<?php

namespace Utils;

/**
 * Portable PHP password hashing framework.
 *
 * @package phpass
 * @version 0.2 / genuine.
 * @link http://www.openwall.com/phpass/
 * @since 2.5
 */
class PasswordHash
{
    private string $itoa64;

    private int $iteration_count_log2;

    private bool $portable_hashes;

    private string $random_state;

    /**
     * @param int $iteration_count_log2
     * @param bool $portable_hashes
     */
    public function __construct(int $iteration_count_log2, bool $portable_hashes)
    {
        $this->itoa64 = './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';

        if ($iteration_count_log2 < 4 || $iteration_count_log2 > 31) {
            $iteration_count_log2 = 8;
        }

        $this->iteration_count_log2 = $iteration_count_log2;

        $this->portable_hashes = $portable_hashes;

        $this->random_state = microtime() . uniqid(rand(), true); // removed getmypid() for compability reasons
    }

    /**
     * @param string $password
     * @return string
     */
    public function hashPassword(string $password): string
    {
        $random = '';

        if (CRYPT_BLOWFISH == 1 && !$this->portable_hashes) {
            $random = $this->getRandomBytes(16);
            $hash =
                crypt($password, $this->gensaltBlowfish($random));

            if (strlen($hash) == 60) {
                return $hash;
            }
        }

        if (CRYPT_EXT_DES == 1 && !$this->portable_hashes) {
            if (strlen($random) < 3) {
                $random = $this->getRandomBytes(3);
            }

            $hash =
                crypt($password, $this->gensaltExtended($random));

            if (strlen($hash) == 20) {
                return $hash;
            }
        }

        if (strlen($random) < 6) {
            $random = $this->getRandomBytes(6);
        }
        
        $hash = $this->cryptPrivate($password, $this->gensaltPrivate($random));
        if (strlen($hash) == 34) {
            return $hash;
        }

# Returning '*' on error is safe here, but would _not_ be safe
# in a crypt(3)-like function used _both_ for generating new
# hashes and for validating passwords against existing hashes.
        return '*';
    }

    /**
     * @param int $count
     * @return string
     */
    private function getRandomBytes(int $count): string
    {
        $output = '';
        if (@is_readable('/dev/urandom') && ($fh = @fopen('/dev/urandom', 'rb'))) {
            $output = fread($fh, $count);
            fclose($fh);
        }

        if (strlen($output) < $count) {
            $output = '';
            for ($i = 0; $i < $count; $i += 16) {
                $this->random_state =
                    md5(microtime() . $this->random_state);
                $output .=
                    pack('H*', md5($this->random_state));
            }
            $output = substr($output, 0, $count);
        }

        return $output;
    }

    /**
     * @param string $input
     * @return string
     */
    private function gensaltBlowfish(string $input): string
    {
# This one needs to use a different order of characters and a
# different encoding scheme from the one in encode64() above.
# We care because the last character in our encoded string will
# only represent 2 bits.  While two known implementations of
# bcrypt will happily accept and correct a salt string which
# has the 4 unused bits set to non-zero, we do not want to take
# chances and we also do not want to waste an additional byte
# of entropy.
        $itoa64 = './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';

        $output = '$2a$';
        $output .= chr(ord('0') + $this->iteration_count_log2 / 10);
        $output .= chr(ord('0') + $this->iteration_count_log2 % 10);
        $output .= '$';

        $i = 0;
        do {
            $c1 = ord($input[$i++]);
            $output .= $itoa64[$c1 >> 2];
            $c1 = ($c1 & 0x03) << 4;
            if ($i >= 16) {
                $output .= $itoa64[$c1];
                break;
            }

            $c2 = ord($input[$i++]);
            $c1 |= $c2 >> 4;
            $output .= $itoa64[$c1];
            $c1 = ($c2 & 0x0f) << 2;

            $c2 = ord($input[$i++]);
            $c1 |= $c2 >> 6;
            $output .= $itoa64[$c1];
            $output .= $itoa64[$c2 & 0x3f];
        } while (1);

        return $output;
    }

    /**
     * @param string $input
     * @return string
     */
    private function gensaltExtended(string $input): string
    {
        $count_log2 = min($this->iteration_count_log2 + 8, 24);
# This should be odd to not reveal weak DES keys, and the
# maximum valid value is (2**24 - 1) which is odd anyway.
        $count = (1 << $count_log2) - 1;

        $output = '_';
        $output .= $this->itoa64[$count & 0x3f];
        $output .= $this->itoa64[($count >> 6) & 0x3f];
        $output .= $this->itoa64[($count >> 12) & 0x3f];
        $output .= $this->itoa64[($count >> 18) & 0x3f];

        $output .= $this->encode64($input, 3);

        return $output;
    }

    /**
     * @param string $input
     * @param int $count
     * @return string
     */
    private function encode64(string $input, int $count): string
    {
        $output = '';
        $i = 0;
        do {
            $value = ord($input[$i++]);
            $output .= $this->itoa64[$value & 0x3f];
            if ($i < $count) {
                $value |= ord($input[$i]) << 8;
            }
            $output .= $this->itoa64[($value >> 6) & 0x3f];
            if ($i++ >= $count) {
                break;
            }
            if ($i < $count) {
                $value |= ord($input[$i]) << 16;
            }
            $output .= $this->itoa64[($value >> 12) & 0x3f];
            if ($i++ >= $count) {
                break;
            }
            $output .= $this->itoa64[($value >> 18) & 0x3f];
        } while ($i < $count);

        return $output;
    }

    /**
     * @param string $password
     * @param string $setting
     * @return string
     */
    private function cryptPrivate(string $password, string $setting): string
    {
        $output = '*0';
        if (substr($setting, 0, 2) == $output) {
            $output = '*1';
        }

        if (substr($setting, 0, 3) != '$P$') {
            return $output;
        }

        $count_log2 = strpos($this->itoa64, $setting[3]);
        if ($count_log2 < 7 || $count_log2 > 30) {
            return $output;
        }

        $count = 1 << $count_log2;

        $salt = substr($setting, 4, 8);
        if (strlen($salt) != 8) {
            return $output;
        }

# We're kind of forced to use MD5 here since it's the only
# cryptographic primitive available in all versions of PHP
# currently in use.  To implement our own low-level crypto
# in PHP would result in much worse performance and
# consequently in lower iteration counts and hashes that are
# quicker to crack (by non-PHP code).
        if (PHP_VERSION >= '5') {
            $hash = md5($salt . $password, true);
            do {
                $hash = md5($hash . $password, true);
            } while (--$count);
        } else {
            $hash = pack('H*', md5($salt . $password));
            do {
                $hash = pack('H*', md5($hash . $password));
            } while (--$count);
        }

        $output = substr($setting, 0, 12);
        $output .= $this->encode64($hash, 16);

        return $output;
    }

    /**
     * @param string $input
     * @return string
     */
    private function gensaltPrivate(string $input): string
    {
        $output = '$P$';
        $output .= $this->itoa64[min($this->iteration_count_log2 +
            ((PHP_VERSION >= '5') ? 5 : 3), 30)];
        $output .= $this->encode64($input, 6);

        return $output;
    }

    /**
     * @param string $password
     * @param string $stored_hash
     * @return bool
     */
    public function checkPassword(string $password, string $stored_hash): bool
    {
        $hash = $this->cryptPrivate($password, $stored_hash);
        if ($hash[0] == '*') {
            $hash = crypt($password, $stored_hash);
        }

        return $hash == $stored_hash;
    }
}