/*
    *  MicroEmulator
    *  Copyright (C) 2002-2003 Bartek Teodorczyk <barteo@barteo.net>
    *
    *  This library is free software; you can redistribute it and/or
    *  modify it under the terms of the GNU Lesser General Public
    *  License as published by the Free Software Foundation; either
    *  version 2.1 of the License, or (at your option) any later version.
    *
   *  This library is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   *  Lesser General Public License for more details.
   *
   *  You should have received a copy of the GNU Lesser General Public
   *  License along with this library; if not, write to the Free Software
   *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  package org.microemu.app.ui.swt;
  
  import org.eclipse.swt.SWT;
  import org.eclipse.swt.events.SelectionAdapter;
  import org.eclipse.swt.events.SelectionEvent;
  import org.eclipse.swt.events.ShellAdapter;
  import org.eclipse.swt.events.ShellEvent;
  import org.eclipse.swt.events.ShellListener;
  import org.eclipse.swt.graphics.Point;
  import org.eclipse.swt.graphics.Rectangle;
  import org.eclipse.swt.layout.GridData;
  import org.eclipse.swt.layout.GridLayout;
  import org.eclipse.swt.widgets.Button;
  import org.eclipse.swt.widgets.Composite;
  import org.eclipse.swt.widgets.Control;
  import org.eclipse.swt.widgets.Display;
  import org.eclipse.swt.widgets.Event;
  import org.eclipse.swt.widgets.Listener;
  import org.eclipse.swt.widgets.Shell;
  
  
  public abstract class SwtDialog
  {
  	public static final int OK = 0;
  	public static final int CANCEL = 1;
  
  	private Shell parentShell;
  	private Shell shell;
  	
  	protected Control dialogArea;
  	protected Control buttonBar;
  	
  	protected Button btOk;
  	protected Button btCancel;
  
  	private boolean resizeHasOccurred = false;
  	private Listener resizeListener;
  	private Control contents;
  	private int shellStyle = SWT.SHELL_TRIM;
  	private boolean block = false;
  	private int returnCode = OK;
  
  
  	public SwtDialog(Shell parentShell)
  	{
  		this.parentShell = parentShell;
  		this.block = true;
  		this.shellStyle = SWT.DIALOG_TRIM | SWT.APPLICATION_MODAL;
  	}
  	
  	
  	public void create() 
  	{
  		shell = createShell();
  		contents = createContents(shell);
  
  		//initialize the bounds of the shell to that appropriate for the contents
  		initializeBounds();
  	}
  
  
  	protected final Shell createShell() 
  	{
  		Shell newShell = new Shell(parentShell, shellStyle);
  
  		resizeListener = new Listener() {
  			public void handleEvent(Event e) {
  				resizeHasOccurred = true;
  			}
  		};
  	
  		newShell.addListener(SWT.Resize,resizeListener);
  		newShell.setData(this);
  
  		newShell.addShellListener(getShellListener());
  
  		configureShell(newShell);
  		
  		return newShell;
  	}
 	
 	
 	protected void configureShell(Shell newShell) 
 	{
 		GridLayout layout = new GridLayout();
 		layout.marginHeight = 0;
 		layout.marginWidth = 0;
 		newShell.setLayout(layout);
 	}
 
 
 	protected Control createContents(Composite parent) 
 	{
 		Composite composite = new Composite(parent, 0);
 		GridLayout layout = new GridLayout();
 		layout.marginHeight = 0;
 		layout.marginWidth = 0;
 		layout.verticalSpacing = 0;
 		composite.setLayout(layout);
 		composite.setLayoutData(new GridData(GridData.FILL_BOTH));
 		composite.setFont(parent.getFont());
 
 		dialogArea = createDialogArea(composite);
 		buttonBar = createButtonBar(composite);
 
 		return composite;
 	}
 
 
 	protected Control createDialogArea(Composite parent) 
 	{
 		Composite composite = new Composite(parent, SWT.NONE);
 		
 		composite.setLayout(new GridLayout());
 		composite.setLayoutData(new GridData(GridData.FILL_BOTH));
 		composite.setFont(parent.getFont());
 
