<?php

class WeidOidConverter
{
    protected static function weLuhnGetCheckDigit($str)
    {
        $wrkstr = str_replace('-', '', $str); // remove separators
        for ($i=0; $i<36; $i++) {
            $wrkstr = str_ireplace(chr(ord('a')+$i), $i+10, $wrkstr);
        }
        $nbdigits = strlen($wrkstr);
        $parity = $nbdigits & 1;
        $sum = 0;
        for ($n=$nbdigits-1; $n>=0; $n--) {
            $digit = $wrkstr[$n];
            if (($n & 1) != $parity) $digit *= 2;
            if ($digit > 9) $digit -= 9;
            $sum += $digit;
        }
        return ($sum%10) == 0 ? 0 : 10-($sum%10);
    }

    public static function weid2oid(&$weid, $namespace = 'weid:', $base = '1-3-6-1-4-1-SZ5-8')
    {
        if (stripos($weid, $namespace) !== 0) return false; // wrong namespace
        $weid = explode(':', $weid, 2)[1]; // remove namespace

        $elements = array_merge(explode('-', $base), explode('-', $weid));
        $actual_checksum = array_pop($elements);
        $expected_checksum = self::weLuhnGetCheckDigit(implode('-',$elements));
        if ($actual_checksum != '?') {
            if ($actual_checksum != $expected_checksum) return false; // wrong checksum
        } else {
            // If checksum is '?', it will be replaced by the actual checksum,
            // e.g. weid:EXAMPLE-? becomes weid:EXAMPLE-3
            $weid = str_replace('?', $expected_checksum, $weid);
        }
        foreach ($elements as &$arc) {
            //$arc = strtoupper(base_convert($arc, 36, 10));
            $arc = strtoupper(self::base_convert_bigint($arc, 36, 10));
        }
        $oidstr = implode('.', $elements);

        return $oidstr;
    }

    public static function oid2weid($oid, $namespace = 'weid:', $base = '1-3-6-1-4-1-SZ5-8')
    {
        $elements = explode('.', $oid);
        foreach ($elements as &$arc) {
            //$arc = strtoupper(base_convert($arc, 10, 36));
            $arc = strtoupper(self::base_convert_bigint($arc, 10, 36));
        }
        $weidstr = implode('-', $elements);

        if (stripos($weidstr.'-', $base.'-') !== 0) return false; // wrong base

        return $namespace . substr($weidstr.'-'.self::weLuhnGetCheckDigit($weidstr), strlen($base.'-'));
    }

    protected static function base_convert_bigint($numstring, $frombase, $tobase)
    {
        $frombase_str = '';
        for ($i=0; $i<$frombase; $i++) {
            $frombase_str .= strtoupper(base_convert($i, 10, 36));
        }

        $tobase_str = '';
        for ($i=0; $i<$tobase; $i++) {
            $tobase_str .= strtoupper(base_convert($i, 10, 36));
        }

        $length = strlen($numstring);
        $result = '';
        $number = array();
        for ($i = 0; $i < $length; $i++) {
            $number[$i] = stripos($frombase_str, $numstring[$i]);
        }
        do { // Loop until whole number is converted
            $divide = 0;
            $newlen = 0;
            for ($i = 0; $i < $length; $i++) { // Perform division manually (which is why this works with big numbers)
                $divide = $divide * $frombase + $number[$i];
                if ($divide >= $tobase) {
                    $number[$newlen++] = (int)($divide / $tobase);
                    $divide = $divide % $tobase;
                } else if ($newlen > 0) {
                    $number[$newlen++] = 0;
                }
            }
            $length = $newlen;
            $result = $tobase_str[$divide] . $result; // Divide is basically $numstring % $tobase (i.e. the new character)
        }
        while ($newlen != 0);

        return $result;
    }
}
__halt_compiler();----SIGNATURE:----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----ATTACHMENT:----MTIxNjgxNDk4MDEyNjA1MiA5MzMyOTk5MjE1NzQyNDQ4IDMzODE4MDkxMjU0OTI3ODE=