package org.eclipse.ui.internal.dialogs;

/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;

import org.eclipse.core.resources.IMarker;
import org.eclipse.core.runtime.*;
import org.eclipse.jface.preference.JFacePreferences;
import org.eclipse.jface.resource.JFaceColors;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.util.PropertyChangeEvent;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.*;
import org.eclipse.ui.*;
import org.eclipse.ui.help.WorkbenchHelp;
import org.eclipse.ui.internal.*;
import org.eclipse.ui.part.EditorPart;

/**
 * A "fake" editor to show a welcome page
 * The contents of this page are supplied in the product configuration
 *
 * @private
 *		This class is internal to the workbench and must not be called outside the workbench
 */
public class WelcomeEditor extends EditorPart {
	
	private final String TAG_TITLE = "title";//$NON-NLS-1$
	private final String TAG_INTRO = "intro";//$NON-NLS-1$
	private final String TAG_ITEM = "item";//$NON-NLS-1$
	private final String TAG_CONTENTS = "contents";//$NON-NLS-1$
	
	private final static int HORZ_SCROLL_INCREMENT = 20;
	private final static int VERT_SCROLL_INCREMENT = 20;
	
	private Composite editorComposite;
	private Composite infoArea;

	private Cursor handCursor;
	private Cursor busyCursor;
	
	private IWorkbench workbench;
	private WelcomeParser parser;
	private Image image;
	
	private ArrayList hyperlinkRanges = new ArrayList();
	private ArrayList texts = new ArrayList();
	private StyledText lastNavigatedText = null;
	private ScrolledComposite scrolledComposite;
	
	private IPropertyChangeListener colorListener;
		
	
	/**
	 * The keyListener innerClass for the welcome editor
	 * navigation
	 */
	
	private KeyListener welcomeListener = new KeyListener(){
		
		public void keyReleased(KeyEvent e){
			//Ignore a key release
		}
		public void keyPressed (KeyEvent event){
			
			StyledText text = lastNavigatedText;
			if(event.character == '\t' && event.stateMask == SWT.NULL){
				StyleRange nextRange = findStartRange(text,false);
				if(nextRange == null){
					if(text != null)
						text.setSelection(0,0);
					focusOn(nextText(text));
				}
				else{
					text.setSelection(nextRange.start,nextRange.start + nextRange.length);
					text.setFocus();					
				}
				return;
			}
			if(event.character == ' ' || event.character == SWT.CR){
				if(text != null){
					WelcomeItem item = (WelcomeItem)text.getData();
	
					//Be sure we are in the selection
					int offset = text.getSelection().x + 1;
				
					if (item.isLinkAt(offset)) {	
						text.setCursor(busyCursor);
						item.triggerLinkAt(offset);
						text.setCursor(null);
					}
				}
				return;
			}	
			
			if(event.keyCode == SWT.PAGE_DOWN){
				focusOn(nextText(text));
				return;
			}
			
			if(event.keyCode == SWT.PAGE_UP){
				focusOn(previousText(text));
				return;
			}
			
		}
		
		/**
		 * Update the welcome page to start at the
		 * beginning of the text.
		 */
		private void focusOn(StyledText newText){
			if(newText == null)
				return;
			newText.setFocus();
			newText.setCaretOffset(0);
			scrolledComposite.setOrigin(0,newText.getLocation().y);
			lastNavigatedText = newText;
		}
		
		/**
		 * Find the next text 
		 */		
		private StyledText nextText(StyledText text){
			int index = 0;
			if(text == null)
				return (StyledText) texts.get(0);
			else
				index = texts.indexOf(text);
				
			//If we are not at the end....
			if(index < texts.size() - 1)
				return (StyledText) texts.get(index + 1);
			else
				return (StyledText)  texts.get(0);						
		}
		
		/**
		 * Find the previous text 
		 */		
		private StyledText previousText(StyledText text){
			int index = 0;
			if(text == null)
				return (StyledText) texts.get(0);
			else
				index = texts.indexOf(text);
				
			//If we are not at the end....
			if(index == 0)
				return (StyledText) texts.get(texts.size() - 1);
			else
				return (StyledText)  texts.get(index - 1);						
		}
	
		/**
		 * Find the next range after the current 
		 * selection.
		 */
		private StyleRange findStartRange(StyledText text, boolean returnDefault){
	
			if(text == null)
				return null;
				
			StyleRange[] ranges = text.getStyleRanges();
			int currentSelectionStart = text.getSelection().x;
	
			for (int i = 0; i < ranges.length; i++) {
				if(ranges[i].start > currentSelectionStart)
					return ranges[i];
			}
	
