Check ISO Container Number

ContainerNumber.php

<?php

class ContainerNumber
{
    private array $charMap;
    private string $containerNumber;

    public function __construct(string $containerNumber)
    {
        $this->setContainerNumber($containerNumber);
        $this->charMap = ['A' => 10, 'B' => 12, 'C' => 13, 'D' => 14, 'E' => 15, 'F' => 16, 'G' => 17, 'H' => 18, 'I' => 19, 'J' => 20, 'K' => 21, 'L' => 23, 'M' => 24, 'N' => 25, 'O' => 26, 'P' => 27, 'Q' => 28, 'R' => 29, 'S' => 30, 'T' => 31, 'U' => 32, 'V' => 34, 'W' => 35, 'X' => 36, 'Y' => 37, 'Z' => 38];
    }

    /**
     * remove space from container number. 
     * In some case container number written like `SITU 123 123 2`
     * 
     * @return string
     */
    private function removeSpace(string $containerNumber)
    {
        return str_replace(" ", "", strtoupper($containerNumber));
    }

    /**
     * @return bool
     */
    public function isValid()
    {
        if ($this->getContainerNumber() == null || empty($this->getContainerNumber()) || strlen($this->getContainerNumber()) < 11) {
            return false;
        }

        $acc = 0;
        $num = str_split($this->getContainerNumber());
        for ($i = 0; $i < 10; $i++) {
            if ($i < 4) {
                $p = isset($num[$i]) ? $num[$i] : 0;
                $c = isset($this->charMap[$p]) ? $this->charMap[$p] : 0;
                if (is_numeric($c)) {
                    $acc += ($c * pow(2, $i));
                }
            } else {
                $p = isset($num[$i]) ? $num[$i] : 0;
                if (is_numeric($p)) {
                    $acc += $p * pow(2, $i);
                }
            }
        }

        $rem = $acc % 11;
        if ($rem == 10) {
            $rem = 0;
        }

        if (strlen($this->getContainerNumber()) == 11 && $num[10] == $rem) {
            return true;
        }

        return false;
    }

    /**
     * Get the value of containerNumber
     *
     * @return mixed
     */
    public function getContainerNumber()
    {
        return $this->containerNumber;
    }

    /**
     * Set the value of containerNumber
     *
     * @param   mixed  $containerNumber  
     *
     * @return  self
     */
    public function setContainerNumber($containerNumber)
    {
        $this->containerNumber = $this->removeSpace($containerNumber);
        return $this;
    }
}

// penggunaan :
// var_dump(
//     (new ContainerNumber('TCNU 549 931 0'))->isValid()
// );