ansi-fahrplan/UiElements/MenuItem.cs

using Mindmagma.Curses;

namespace SCI.CursesWrapper.UiElements;

public class MenuItem {
	private List<MenuItem> _childItems;
	public List<MenuItem> ChildItems { get { return _childItems; }}

	private string _label;
	public string Label { get { return _label; }}

	private string? _key;
	public string? Key { get { return _key; }}

	public delegate	void ItemActivated (object sender, MenuItemActivatedEventArgs e);

	// Event fired when menu item is activated
	public event ItemActivated? OnItemActivated;

	private TopMenu? _parentTopMenuWindow;
	public TopMenu? ParentTopMenuWindow { get { return _parentTopMenuWindow; }}

	/// <summary>
	/// Class constructor
	/// </summary>
	/// <param name="label"></param>
	/// <param name="key"></param>
	/// <param name="childItems"></param>
	public MenuItem (string label, string? key = null, List<MenuItem>? childItems = null) {
		_childItems = childItems ?? new List<MenuItem> ();
		_key = key;
		_label = label;
	}

	/// <summary>
	/// Sets this menu items parent TopMenu window
	/// </summary>
	/// <param name="parent">TopMenu window this menu item belongs to</param>
	public void AssignParentTopMenuWindow (TopMenu parent) {
		if (_parentTopMenuWindow is not null) return;
		_parentTopMenuWindow = parent;
	}

	/// <summary>
	/// Called when key on parent TopMenu window is pressed
	/// </summary>
	/// <param name="sender">Event sender, should be a Window object</param>
	/// <param name="e">Key Press Event arguments</param>
	public void KeypressHandler (object sender, NCursesKeyPressEventArgs e) {
		// Do not listen to key presses if not hotkey is assigned
		if (Key is null) return;
		
		// Do not react to key presses unless this menu items belongs to a window
		// and has event listeners upon menu item activation
		if (OnItemActivated is null) return;
		if (ParentTopMenuWindow is null) return;

		if (Key.Length > 1 && Key.StartsWith ("F")) { // Handle F keys
			if (e.KeyCode == CursesKey.KEY_F (int.Parse (Key.Substring (1)))) {
				ActivateItem ();
			}
		} else if (Key.Length == 1) { // Handle letters and numbers
			if (e.KeyCode == Key [0]) {
				ActivateItem ();
			}
		} else throw new NotImplementedException ("Currently only F-keys and letters work for Top Menu actions");
	}

	/// <summary>
	/// Call event handler assigned to this item being activated
	/// </summary>
	public void ActivateItem () {
		if (OnItemActivated is null) return;
		if (ParentTopMenuWindow is null) return;

		var eventArgs = new MenuItemActivatedEventArgs (ParentTopMenuWindow, this);
		OnItemActivated (this, eventArgs);
	}
}

public class MenuItemActivatedEventArgs : EventArgs {
	private TopMenu _topMenuWindow;
	public TopMenu TopMenuWindow { get { return _topMenuWindow; }}

	private MenuItem _relatedMenuItem;
	public MenuItem RelatedMenuItem { get { return _relatedMenuItem; }}

	public MenuItemActivatedEventArgs (TopMenu sourceTopMenuWindow, MenuItem relatedMenuItem) {
		_topMenuWindow = sourceTopMenuWindow;
		_relatedMenuItem = relatedMenuItem;
	}
}