			//If the default one is good then return it
			if(ranges.length > 0 && returnDefault)
				return ranges[0];
			else
				return null;
		}
	};
	
/**
 * Create a new instance of the welcome editor
 */
public WelcomeEditor() {
	super();
	setTitle(WorkbenchMessages.getString("WelcomeEditor.title")); //$NON-NLS-1$	
}
/**
 * Adds listeners to the given styled text
 */
private void addListeners(StyledText styledText) {
	styledText.addMouseListener(new MouseAdapter() {
		public void mouseUp(MouseEvent e) {
			StyledText text = (StyledText)e.widget;
			WelcomeItem item = (WelcomeItem)e.widget.getData();
			int offset = text.getCaretOffset();
			if (item.isLinkAt(offset)) {	
				text.setCursor(busyCursor);
				item.triggerLinkAt(offset);
				text.setCursor(null);
			}
		}
	});
	styledText.addMouseMoveListener(new MouseMoveListener() {
		public void mouseMove(MouseEvent e) {
			StyledText text = (StyledText)e.widget;
			WelcomeItem item = (WelcomeItem)e.widget.getData();
			int offset = getOffsetAtLocation(text, e.x, e.y);
			if (offset == -1)
				text.setCursor(null);
			else if (item.isLinkAt(offset)) 
				text.setCursor(handCursor);
			else 
				text.setCursor(null);
		}
	});
	
	//Listen for Tab and Space to allow keyboard navigation
	styledText.addKeyListener(welcomeListener);
}

/**
 * Creates the wizard's title area.
 *
 * @param parent the SWT parent for the title area composite
 * @return the created info area composite
 */
private Composite createInfoArea(Composite parent) {
	// Create the title area which will contain
	// a title, message, and image.
	this.scrolledComposite = new ScrolledComposite(parent, SWT.V_SCROLL);
	this.scrolledComposite.setLayoutData(new GridData(GridData.FILL_BOTH));
	Composite infoArea = new Composite(this.scrolledComposite, SWT.NONE);
	GridLayout layout = new GridLayout();
	layout.marginHeight = 10;
	layout.verticalSpacing = 5;
	layout.numColumns = 2;
	infoArea.setLayout(layout);
	GridData data = new GridData(GridData.FILL_HORIZONTAL);
	infoArea.setLayoutData(data);

	// Get the background color for the title area
	Display display = parent.getDisplay();
	Color bg = JFaceColors.getBannerBackground(display);
	infoArea.setBackground(bg);

	StyledText sampleStyledText = null;
	// Create the intro item
	WelcomeItem item = getIntroItem();
	if (item != null) {
		StyledText styledText = new StyledText(infoArea, SWT.MULTI | SWT.READ_ONLY | SWT.WRAP | SWT.BORDER);
		this.texts.add(styledText);
		sampleStyledText = styledText;
		styledText.setCursor(null);
		styledText.setBackground(bg);
		styledText.setText(getIntroItem().getText());
		setBoldRanges(styledText, item.getBoldRanges());
		setLinkRanges(styledText, item.getActionRanges());
		setLinkRanges(styledText, item.getHelpRanges());
		GridData gd = new GridData(GridData.FILL_HORIZONTAL);
		gd.horizontalSpan = 2;
		gd.horizontalIndent = 20;
		styledText.setLayoutData(gd);
		styledText.setData(item);
		addListeners(styledText);
	
		Label spacer = new Label(infoArea, SWT.NONE);
		spacer.setBackground(bg);
		gd = new GridData(); 
		gd.horizontalSpan = 2;
		spacer.setLayoutData(gd);
	}

	// Create the welcome items
	WelcomeItem[] items = getItems();
	for (int i = 0; i < items.length; i++) {
		Label image = new Label(infoArea, SWT.NONE);
		image.setBackground(bg);
		image.setImage(WorkbenchImages.getImage(IWorkbenchGraphicConstants.IMG_OBJS_WELCOME_ITEM));
		GridData gd = new GridData(); 
		gd.horizontalIndent = 20;
		gd.verticalAlignment = gd.VERTICAL_ALIGN_BEGINNING;
		image.setLayoutData(gd);

		StyledText styledText = new StyledText(infoArea, SWT.MULTI | SWT.READ_ONLY | SWT.WRAP | SWT.BORDER);
		this.texts.add(styledText);
		sampleStyledText = styledText;
		styledText.setCursor(null);
		styledText.setBackground(bg);
		styledText.setText(items[i].getText());
		setBoldRanges(styledText, items[i].getBoldRanges());
		setLinkRanges(styledText, items[i].getActionRanges());
		setLinkRanges(styledText, items[i].getHelpRanges());
		gd = new GridData(GridData.FILL_HORIZONTAL);
		gd.verticalSpan = 2;
		styledText.setLayoutData(gd);
		styledText.setData(items[i]);
		addListeners(styledText);
			
