
            MessageBoxImage.Question);
        if (result == MessageBoxResult.Yes)
            Application.Current.Shutdown();
    }

    private bool CanExecuteCancel => !IsInstalling && !IsCompleted;

    [RelayCommand]
    private void Finish()
    {
        if (State.StartAfterInstall)
            _installer.LaunchTrayApp();
        Application.Current.Shutdown();
    }
}

public partial class WizardStep(string title, string icon) : ObservableObject
{
    public string Title { get; } = title;
    public string Icon  { get; } = icon;
    [ObservableProperty] private bool _isActive;
    [ObservableProperty] private bool _isCompleted;
}