<?php
namespace Szurubooru\Tests\Service;
use Szurubooru\Services\PasswordService;
use Szurubooru\Tests\AbstractTestCase;

final class PasswordServiceTest extends AbstractTestCase
{
    private $configMock;

    public function setUp()
    {
        parent::setUp();
        $this->configMock = $this->mockConfig();
    }

    public function testLegacyPasswordValidation()
    {
        $passwordService = $this->getPasswordService();
        $this->configMock->set('security/secret', 'doesnt matter');
        $this->assertTrue($passwordService->isHashValid('testt', 'ac63e0bcdf20b82db509d123166c4592', '2602572e077d48b35af39d1cff84bfcaa5363116'));
    }

    public function testPasswordValidation()
    {
        $passwordService = $this->getPasswordService();
        $this->configMock->set('security/secret', 'change');
        $this->assertTrue($passwordService->isHashValid('testt', '/', '4f4f8b836cd65f3f1d0b7751fc442f79595c23439cd8a928af15e10807bf08cc'));
    }

    public function testGeneratingPasswords()
    {
        $passwordService = $this->getPasswordService();

        $sampleCount = 10000;
        $distribution = [];
        for ($i = 0; $i < $sampleCount; $i ++)
        {
            $password = $passwordService->getRandomPassword();
            for ($j = 0; $j < strlen($password); $j ++)
            {
                $c = $password{$j};
                if (!isset($distribution[$j]))
                    $distribution[$j] = [$c => 1];
                elseif (!isset($distribution[$j][$c]))
                    $distribution[$j][$c] = 1;
                else
                    $distribution[$j][$c] ++;
            }
        }

        foreach ($distribution as $index => $characterDistribution)
        {
            $this->assertLessThan(10, $this->getRelativeStandardDeviation($characterDistribution));
        }
    }

    private function getStandardDeviation($sample)
    {
        $mean = array_sum($sample) / count($sample);
        foreach ($sample as $key => $num)
            $devs[$key] = pow($num - $mean, 2);
        return sqrt(array_sum($devs) / (count($devs)));
    }

    private function getRelativeStandardDeviation($sample)
    {
        $mean = array_sum($sample) / count($sample);
        return 100 * $this->getStandardDeviation($sample) / $mean;
    }

    private function getPasswordService()
    {
        return new PasswordService($this->configMock);
    }
}