/*
 * Beanfabrics Framework Copyright (C) by Michael Karneim, beanfabrics.org
 * Use is subject to license terms. See license.txt.
 */
package org.beanfabrics.swt;

import org.beanfabrics.validation.ValidationState;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Control;

import com.swtdesigner.SWTResourceManager;

/**
 * Overlay icon to render above a {@link Control} and to indicate an invalid
 * validation state.
 * <p>
 * IMPORTANT: this class does not work correctly for all controls since it can
 * not be ensured that it paints at last.
 * </p>
 * 
 * @author Michael Karneim
 */
public class ErrorOverlayIcon implements ValidationIndicator {
    private final String IMAGE_NAME = "error_overlay.gif";
    private final Control control;
    private boolean visible = false;
    private int xOffset = 10;
    private int yOffset = 0;

    public ErrorOverlayIcon(Control aControl) {
        control = aControl;
        control.addPaintListener(new PaintListener() {
            public void paintControl(PaintEvent e) {
                paint(e.gc);
            }
        });
    }

    public int getXOffset() {
        return xOffset;
    }

    public void setXOffset(int offset) {
        xOffset = offset;
    }

    public int getYOffset() {
        return yOffset;
    }

    public void setYOffset(int offset) {
        yOffset = offset;
    }

    public void setVisible(boolean newValue) {
        this.visible = newValue;
        control.redraw();
    }

    private void paint(GC gc) {
        if (visible) {
            gc.drawImage(getImage(), getXOffset(), getYOffset());
        }
    }

    private Image getImage() {
        return SWTResourceManager.getImage(ErrorOverlayIcon.class, IMAGE_NAME);
    }

    public void setValidationState(ValidationState state) {
        if (state == null) {
            setVisible(false);
        } else {
            setVisible(true);
        }
    }
}