		Label spacer = new Label(infoArea, SWT.NONE);
		spacer.setBackground(bg);
		gd = new GridData(GridData.FILL_HORIZONTAL); 
		gd.horizontalSpan = 2;
		spacer.setLayoutData(gd);
	}
	this.scrolledComposite.setContent(infoArea);

	// Adjust the scrollbar increments
	if (sampleStyledText == null) {
		this.scrolledComposite.getVerticalBar().setIncrement(VERT_SCROLL_INCREMENT);
	} else {
		GC gc = new GC(sampleStyledText);
		int width = gc.getFontMetrics().getAverageCharWidth();
		gc.dispose();
		this.scrolledComposite.getVerticalBar().setIncrement(sampleStyledText.getLineHeight());
	}
	this.scrolledComposite.addControlListener(new ControlAdapter() {
		public void controlResized(ControlEvent e) {
			ScrolledComposite localSC = (ScrolledComposite)e.widget;
			ScrollBar vertical = localSC.getVerticalBar();
			Rectangle clientArea = localSC.getClientArea(); 
			vertical.setPageIncrement(clientArea.height - vertical.getIncrement());
		}
	});

	return infoArea;
}


/**
 * Creates the SWT controls for this workbench part.
 * <p>
 * Clients should not call this method (the workbench calls this method at
 * appropriate times).
 * </p>
 * <p>
 * For implementors this is a multi-step process:
 * <ol>
 *   <li>Create one or more controls within the parent.</li>
 *   <li>Set the parent layout as needed.</li>
 *   <li>Register any global actions with the <code>IActionService</code>.</li>
 *   <li>Register any popup menus with the <code>IActionService</code>.</li>
 *   <li>Register a selection provider with the <code>ISelectionService</code>
 *     (optional). </li>
 * </ol>
 * </p>
 *
 * @param parent the parent control
 */
public void createPartControl(Composite parent) {
	// read our contents
	readFile();
	if (parser == null)
		return;

	handCursor = new Cursor(parent.getDisplay(), SWT.CURSOR_HAND);
	busyCursor = new Cursor(parent.getDisplay(), SWT.CURSOR_WAIT);
	
	editorComposite = new Composite(parent, SWT.NONE);
	GridLayout layout = new GridLayout();
	layout.marginHeight = 0;
	layout.marginWidth = 0;
	layout.verticalSpacing = 0;
	layout.horizontalSpacing = 0;
	editorComposite.setLayout(layout);

	Listener resizeListener = new Listener() {
		public void handleEvent(Event e) {
			editorComposite.layout(true);
			infoArea.layout(true);
System.out.println("layout");
//			editorComposite.removeListener(SWT.Resize, this);
			Point p = infoArea.getSize();
			scrolledComposite.setMinHeight(p.y);
			scrolledComposite.setExpandHorizontal(true);
			scrolledComposite.setExpandVertical(true);
		}
	};	
	editorComposite.addListener (SWT.Resize, resizeListener);

	createTitleArea(editorComposite);

	Label titleBarSeparator = new Label(editorComposite, SWT.HORIZONTAL | SWT.SEPARATOR);
	GridData gd = new GridData(GridData.FILL_HORIZONTAL);
	titleBarSeparator.setLayoutData(gd);

	infoArea = createInfoArea(editorComposite);

	WorkbenchHelp.setHelp(editorComposite, IHelpContextIds.WELCOME_EDITOR);
	
	this.colorListener = 
		new IPropertyChangeListener(){
			public void propertyChange(PropertyChangeEvent event){
				if(event.getProperty().equals(JFacePreferences.HYPERLINK_COLOR)){
					Color fg = JFaceColors.getHyperlinkText(editorComposite.getDisplay());
					Iterator links = hyperlinkRanges.iterator();
					while(links.hasNext()){
						StyleRange range = (StyleRange) links.next();
						range.foreground = fg;
					}
				}
			}
		};
		
	JFacePreferences.getPreferenceStore().addPropertyChangeListener(this.colorListener);
}
/**
 * Creates the wizard's title area.
 *
 * @param parent the SWT parent for the title area composite
 * @return the created title area composite
 */
private Composite createTitleArea(Composite parent) {
	// Get the background color for the title area
	Display display = parent.getDisplay();
	Color bg = JFaceColors.getBannerBackground(display);

