/*
 * Copyright 2016 dorkbox, llc
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package dorkbox.systemTray.util;

/**
 * Utility methods for SWT.
 * <p>
 * SWT system tray types are just GTK trays.
 * <p>
 * Creating custom methods for a class is not possible with reflection - so we compile it AHEAD of time as Java 1.6, and save the bytecode
 * (which is then included with the release)
 * <p>
 * We **COULD** do some ASM/Bytecode generation, but why bother with even more libraries when it's just as easy to include it pre-compiled.
 */
public
class Swt {
    public static
    boolean isLoaded() throws Exception {
        // maybe we should load the SWT version? (In order for us to work with SWT, BOTH must be GTK2!!
        // SWT is GTK2, but if -DSWT_GTK3=1 is specified, it can be GTK3

        java.lang.reflect.Method m = ClassLoader.class.getDeclaredMethod("findLoadedClass", String.class);
        m.setAccessible(true);
        ClassLoader cl = ClassLoader.getSystemClassLoader();
        return null != m.invoke(cl, "org.eclipse.swt.widgets.Display");
    }

    public static
    void dispatch(final Runnable runnable) {
         org.eclipse.swt.widgets.Display.getCurrent()
                                        .asyncExec(runnable);
    }

    public static
    void onShutdown(final Runnable runnable) {
        org.eclipse.swt.widgets.Display.getCurrent()
                                       .getShells()[0].addListener(org.eclipse.swt.SWT.Close, new org.eclipse.swt.widgets.Listener() {
            @Override
            public
            void handleEvent(final org.eclipse.swt.widgets.Event event) {
                runnable.run();
            }
        });
    }
}