<?php

namespace CMPayments;

/**
 * IBAN information and validation library
 *
 * based on https://github.com/jschaedl/Iban by Jan Schaedlich <schaedlich.jan@gmail.com>
 *
 * @category Utility
 * @package  IBAN
 * @author   Bas Peters <bp@cm.nl>
 *
 * @link     https://github.com/cmpayments/iban
 */

class IBAN
{
    /**
     * Semantic IBAN structure constants
     */
    const COUNTRY_CODE_OFFSET             = 0;
    const COUNTRY_CODE_LENGTH             = 2;
    const CHECKSUM_OFFSET                 = 2;
    const CHECKSUM_LENGTH                 = 2;
    const ACCOUNT_IDENTIFICATION_OFFSET   = 4;
    const INSTITUTE_IDENTIFICATION_OFFSET = 4;
    const INSTITUTE_IDENTIFICATION_LENGTH = 4;
    const BANK_ACCOUNT_NUMBER_OFFSET      = 8;
    const BANK_ACCOUNT_NUMBER_LENGTH      = 10;

    /**
     * @var array Country code to size, regex format for each country that supports IBAN
     */
    public static $ibanFormatMap = [
        'AA' => [12, '^[A-Z0-9]{12}$'],
        'AD' => [20, '^[0-9]{4}[0-9]{4}[A-Z0-9]{12}$'],
        'AE' => [19, '^[0-9]{3}[0-9]{16}$'],
        'AL' => [24, '^[0-9]{8}[A-Z0-9]{16}$'],
        'AO' => [21, '^[0-9]{21}$'],
        'AT' => [16, '^[0-9]{5}[0-9]{11}$'],
        'AX' => [14, '^[0-9]{6}[0-9]{7}[0-9]{1}$'],
        'AZ' => [24, '^[A-Z]{4}[A-Z0-9]{20}$'],
        'BA' => [16, '^[0-9]{3}[0-9]{3}[0-9]{8}[0-9]{2}$'],
        'BE' => [12, '^[0-9]{3}[0-9]{7}[0-9]{2}$'],
        'BF' => [23, '^[0-9]{23}$'],
        'BG' => [18, '^[A-Z]{4}[0-9]{4}[0-9]{2}[A-Z0-9]{8}$'],
        'BH' => [18, '^[A-Z]{4}[A-Z0-9]{14}$'],
        'BI' => [12, '^[0-9]{12}$'],
        'BJ' => [24, '^[A-Z]{1}[0-9]{23}$'],
        'BL' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$'],
        'BR' => [25, '^[0-9]{8}[0-9]{5}[0-9]{10}[A-Z]{1}[A-Z0-9]{1}$'],
        'CH' => [17, '^[0-9]{5}[A-Z0-9]{12}$'],
        'CI' => [24, '^[A-Z]{1}[0-9]{23}$'],
        'CM' => [23, '^[0-9]{23}$'],
        'CR' => [17, '^[0-9]{4}[0-9]{13}$'],
        'CV' => [21, '^[0-9]{21}$'],
        'CY' => [24, '^[0-9]{3}[0-9]{5}[A-Z0-9]{16}$'],
        'CZ' => [20, '^[0-9]{4}[0-9]{6}[0-9]{10}$'],
        'DE' => [18, '^[0-9]{8}[0-9]{10}$'],
        'DK' => [14, '^[0-9]{4}[0-9]{9}[0-9]{1}$'],
        'DO' => [24, '^[A-Z0-9]{4}[0-9]{20}$'],
        'DZ' => [20, '^[0-9]{20}$'],
        'EE' => [16, '^[0-9]{2}[0-9]{2}[0-9]{11}[0-9]{1}$'],
        'ES' => [20, '^[0-9]{4}[0-9]{4}[0-9]{1}[0-9]{1}[0-9]{10}$'],
        'FI' => [14, '^[0-9]{6}[0-9]{7}[0-9]{1}$'],
        'FO' => [14, '^[0-9]{4}[0-9]{9}[0-9]{1}$'],
        'FR' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$'],
        'GB' => [18, '^[A-Z]{4}[0-9]{6}[0-9]{8}$'],
        'GE' => [18, '^[A-Z]{2}[0-9]{16}$'],
        'GF' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$'],
        'GI' => [19, '^[A-Z]{4}[A-Z0-9]{15}$'],
        'GL' => [14, '^[0-9]{4}[0-9]{9}[0-9]{1}$'],
        'GP' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$'],
        'GR' => [23, '^[0-9]{3}[0-9]{4}[A-Z0-9]{16}$'],
        'GT' => [24, '^[A-Z0-9]{4}[A-Z0-9]{20}$'],
        'HR' => [17, '^[0-9]{7}[0-9]{10}$'],