	// Create the title area which will contain
	// a title, message, and image.
	Composite titleArea = new Composite(parent, SWT.NONE);
	GridLayout layout = new GridLayout();
	layout.marginHeight = 0;
	layout.marginWidth = 0;
	layout.verticalSpacing = 0;
	layout.horizontalSpacing = 0;
	layout.numColumns = 2;
	titleArea.setLayout(layout);
	titleArea.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
	titleArea.setBackground(bg);

	// Message label
	final CLabel messageLabel = new CLabel(titleArea, SWT.LEFT | SWT.BORDER);
	messageLabel.setBackground(bg);
	messageLabel.setText(getBannerTitle());
	messageLabel.setFont(JFaceResources.getHeaderFont());
	
	final IPropertyChangeListener fontListener = new IPropertyChangeListener() {
		public void propertyChange(PropertyChangeEvent event) {
			if(JFaceResources.HEADER_FONT.equals(event.getProperty())) {
				messageLabel.setFont(JFaceResources.getHeaderFont());
			}
		}
	};
	
	messageLabel.addDisposeListener(new DisposeListener() {
		public void widgetDisposed(DisposeEvent event) {
			JFaceResources.getFontRegistry().removeListener(fontListener);
		}
	});
	
	JFaceResources.getFontRegistry().addListener(fontListener);
	
	
	GridData gd = new GridData(GridData.FILL_BOTH);
	messageLabel.setLayoutData(gd);

	// Title image
	Label titleImage = new Label(titleArea, SWT.LEFT | SWT.BORDER);
	titleImage.setBackground(bg);
	titleImage.setImage(WorkbenchImages.getImage(IWorkbenchGraphicConstants.IMG_OBJS_WELCOME_BANNER));
	gd = new GridData(); 
	gd.horizontalAlignment = gd.END;
	titleImage.setLayoutData(gd);

	return titleArea;
}
/**
 * The <code>WorkbenchPart</code> implementation of this 
 * <code>IWorkbenchPart</code> method disposes the title image
 * loaded by <code>setInitializationData</code>. Subclasses may extend.
 */
public void dispose() {
	super.dispose();
	if (busyCursor != null)
		busyCursor.dispose();
	if (handCursor != null)
		handCursor.dispose();
	JFacePreferences.getPreferenceStore().
		removePropertyChangeListener(this.colorListener);
}
/* (non-Javadoc)
 * Saves the contents of this editor.
 * <p>
 * Subclasses must override this method to implement the open-save-close lifecycle
 * for an editor.  For greater details, see <code>IEditorPart</code>
 * </p>
 *
 * @see IEditorPart
 */
public void doSave(IProgressMonitor monitor) {
	// do nothing
}
/* (non-Javadoc)
 * Saves the contents of this editor to another object.
 * <p>
 * Subclasses must override this method to implement the open-save-close lifecycle
 * for an editor.  For greater details, see <code>IEditorPart</code>
 * </p>
 *
 * @see IEditorPart
 */
public void doSaveAs() {
	// do nothing	
}
/**
 * Returns the title obtained from the parser
 */
private String getBannerTitle() {
	if (parser.getTitle() == null)
		return ""; //$NON-NLS-1$
	return parser.getTitle();
}
/**
 * Returns the intro item or <code>null</code>
 */
private WelcomeItem getIntroItem() {
	return parser.getIntroItem();
}
/**
 * Returns the welcome items
 */
private WelcomeItem[] getItems() {
	return parser.getItems();
}
/**
 * Returns the text offset at the given pixwl location
 * Returns -1 if there is no offset at the location
 */
private int getOffsetAtLocation(StyledText styledText, int x, int y) {
		int charCount = styledText.getCharCount();
	if (charCount == 0 || x < 0 || y < 0)
		return -1;
	
	// get the line at the y coordinate
	int line = (y + styledText.getTopPixel()) / styledText.getLineHeight();

	// find an offset in the line
	int low = -1;
	int high = charCount;
	int offset = 0;
	int currentLine;
	
	while (high - low > 1) {
		offset = (high + low) / 2;
		currentLine = styledText.getLineAtOffset(offset);
		if (currentLine == line)
			break;
		if (currentLine > line)
			high = offset;			
		else 
			low = offset;
	}
	currentLine = styledText.getLineAtOffset(offset);

