/*
 * The NIE (Número de Identificación de Extranjero) is a Spanish tax identification number assigned by the Spanish
 * authorities to any foreigner.
 *
 * The NIE is the equivalent of a Spaniards Número de Identificación Fiscal (NIF) which serves as a fiscal
 * identification number. The CIF number (Certificado de Identificación Fiscal) is equivalent to the NIF, but applies to
 * companies rather than individuals. The NIE consists of an 'X' or 'Y' followed by 7 or 8 digits then another letter.
 */
$.validator.addMethod( "nieES", function( value ) {
	"use strict";

	var nieRegEx = new RegExp( /^[MXYZ]{1}[0-9]{7,8}[TRWAGMYFPDXBNJZSQVHLCKET]{1}$/gi );
	var validChars = "TRWAGMYFPDXBNJZSQVHLCKET",
		letter = value.substr( value.length - 1 ).toUpperCase(),
		number;

	value = value.toString().toUpperCase();

	// Quick format test
	if ( value.length > 10 || value.length < 9 || !nieRegEx.test( value ) ) {
		return false;
	}

	// X means same number
	// Y means number + 10000000
	// Z means number + 20000000
	value = value.replace( /^[X]/, "0" )
		.replace( /^[Y]/, "1" )
		.replace( /^[Z]/, "2" );

	number = value.length === 9 ? value.substr( 0, 8 ) : value.substr( 0, 9 );

	return validChars.charAt( parseInt( number, 10 ) % 23 ) === letter;

}, "Please specify a valid NIE number." );
