package ie.dcu.apps.ist.actions;

import ie.dcu.swt.layout.LayoutFactory;

import org.eclipse.swt.*;
import org.eclipse.swt.browser.Browser;
import org.eclipse.swt.events.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

/**
 * Show a help dialog.
 * 
 * @author Kevin McGuinness
 */
public class HelpAction extends AppAction {
	
	private HelpBox dialog;
	
	
	public HelpAction(ActionManager m) {
		super(m);
	}

	
	@Override 
	public void run() { 
		if (dialog == null) {
			dialog = new HelpBox();
		}
		
		if (dialog.available()) {
			dialog.open();
		} else {
			info("Help browser unavailable on this system");
		}
	}
	
	
	/**
	 * Help dialog box, just wraps a browser.
	 */
	private class HelpBox {
		private Shell shell;
		private Composite content;
		private Browser browser;
		
		
		public HelpBox() {
			createShell();
			createContent();
		}


		private void createShell() {
			shell = new Shell(window.getShell(), SWT.SHELL_TRIM);
			
			// Prevent the shell from disposing on close
			shell.addShellListener(new ShellAdapter() {
				public void shellClosed(ShellEvent evt) {
					evt.doit = false;
					close();
				}
			});
			
			// Use a fill layout
			shell.setLayout(new GridLayout());
			
			// Set size and title
			shell.setSize(640, 480);
			shell.setText("Help");
		}


		private void createContent() {
			// Create content pane
			content = new Composite(shell, SWT.BORDER);
			content.setLayout(new FillLayout());
			content.setLayoutData(LayoutFactory.createGridData());
			
			// Add browser widget
			try {
				browser = new Browser(content, SWT.NONE);
			} catch (SWTError e) {
				
				// Log warning and return
				log.warning("Browser unavailable: " + e.getMessage());
				browser = null;
				return;
			}
			
			// Go to help home page
			home();
		}


		public void home() {
			String urlString = string("helpURL");
			if (urlString != null) {
				go(urlString);
			} else {
				browser.setText("Help file is unavailable.");
			}
		}
		
		
		public void go(String url) {
			browser.setUrl(url);
		}
				
		
		public boolean available() {
			return browser != null;
		}
		
		
		public void open() {
			shell.setVisible(true);
		}
		
		
		public void close() {
			shell.setVisible(false);
		}
	}	
}