<?php

/*
 * This file is part of the PHPASN1 library.
 *
 * Copyright © Friedrich Große <friedrich.grosse@gmail.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace RSSProVendor\FG\ASN1\Universal;

use Exception;
use RSSProVendor\FG\ASN1\Base128;
use RSSProVendor\FG\ASN1\OID;
use RSSProVendor\FG\ASN1\ASNObject;
use RSSProVendor\FG\ASN1\Parsable;
use RSSProVendor\FG\ASN1\Identifier;
use RSSProVendor\FG\ASN1\Exception\ParserException;
class ObjectIdentifier extends ASNObject implements Parsable
{
    protected $subIdentifiers;
    protected $value;
    public function __construct($value)
    {
        $this->subIdentifiers = explode('.', $value);
        $nrOfSubIdentifiers = count($this->subIdentifiers);
        for ($i = 0; $i < $nrOfSubIdentifiers; $i++) {
            if (is_numeric($this->subIdentifiers[$i])) {
                // enforce the integer type
                $this->subIdentifiers[$i] = intval($this->subIdentifiers[$i]);
            } else {
                throw new Exception("[{$value}] is no valid object identifier (sub identifier " . ($i + 1) . ' is not numeric)!');
            }
        }
        // Merge the first to arcs of the OID registration tree (per ASN definition!)
        if ($nrOfSubIdentifiers >= 2) {
            $this->subIdentifiers[1] = $this->subIdentifiers[0] * 40 + $this->subIdentifiers[1];
            unset($this->subIdentifiers[0]);
        }
        $this->value = $value;
    }
    public function getContent()
    {
        return $this->value;
    }
    public function getType()
    {
        return Identifier::OBJECT_IDENTIFIER;
    }
    protected function calculateContentLength()
    {
        $length = 0;
        foreach ($this->subIdentifiers as $subIdentifier) {
            do {
                $subIdentifier = $subIdentifier >> 7;
                $length++;
            } while ($subIdentifier > 0);
        }
        return $length;
    }
    protected function getEncodedValue()
    {
        $encodedValue = '';
        foreach ($this->subIdentifiers as $subIdentifier) {
            $encodedValue .= Base128::encode($subIdentifier);
        }
        return $encodedValue;
    }
    public function __toString()
    {
        return OID::getName($this->value);
    }
    public static function fromBinary(&$binaryData, &$offsetIndex = 0)
    {
        self::parseIdentifier($binaryData[$offsetIndex], Identifier::OBJECT_IDENTIFIER, $offsetIndex++);
        $contentLength = self::parseContentLength($binaryData, $offsetIndex, 1);
        $firstOctet = ord($binaryData[$offsetIndex++]);
        $oidString = floor($firstOctet / 40) . '.' . $firstOctet % 40;
        $oidString .= '.' . self::parseOid($binaryData, $offsetIndex, $contentLength - 1);
        $parsedObject = new self($oidString);
        $parsedObject->setContentLength($contentLength);
        return $parsedObject;
    }
    /**
     * Parses an object identifier except for the first octet, which is parsed
     * differently. This way relative object identifiers can also be parsed
     * using this.
     *
     * @param $binaryData
     * @param $offsetIndex
     * @param $octetsToRead
     *
     * @throws ParserException
     *
     * @return string
     */
    protected static function parseOid(&$binaryData, &$offsetIndex, $octetsToRead)
    {
        $oid = '';
        while ($octetsToRead > 0) {
            $octets = '';
            do {
                if (0 === $octetsToRead) {
                    throw new ParserException('Malformed ASN.1 Object Identifier', $offsetIndex - 1);
                }
                $octetsToRead--;
                $octet = $binaryData[$offsetIndex++];
                $octets .= $octet;
            } while (ord($octet) & 0x80);
            $oid .= sprintf('%d.', Base128::decode($octets));
        }
        // Remove trailing '.'
        return substr($oid, 0, -1) ?: '';
    }
}
