using IBKRTrader.Core.Modularity;

namespace IBKRTrader.UI;

/// <summary>
/// Verwaltet die registrierten Fenster-Views: öffnet sie als eigenständige Forms, hält je View
/// höchstens eine Instanz offen und holt ein bereits offenes Fenster wieder in den Vordergrund.
/// Meldet Änderungen am Offen-Status (für die Button-Markierung im Launcher).
/// Vorbild: PolytraderSharp <c>ShellUiHost</c>.
/// </summary>
public sealed class ShellUiHost : IModuleUiHost
{
    private readonly List<ModuleView>       _views = new();
    private readonly Dictionary<string, Form> _open = new(StringComparer.OrdinalIgnoreCase);
    private Form? _mainWindow;

    /// <summary>True, sobald das Beenden bestätigt wurde (der Launcher wertet das in FormClosing aus).</summary>
    public bool ShutdownConfirmed { get; private set; }

    public event Action? OpenStateChanged;

    public IReadOnlyList<ModuleView> Views => _views;

    public void RegisterView(ModuleView view) => _views.Add(view);

    /// <summary>Setzt das Hauptfenster (Launcher) – Ziel für <see cref="ActivateMain"/>.</summary>
    public void SetMainWindow(Form main) => _mainWindow = main;

    public bool IsOpen(string viewId) =>
        _open.TryGetValue(viewId, out var form) && !form.IsDisposed;

    public void ActivateMain()
    {
        if (_mainWindow is null || _mainWindow.IsDisposed) return;
        if (_mainWindow.WindowState == FormWindowState.Minimized)
            _mainWindow.WindowState = FormWindowState.Normal;
        _mainWindow.BringToFront();
        _mainWindow.Activate();
    }

    /// <summary>Sicherheitsabfrage; bei Bestätigung wird die Message-Loop beendet.</summary>
    public void RequestShutdown()
    {
        if (ShutdownConfirmed) return;
        var owner = _mainWindow is { IsDisposed: false } ? _mainWindow : null;
        var result = MessageBox.Show(owner,
            "IBKRTrader wirklich beenden? Laufende Worker/Services werden gestoppt.",
            "Beenden", MessageBoxButtons.OKCancel, MessageBoxIcon.Warning);
        if (result != DialogResult.OK) return;

        ShutdownConfirmed = true;
        Application.Exit();
    }

    public void OpenView(string viewId)
    {
        var view = _views.FirstOrDefault(v => v.Id == viewId);
        if (view is not null) OpenView(view);
    }

    private void OpenView(ModuleView view)
    {
        if (_open.TryGetValue(view.Id, out var existing) && !existing.IsDisposed)
        {
            if (existing.WindowState == FormWindowState.Minimized)
                existing.WindowState = FormWindowState.Normal;
            existing.BringToFront();
            existing.Activate();
            return;
        }

        // Der Core-Contract ist toolkit-neutral (CreateView liefert object). Ein anderer Typ als
        // Form ist ein Programmierfehler und soll laut scheitern, nicht still ein leeres Fenster geben.
        var form = (Form)view.CreateView();
        if (string.IsNullOrEmpty(form.Text) || form.Text == form.Name)
            form.Text = view.Title;

        // Gemeinsames „Fenster"-Menü in jedes Fenster injizieren (identische Shell-Chrome).
        if (form.MainMenuStrip is null)
            AttachWindowMenu(form, view.Id);

        _open[view.Id] = form;
        form.FormClosed += (_, _) =>
        {
            _open.Remove(view.Id);
            OpenStateChanged?.Invoke();
        };

        form.Show();
        OpenStateChanged?.Invoke();
    }

    private void AttachWindowMenu(Form form, string currentViewId)
    {
        var menu = new MenuStrip { Dock = DockStyle.Top, ImageScalingSize = new Size(24, 24) };
        WindowMenu.Wire(menu, this, currentViewId);
        form.Controls.Add(menu);
        form.MainMenuStrip = menu;
    }

    /// <summary>Schließt alle offenen View-Fenster (beim Herunterfahren).</summary>
    public void CloseAllViews()
    {
        foreach (var form in _open.Values.ToList())
            if (!form.IsDisposed)
                form.Close();
        _open.Clear();
    }
}