/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.commons.math.util;

import java.io.Serializable;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.math.MathContext;

import org.apache.commons.math.Field;
import org.apache.commons.math.FieldElement;

/**
 * Arbitrary precision decimal number.
 * <p>
 * This class is a simple wrapper around the standard <code>BigDecimal</code> in
 * order to implement the {@link FieldElement} interface.
 * </p>
 * 
 * @since 2.0
 * @version $Revision$ $Date$
 */
public class BigReal implements FieldElement<BigReal>, Comparable<BigReal>, Serializable {
	// TODO: Add Serializable documentation
	// TODO: Check Serializable implementation

	/** Serializable version identifier. */
	private static final long serialVersionUID = 7887631840434052850L;

	/** A big real representing 0. */
	public static final BigReal ZERO = new BigReal(BigDecimal.ZERO);

	/** A big real representing 1. */
	public static final BigReal ONE = new BigReal(BigDecimal.ONE);

	/** Underlying BigDecimal. */
	private final BigDecimal d;

	/**
	 * Build an instance from a BigDecimal.
	 * 
	 * @param val
	 *            value of the instance
	 */
	public BigReal(BigDecimal val) {
		d = val;
	}

	/**
	 * Build an instance from a BigInteger.
	 * 
	 * @param val
	 *            value of the instance
	 */
	public BigReal(BigInteger val) {
		d = new BigDecimal(val);
	}

	/**
	 * Build an instance from an unscaled BigInteger.
	 * 
	 * @param unscaledVal
	 *            unscaled value
	 * @param scale
	 *            scale to use
	 */
	public BigReal(BigInteger unscaledVal, int scale) {
		d = new BigDecimal(unscaledVal, scale);
	}

	/**
	 * Build an instance from an unscaled BigInteger.
	 * 
	 * @param unscaledVal
	 *            unscaled value
	 * @param scale
	 *            scale to use
	 * @param mc
	 *            to used
	 */
	public BigReal(BigInteger unscaledVal, int scale, MathContext mc) {
		d = new BigDecimal(unscaledVal, scale, mc);
	}

	/**
	 * Build an instance from a BigInteger.
	 * 
	 * @param val
	 *            value of the instance
	 * @param mc
	 *            context to use
	 */
	public BigReal(BigInteger val, MathContext mc) {
		d = new BigDecimal(val, mc);
	}

	/**
	 * Build an instance from a characters representation.
	 * 
	 * @param in
	 *            character representation of the value
	 */
	public BigReal(char[] in) {
		d = new BigDecimal(in);
	}

	/**
	 * Build an instance from a characters representation.
	 * 
	 * @param in
	 *            character representation of the value
	 * @param offset
	 *            offset of the first character to analyze
	 * @param len
	 *            length of the array slice to analyze
	 */
	public BigReal(char[] in, int offset, int len) {
		d = new BigDecimal(in, offset, len);
	}

	/**
	 * Build an instance from a characters representation.
	 * 
	 * @param in
	 *            character representation of the value
	 * @param offset
	 *            offset of the first character to analyze
	 * @param len
	 *            length of the array slice to analyze
	 * @param mc
	 *            context to use
	 */
	public BigReal(char[] in, int offset, int len, MathContext mc) {
		d = new BigDecimal(in, offset, len, mc);
	}

	/**
	 * Build an instance from a characters representation.
	 * 
	 * @param in
	 *            character representation of the value
	 * @param mc
	 *            context to use
	 */
	public BigReal(char[] in, MathContext mc) {
		d = new BigDecimal(in, mc);
	}

	/**
	 * Build an instance from a double.
	 * 
	 * @param val
	 *            value of the instance
	 */
	public BigReal(double val) {
		d = new BigDecimal(val);
	}

	/**
	 * Build an instance from a double.
	 * 
	 * @param val
	 *            value of the instance
	 * @param mc
	 *            context to use
	 */
	public BigReal(double val, MathContext mc) {
		d = new BigDecimal(val, mc);
	}

	/**
	 * Build an instance from an int.
	 * 
	 * @param val
	 *            value of the instance
	 */
	public BigReal(int val) {
		d = new BigDecimal(val);
	}

	/**
	 * Build an instance from an int.
	 * 
	 * @param val
	 *            value of the instance
	 * @param mc
	 *            context to use
	 */
	public BigReal(int val, MathContext mc) {
		d = new BigDecimal(val, mc);
	}

	/**
	 * Build an instance from a long.
	 * 
	 * @param val
	 *            value of the instance
	 */
	public BigReal(long val) {
		d = new BigDecimal(val);
	}

	/**
	 * Build an instance from a long.
	 * 
	 * @param val
	 *            value of the instance
	 * @param mc
	 *            context to use
	 */
	public BigReal(long val, MathContext mc) {
		d = new BigDecimal(val, mc);
	}

	/**
	 * Build an instance from a String representation.
	 * 
	 * @param val
	 *            character representation of the value
	 */
	public BigReal(String val) {
		d = new BigDecimal(val);
	}

	/**
	 * Build an instance from a String representation.
	 * 
	 * @param val
	 *            character representation of the value
	 * @param mc
	 *            context to use
	 */
	public BigReal(String val, MathContext mc) {
		d = new BigDecimal(val, mc);
	}

	/** {@inheritDoc} */
	public BigReal add(BigReal a) {
		return new BigReal(d.add(a.d));
	}

	/** {@inheritDoc} */
	public BigReal subtract(BigReal a) {
		return new BigReal(d.subtract(a.d));
	}

	/** {@inheritDoc} */
	public BigReal divide(BigReal a) throws ArithmeticException {
		return new BigReal(d.divide(a.d));
	}

	/** {@inheritDoc} */
	public BigReal multiply(BigReal a) {
		return new BigReal(d.multiply(a.d));
	}

	/** {@inheritDoc} */
	public int compareTo(BigReal a) {
		return d.compareTo(a.d);
	}

	/** {@inheritDoc} */
	@Override
	public boolean equals(Object other) {
		try {
			if (other == null) {
				return false;
			}
			return d.equals(((BigReal) other).d);
		} catch (ClassCastException cce) {
			return false;
		}
	}

	/** {@inheritDoc} */
	@Override
	public int hashCode() {
		return d.hashCode();
	}

	/** {@inheritDoc} */
	public Field<BigReal> getField() {
		return BigRealField.getInstance();
	}

}
