/*
 * Brazillian CPF number (Cadastrado de Pessoas Físicas) is the equivalent of a Brazilian tax registration number.
 * CPF numbers have 11 digits in total: 9 numbers followed by 2 check numbers that are being used for validation.
 */
$.validator.addMethod( "cpfBR", function( value, element ) {
	"use strict";

	if ( this.optional( element ) ) {
		return true;
	}

	// Removing special characters from value
	value = value.replace( /([~!@#$%^&*()_+=`{}\[\]\-|\\:;'<>,.\/? ])+/g, "" );

	// Checking value to have 11 digits only
	if ( value.length !== 11 ) {
		return false;
	}

	var sum = 0,
		firstCN, secondCN, checkResult, i;

	firstCN = parseInt( value.substring( 9, 10 ), 10 );
	secondCN = parseInt( value.substring( 10, 11 ), 10 );

	checkResult = function( sum, cn ) {
		var result = ( sum * 10 ) % 11;
		if ( ( result === 10 ) || ( result === 11 ) ) {
			result = 0;
		}
		return ( result === cn );
	};

	// Checking for dump data
	if ( value === "" ||
		value === "00000000000" ||
		value === "11111111111" ||
		value === "22222222222" ||
		value === "33333333333" ||
		value === "44444444444" ||
		value === "55555555555" ||
		value === "66666666666" ||
		value === "77777777777" ||
		value === "88888888888" ||
		value === "99999999999"
	) {
		return false;
	}

	// Step 1 - using first Check Number:
	for ( i = 1; i <= 9; i++ ) {
		sum = sum + parseInt( value.substring( i - 1, i ), 10 ) * ( 11 - i );
	}

	// If first Check Number (CN) is valid, move to Step 2 - using second Check Number:
	if ( checkResult( sum, firstCN ) ) {
		sum = 0;
		for ( i = 1; i <= 10; i++ ) {
			sum = sum + parseInt( value.substring( i - 1, i ), 10 ) * ( 12 - i );
		}
		return checkResult( sum, secondCN );
	}
	return false;

}, "Please specify a valid CPF number" );
