/*******************************************************************************
 * Copyright (c) 2000, 2007 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.jface.text;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.eclipse.core.runtime.Assert;

/**
 * Event describing the change of document partitionings.
 *
 * @see org.eclipse.jface.text.IDocumentExtension3
 * @since 3.0
 */
public class DocumentPartitioningChangedEvent {

	/** The document whose partitionings changed */
	private final IDocument fDocument;
	/** The map of partitionings to changed regions. */
	private final Map<String, Region> fMap= new HashMap<>();


	/**
	 * Creates a new document partitioning changed event for the given document.
	 * Initially this event is empty, i.e. does not describe any change.
	 *
	 * @param document the changed document
	 */
	public DocumentPartitioningChangedEvent(IDocument document) {
		fDocument= document;
	}

	/**
	 * Returns the changed document.
	 *
	 * @return the changed document
	 */
	public IDocument getDocument() {
		return fDocument;
	}

	/**
	 * Returns the changed region of the given partitioning or <code>null</code>
	 * if the given partitioning did not change.
	 *
	 * @param partitioning the partitioning
	 * @return the changed region of the given partitioning or <code>null</code>
	 */
	public IRegion getChangedRegion(String partitioning) {
		return fMap.get(partitioning);
	}

	/**
	 * Returns the set of changed partitionings.
	 *
	 * @return the set of changed partitionings
	 */
	public String[] getChangedPartitionings() {
		String[] partitionings= new String[fMap.size()];
		fMap.keySet().toArray(partitionings);
		return partitionings;
	}

	/**
	 * Sets the specified range as changed region for the given partitioning.
	 *
	 * @param partitioning the partitioning
	 * @param offset the region offset
	 * @param length the region length
	 */
	public void setPartitionChange(String partitioning, int offset, int length) {
		Assert.isNotNull(partitioning);
		fMap.put(partitioning, new Region(offset, length));
	}

	/**
	 * Returns <code>true</code> if the set of changed partitionings is empty,
	 * <code>false</code> otherwise.
	 *
	 * @return <code>true</code> if the set of changed partitionings is empty
	 */
	public boolean isEmpty() {
		return fMap.isEmpty();
	}

	/**
	 * Returns the coverage of this event. This is the minimal region that
	 * contains all changed regions of all changed partitionings.
	 *
	 * @return the coverage of this event
	 */
	public IRegion getCoverage() {
		if (fMap.isEmpty())
			return new Region(0, 0);

		int offset= -1;
		int endOffset= -1;
		Iterator<Region> e= fMap.values().iterator();
		while (e.hasNext()) {
			IRegion r= e.next();

			if (offset < 0 || r.getOffset() < offset)
				offset= r.getOffset();

			int end= r.getOffset() + r.getLength();
			if (end > endOffset)
				endOffset= end;
		}

		return new Region(offset, endOffset - offset);
	}
}