        'HU' => [24, '^[0-9]{3}[0-9]{4}[0-9]{1}[0-9]{15}[0-9]{1}$'],
        'IE' => [18, '^[A-Z]{4}[0-9]{6}[0-9]{8}$'],
        'IL' => [19, '^[0-9]{3}[0-9]{3}[0-9]{13}$'],
        'IR' => [22, '^[0-9]{22}$'],
        'IS' => [22, '^[0-9]{4}[0-9]{2}[0-9]{6}[0-9]{10}$'],
        'IT' => [23, '^[A-Z]{1}[0-9]{5}[0-9]{5}[A-Z0-9]{12}$'],
        'JO' => [26, '^[A-Z]{4}[0-9]{4}[A-Z0-9]{18}$'],
        'KW' => [26, '^[A-Z]{4}[A-Z0-9]{22}$'],
        'KZ' => [16, '^[0-9]{3}[A-Z0-9]{13}$'],
        'LB' => [24, '^[0-9]{4}[A-Z0-9]{20}$'],
        'LC' => [28, '^[A-Z]{4}[A-Z0-9]{24}$'],
        'LI' => [17, '^[0-9]{5}[A-Z0-9]{12}$'],
        'LT' => [16, '^[0-9]{5}[0-9]{11}$'],
        'LU' => [16, '^[0-9]{3}[A-Z0-9]{13}$'],
        'LV' => [17, '^[A-Z]{4}[A-Z0-9]{13}$'],
        'MC' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$'],
        'MD' => [20, '^[A-Z0-9]{2}[A-Z0-9]{18}$'],
        'ME' => [18, '^[0-9]{3}[0-9]{13}[0-9]{2}$'],
        'MF' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$'],
        'MG' => [23, '^[0-9]{23}$'],
        'MK' => [15, '^[0-9]{3}[A-Z0-9]{10}[0-9]{2}$'],
        'ML' => [24, '^[A-Z]{1}[0-9]{23}$'],
        'MQ' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$'],
        'MR' => [23, '^[0-9]{5}[0-9]{5}[0-9]{11}[0-9]{2}$'],
        'MT' => [27, '^[A-Z]{4}[0-9]{5}[A-Z0-9]{18}$'],
        'MU' => [26, '^[A-Z]{4}[0-9]{2}[0-9]{2}[0-9]{12}[0-9]{3}[A-Z]{3}$'],
        'MZ' => [21, '^[0-9]{21}$'],
        'NC' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$'],
        'NL' => [14, '^[A-Z]{4}[0-9]{10}$'],
        'NO' => [11, '^[0-9]{4}[0-9]{6}[0-9]{1}$'],
        'PF' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$'],
        'PK' => [20, '^[A-Z]{4}[A-Z0-9]{16}$'],
        'PL' => [24, '^[0-9]{8}[0-9]{16}$'],
        'PM' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$'],
        'PS' => [25, '^[A-Z]{4}[A-Z0-9]{21}$'],
        'PT' => [21, '^[0-9]{4}[0-9]{4}[0-9]{11}[0-9]{2}$'],
        'QA' => [25, '^[A-Z]{4}[0-9]{4}[A-Z0-9]{17}$'],
        'RE' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$'],
        'RO' => [20, '^[A-Z]{4}[A-Z0-9]{16}$'],
        'RS' => [18, '^[0-9]{3}[0-9]{13}[0-9]{2}$'],
        'SA' => [20, '^[0-9]{2}[A-Z0-9]{18}$'],
        'SC' => [27, '^[A-Z]{4}[0-9]{4}[0-9]{16}[A-Z]{3}$'],
        'SE' => [20, '^[0-9]{3}[0-9]{16}[0-9]{1}$'],
        'SI' => [15, '^[0-9]{5}[0-9]{8}[0-9]{2}$'],
        'SK' => [20, '^[0-9]{4}[0-9]{6}[0-9]{10}$'],
        'SM' => [23, '^[A-Z]{1}[0-9]{5}[0-9]{5}[A-Z0-9]{12}$'],
        'SN' => [24, '^[A-Z]{1}[0-9]{23}$'],
        'ST' => [21, '^[0-9]{8}[0-9]{11}[0-9]{2}$'],
        'TF' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$'],
        'TL' => [19, '^[0-9]{3}[0-9]{14}[0-9]{2}$'],
        'TN' => [20, '^[0-9]{2}[0-9]{3}[0-9]{13}[0-9]{2}$'],
        'TR' => [22, '^[0-9]{5}[0-9]{1}[A-Z0-9]{16}$'],
        'UA' => [25, '^[0-9]{6}[A-Z0-9]{19}$'],
        'VG' => [20, '^[A-Z]{4}[0-9]{16}$'],
        'WF' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$'],
        'XK' => [16, '^[0-9]{4}[0-9]{10}[0-9]{2}$'],
        'YT' => [23, '^[0-9]{5}[0-9]{5}[A-Z0-9]{11}[0-9]{2}$']
    ];

