/*
 * This file is part of lanterna (https://github.com/mabe02/lanterna).
 *
 * lanterna is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Copyright (C) 2010-2020 Martin Berglund
 * Copyright (C) 2017 Bruno Eberhard
 * Copyright (C) 2017 University of Waikato, Hamilton, NZ
 */
package com.googlecode.lanterna.gui2.menu;

import com.googlecode.lanterna.gui2.MenuPopupWindow;
import com.googlecode.lanterna.gui2.Window;
import com.googlecode.lanterna.gui2.WindowBasedTextGUI;
import com.googlecode.lanterna.gui2.WindowListenerAdapter;
import com.googlecode.lanterna.input.KeyStroke;
import com.googlecode.lanterna.input.KeyType;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicBoolean;

/**
 * Implementation of a drop-down menu contained in a {@link MenuBar} and also a sub-menu inside another {@link Menu}.
 */
public class Menu extends MenuItem {
    private final List<MenuItem> subItems;

    /**
     * Creates a menu with the specified label
     * @param label Label to use for the menu item that will trigger this menu to pop up
     */
    public Menu(String label) {
        super(label);
        this.subItems = new ArrayList<>();
    }

    /**
     * Adds a new menu item to this menu, this can be either a regular {@link MenuItem} or another {@link Menu}
     * @param menuItem The item to add to this menu
     * @return Itself
     */
    public Menu add(MenuItem menuItem) {
        synchronized (subItems) {
            subItems.add(menuItem);
        }
        return this;
    }

    @Override
    protected boolean onActivated() {
        boolean result = true;
        if (!subItems.isEmpty()) {
            final MenuPopupWindow popupMenu = new MenuPopupWindow(this);
            final AtomicBoolean popupCancelled = new AtomicBoolean(false);
            for (MenuItem menuItem: subItems) {
                popupMenu.addMenuItem(menuItem);
            }
            if (getParent() instanceof MenuBar) {
                final MenuBar menuBar = (MenuBar)getParent();
                popupMenu.addWindowListener(new WindowListenerAdapter() {
                    @Override
                    public void onUnhandledInput(Window basePane, KeyStroke keyStroke, AtomicBoolean hasBeenHandled) {
                        if (keyStroke.getKeyType() == KeyType.ArrowLeft) {
                            int thisMenuIndex = menuBar.getChildren().indexOf(Menu.this);
                            if (thisMenuIndex > 0) {
                                popupMenu.close();
                                Menu nextSelectedMenu = menuBar.getMenu(thisMenuIndex - 1);
                                nextSelectedMenu.takeFocus();
                                nextSelectedMenu.onActivated();
                            }
                        }
                        else if (keyStroke.getKeyType() == KeyType.ArrowRight) {
                            int thisMenuIndex = menuBar.getChildren().indexOf(Menu.this);
                            if (thisMenuIndex >= 0 && thisMenuIndex < menuBar.getMenuCount() - 1) {
                                popupMenu.close();
                                Menu nextSelectedMenu = menuBar.getMenu(thisMenuIndex + 1);
                                nextSelectedMenu.takeFocus();
                                nextSelectedMenu.onActivated();
                            }
                        }
                    }
                });
            }
            popupMenu.addWindowListener(new WindowListenerAdapter() {
                @Override
                public void onUnhandledInput(Window basePane, KeyStroke keyStroke, AtomicBoolean hasBeenHandled) {
                    if (keyStroke.getKeyType() == KeyType.Escape) {
                        popupCancelled.set(true);
                        popupMenu.close();
                    }
                }
            });
            ((WindowBasedTextGUI)getTextGUI()).addWindowAndWait(popupMenu);
            result = !popupCancelled.get();
        }
        return result;
    }
}