/*
 * (c) Copyright 2009-2010 by Volker Bergmann. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, is permitted under the terms of the
 * GNU General Public License (GPL).
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * WITHOUT A WARRANTY OF ANY KIND. ALL EXPRESS OR IMPLIED CONDITIONS,
 * REPRESENTATIONS AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE
 * HEREBY EXCLUDED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

package org.databene.domain.br;

import javax.validation.ConstraintValidatorContext;

import org.databene.commons.MathUtil;
import org.databene.commons.validator.bean.AbstractConstraintValidator;

/**
 * Validates Brazilian CNPJ numbers.
 * CNPJ stands for <i>Cadastro Nacional da Pessoa Jurídica</i>
 * and is a tax payer number assigned to a 
 * legal person (Pessoa Jurídica).
 * Created: 17.10.2009 08:24:23
 * @since 0.6.0
 * @author Volker Bergmann
 */
public class CNPJValidator extends AbstractConstraintValidator<CNPJ, CharSequence> {
	
	private boolean acceptingFormattedNumbers = true;
	
	public CNPJValidator() {
	    this(false);
    }

	public CNPJValidator(boolean acceptingFormattedNumbers) {
	    this.acceptingFormattedNumbers = acceptingFormattedNumbers;
    }

	public boolean isAcceptingFormattedNumbers() {
    	return acceptingFormattedNumbers;
    }

	public void setAcceptingFormattedNumbers(boolean acceptingFormattedNumbers) {
    	this.acceptingFormattedNumbers = acceptingFormattedNumbers;
    }
	
	@Override
	public void initialize(CNPJ params) {
	    super.initialize(params);
	    acceptingFormattedNumbers = params.formatted();
	}

	public boolean isValid(CharSequence number, ConstraintValidatorContext context) {
		// do simple checks first
		if (number == null)
			return false;
		int length = number.length();
		boolean formattedNumber = (acceptingFormattedNumbers && length == 18);
		if (length != 14 && !formattedNumber)
			return false;
		if (formattedNumber) {
			// check grouping characters
			if (number.charAt(2) != '.' || number.charAt(6) != '.' || number.charAt(10) != '/' || number.charAt(15) != '-')
				return false;
			// remove grouping
			number = "" + number.subSequence(0, 2) + number.subSequence(3, 6) + number.subSequence(7, 10) + 
				number.subSequence(11,15) + number.subSequence(16, 18);
		}
		// compute 1st verification digit
		int v1 = MathUtil.weightedSumOfDigits(number, 0, 5, 4, 3, 2, 9, 8, 7, 6, 5, 4, 3, 2);
		v1 = 11 - v1 % 11;
		if (v1 >= 10)
			v1 = 0;

	    // Check 1st verification digit
		if (v1 != number.charAt(12) - '0')
			return false;
		
		// compute 2nd verification digit
		int v2 = MathUtil.weightedSumOfDigits(number, 0, 6, 5, 4, 3, 2, 9, 8, 7, 6, 5, 4, 3);
		v2 += 2 * v1;
	    v2 = 11 - v2 % 11;
	    if (v2 >= 10)
	    	v2 = 0;
	    
	    // Check 2nd verification digit
	    return  (v2 == number.charAt(13) - '0');
    }

}