PHP Dart score calculater

Darts.class.php

<?php
/**
 * PHP Dartgame calculating class
 * @author Youri van den Bogert
 */

class Darts {

    /**
     * @var string
     */
    public static $notation_triple = 'T';

    /**
     * @var string
     */
    public static $notation_double = 'D';

    /**
     * @var int
     */
    private static $maxCheckout = 170;

    /**
     * @var string
     */
    private static $doubleBull = 'Bull';

    /**
     * @var string
     */
    private static $singleBull = 'Single';

    /**
     * @var array
     */
    private static $scoreSheet = array('1', '2', '3', '4', '5', '6', '7', '8', '9', '10', '11', '12', '13', '14', '15', '16', '17', '18', '19', '20', '25', '50');

    /**
     * Get a total thrown score
     * @param $score1
     * @param $score2
     * @param $score3
     * @return array
     */
    public static function getTotalScore ($score1, $score2, $score3) {
        return array(
          'dart1' => self::getScoreOfDart($score1),
          'dart2' => self::getScoreOfDart($score2),
          'dart3' => self::getScoreOfDart($score3),
          'total' => self::getScoreOfDart($score1) + self::getScoreOfDart($score2) + self::getScoreOfDart($score3)
        );
    }


    /**
     * Get score of a single dart
     * @param $score
     * @return mixed
     */
    public static function getScoreOfDart ($score) {

        if (is_numeric($score)) {
            return $score;
        }

        if ($score[0] == self::$notation_triple) {
            $multiplier = 3;
        } elseif ($score[0] == self::$notation_double) {
            $multiplier = 2;
        } else {
            $multiplier = 1;
        }

        $correctScore = filter_var($score, FILTER_SANITIZE_NUMBER_INT);

        return ($correctScore * $multiplier);

    }

    public static function getScoreSheet () {

        return self::$scoreSheet;

    }

    public static function calculatePossibleCheckout ($currentScore) {

        // We cant checkout higher then $maxCheckout
        if ($currentScore > self::$maxCheckout || $currentScore == 1) {
            return false;
        }

        // Return bull
        if ($currentScore == 50) {
            return array(
                'dart1' => self::$doubleBull
            );
        }

        if ($currentScore == self::$maxCheckout) {
            return array(
                'dart1' => self::$notation_triple . '20',
                'dart2' => self::$notation_triple . 'T20',
                'dart3' => 'Bull'
            );
        }

        $lastScore = $currentScore;
        $lastPossibleThrow = 0;
        $checkOut = array();

        // Can current score be checked out?
        if (self::canScore($currentScore) == true) {

            return array(
                'dart1' => self::$notation_double . ($currentScore / 2)
            );

        // Current score can't be checked out - calculate what to throw
        } else {

            for ($x=60; $x >= 0; --$x) {

                if ($x <= 20 || $x == 50 || $x == 25 || ($x % 3 == 0) || ($x <= 40 && ($x % 2 == 0))) {

                    for ($xx=60; $xx >= 0; --$xx) {

                        if ($x <= 20 || $x == 50 || $x == 25 || ($x % 3 == 0) || ($x <= 40 && ($x % 2 == 0))) {

                            for ($xxx=50; $xxx > 0; $xxx = $xxx - 2) {

                                if ($xxx == 48) {
                                    $xxx = 40;
                                }

                                if (self::checkIfScoreExists($xxx) == true && self::checkIfScoreExists($xx) == true && self::checkIfScoreExists($x) == true && ($xxx + $xx + $x) == $currentScore) {

                                    $score_1 = self::getCorrectDartName($xxx);
                                    $score_2 = self::getCorrectDartName($xx);
                                    $score_3 = self::getCorrectDartName($x, true);

                                    if ($score_1[0] == 'D' || $score_2[0] == 'D' || $score_3[0] == 'D') {
                                        $nextKey = (count($checkOut)+1);
                                        if ($xxx != 0) $checkOut[$nextKey][] = $score_1;
                                        if ($xx != 0) $checkOut[$nextKey][] = $score_2;
                                        if ($x != 0) $checkOut[$nextKey][] = $score_3;

                                        usort($checkOut[$nextKey], function($a, $b) {
                                            if (is_int($a) || is_float($a)) {
                                                if (is_int($b) || is_float($b)) {
                                                    return $a - $b;
                                                }
                                                else
                                                    return -1;
                                            }
                                            elseif (is_int($b) || is_float($b)) {
                                                return 1;
                                            }
                                            else {
                                                return strcmp($b, $a);
                                            }
                                        });
                                    }

                                }
                            }
                        }
                    }
                }
            }

        }

        return array_unique($checkOut, SORT_REGULAR);

    }

    public static function getCorrectDartName ($total, $isLast = false) {

        if ($total == 25 || $total == 50) {
            return $total;
        }

        if ($total < 20 && $isLast == false) {
            return $total;
        }

        if ($total %3 == 0) {
            return self::$notation_triple . ($total/3);
        } elseif ($total %2 == 0) {
            return self::$notation_double . ($total/2);
        }

        return $total;


    }

    /**
     * Check if score exists
     * @param $score
     * @return bool
     */
    public static function checkIfScoreExists ($score) {

        if ($score == 50 || $score == 25 || $score == 0) return true;

        $possibleScores = array_merge(range(1,20));

        foreach ($possibleScores as $posScore) {
            if ($score == self::getScoreOfDart(self::$notation_double . $posScore) || $score == self::getScoreOfDart(self::$notation_triple . $posScore) || $score == $posScore) {
                return true;
            }
        }

        return false;

    }

    /**
     * Check if a specific score can be thrown by one dart
     * @param $score
     * @return bool
     */
    public static function canScore ($score) {
        if ($score == 50) {
            return true;
        } elseif ($score < 40 || $score == 40) {

            if ($score % 2 == 0) {
                return true; // Score is even - so its possible to throw
            } else {
                return false;
            }
        }

        return false;
    }


}