 		return composite;
 	}
 	
 
 	protected Control createButtonBar(Composite parent) 
 	{
 		Composite composite = new Composite(parent, SWT.NONE);
 		
 		composite.setLayout(new GridLayout(2, false));
 		composite.setLayoutData(new GridData(GridData.HORIZONTAL_ALIGN_CENTER));
 		composite.setFont(parent.getFont());
 
 		btOk = new Button(composite, SWT.PUSH);
 		btOk.setText("OK");		
 		btOk.addSelectionListener(new SelectionAdapter() 
 		{
 			public void widgetSelected(SelectionEvent event) 
 			{
 				buttonPressed(OK);
 			}
 		});
 		
 		btCancel = new Button(composite, SWT.PUSH);
 		btCancel.setText("Cancel");		
 		btCancel.addSelectionListener(new SelectionAdapter() 
 		{
 			public void widgetSelected(SelectionEvent event) 
 			{
 				buttonPressed(CANCEL);
 			}
 		});
 
 		return composite;
 	}
 	
 
 	protected void initializeBounds() 
 	{
 		if (resizeListener != null) {
 			shell.removeListener(SWT.Resize,resizeListener);
 		}
 	
 		if (resizeHasOccurred) { // Check if shell size has been set already.
 			return;
 		}
 
 		Point size = getInitialSize();
 		Point location = getInitialLocation(size);
 
 		shell.setBounds(location.x, location.y, size.x, size.y);
 	}
 	
 	
 	protected Point getInitialSize() 
 	{
 		return shell.computeSize(SWT.DEFAULT, SWT.DEFAULT, true);
 	}
 
 
 	protected Point getInitialLocation(Point initialSize) 
 	{
 		Composite parentShell = shell.getParent();
 		Rectangle containerBounds = (parentShell != null) ? parentShell.getBounds() : shell.getDisplay().getClientArea();
 		int x = Math.max(0, containerBounds.x + (containerBounds.width - initialSize.x) / 2);
 		int y = Math.max(0, containerBounds.y + (containerBounds.height - initialSize.y) / 3);
 		return new Point(x, y);
 	}
 	
 	
 	protected void buttonPressed(int buttonId) 
 	{
 		if (buttonId == OK) {
 			okPressed();
 		} else if (buttonId == CANCEL) {
 			cancelPressed();
 		}
 	}
 
 
 	protected void okPressed() 
 	{
 		setReturnCode(OK);
 		close();
 	}
 	
 	
 	protected void cancelPressed() {
 		setReturnCode(CANCEL);
 		close();
 	}
 	
 	
 	protected int getReturnCode() 
 	{
 		return returnCode;
 	}
 	
 	
 	protected void setReturnCode(int code) 
 	{
 		returnCode = code;
 	}
 	
 	
 	protected ShellListener getShellListener() 
 	{
 		return new ShellAdapter() 
 		{
 			public void shellClosed(ShellEvent event) 
 			{
 				event.doit= false;	// don't close now
 				setReturnCode(CANCEL);
 				close();
 			}
 		};
 	}
 
 
 	public boolean close() 
 	{
 		if (shell != null || !shell.isDisposed()) {
 			shell.dispose();
 			shell = null;
 			contents = null;
 		}
 
 		buttonBar = null;
 		dialogArea = null;
 
 		return true;
 	}
 
 
 	public Shell getShell() 
 	{
 		return shell;
 	}
 
 
 	public int open() 
 	{
 
 		if (shell == null) {
 			create();
 		}
 
 		shell.open();
 
 		if (block) { 
 			runEventLoop(shell);
 		}	
 
 		return returnCode;
 	}
 
 
 	private void runEventLoop(Shell shell) 
 	{
 		Display display;
 		if(shell == null) {
 			 display = Display.getCurrent();
 		}	else {
 			display = shell.getDisplay();
 		}
 		
 		while (shell != null && ! shell.isDisposed()) {
 			try {
 				if (!display.readAndDispatch()) {
 					display.sleep();
 				}
 			} catch (Throwable ex) {
 				System.err.println(ex);
 			}
 		}
 		display.update();
 	}
 
 }