Copyright (c) 2000, 2009 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
/*******************************************************************************
 * Copyright (c) 2000, 2009 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
 *******************************************************************************/
package org.eclipse.ltk.internal.core.refactoring;

import org.eclipse.core.runtime.Assert;
import org.eclipse.core.runtime.CoreException;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.resources.IResource;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IDocumentExtension4;

import org.eclipse.ltk.core.refactoring.ContentStamp;


public class ContentStamps {

	private static class ContentStampImpl extends ContentStamp {
		private int fKind;
		private long fValue;
		private long fFileStamp;

		public static final int FILE= 1;
		public static final int DOCUMENT= 2;

		private static ContentStamp createFileStamp(long value) {
			return new ContentStampImpl(FILE, value, value);
		}

		private static ContentStamp createDocumentStamp(long value, long fileValue) {
			return new ContentStampImpl(DOCUMENT, value, fileValue);
		}

		private ContentStampImpl(int kind, long value, long filestamp) {
			fKind= kind;
			fValue= value;
			fFileStamp= filestamp;
		}
		public boolean isDocumentStamp() {
			return fKind == DOCUMENT;
		}
		public long getValue() {
			return fValue;
		}
		public long getFileValue() {
			return fFileStamp;
		}
		@Override
		public boolean isNullStamp() {
			return false;
		}
		@Override
		public boolean equals(Object obj) {
			if (!(obj instanceof ContentStampImpl))
				return false;
			return ((ContentStampImpl)obj).fValue == fValue;
		}
		@Override
		public int hashCode() {
			return (int)fValue;
		}
		@Override
		public String toString() {
			return "Stamp: " + fValue; //$NON-NLS-1$
		}
	}

	private static class NullContentStamp extends ContentStamp {
		@Override
		public boolean isNullStamp() {
			return true;
		}
		@Override
		public String toString() {
			return "Null Stamp"; //$NON-NLS-1$
		}
	}

	public static final ContentStamp NULL_CONTENT_STAMP= new NullContentStamp();

	public static ContentStamp get(IFile file, IDocument document) {
		if (document instanceof IDocumentExtension4) {
			long stamp= ((IDocumentExtension4)document).getModificationStamp();
			if (stamp == IDocumentExtension4.UNKNOWN_MODIFICATION_STAMP)
				return NULL_CONTENT_STAMP;
			return ContentStampImpl.createDocumentStamp(stamp, file.getModificationStamp());
		}
		long stamp= file.getModificationStamp();
		if (stamp == IResource.NULL_STAMP)
			return NULL_CONTENT_STAMP;
		return ContentStampImpl.createFileStamp(stamp);
	}

	public static void set(IFile file, ContentStamp s) throws CoreException {
		if (!(s instanceof ContentStampImpl))
			return;
		ContentStampImpl stamp= (ContentStampImpl)s;
		long value= stamp.getFileValue();
		Assert.isTrue(value != IResource.NULL_STAMP);
		file.revertModificationStamp(value);
	}

	public static boolean set(IDocument document, ContentStamp s) throws CoreException {
		if (!(s instanceof ContentStampImpl))
			return false;
		ContentStampImpl stamp= (ContentStampImpl)s;
		if (document instanceof IDocumentExtension4 && stamp.isDocumentStamp()) {
			try {
				((IDocumentExtension4)document).replace(0, 0, "", stamp.getValue()); //$NON-NLS-1$
				return true;
			} catch (BadLocationException e) {
				throw Changes.asCoreException(e);
			}
		}
		return false;
	}
}