package org.bndtools.utils.swt;

import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Text;

public class FilterPanelPart {

	private static final String				PROP_FILTER				= "filter";
	private static final long				SEARCH_DELAY			= 1000;

	private final ScheduledExecutorService	scheduler;

	private String							filter;

	private Composite						panel;
	private Text							txtFilter;

	private final PropertyChangeSupport		propSupport				= new PropertyChangeSupport(this);
	private final Lock						scheduledFilterLock		= new ReentrantLock();
	private final Runnable					updateFilterTask		= () -> {
																		Display display = panel.getDisplay();
																		Runnable update = () -> {
																																			String newFilter = txtFilter
																																				.getText();
																																			setFilter(
																																				newFilter);
																																		};
																		if (display.getThread() == Thread
																			.currentThread())
																			update.run();
																		else
																			display.asyncExec(update);
																	};
	private ScheduledFuture<?>				scheduledFilterUpdate	= null;

	public FilterPanelPart(ScheduledExecutorService scheduler) {
		this.scheduler = scheduler;
	}

	public Control createControl(Composite parent) {
		return createControl(parent, 0, 0);
	}

	public Control createControl(Composite parent, int marginWidth, int marginHeight) {
		// CREATE CONTROLS
		panel = new Composite(parent, SWT.NONE);
		panel.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));
		txtFilter = new Text(panel, SWT.SEARCH | SWT.ICON_SEARCH | SWT.ICON_CANCEL);
		txtFilter.setMessage("Enter search string");

		// INITIAL PROPERTIES
		if (filter != null)
			txtFilter.setText(filter);

		// LAYOUT
		GridLayout layout = new GridLayout(2, false);
		layout.marginHeight = marginHeight;
		layout.marginWidth = marginWidth;
		panel.setLayout(layout);
		txtFilter.setLayoutData(new GridData(SWT.FILL, SWT.FILL, true, false));

		// LISTENERS
		txtFilter.addSelectionListener(new SelectionAdapter() {
			@Override
			public void widgetDefaultSelected(SelectionEvent ev) {
				try {
					scheduledFilterLock.lock();
					if (scheduledFilterUpdate != null)
						scheduledFilterUpdate.cancel(true);
				} finally {
					scheduledFilterLock.unlock();
				}

				String newFilter = (ev.detail == SWT.CANCEL) ? "" : txtFilter.getText();
				setFilter(newFilter);
			}
		});
		txtFilter.addModifyListener(ev -> {
			try {
				scheduledFilterLock.lock();
				if (scheduledFilterUpdate != null)
					scheduledFilterUpdate.cancel(true);
				scheduledFilterUpdate = scheduler.schedule(updateFilterTask, SEARCH_DELAY, TimeUnit.MILLISECONDS);
			} finally {
				scheduledFilterLock.unlock();
			}
		});
		return panel;
	}

	public Text getFilterControl() {
		return txtFilter;
	}

	public String getFilter() {
		return filter;
	}

	public void setFilter(String filter) {
		String old = this.filter;
		this.filter = filter;
		propSupport.firePropertyChange(PROP_FILTER, old, filter);
	}

	public void setFocus() {
		if (txtFilter != null && !txtFilter.isDisposed())
			txtFilter.setFocus();
	}

	public void addPropertyChangeListener(PropertyChangeListener listener) {
		propSupport.addPropertyChangeListener(PROP_FILTER, listener);
	}

	public void removePropertyChangeListener(PropertyChangeListener listener) {
		propSupport.removePropertyChangeListener(PROP_FILTER, listener);
	}

}
