/*******************************************************************************
 * Copyright (c) 2015, 2016 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 *     Angelo Zerr <angelo.zerr@gmail.com> - copied from org.eclipse.wst.xml.ui.internal.projection.XMLFoldingStrategy
 *                                           modified in order to process JSON Objects.                                   
 *******************************************************************************/
package org.eclipse.wst.json.ui.internal.projection;

import org.eclipse.jface.text.Position;
import org.eclipse.wst.json.core.document.IJSONArray;
import org.eclipse.wst.json.core.document.IJSONNode;
import org.eclipse.wst.json.core.document.IJSONObject;
import org.eclipse.wst.json.core.document.IJSONPair;
import org.eclipse.wst.json.core.document.IJSONValue;
import org.eclipse.wst.sse.core.internal.provisional.IndexedRegion;
import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredDocumentRegion;
import org.eclipse.wst.sse.ui.internal.projection.AbstractStructuredFoldingStrategy;

/**
 * A folding strategy for JSON type structured documents. See
 * AbstractStructuredFoldingStrategy for more details.
 */
public class JSONFoldingStrategy extends AbstractStructuredFoldingStrategy {

	/**
	 * Create an instance of the folding strategy. Be sure to set the viewer and
	 * document after creation.
	 */
	public JSONFoldingStrategy() {
		super();
	}

	/**
	 * @see org.eclipse.wst.sse.ui.internal.projection.AbstractFoldingStrategy#calcNewFoldPosition(org.eclipse.wst.sse.core.internal.provisional.IndexedRegion)
	 */
	protected Position calcNewFoldPosition(IndexedRegion indexedRegion) {
		Position retPos = null;

		// only want to fold regions of the valid type and with a valid range
		if (indexedRegion.getStartOffset() >= 0 && indexedRegion.getLength() >= 0) {
			IJSONNode node = (IJSONNode) indexedRegion;
			IStructuredDocumentRegion startRegion = node
					.getStartStructuredDocumentRegion();
			IStructuredDocumentRegion endRegion = node
					.getEndStructuredDocumentRegion();

			// if the node has an endRegion (end tag) then folding region is
			// between the start and end tag
			// else if the region is a comment
			// else if the region is only an open tag or an open/close tag then
			// don't fold it
			if (startRegion != null && endRegion != null) {
				if (endRegion.getEndOffset() >= startRegion.getStartOffset() && 
						endRegion.getEndOffset() <= getDocument().getLength())
					retPos = new JSONObjectFoldingPosition(startRegion,
							endRegion);
			}
			// else if(startRegion != null && indexedRegion instanceof
			// CommentImpl) {
			// retPos = new JSONCommentFoldingPosition(startRegion);
			// }
		}

		return retPos;
	}

	@Override
	protected boolean indexedRegionValidType(IndexedRegion indexedRegion) {
		return (indexedRegion instanceof IJSONObject
				|| indexedRegion instanceof IJSONArray || indexedRegion instanceof IJSONPair);
	}
}