/*=============================================================================#
 # Copyright (c) 2018, 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.jcommons.text.core;

import org.eclipse.statet.jcommons.lang.NonNullByDefault;
import org.eclipse.statet.jcommons.lang.Nullable;


@NonNullByDefault
public class BasicTextRegion implements TextRegion {
	
	
	private final int startOffset;
	private final int endOffset;
	
	
	/**
	 * @param startOffset the starting offset, inclusive
	 * @param endOffset the ending offset, exclusive
	 */
	public BasicTextRegion(final int startOffset, final int endOffset) {
		if (startOffset > endOffset) {
			throw new IllegalArgumentException("startOffset > endOffset: startOffset= " + startOffset + ", endOffset= " + endOffset); //$NON-NLS-1$ //$NON-NLS-2$
		}
		this.startOffset= startOffset;
		this.endOffset= endOffset;
	}
	
	public BasicTextRegion(final int offset) {
		this.startOffset= offset;
		this.endOffset= offset;
	}
	
	public BasicTextRegion(final TextRegion region) {
		this(region.getStartOffset(), region.getEndOffset());
	}
	
	
	@Override
	public final int getStartOffset() {
		return this.startOffset;
	}
	
	@Override
	public final int getEndOffset() {
		return this.endOffset;
	}
	
	@Override
	public final int getLength() {
		return this.endOffset - this.startOffset;
	}
	
	
	@Override
	public int hashCode() {
		return (this.startOffset << 24) | (getLength() << 16);
	}
	
	protected boolean equalsByOffsets(final TextRegion other) {
		return (this.startOffset == other.getStartOffset()
				&& this.endOffset == other.getEndOffset() );
	}
	
	@Override
	public boolean equals(final @Nullable Object obj) {
		if (this == obj) {
			return true;
		}
		if (obj instanceof TextRegion) {
			return equalsByOffsets((TextRegion) obj);
		}
		return false;
	}
	
	
	protected final void appendIntervalString(final StringBuilder sb) {
		sb.append('[');
		sb.append(this.startOffset);
		sb.append(',');
		sb.append(this.endOffset);
		sb.append(')');
	}
	
	@Override
	public String toString() {
		final StringBuilder sb= new StringBuilder();
		appendIntervalString(sb);
		return sb.toString();
	}
	
}