DataApi.php

<?php
/**
 *     This program is free software: you can redistribute it and/or modify
 *     it under the terms of the GNU General Public License as published by
 *     the Free Software Foundation, either version 3 of the License, or
 *     (at your option) any later version.
 *
 *     This program is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *     GNU General Public License for more details.
 *
 *     You should have received a copy of the GNU General Public License
 *     along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 */

declare(strict_types=1);

namespace ArrayIterator\DataApi;

use Exception;

/**
 * LiveScore API Decryption Class
 *
 * Class DataApi
 * @package ArrayIterator\DataApi
 *
 * $decoder = new DataApi();
 * $json = $decoder->decrypt(); // string
 * @license GPLv3 or later
 */
class DataApi
{
    /**
     * Decrypt plain data from live score api
     *
     * @param string $body
     * @return string returning json if data valid
     */
    public function decrypt(string $body): string
    {
        // <editor-folding>
        // data
        $data = '';
        // "Query-Expiry::: "
        $queryFirstColon = ord($body[12]);
        $querySecondColon = ord($body[13]);
        $queryThirdColon = ord($body[14]);
        $querySpace = ord($body[15]);
        // data contain body
        $startOffsetBody = 0;
        $bracketPos = 0;
        $tildePos = 0;
        $carriageReturn = chr(13);
        $lineFeed = chr(10);
        $space = chr(32);
        $currentOrdinal = null;
        $offsetPrev1 = null;
        $offsetPrev2 = null;
        $modulus = null;
        $currentOffset = null;
        $magic_point_1 = [];
        $magic_point_2 = [];
        $magic_point_3 = [];
        // YYYY-MM-DD HH:mm:ii
        $offsetDate = 0;
        $bodyLength = strlen($body);
        // </editor-folding>
        // <editor-folding>
        if (58 === $queryFirstColon && 32 === $querySecondColon) {
            $magic_point_1 = [33];
            $magic_point_2 = [36];
            $magic_point_3 = [37];
            $offsetDate = $this->populateDate(substr($body, 14, 19));
            $startOffsetBody = 33;
            $bracketPos = 40;
            $tildePos = 126;
        } elseif (58 === $queryFirstColon && 58 === $querySecondColon && 32 === $queryThirdColon) {
            $magic_point_1 = [171];
            $magic_point_2 = [169];
            $magic_point_3 = [187];
            $offsetDate = $this->populateDate(substr($body, 15, 19));
            $startOffsetBody = 34;
            $bracketPos = 40;
            $tildePos = 126;
        } elseif (58 === $queryFirstColon
            && 58 == $querySecondColon
            && 58 === $queryThirdColon
            && 32 === $querySpace
        ) {
            $magic_point_1 = [33, 36, 34];
            $magic_point_2 = [35, 37, 38];
            $magic_point_3 = [37, 35, 36];
            $offsetDate = $this->populateDate(substr($body, 16, 19));
            $startOffsetBody = 35;
            $bracketPos = 40;
            $tildePos = 126;
        }
        // </editor-folding>

        $sumW = ($tildePos - $bracketPos + 1);
        $startingIncrement = $bodyLength - $startOffsetBody;
        $increment = $startingIncrement;
        while ($increment > 0) {
            $currentOffset = $startOffsetBody + $increment - 1;
            $currentOrdinal = ord($body[$currentOffset]);
            $modulus = ($startingIncrement - $increment + 1) % 10;
            if ($currentOrdinal >= $bracketPos && $tildePos >= $currentOrdinal) {
                if ($bracketPos > $currentOrdinal - $offsetDate - $modulus) {
                    $data .= chr($currentOrdinal - $offsetDate - $modulus + $sumW);
                } else {
                    $data .= chr($currentOrdinal - $offsetDate - $modulus);
                }
            } else {
                if ($currentOffset >= 1) {
                    $offsetPrev1 = ord($body[$currentOffset - 1]);
                }
                if ($currentOffset >= 2) {
                    $offsetPrev2 = ord($body[$currentOffset - 2]);
                }
                if ($this->check($offsetPrev2, $offsetPrev1, $currentOrdinal, $magic_point_1)) {
                    $increment -= count($magic_point_1) - 1;
                    $data .= $lineFeed;
                } elseif ($this->check($offsetPrev2, $offsetPrev1, $currentOrdinal, $magic_point_2)) {
                    $increment -= count($magic_point_2) - 1;
                    $data .= $carriageReturn;
                } elseif ($this->check($offsetPrev2, $offsetPrev1, $currentOrdinal, $magic_point_3)) {
                    $increment -= count($magic_point_3) - 1;
                    $data .= $space;
                } else {
                    $data .= $body[$currentOffset];
                }
            }
            $increment--;
        }

        unset($body);
        return $data;
    }

    /**
     * @param string $chr
     * @return int
     * @throws Exception
     */
    private function subPopulate(string $chr): int
    {
        $ordinal = ord($chr);
        if ($ordinal >= 48 && 57 >= $ordinal) {
            return $ordinal - 48;
        }

        throw new Exception(
            sprintf(
                "Char value \"%s\" is not a number character",
                $chr
            )
        );
    }

    /**
     * @param string $dateString
     * @return int
     */
    protected function populateDate(string $dateString): int
    {
        $default = 27;
        // YYYY-MM-DD HH:mm:ii -> 19
        if (!preg_match('
            ~^[0-9]{4}(-)[0-9]{2}(-)[0-9]{2}(\s)[0-9]{2}(:)[0-9]{2}(:)[0-9]{2}~',
            $dateString,
            $match,
            PREG_OFFSET_CAPTURE
        )) {
            return $default;
        }

        array_shift($match);
        $range = range(0, 18);
        array_map(function ($e) use (&$range) {
            unset($range[$e[1]]);
        }, $match);

        try {
            $b = $this->subPopulate($dateString[17]);
            $c = $this->subPopulate($dateString[18]);
            $e = $this->subPopulate($dateString[11]);
            unset($range[17], $range[18], $range[11]);
            $f = $b + $c + $e;
            foreach ($range as $item) {
                $f += $this->subPopulate($dateString[$item]);
            }
            return (($c >= $b) ? $f + $c - $b : $f + (3 * ($e + 1)));
        } catch (Exception $g) {
            return $default;
        }
    }

    /**
     * @param int $offsetPrev
     * @param int $offsetPrev1
     * @param int $current
     * @param array $bytes
     * @return bool
     */
    protected function check(int $offsetPrev, int $offsetPrev1, int $current, array $bytes): bool
    {
        switch (count($bytes)) {
            case 1:
                return $offsetPrev === $bytes[0];
            case 2:
                return $offsetPrev === $bytes[0] && $offsetPrev1 === $bytes[1];
            case 3:
                return $offsetPrev === $bytes[0] && $offsetPrev1 === $bytes[1] && $current === $bytes[2];
            default:
                return false;
        }
    }
}