IBAN

package Project

object IBANAlgorithm extends App {

  print(apply("DE89370400440532013000"))

  def apply(iban:String):Boolean = {

    val letters = "[A-Z]".r

    val rearranged = iban.takeRight(iban.length-4) + iban.take(4)

    val decimal =
      letters.findAllIn(rearranged).map(l => l.toCharArray.map(c => (l,c.toInt - 55)).head)
        .foldLeft(rearranged){(s,t) => t match{case (char,value) =>s.replace(char,value.toString)}}

    BigDecimal(decimal) % BigDecimal("97") == BigDecimal("1")

  }

}

/*/*/*///////////////////////////////////************

package Project

import scala.collection.immutable.SortedMap
import scala.math.BigInt
import scala.util.matching.Regex

/** The International Bank Account Number (IBAN) is an internationally agreed means of identifying  *  bank accounts across national borders with a reduced risk of propagating transcription errors. The  *  IBAN consists of up to 34 alphanumeric characters: first the two-letter ISO 3166-1 alpha-2 country  *  code, then two check digits, and finally a country-specific Basic Bank Account Number (BBAN). The  *  check digits enable a sanity check of the bank account number to confirm its integrity even before  *  submitting a transaction.  */class Iban(val iban: String) {

  // Isolated tests
  def isAllUpperCase = iban.toUpperCase() == iban

  def isValidpattern = (Iban.pattern findFirstIn iban).nonEmpty

  def isNationalSize = { Iban.ccVsLength.getOrElse(iban.take(2), 0) == iban.size }

  def isCheckNumberOK = {
    def rearrange = ((iban.drop(4) + iban.take(4)). // Move left country code part to end      // continue with each char converted to Int      map(ch => if (ch.isDigit) ch.toInt - '0' else (ch - 'A' + 10))).mkString

    (BigInt(rearrange) mod 97) == 1  }

  def isValidIban = {
    isAllUpperCase &&
      isValidpattern &&
      isNationalSize &&
      isCheckNumberOK
  }
}

object Iban { // IBAN length database  lazy val ccVsLength: SortedMap[String, Int] = SortedMap[String, Int]() ++
    ("""AD24 AE23 AL28 AO25 AT20 AZ28 BA20 BE16 BF27 BG22 BH22 BI16          |BJ28 BR29 CG27 CH21 CI28 CM27 CR21 CV25 CY28 CZ24 DE22 DK18          |DO28 DZ24 EE20 EG27 ES24 FI18 FO18 FR27 GA27 GB22 GE22 GI23          |GL18 GR27 GT28 HR21 HU28 IE22 IL23 IR26 IS26 IT27 JO30 KW30          |KZ20 LB28 LI21 LT20 LU20 LV21 MC27 MD24 ME22 MG27 MK19 ML28          |MR27 MT31 MU30 MZ25 NL18 NO15 PK24 PL28 PS29 PT25 QA29 RO24          |RS22 SA24 SE24 SI19 SK24 SM27 SN28 TN24 TR26 UA29 VG24""".
      stripMargin.replaceAll("""\s""", " ").split(' ').
      map(v => (v.take(2), if (v.isEmpty()) 0 else v.slice(2, 4).toInt)))

  lazy val pattern = "([A-Z]{2})([0-9]{2})([A-Z0-9]{4})([A-Z0-9]{0,2})([0-9]{7})(([A-Z0-9]?){0,16})".r

  def apply(s: String) = new Iban(s.replaceAll("""\s""", ""))
}