<?php
/**
 * Karaka
 *
 * PHP Version 8.1
 *
 * @package   tests
 * @copyright Dennis Eichhorn
 * @license   OMS License 1.0
 * @version   1.0.0
 * @link      https://karaka.app
 */
declare(strict_types=1);

namespace phpOMS\tests\Math\Stochastic\Distribution;

use phpOMS\Math\Stochastic\Distribution\BernoulliDistribution;

/**
 * @internal
 */
final class BernoulliDistributionTest extends \PHPUnit\Framework\TestCase
{
    /**
     * @covers phpOMS\Math\Stochastic\Distribution\BernoulliDistribution
     * @group framework
     */
    public function testPmf() : void
    {
        self::assertEqualsWithDelta(0.3, BernoulliDistribution::getPmf(0.7, 0), 0.01);
        self::assertEqualsWithDelta(0.7, BernoulliDistribution::getPmf(0.7, 1), 0.01);
    }

    /**
     * @covers phpOMS\Math\Stochastic\Distribution\BernoulliDistribution
     * @group framework
     */
    public function testMode() : void
    {
        self::assertEqualsWithDelta(1, BernoulliDistribution::getMode(0.7), 0.01);
        self::assertEqualsWithDelta(0, BernoulliDistribution::getMode(0.5), 0.01);
        self::assertEqualsWithDelta(0, BernoulliDistribution::getMode(0.3), 0.01);
    }

    /**
     * @covers phpOMS\Math\Stochastic\Distribution\BernoulliDistribution
     * @group framework
     */
    public function testMean() : void
    {
        self::assertEqualsWithDelta(0.4, BernoulliDistribution::getMean(0.4), 0.01);
    }

    /**
     * @covers phpOMS\Math\Stochastic\Distribution\BernoulliDistribution
     * @group framework
     */
    public function testCdf() : void
    {
        self::assertEqualsWithDelta(0, BernoulliDistribution::getCdf(0.4, -2), 0.01);
        self::assertEqualsWithDelta(1, BernoulliDistribution::getCdf(0.4, 2), 0.01);
        self::assertEqualsWithDelta(0.3, BernoulliDistribution::getCdf(0.7, 0.4), 0.01);
    }

    /**
     * @covers phpOMS\Math\Stochastic\Distribution\BernoulliDistribution
     * @group framework
     */
    public function testMedian() : void
    {
        self::assertEqualsWithDelta(0.5, BernoulliDistribution::getMedian(0.5), 0.01);
        self::assertEqualsWithDelta(1, BernoulliDistribution::getMedian(0.7), 0.01);
        self::assertEqualsWithDelta(0, BernoulliDistribution::getMedian(0.3), 0.01);
    }

    /**
     * @covers phpOMS\Math\Stochastic\Distribution\BernoulliDistribution
     * @group framework
     */
    public function testVariance() : void
    {
        $p = 0.3;
        $q = 1 - $p;

        self::assertEqualsWithDelta($p * $q, BernoulliDistribution::getVariance($p), 0.01);
    }

    /**
     * @covers phpOMS\Math\Stochastic\Distribution\BernoulliDistribution
     * @group framework
     */
    public function testStandardDeviation() : void
    {
        $p = 0.3;
        $q = 1 - $p;

        self::assertEqualsWithDelta(\sqrt($p * $q), BernoulliDistribution::getStandardDeviation($p), 0.01);
    }

    /**
     * @covers phpOMS\Math\Stochastic\Distribution\BernoulliDistribution
     * @group framework
     */
    public function testSkewness() : void
    {
        $p = 0.3;
        $q = 1 - $p;

        self::assertEqualsWithDelta((1 - 2 * $p) / \sqrt($p * $q), BernoulliDistribution::getSkewness($p), 0.01);
    }

    /**
     * @covers phpOMS\Math\Stochastic\Distribution\BernoulliDistribution
     * @group framework
     */
    public function testExKurtosis() : void
    {
        $p = 0.3;
        $q = 1 - $p;

        self::assertEqualsWithDelta((1 - 6 * $p * $q) / ($p * $q), BernoulliDistribution::getExKurtosis($p), 0.01);
    }

    /**
     * @covers phpOMS\Math\Stochastic\Distribution\BernoulliDistribution
     * @group framework
     */
    public function testEntropy() : void
    {
        $p = 0.3;
        $q = 1 - $p;

        self::assertEqualsWithDelta(-$q * \log($q) - $p * \log($p), BernoulliDistribution::getEntropy($p), 0.01);
    }

    /**
     * @covers phpOMS\Math\Stochastic\Distribution\BernoulliDistribution
     * @group framework
     */
    public function testMgf() : void
    {
        $p = 0.3;
        $q = 1 - $p;
        $t = 2;

        self::assertEqualsWithDelta($q + $p * \exp($t), BernoulliDistribution::getMgf($p, $t), 0.01);
    }

    /**
     * @covers phpOMS\Math\Stochastic\Distribution\BernoulliDistribution
     * @group framework
     */
    public function testFisherInformation() : void
    {
        $p = 0.3;
        $q = 1 - $p;

        self::assertEqualsWithDelta(1 / ($p * $q), BernoulliDistribution::getFisherInformation($p), 0.01);
    }

    /**
     * @covers phpOMS\Math\Stochastic\Distribution\BernoulliDistribution
     * @group framework
     */
    public function testInvalidPmfParameter() : void
    {
        $this->expectException(\InvalidArgumentException::class);
        BernoulliDistribution::getPmf(0.7, 3);
    }
}