/*******************************************************************************
 * Copyright (c) 2012, 2013 Original authors and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     Original authors and others - initial API and implementation
 ******************************************************************************/
package org.eclipse.nebula.widgets.nattable.viewport;

import static org.eclipse.nebula.widgets.nattable.selection.SelectionLayer.MoveDirectionEnum.LEFT;
import static org.eclipse.nebula.widgets.nattable.selection.SelectionLayer.MoveDirectionEnum.RIGHT;

import org.eclipse.nebula.widgets.nattable.selection.SelectionLayer.MoveDirectionEnum;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.ScrollBar;

/**
 * Listener for the Horizontal scroll bar events on the Viewport Layer. State is
 * exposed to this class from the viewport, since it works in close conjnuction
 * with it.
 */
public class HorizontalScrollBarHandler extends ScrollBarHandlerTemplate {

    public HorizontalScrollBarHandler(ViewportLayer viewportLayer,
            ScrollBar scrollBar) {
        this(viewportLayer, new ScrollBarScroller(scrollBar));
    }

    public HorizontalScrollBarHandler(ViewportLayer viewportLayer,
            IScroller<?> scroller) {
        super(viewportLayer, scroller);

    }

    @Override
    int getViewportOrigin() {
        return this.viewportLayer.getOrigin().getX();
    }

    @Override
    int getViewportMinimumOrigin() {
        return this.viewportLayer.getMinimumOrigin().getX();
    }

    @Override
    void setViewportOrigin(int x) {
        this.viewportLayer.setOriginX(x);
    }

    @Override
    MoveDirectionEnum scrollDirectionForEventDetail(int eventDetail) {
        return (eventDetail == SWT.PAGE_UP || eventDetail == SWT.ARROW_UP) ? LEFT
                : RIGHT;
    }

    @Override
    boolean keepScrolling() {
        return !this.viewportLayer.isLastColumnCompletelyDisplayed();
    }

    @Override
    int getViewportWindowSpan() {
        return this.viewportLayer.getClientAreaWidth();
    }

    @Override
    int getScrollableLayerSpan() {
        if (this.viewportLayer.getMaxWidth() >= 0
                && this.viewportLayer.getMaxWidth() < this.scrollableLayer.getWidth()) {
            return this.viewportLayer.getMaxWidth();
        } else {
            return this.scrollableLayer.getWidth();
        }
    }

    @Override
    int getScrollIncrement() {
        return this.viewportLayer.getColumnCount() > 0 ? this.viewportLayer
                .getColumnWidthByPosition(0) : 0;
    }
}