package org.eclipse.dltk.debug.ui.preferences;

import java.net.MalformedURLException;
import java.net.URL;
import java.util.Map;

import org.eclipse.core.resources.IProject;
import org.eclipse.dltk.core.DLTKCore;
import org.eclipse.dltk.core.environment.EnvironmentPathUtils;
import org.eclipse.dltk.core.environment.IEnvironment;
import org.eclipse.dltk.ui.environment.EnvironmentPathBlock;
import org.eclipse.dltk.ui.preferences.PreferenceKey;
import org.eclipse.dltk.ui.util.IStatusChangeListener;
import org.eclipse.dltk.ui.util.SWTFactory;
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.widgets.Composite;
import org.eclipse.swt.widgets.Group;
import org.eclipse.swt.widgets.Link;
import org.eclipse.ui.PartInitException;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.browser.IWebBrowser;
import org.eclipse.ui.preferences.IWorkbenchPreferenceContainer;

/**
 * Options block for external debugging engine that require the user to specify
 * their location on disk.
 */
public abstract class ExternalDebuggingEngineOptionsBlock
		extends DebuggingEngineConfigOptionsBlock {

	EnvironmentPathBlock enginePaths;

	public ExternalDebuggingEngineOptionsBlock(IStatusChangeListener context,
			IProject project, PreferenceKey[] allKeys,
			IWorkbenchPreferenceContainer container) {
		super(context, project, allKeys, container);
	}

	/**
	 * Add a link to an external site where the debugging engine can be
	 * downloaded from
	 *
	 * @param parent
	 *            parent composite
	 * @param text
	 *            link text
	 * @param url
	 *            link url
	 */
	protected void addDownloadLink(Composite parent, String text,
			final String url) {
		Link link = new Link(parent, SWT.NONE);
		link.addSelectionListener(new SelectionAdapter() {
			@Override
			public void widgetSelected(SelectionEvent e) {
				openExternalUrl(url);
			}
		});

		link.setText(text);
	}

	/**
	 * Returns the debugging engine path preference key.
	 */
	protected abstract PreferenceKey getDebuggingEnginePathKey();

	/**
	 * Creates the engine path block.
	 *
	 * <p>
	 * Sub-classes are free to override if they wish to make additional
	 * contributions to the parent composite to provide additional options for
	 * their specific engine.
	 * </p>
	 *
	 * @param parent
	 *            parent composite
	 */
	@Override
	protected void createEngineBlock(final Composite parent) {
		final Group group = SWTFactory.createGroup(parent,
				ScriptDebugPreferencesMessages.ExternalEngineGroup, 3, 1,
				getExternalEngineBlockFillType());

		enginePaths = new EnvironmentPathBlock();
		enginePaths.createControl(group, getRelevantEnvironments());
		enginePaths.setPaths(getEnvironmentPaths());
	}

	protected int getExternalEngineBlockFillType() {
		return GridData.FILL_BOTH;
	}

	@Override
	protected boolean processChanges(IWorkbenchPreferenceContainer container) {
		setEnvironmentPaths(enginePaths.getPaths());
		return super.processChanges(container);
	}

	/**
	 * @since 2.0
	 */
	protected Map<IEnvironment, String> getEnvironmentPaths() {
		String pathKeyValue = getString(getDebuggingEnginePathKey());
		return EnvironmentPathUtils.decodePaths(pathKeyValue);
	}

	private void setEnvironmentPaths(Map<IEnvironment, String> env2path) {
		String pathKeyValue = EnvironmentPathUtils.encodePaths(env2path);
		setString(getDebuggingEnginePathKey(), pathKeyValue);
	}

	protected void openExternalUrl(String url) {
		try {
			final IWebBrowser browser = PlatformUI.getWorkbench()
					.getBrowserSupport().getExternalBrowser();
			browser.openURL(new URL(url));
		} catch (PartInitException e) {
			if (DLTKCore.DEBUG) {
				e.printStackTrace();
			}
		} catch (MalformedURLException e) {
			if (DLTKCore.DEBUG) {
				e.printStackTrace();
			}
		}
	}
}