<?php

/**
 * Class Number
 *
 * @created      26.11.2015
 * @author       Smiley <smiley@chillerlan.net>
 * @copyright    2015 Smiley
 * @license      MIT
 */
namespace WCPOS\Vendor\chillerlan\QRCode\Data;

use WCPOS\Vendor\chillerlan\QRCode\Common\BitBuffer;
use WCPOS\Vendor\chillerlan\QRCode\Common\Mode;
use function ceil, intdiv, substr, unpack;
/**
 * Numeric mode: decimal digits 0 to 9
 *
 * ISO/IEC 18004:2000 Section 8.3.2
 * ISO/IEC 18004:2000 Section 8.4.2
 */
final class Number extends QRDataModeAbstract
{
    /**
     * @inheritDoc
     */
    public const DATAMODE = Mode::NUMBER;
    /**
     * @inheritDoc
     */
    public function getLengthInBits() : int
    {
        return (int) ceil($this->getCharCount() * (10 / 3));
    }
    /**
     * @inheritDoc
     */
    public static function validateString(string $string) : bool
    {
        return (bool) \preg_match('/^\\d+$/', $string);
    }
    /**
     * @inheritDoc
     */
    public function write(BitBuffer $bitBuffer, int $versionNumber) : QRDataModeInterface
    {
        $len = $this->getCharCount();
        $bitBuffer->put(self::DATAMODE, 4)->put($len, $this::getLengthBits($versionNumber));
        $i = 0;
        // encode numeric triplets in 10 bits
        while ($i + 2 < $len) {
            $bitBuffer->put($this->parseInt(substr($this->data, $i, 3)), 10);
            $i += 3;
        }
        if ($i < $len) {
            // encode 2 remaining numbers in 7 bits
            if ($len - $i === 2) {
                $bitBuffer->put($this->parseInt(substr($this->data, $i, 2)), 7);
            } elseif ($len - $i === 1) {
                $bitBuffer->put($this->parseInt(substr($this->data, $i, 1)), 4);
            }
        }
        return $this;
    }
    /**
     * get the code for the given numeric string
     *
     * @throws \chillerlan\QRCode\Data\QRCodeDataException
     */
    private function parseInt(string $string) : int
    {
        $num = 0;
        $ords = unpack('C*', $string);
        if ($ords === \false) {
            throw new QRCodeDataException('unpack() error');
        }
        foreach ($ords as $ord) {
            $num = $num * 10 + $ord - 48;
        }
        return $num;
    }
    /**
     * @inheritDoc
     *
     * @throws \chillerlan\QRCode\Data\QRCodeDataException
     */
    public static function decodeSegment(BitBuffer $bitBuffer, int $versionNumber) : string
    {
        $length = $bitBuffer->read(self::getLengthBits($versionNumber));
        $result = '';
        // Read three digits at a time
        while ($length >= 3) {
            // Each 10 bits encodes three digits
            if ($bitBuffer->available() < 10) {
                throw new QRCodeDataException('not enough bits available');
                // @codeCoverageIgnore
            }
            $threeDigitsBits = $bitBuffer->read(10);
            if ($threeDigitsBits >= 1000) {
                throw new QRCodeDataException('error decoding numeric value');
            }
            $result .= intdiv($threeDigitsBits, 100);
            $result .= intdiv($threeDigitsBits, 10) % 10;
            $result .= $threeDigitsBits % 10;
            $length -= 3;
        }
        if ($length === 2) {
            // Two digits left over to read, encoded in 7 bits
            if ($bitBuffer->available() < 7) {
                throw new QRCodeDataException('not enough bits available');
                // @codeCoverageIgnore
            }
            $twoDigitsBits = $bitBuffer->read(7);
            if ($twoDigitsBits >= 100) {
                throw new QRCodeDataException('error decoding numeric value');
            }
            $result .= intdiv($twoDigitsBits, 10);
            $result .= $twoDigitsBits % 10;
        } elseif ($length === 1) {
            // One digit left over to read
            if ($bitBuffer->available() < 4) {
                throw new QRCodeDataException('not enough bits available');
                // @codeCoverageIgnore
            }
            $digitBits = $bitBuffer->read(4);
            if ($digitBits >= 10) {
                throw new QRCodeDataException('error decoding numeric value');
            }
            $result .= $digitBits;
        }
        return $result;
    }
}