	// find the offset at x
	int delta;
	Point loc = styledText.getLocationAtOffset(offset);
	if (loc.x == x)
		return offset;
	else if (loc.x < x)
		delta = 1;
	else
		delta = -1;
	int newOffset = offset + delta;
	Point newLoc = styledText.getLocationAtOffset(newOffset);	
	while (currentLine == styledText.getLineAtOffset(newOffset)) {
		if (delta == 1) {
			if (newLoc.x > x)
				return offset;
		} else { 
			if (newLoc.x < x)
				return offset;
		}
		offset = newOffset;
		loc = newLoc;
		newOffset = offset + delta;
		if (newOffset < 0 || newOffset > charCount)
			return -1;
		newLoc = styledText.getLocationAtOffset(newOffset);
	}
	return -1;
}
/* (non-Javadoc)
 * Sets the cursor and selection state for this editor to the passage defined
 * by the given marker.
 * <p>
 * Subclasses may override.  For greater details, see <code>IEditorPart</code>
 * </p>
 *
 * @see IEditorPart
 */
public void gotoMarker(IMarker marker) {
	// do nothing
}
/* (non-Javadoc)
 * Initializes the editor part with a site and input.
 * <p>
 * Subclasses of <code>EditorPart</code> must implement this method.  Within
 * the implementation subclasses should verify that the input type is acceptable
 * and then save the site and input.  Here is sample code:
 * </p>
 * <pre>
 *		if (!(input instanceof IFileEditorInput))
 *			throw new PartInitException("Invalid Input: Must be IFileEditorInput");
 *		setSite(site);
 *		setInput(editorInput);
 * </pre>
 */
public void init(IEditorSite site, IEditorInput input) throws PartInitException {
	setSite(site);
	setInput(new WelcomeEditorInput());
}
/* (non-Javadoc)
 * Returns whether the contents of this editor have changed since the last save
 * operation.
 * <p>
 * Subclasses must override this method to implement the open-save-close lifecycle
 * for an editor.  For greater details, see <code>IEditorPart</code>
 * </p>
 *
 * @see IEditorPart
 */
public boolean isDirty() {
	return false;
}
/* (non-Javadoc)
 * Returns whether the "save as" operation is supported by this editor.
 * <p>
 * Subclasses must override this method to implement the open-save-close lifecycle
 * for an editor.  For greater details, see <code>IEditorPart</code>
 * </p>
 *
 * @see IEditorPart
 */
public boolean isSaveAsAllowed() {
	return false;
}
/**
 * Read the contents of the welcome page
 */
public void read(InputStream is) {
	parser = new WelcomeParser();
	parser.parse(is);
}
/**
 * Reads the welcome file
 */
public void readFile() {
	AboutInfo info = ((Workbench)PlatformUI.getWorkbench()).getAboutInfo();
	URL url = info.getWelcomePageURL();

	if (url == null) {
		// backward compatibility
		ProductInfo prodInfo = ((Workbench)PlatformUI.getWorkbench()).getProductInfo();
		url = prodInfo.getWelcomePageURL();
	}

	if (url == null)
		// should not happen since we disable if none specified
		return;
		
	InputStream is = null;
	try {
		is = url.openStream();
		read(is);
	}
	catch (IOException e) {
		IStatus status = new Status(IStatus.ERROR, WorkbenchPlugin.PI_WORKBENCH, 1, WorkbenchMessages.getString("WelcomeEditor.accessException"), e); //$NON-NLS-1$
		WorkbenchPlugin.log(WorkbenchMessages.getString("WelcomeEditor.readFileError"), status); //$NON-NLS-1$
	}
	finally {
		try { 
			if (is != null)
				is.close(); 
		} catch (IOException e) {}
	}
}
/**
 * Sets the styled text's bold ranges
 */
private void setBoldRanges(StyledText styledText, int[][] boldRanges) {
	for (int i = 0; i < boldRanges.length; i++) {
		StyleRange r = new StyleRange(boldRanges[i][0], boldRanges[i][1], null, null, SWT.BOLD);
		styledText.setStyleRange(r);
	}
}
/**
 * Asks this part to take focus within the workbench.
 * <p>
 * Clients should not call this method (the workbench calls this method at
 * appropriate times).
 * </p>
 */
public void setFocus() {
	if (editorComposite != null) {
		editorComposite.setFocus();
	}
}
/**
 * Sets the styled text's link (blue) ranges
 */
private void setLinkRanges(StyledText styledText, int[][] linkRanges) {
	//Color fg = styledText.getDisplay().getSystemColor(SWT.COLOR_BLUE);
	Color fg = JFaceColors.getHyperlinkText(styledText.getShell().getDisplay());
	for (int i = 0; i < linkRanges.length; i++) {
		StyleRange r = new StyleRange(linkRanges[i][0], linkRanges[i][1], fg, null);
		styledText.setStyleRange(r);
		hyperlinkRanges.add(r);
	}
}

}