/*

* Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies this distribution, and is available

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description: 

*

*/

package javax.microedition.lcdui;

import org.eclipse.swt.SWT;

import org.eclipse.swt.graphics.Point;

import org.eclipse.swt.graphics.Rectangle;

import org.eclipse.swt.widgets.Composite;

import org.eclipse.swt.widgets.Event;

import org.eclipse.swt.widgets.Label;

import org.eclipse.swt.widgets.Layout;

import org.eclipse.swt.widgets.Listener;

import org.eclipse.swt.widgets.ScrollBar;

/**

 * Composite control which is able to scroll text with a vertical scroll bar.

 */

class ScrolledTextComposite extends Composite {

    private Label iESWTTextLabel;

    private ScrollBar vBar;

    private boolean resizing;

    private boolean iTextScrolling;

    /**

     * Constructor.

     */

    public ScrolledTextComposite(Composite parent, ScrollBar vertBar) {

        super(parent, 0);

        vBar = vertBar;

        vBar.setVisible(false);

        vBar.setMaximum(0);

        vBar.setThumb(0);

        vBar.setSelection(0);

        vBar.addListener(SWT.Selection, new Listener() {

            public void handleEvent(Event e) {

                vScroll();

            }

        });

        addListener(SWT.Resize, new Listener() {

            public void handleEvent(Event e) {

                resize();

            }

        });

        iESWTTextLabel = new Label(this, SWT.WRAP);

        iESWTTextLabel.setLocation(0, 0);

        layout();

        iESWTTextLabel.addListener(SWT.Resize, new Listener() {

            public void handleEvent(Event e) {

                if (e.type == SWT.Resize) {

                    resize();

                }

            }

        });

    }

    public void setText(String aText) {

        iESWTTextLabel.setText(aText);

        iESWTTextLabel.setSize(calculateTextSize());

    }

    private Point calculateTextSize() {

        iTextScrolling = false;

        vBar.setVisible(false);

        Point nextSize = iESWTTextLabel.computeSize(getClientArea().width,

                                                    SWT.DEFAULT);

        if (nextSize.y > getClientArea().height) {

            iTextScrolling = true;

            vBar.setVisible(true);

            nextSize = iESWTTextLabel.computeSize(getClientArea().width,

                                                  SWT.DEFAULT);

        }

        return nextSize;

    }

    /**

     * Return if the text is scrolling. The vBar.isVisible() is not good,

     * because it depends on parent's visibility.

     */

    public boolean isTextScrolling() {

        return iTextScrolling;

    }

    public void setLayout(Layout layout) {

        // do not allow a layout to be set

    }

    public void layout(boolean changed) {

        iESWTTextLabel.setSize(calculateTextSize());

        Rectangle contentRect = iESWTTextLabel.getBounds();

        Rectangle hostRect = getClientArea();

        vBar.setMaximum(contentRect.height);

        vBar.setThumb(Math.min(contentRect.height, hostRect.height));

        int vPage = contentRect.height - hostRect.height;

        int vSelection = vBar.getSelection();

        if (vSelection >= vPage) {

            if (vPage <= 0) {

                vSelection = 0;

                vBar.setSelection(0);

            }

            contentRect.y = -vSelection;

        }

        iESWTTextLabel.setLocation(contentRect.x, contentRect.y);

    }

    public Point computeSize(int wHint, int hHint, boolean changed) {

        Point size = iESWTTextLabel.computeSize(wHint, hHint, changed);

        Rectangle trim = computeTrim(0, 0, size.x, size.y);

        return new Point(trim.width, trim.height);

    }

    public Point getOrigin() {

        Point location = iESWTTextLabel.getLocation();

        return new Point(-location.x, -location.y);

    }

    public void setOrigin(Point origin) {

        setOrigin(origin.x, origin.y);

    }

    public void setOrigin(int x, int y) {

        if (iESWTTextLabel != null) {

            vBar.setSelection(y);

            iESWTTextLabel.setLocation(0, -vBar.getSelection());

        }

    }

    private void resize() {

        if (!resizing) {

            resizing = true;

            layout();

            resizing = false;

        }

    }

    private void vScroll() {

        Point location = iESWTTextLabel.getLocation();

        int vSelection = vBar.getSelection();

        iESWTTextLabel.setLocation(location.x, -vSelection);

    }

}