    /**
     * @var string Internal IBAN number
     */
    private $iban;

    /**
     * IBAN constructor.
     *
     * @param $iban
     */
    public function __construct($iban)
    {
        $this->iban = $this->normalize($iban);
    }

    /**
     * Validates the supplied IBAN and provides passthrough failure message when validation fails
     *
     * @param null $error passthrough variable
     *
     * @return bool
     */
    public function validate(&$error = null)
    {
        if (!$this->isCountryCodeValid()) {
            $error = 'IBAN country code not valid or not supported';
        } elseif (!$this->isLengthValid()) {
            $error = 'IBAN length is invalid';
        } elseif (!$this->isFormatValid()) {
            $error = 'IBAN format is invalid';
        } elseif (!$this->isChecksumValid()) {
            $error = 'IBAN checksum is invalid';
        } else {
            $error = '';
            return true;
        }

        return false;
    }

    /**
     * Pretty print IBAN
     *
     * @return string
     */
    public function format()
    {
        return sprintf(
            '%s %s %s',
            $this->getCountryCode() . $this->getChecksum(),
            substr($this->getInstituteIdentification(), 0, 4),
            implode(' ', str_split($this->getBankAccountNumber(), 4))
        );
    }

    /**
     * Extract country code from IBAN
     *
     * @return string
     */
    public function getCountryCode()
    {
        return substr($this->iban, static::COUNTRY_CODE_OFFSET, static::COUNTRY_CODE_LENGTH);
    }

    /**
     * Extract checksum number from IBAN
     *
     * @return string
     */
    public function getChecksum()
    {
        return substr($this->iban, static::CHECKSUM_OFFSET, static::CHECKSUM_LENGTH);
    }

    /**
     * Extract Account Identification from IBAN
     *
     * @return string
     */
    public function getAccountIdentification()
    {
        return substr($this->iban, static::ACCOUNT_IDENTIFICATION_OFFSET);
    }

    /**
     * Extract Institute from IBAN
     *
     * @return string
     */
    public function getInstituteIdentification()
    {
        return substr($this->iban, static::INSTITUTE_IDENTIFICATION_OFFSET, static::INSTITUTE_IDENTIFICATION_LENGTH);
    }

