package org.myproject;

import java.util.Dictionary;

import nato.namsa.sssb.console.ConsoleActivator;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.core.commands.IHandler;
import org.eclipse.core.runtime.Platform;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.handlers.HandlerUtil;
import org.eclipse.ui.plugin.AbstractUIPlugin;
import org.osgi.framework.Bundle;

public class AboutHandler extends AbstractHandler implements IHandler {

	// -------------------------------------------------------------------------
	// Constants
	// -------------------------------------------------------------------------
	/**
	 * The company logo to be displayed on the left of the dialog.
	 */
	private static final Image DIALOG_IMAGE = AbstractUIPlugin
			.imageDescriptorFromPlugin(ConsoleActivator.PLUGIN_ID,
					"icons/logo.gif").createImage();
	/**
	 * The string displayed on the bar of the dialog.
	 */
	private static final String DIALOG_TITLE = "About My Project";
	/**
	 * The type of the dialog. Not used in our case.
	 */
	private static final int NONE = 0;
	/**
	 * Label for the only button on the dialogue.
	 */
	private static final String[] DIALOG_BUTTONS_LABELS = new String[] { IDialogConstants.OK_LABEL };
	/**
	 * The index for the selected button by default.
	 */
	private static final int DEFAULT_INDEX = 0;
	/**
	 * First line displayed in the text dialogue area.
	 */
	private static final String DIALOG_MESSAGE_TITLE = "\n\n\nMy Project";
	/**
	 * The copyright line
	 */
	private static final String COPYRIGHT_LINE = "(c) Copyright Matrix (2011-2012)";

	// -------------------------------------------------------------------------
	// Inner classes
	// -------------------------------------------------------------------------
	/**
	 * Custom dialogue displaying information about the console version and
	 * build.
	 * 
	 * 
	 */
	class AboutDialog extends MessageDialog {

		// ---------------------------------------------------------------------
		// Constructor
		// ---------------------------------------------------------------------
		/**
		 * Constructor for the custom dialog.
		 * 
		 * @param parentShell
		 *            the shell containing the dialog.
		 * @param dialogTitle
		 *            title displayed in bar of the dialog.
		 * @param dialogTitleImage
		 *            image to display in the bar of the dialogue. None is used.
		 * @param dialogMessage
		 *            The message to be displayed in the dialogue area. the
		 *            version and build numbers plus the copyright notice.
		 * @param dialogImageType
		 *            no used.
		 * @param dialogButtonLabels
		 *            only the OK button is displayed.
		 * @param defaultIndex
		 *            only one button is used on this dialog so it must be 0.
		 */
		public AboutDialog(Shell parentShell, String dialogTitle,
				Image dialogTitleImage, String dialogMessage,
				int dialogImageType, String[] dialogButtonLabels,
				int defaultIndex) {
			super(parentShell, dialogTitle, dialogTitleImage, dialogMessage,
					dialogImageType, dialogButtonLabels, defaultIndex);

		}

		// ---------------------------------------------------------------------
		// MessageDialog implementation.
		// ---------------------------------------------------------------------
		/**
		 * Overridden to return the company logo.
		 * 
		 * @return NSPA logo.
		 */
		@Override
		public Image getImage() {
			return DIALOG_IMAGE;
		}

	}

	// -------------------------------------------------------------------------
	// AbstractHandler implementation
	// -------------------------------------------------------------------------
	@Override
	public Object execute(ExecutionEvent event) throws ExecutionException {

		Shell parentShell = HandlerUtil.getActiveShell(event);

		String dialogMessage = getDialogMessage();
		AboutDialog dialog = new AboutDialog(parentShell, DIALOG_TITLE,
				DIALOG_IMAGE, dialogMessage, NONE, DIALOG_BUTTONS_LABELS,
				DEFAULT_INDEX);

		dialog.open();
		return null;
	}

	// -------------------------------------------------------------------------
	// Private Methods
	// -------------------------------------------------------------------------
	/**
	 * Computes the line to be displayed in the text area. This label contains
	 * the number of the product, the version, the build and a copyright notice.
	 * The text if formatted using '\n'.
	 * 
	 * @return the text in the dialog.
	 */
	private String getDialogMessage() {

		Bundle bundle = Platform.getBundle(ConsoleActivator.PLUGIN_ID);
		Dictionary<?, ?> dictionary = bundle.getHeaders();

		String versionLine = getVersionLine((String) dictionary
				.get("Bundle-version"));
		String buildLine = getBuildLine((String) dictionary
				.get("Bundle-version"));
		return DIALOG_MESSAGE_TITLE + "\n\n\n" + versionLine + "\n" + buildLine
				+ "\n\n" + COPYRIGHT_LINE;
	}

	/**
	 * Extract the version part of the bundle version.
	 * 
	 * @param bundleVersion
	 *            the version of the bundle in the format v.m.n.qualifier
	 * @return the version part, i.e. "v.m.n"
	 */
	private String getVersionLine(String bundleVersion) {
		int index = bundleVersion.lastIndexOf('.');

		return "Version: " + bundleVersion.substring(0, index);
	}

	/**
	 * Extract the qualifier part of the bundle version. This has been replaced
	 * in the build by the time stamp in the format yyyymmdd.
	 * 
	 * @param bundleVersion
	 *            the version of the bundle in the format v.m.n.qualifier
	 * @return the version part, i.e. "qualifier"
	 */
	private String getBuildLine(String bundleVersion) {
		int index = bundleVersion.lastIndexOf('.');

		return "Build: " + bundleVersion.substring(index + 1);
	}
}