/*=============================================================================#
 # Copyright (c) 2007, 2021 Stephan Wahlbrink and others.
 # 
 # This program and the accompanying materials are made available under the
 # terms of the Eclipse Public License 2.0 which is available at
 # https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
 # which is available at https://www.apache.org/licenses/LICENSE-2.0.
 # 
 # SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
 # 
 # Contributors:
 #     Stephan Wahlbrink <sw@wahlbrink.eu> - initial API and implementation
 #=============================================================================*/

package org.eclipse.statet.ecommons.text;

import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.ITypedRegion;
import org.eclipse.jface.text.TypedRegion;
import org.eclipse.jface.text.rules.FastPartitioner;
import org.eclipse.jface.text.rules.IPartitionTokenScanner;


/**
 * Extended {@link FastPartitioner}.
 */
public class Partitioner extends FastPartitioner {
	
	
	public Partitioner(final IPartitionTokenScanner scanner, final String[] legalContentTypes) {
		super(scanner, legalContentTypes);
	}
	
	
	public void setStartPartitionType(final String partitionType) {
		if (this.fScanner instanceof IPartitionScannerConfigExt) {
			((IPartitionScannerConfigExt)this.fScanner).setStartPartitionType(partitionType);
		}
		else {
			throw new UnsupportedOperationException();
		}
	}
	
	
	public void resetCache() {
		clearPositionCache();
	}
	
	@Override
	public ITypedRegion getPartition(final int offset, final boolean preferOpenPartitions) {
		final ITypedRegion region= getPartition(offset);
		if (preferOpenPartitions) {
			if (offset > 0) {
				if (offset == this.fDocument.getLength()) {
					return getPartition(offset - 1);
				}
				try {
					char c= this.fDocument.getChar(offset);
					if ((c == '\n' || c == '\r') &&
							((c= this.fDocument.getChar(offset - 1)) != '\n' && c != '\r') ) {
						return getPartition(offset - 1);
					}
				} catch (final BadLocationException e) {
				}
			}
			
			final String contentType= region.getType();
			if (region.getOffset() == offset && !(
					contentType.equals(IDocument.DEFAULT_CONTENT_TYPE) || contentType.endsWith("_default"))) { //$NON-NLS-1$
				String type;
				if (offset > 0) {
					final ITypedRegion open= getPartition(offset - 1);
					type= getPrefereOpenType(open.getType(), contentType);
					if (type == open.getType()) {
						return open;
					}
					if (type == contentType) {
						return region;
					}
				}
				else {
					type= IDocument.DEFAULT_CONTENT_TYPE;
				}
				return new TypedRegion(offset, 0, type);
			}
		}
		return region;
	}
	
	protected String getPrefereOpenType(final String open, final String opening) {
		if (open.equals(IDocument.DEFAULT_CONTENT_TYPE) || open.endsWith("_default")) {
			return open;
		}
		return IDocument.DEFAULT_CONTENT_TYPE;
	}
	
}