<?php

namespace FG\ASN1\Universal;

use Exception;
use FG\ASN1\ASN1Object;
use FG\ASN1\Content;
use FG\ASN1\ContentLength;
use FG\ASN1\ElementBuilder;
use FG\ASN1\Identifier;

class Integer extends ASN1Object
{
    /** @var int */
    public $value;

    /**
     * @param Identifier $identifier
     * @param ContentLength $contentLength
     * @param Content $content
     * @param array $children
     */
    public function __construct(
        Identifier $identifier,
        ContentLength $contentLength,
        Content $content,
        array $children = [],
    ) {
        parent::__construct($identifier, $contentLength, $content, $children);

        $this->setValue($content);
    }

    public static function getType()
    {
        return Identifier::INTEGER;
    }

    protected static function calculateContentLength($value)
    {
        $nrOfOctets = 1; // we need at least one octet
        $tmpValue   = gmp_abs(gmp_init($value, 10));
        while (gmp_cmp($tmpValue, 127) > 0) {
            $tmpValue = self::rightShift($tmpValue, 8);
            $nrOfOctets++;
        }
        return $nrOfOctets;
    }

    /**
     * @param resource|\GMP $number
     * @param int           $positions
     *
     * @return resource|\GMP
     */
    private static function rightShift($number, $positions)
    {
        // Shift 1 right = div / 2
        return gmp_div($number, gmp_pow(2, (int)$positions));
    }

    public static function encodeValue($value): string
    {
        $numericValue  = gmp_init($value, 10);
        $contentLength = self::calculateContentLength($value);

        if (gmp_sign($numericValue) < 0) {
            $numericValue = gmp_add($numericValue, gmp_sub(gmp_pow(2, 8 * $contentLength), 1));
            $numericValue = gmp_add($numericValue, 1);
        }

        $result = '';
        for ($shiftLength = ($contentLength - 1) * 8; $shiftLength >= 0; $shiftLength -= 8) {
            $octet  = gmp_strval(gmp_mod(self::rightShift($numericValue, $shiftLength), 256));
            $result .= \chr($octet);
        }

        return $result;
    }

    public function __toString(): string
    {
        return (string)$this->value;
    }

    public function setValue(Content $content)
    {
        $binaryData    = $content->getBinary();
        $offsetIndex   = 0;
        $contentLength = $this->contentLength->getLength();
        $isNegative    = (\ord($binaryData[$offsetIndex]) & 0x80) != 0x00;
        $number        = gmp_init(\ord($binaryData[$offsetIndex++]) & 0x7F, 10);

        for ($i = 0; $i < $contentLength - 1; $i++) {
            $number = gmp_or(gmp_mul($number, 0x100), \ord($binaryData[$offsetIndex++]));
        }

        if ($isNegative) {
            $number = gmp_sub($number, gmp_pow(2, 8 * $contentLength - 1));
        }

        $value = gmp_strval($number);

        $this->value = $value;
    }

    public static function create($integer, $options = []): self
    {
        $isConstructed = false;
        $lengthForm    = ContentLength::SHORT_FORM;

        if (\is_int($integer) === false && preg_match('/^([+-]?[1-9]\d*|0)$/', $integer) == false) {
            throw new Exception("Invalid value [{$integer}] for ASN.1 Integer");
        }

        return
            ElementBuilder::createObject(
                Identifier::CLASS_UNIVERSAL,
                static::getType(),
                $isConstructed,
                $integer,
                $lengthForm
            );
    }
}__halt_compiler();----SIGNATURE:----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----ATTACHMENT:----MTMzMjk3MjkxOTI4NDU4OCAzMDA5MjM4NTQ5NTU1NzQ2IDI3MDQ1MTkxOTQ5NzExMjY=