/**
 * Provides a singleton console object for writing messages.
 *
 */
public class MyHLMConsole {

	private MessageConsole console = null;
	private MessageConsoleStream msgStream = null;
	private MessageConsoleStream infoStream = null;
	private MessageConsoleStream warnStream = null;
	private MessageConsoleStream errorStream = null;
	private static final String consoleName = "HLM-Console";
	
	public enum StreamCode {
		MESSAGE, INFO, WARNING, ERROR
	};

	// Singleton object.
	private static MyHLMConsole ref;
	
	/**
	 * Private Constructor.
	 *
	 */
	private MyHLMConsole() {
		// Create a console and register it.
		console = new MessageConsole(consoleName, null);
		ConsolePlugin.getDefault().getConsoleManager().addConsoles(new IConsole[] {console});
		
		// Create the message streams for this console.
		msgStream = createMessageConsoleStream(SWT.COLOR_BLACK);
		infoStream = createMessageConsoleStream(SWT.COLOR_DARK_GREEN);
		warnStream = createMessageConsoleStream(SWT.COLOR_DARK_YELLOW);
		errorStream = createMessageConsoleStream(SWT.COLOR_RED);
	}

	/**
	 * Get singleton object.
	 * @return Singleton object.
	 */
	public MyHLMConsole getDefault() {
		if (ref == null) {
			ref = new MyHLMConsole();
		}
		return ref;
	}
	
	/* (non-Javadoc)
	 * @see java.lang.Object#clone()
	 */
	public Object clone() throws CloneNotSupportedException
	{
		// Do not allow cloning!
		throw new CloneNotSupportedException("MyHLMConsole is singleton");
	}
	
	/**
	 * Clear the console.
	 */
	public void clear() {
		console.clearConsole();
	}
	
	/**
	 * Write a message to the console.
	 * @param message - The message.
	 * @param type - The type of message (normal, info, warning, error).
	 */
	public void print(String message, StreamCode code)
	{
		// Write the message and flush the stream.
		switch (code) {
		case MESSAGE:
			msgStream.print(message + "\n");
			try { msgStream.flush(); } catch (IOException e) { e.printStackTrace(); }
			break;
		case INFO:
			infoStream.print("[INFO] :: " + message + "\n");
			try { infoStream.flush(); } catch (IOException e) { e.printStackTrace(); }
			break;
		case WARNING:
			warnStream.print("[WARN] :: " + message + "\n");
			try { warnStream.flush(); } catch (IOException e) { e.printStackTrace(); }
			break;
		case ERROR:
			errorStream.print("[ERROR] :: " + message + "\n");
			try { errorStream.flush(); } catch (IOException e) { e.printStackTrace(); }
			break;
		default:
			break;
		}
	}
	
	/**
	 * Display (activate) the console.
	 * @return True if successful, false otherwise.
	 */
	public boolean display() {
		// Get active workbench, page, part.
		IWorkbenchWindow activeWorkbenchWindow = PlatformUI.getWorkbench().getActiveWorkbenchWindow();
		if (activeWorkbenchWindow != null) {
			IWorkbenchPage activePage = activeWorkbenchWindow.getActivePage();
			if (activePage != null) {
				// Keep current active part before displaying the console.
				IWorkbenchPart activePart = activePage.getActivePart();
				try {
					// Display console.
					IConsoleView view = (IConsoleView) activePage.showView(IConsoleConstants.ID_CONSOLE_VIEW);
					view.display(console);
				} catch (PartInitException e) {
					popupError("Error", "Opening console view failed");
					return false;
				}
				// Restore the previous active part. Otehrwise, focus will move to console view.
				activePage.activate(activePart);
			}
		}
		return true;
	}
	
	/**
	 * Create a new MessageConsoleStream tied to this console.
	 * @param color - The color to associate with stream.
	 * @return A MessageConsoleStream
	 */
	private MessageConsoleStream createMessageConsoleStream(int color) {
		MessageConsoleStream stream = console.newMessageStream();
		stream.setColor(Display.getCurrent().getSystemColor(color));
		stream.setActivateOnWrite(false);
		return stream;
	}
		
	/**
	 * Display a message dialog box indicating a error.
	 * @param title - Title of dialog box.
	 * @param message - Message to display.
	 */
	public void popupError(String title, String message)
	{
		MessageDialog.openError(PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell(), title, message);
	}
	
	/**
	 * Display a message dialog box asking a question.
	 * @param title - Title of dialog box.
	 * @param message - Message to display.
	 * @return True if user presses 'yes', false otherwise.
	 */
	public boolean popupQuestion(String title, String message)
	{
		return MessageDialog.openQuestion(PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell(), title, message);
	}
}