/*

* Copyright (c) 2006 Nokia Corporation and/or its subsidiary(-ies).

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of the License "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 com.nokia.sdt.sourcegen.patcher;

import com.nokia.sdt.sourcegen.ISourceGenPatch;

import com.nokia.cpp.internal.api.utils.core.Check;

import java.util.List;

/**

 * Match a list of lines

 * 

 *

 */

public class MatchLinesPatchInstruction extends AbstractPatchInstruction {

	protected List<String> contextLines;

	/**

	 * Create instruction and pass modifiable list of lines to match.

	 */

	public MatchLinesPatchInstruction(List<String> contextLines) {

		this.contextLines = contextLines;

	}

	/**

	 * Try to match the context lines against the provided lines,

	 * skipping blank lines, starting from the given line.

	 * @return number of lines matched (0 == failed)

	 */

	protected int matchContext(IPatchHandler handler, int fromLine) {

		int matched = 0;

		int j = 0;

		while (j < contextLines.size()) {

			if (!handler.hasLine(fromLine))

				return 0;

			String line = handler.getLine(fromLine);

			Check.checkState(line != null);

			String ctxLine = contextLines.get(j);

			if (handler.matchLines(line, ctxLine)) {

				matched++;

				fromLine++;

				j++;

			} else if (handler.isLineEmpty(line) && !handler.isLineEmpty(ctxLine)) {

				fromLine++;

				matched++;

			} else {

				return 0;

			}

		}

		return matched;

	}

	/* (non-Javadoc)

	 * @see src.IPatchInstruction#match(java.util.List)

	 */

	public int match(ISourceGenPatch patch, int startLine, IPatchHandler handler) {

		int matched = matchContext(handler, startLine);

		if (matched != 0)

			return startLine + matched;

		return -1;

	}

	/* (non-Javadoc)

	 * @see src.IPatchInstruction#apply(int, java.util.List)

	 */

	public int apply(ISourceGenPatch patch, int index, IPatchHandler handler) {

		// next changes occur after the match

		return match(patch, index, handler);

	}

}