/*******************************************************************************
 * Copyright (c) 2005, 2018 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Lars Vogel <Lars.Vogel@gmail.com> - Bug 414565
 *******************************************************************************/
package org.eclipse.jface.snippets.viewers;

import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.viewers.ColumnViewer;
import org.eclipse.jface.viewers.FocusCellHighlighter;
import org.eclipse.jface.viewers.ViewerCell;
import org.eclipse.jface.viewers.ViewerRow;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;

public class FocusBorderCellHighlighter extends FocusCellHighlighter {
	private ViewerCell oldCell;

	/**
	 * @param viewer
	 *            the viewer
	 */
	public FocusBorderCellHighlighter(ColumnViewer viewer) {
		super(viewer);
		hookListener(viewer);
	}

	private void markFocusedCell(Event event, ViewerCell cell) {
		GC gc = event.gc;

		Rectangle rect = event.getBounds();
		gc.drawFocus(rect.x, rect.y, rect.width, rect.height);

		event.detail &= ~SWT.SELECTED;
	}

	private void removeSelectionInformation(Event event, ViewerCell cell) {

	}

	private void hookListener(final ColumnViewer viewer) {

		Listener listener = event -> {
			if ((event.detail & SWT.SELECTED) > 0) {
				ViewerCell focusCell = getFocusCell();
				ViewerRow row = focusCell.getViewerRow();

				Assert.isNotNull(row, "Internal structure invalid. Item without associated row is not possible."); //$NON-NLS-1$

				ViewerCell cell = row.getCell(event.index);

				if (focusCell == null || !cell.equals(focusCell)) {
					removeSelectionInformation(event, cell);
				} else {
					markFocusedCell(event, cell);
				}
			}
		};
		viewer.getControl().addListener(SWT.EraseItem, listener);
	}

	/**
	 * @param cell
	 *            the cell which is colored
	 * @return the color
	 */
	protected Color getSelectedCellBackgroundColor(ViewerCell cell) {
		return null;
	}

	/**
	 * @param cell
	 *            the cell which is colored
	 * @return the color
	 */
	protected Color getSelectedCellForegroundColor(ViewerCell cell) {
		return null;
	}

	@Override
	protected void focusCellChanged(ViewerCell cell) {
		super.focusCellChanged(cell);

		// Redraw new area
		if (cell != null) {
			Rectangle rect = cell.getBounds();
			int x = cell.getColumnIndex() == 0 ? 0 : rect.x;
			int width = cell.getColumnIndex() == 0 ? rect.x + rect.width
					: rect.width;
			cell.getControl().redraw(x, rect.y, width, rect.height, true);
		}

		if (oldCell != null) {
			Rectangle rect = oldCell.getBounds();
			int x = oldCell.getColumnIndex() == 0 ? 0 : rect.x;
			int width = oldCell.getColumnIndex() == 0 ? rect.x + rect.width
					: rect.width;
			oldCell.getControl().redraw(x, rect.y, width, rect.height, true);
		}

		this.oldCell = cell;
	}
}