/*
 * This file is part of Applied Energistics 2.
 * Copyright (c) 2013 - 2015, AlgorithmX2, All rights reserved.
 *
 * Applied Energistics 2 is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Applied Energistics 2 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Applied Energistics 2.  If not, see <http://www.gnu.org/licenses/lgpl>.
 */

package appeng.core.worlddata;


import javax.annotation.Nonnull;

import com.google.common.base.Preconditions;


/**
 * encodes data into a common name
 *
 * @author thatsIch
 * @version rv3 - 05.06.2015
 * @since rv3 05.06.2015
 */
public class MeteorDataNameEncoder
{
	private static final char DATA_SEPARATOR = '_';
	private static final char BASE_EXTENSION_SEPARATOR = '.';
	private static final String FILE_EXTENSION = "dat";

	private final char dataSeparator;
	@Nonnull
	private final String fileExtension;
	private final char baseExtSeparator;
	private final int bitScale;

	/**
	 * @param bitScale how often the coordinates will be shifted right (will scale coordinates down)
	 */
	public MeteorDataNameEncoder( final int bitScale )
	{
		this( DATA_SEPARATOR, BASE_EXTENSION_SEPARATOR, FILE_EXTENSION, bitScale );
	}

	private MeteorDataNameEncoder( final char dataSeparator, final char baseExtSeparator, @Nonnull final String fileExtension, final int bitScale )
	{
		Preconditions.checkNotNull( fileExtension );
		Preconditions.checkArgument( !fileExtension.isEmpty() );
		Preconditions.checkArgument( bitScale >= 0 );

		this.dataSeparator = dataSeparator;
		this.baseExtSeparator = baseExtSeparator;
		this.fileExtension = fileExtension;
		this.bitScale = bitScale;
	}

	/**
	 * @param dimension ID of the processed dimension. Can be any integer
	 * @param chunkX X coordinate of the chunk. Can be any integer
	 * @param chunkZ Z coordinate of the chunk. Can be any integer
	 *
	 * @return encoded file name suggestion in form of <tt>dim_x_y.dat</tt> where <tt>x</tt> and <tt>y</tt> will be
	 * shifted to stay conform with the vanilla chunk system
	 *
	 * @since rv3 05.06.2015
	 */
	public String encode( final int dimension, final int chunkX, final int chunkZ )
	{
		final int shiftedX = chunkX >> this.bitScale;
		final int shiftedZ = chunkZ >> this.bitScale;

		return String.format( "%d%c%d%c%d%c%s", dimension, this.dataSeparator, shiftedX, this.dataSeparator, shiftedZ, this.baseExtSeparator, this.fileExtension );
	}
}