Stu\Module\Control\StuRandom

Complexity

Total Complexity

10

Size/Duplication

Total Lines	48
Duplicated Lines	0 %

Test Coverage

Coverage

50%

Importance

Changes

0

4 Methods

Rating	Name	Duplication	Size	Complexity
A	array_rand()	0	3	1
A	generateRandomValueStandardNormalDistribution()	0	14	4
A	rand()	0	7	2
A	randomKeyOfProbabilities()	0	15	3

<?php

namespace Stu\Module\Control;

use RuntimeException;

/**
 * This class adds the possibility to inject a random generator
 */
class StuRandom
{
    public function rand(int $min, int $max, bool $useStandardNormalDistribution = false, int $mean = null): int
    {
        if ($useStandardNormalDistribution) {
            return $this->generateRandomValueStandardNormalDistribution($min, $max, $mean);
        }

        return random_int($min, $max);
    }

    public function array_rand(array $array): string|int
    {
        return array_rand($array);

The expression return array_rand($array) could return the type array which is incompatible with the type-hinted return integer|string. Consider adding an additional type-check to rule them out.

    }

    /** @param array<int, int> $probabilities */
    public function randomKeyOfProbabilities(array $probabilities): int
    {
        $totalProbability = array_sum($probabilities);

        $randomNumber = random_int(1, $totalProbability);

It seems like $totalProbability can also be of type double; however, parameter $max of random_int() does only seem to accept integer, maybe add an additional type check?

        $cumulativeProbability = 0;

        foreach ($probabilities as $key => $prob) {
            $cumulativeProbability += $prob;
            if ($randomNumber <= $cumulativeProbability) {
                return $key;
            }
        }

        throw new RuntimeException('this should not happen');
    }

    private function generateRandomValueStandardNormalDistribution(int $min, int $max, ?int $mean): int
    {
        $usedMean = $mean === null ? (($min + $max) / 2) : $mean; // MW
        $stdDeviation = $usedMean / 2.5; // FWHM

        do {
            $value = random_int($min, $max);
            $probability = exp(-0.5 * (($value - $usedMean) / $stdDeviation) ** 2); // normal distribution
            $randomProbability = random_int(0, mt_getrandmax()) / mt_getrandmax();

            if ($randomProbability <= $probability) {
                return $value;
            }
        } while (true);

In this branch, the function will implicitly return null which is incompatible with the type-hinted return integer. Consider adding a return statement or allowing null as return value.

    }
}