    /**
     * Extract Bank Account number from IBAN
     *
     * @return string
     */
    public function getBankAccountNumber()
    {
        $countryCode = $this->getCountryCode();
        $length = static::$ibanFormatMap[$countryCode][0] - static::INSTITUTE_IDENTIFICATION_LENGTH;
        return substr($this->iban, static::BANK_ACCOUNT_NUMBER_OFFSET, $length);
    }

    /**
     * Validate IBAN length boundaries
     *
     * @return bool
     */
    private function isLengthValid()
    {
        $countryCode = $this->getCountryCode();
        $validLength = static::COUNTRY_CODE_LENGTH + static::CHECKSUM_LENGTH + static::$ibanFormatMap[$countryCode][0];

        return strlen($this->iban) === $validLength;
    }

    /**
     * Validate IBAN country code
     *
     * @return bool
     */
    private function isCountryCodeValid()
    {
        $countryCode = $this->getCountryCode();

        return !(isset(static::$ibanFormatMap[$countryCode]) === false);
    }

    /**
     * Validate the IBAN format according to the country code
     *
     * @return bool
     */
    private function isFormatValid()
    {
        $countryCode = $this->getCountryCode();
        $accountIdentification = $this->getAccountIdentification();

        return !(preg_match('/' . static::$ibanFormatMap[$countryCode][1] . '/', $accountIdentification) !== 1);
    }

    /**
     * Validates if the checksum number is valid according to the IBAN
     *
     * @return bool
     */
    private function isChecksumValid()
    {
        $countryCode = $this->getCountryCode();
        $checksum = $this->getChecksum();
        $accountIdentification = $this->getAccountIdentification();
        $numericCountryCode = $this->getNumericCountryCode($countryCode);
        $numericAccountIdentification = $this->getNumericAccountIdentification($accountIdentification);
        $invertedIban = $numericAccountIdentification . $numericCountryCode . $checksum;

        return $this->bcmod($invertedIban, 97) === '1';
    }

    /**
     * Extract country code from the IBAN as numeric code
     *
     * @param $countryCode
     *
     * @return string
     */
    private function getNumericCountryCode($countryCode)
    {
        return $this->getNumericRepresentation($countryCode);
    }

    /**
     * Extract account identification from the IBAN as numeric value
     *
     * @param $accountIdentification
     *
     * @return string
     */
    private function getNumericAccountIdentification($accountIdentification)
    {
        return $this->getNumericRepresentation($accountIdentification);
    }

    /**
     * Retrieve numeric presentation of a letter part of the IBAN
     *
     * @param $letterRepresentation
     *
     * @return string
     */
    private function getNumericRepresentation($letterRepresentation)
    {
        $numericRepresentation = '';

        foreach (str_split($letterRepresentation) as $char) {
            $ord = ord($char);
            if ($ord >= 65 && $ord <= 90) {
                $numericRepresentation .= (string) ($ord - 55);
            } elseif ($ord >= 48 && $ord <= 57) {
                $numericRepresentation .= (string) ($ord - 48);
            }
        }

        return $numericRepresentation;
    }

    /**
     * Normailze IBAN by removing non-relevant characters and proper casing
     *
     * @param $iban
     *
     * @return mixed|string
     */
    private function normalize($iban)
    {
        return preg_replace('/[^a-z0-9]+/i', '', trim(strtoupper($iban)));
    }

    /**
     * Get modulus of an arbitrary precision number
     *
     * @param $x
     * @param $y
     *
     * @return string
     */
    private function bcmod($x, $y)
    {
        if (!function_exists('bcmod')) {
            $take = 5;
            $mod = '';

            do {
                $a = (int)$mod . substr($x, 0, $take);
                $x = substr($x, $take);
                $mod = $a % $y;
            } while (strlen($x));

            return (string)$mod;
        } else {
            return bcmod($x, $y);
        }
    }
}