<?php

if (!function_exists('http_response_code')) {
    function http_response_code($code = NULL) {
        $codes = array(400 => "Bad Request",
                       500 => "Internal Server Error");
        if (!isset($codes[$code])) {
            return;
        }
        $protocol = (isset($_SERVER['SERVER_PROTOCOL']) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.0');
        header($protocol . ' ' . $code . ' ' . $codes[$code]);
    }
}

function safe_ceil($value, $precision = 1e-6) {
    $ceilValue = ceil($value);
    return (abs($value - $ceilValue) < (1-$precision)) ? $ceilValue : round($value);
}

function recursive_ksort(&$array, $flags = SORT_REGULAR) {
    if (!is_array($array)) return false;
    ksort($array, $flags);
    foreach ($array as &$arr) {
        recursive_ksort($arr, $flags);
    }
    return true;
}

class ParametersException extends Exception {};

function run($parameters) {
    $versionClasses = array(
        '1' => 'ApiPklV1',       // RegKlas 2018.11.01
        '2' => 'ApiPklV2',       // RegKMP  2020.01.01
        '3' => 'ApiPklV3',       // local BNET 2020.05.01
        '_default' => 'ApiPklV3'
    );
    $version = isset($parameters['version']) ? $parameters['version'] : '_default';
    $apiClass = isset($versionClasses[$version]) ? $versionClasses[$version] : $versionClasses['_default'];
    $api = new $apiClass($parameters);
    if ($parameters['tournament_rank'] == ApiPkl::RANK_KMP) {
        $result = $api->calculate_kmp_points();
    } else {
        $result = $api->calculate_points();
    }
    return $result;
}

class ApiPkl {

    const RANK_KMP = 101;

    protected $parameters;

    function __construct($parameters) {
        $this->parameters = $parameters;
        $this->check_parameters($parameters);
        $this->parameters = $this->parse_parameters($parameters);
    }

    function ensure_parameters($params) {
        foreach ($params as $param) {
            if (!isset($this->parameters[$param])) {
                throw new ParametersException('Missing parameter: ' . $param);
            }
            if (!is_numeric($this->parameters[$param])) {
                throw new ParametersException('Parameter: ' . $param . ' is not a numeric value (' . $this->parameters[$param] . ')');
            }
        }
    }

    function check_values($parameters, $params) {
        foreach ($params as $param => $test) {
            if (!$test($parameters[$param])) {
                throw new ParametersException('Parameter: ' . $param . ' has incorrect value (' . $parameters[$param] . ')');
            }
        }
    }

    function check_parameters() {
        $this->ensure_parameters(array('type', 'contestants', 'title_sum'));
        $this->check_values($this->parameters, array(
            'type' => function($r) { return ctype_digit($r) && intval($r) > 0; },
            'contestants' => function($r) { return ctype_digit($r) && intval($r) > 0; },
            'title_sum' => function($r) { return floatval($r) >= 0; }
        ));
        if (isset($this->parameters['players'])) {
            $this->check_values($this->parameters, array(
                'players' => function($r) { return ctype_digit($r) && intval($r) > 0; }
            ));
        }
        if (!isset($this->parameters['manual']) || !isset($this->parameters['manual']['min_points']) || !isset($this->parameters['manual']['tournament_weight'])) {
            $this->ensure_parameters(array('tournament_rank', 'over39_boards'));
            $this->check_values($this->parameters, array(
                'tournament_rank' => function($r) { return ctype_digit($r) && ((intval($r) >= 0 && intval($r) <= 7) || intval($r) == ApiPkl::RANK_KMP); },
                'over39_boards' => function($r) { return ctype_digit($r) && intval($r) >= 0 && intval($r) <= 1; }
            ));
        } else {
            $this->check_values($this->parameters['manual'], array(
                'min_points' => function($r) { return ctype_digit($r) && intval($r) >= 0; },
                'tournament_weight' => function($r) { return ctype_digit($r) && intval($r) > 0; }
            ));
        }
        if (isset($this->parameters['manual']) && isset($this->parameters['manual']['players_coefficient'])) {
            $this->check_values($this->parameters['manual'], array(
                'players_coefficient' => function($r) { return floatval($r) >= 0; }
            ));
        }
    }

    function parse_parameters() {
        $return = array();
        $return['type'] = intval($this->parameters['type']);
        if ($return['type'] == 3 || $return['type'] > 4) {
            throw new ParametersException('Parameter: type has incorrect value (' . $return['type'] . ')');
        }
        if ($return['type'] != 2 && $this->parameters['tournament_rank'] == ApiPkl::RANK_KMP) {
            throw new ParametersException('Parameter: type has incorrect value (' . $return['type'] . ') for KMP tournament');
        }
        $return['contestants'] = intval($this->parameters['contestants']);
        $return['players'] = isset($this->parameters['players']) ? intval($this->parameters['players']) : intval($this->parameters['contestants']) * $return['type'];
        $return['title_sum'] = floatval($this->parameters['title_sum']);
        $weights = array(
            array(1, 2, 4, 5, 7, 10, 15, 25, ApiPkl::RANK_KMP => 0),
            array(2, 3, 5, 7, 10, 15, 25, 40, ApiPkl::RANK_KMP => 0)
        );
        $return['tournament_weight'] = (isset($this->parameters['manual']) && isset($this->parameters['manual']['tournament_weight'])) ? intval($this->parameters['manual']['tournament_weight']) : $weights[intval($this->parameters['over39_boards'])][intval($this->parameters['tournament_rank'])];
        $min_points = array(
            array(0, 0, 0, 0, 50, 75, 150, 200, ApiPkl::RANK_KMP => 0),
            array(0, 0, 0, 0, 70, 100, 200, 300, ApiPkl::RANK_KMP => 0)
        );
        $return['min_points'] = (isset($this->parameters['manual']) && isset($this->parameters['manual']['min_points'])) ? intval($this->parameters['manual']['min_points']) : $min_points[intval($this->parameters['over39_boards'])][intval($this->parameters['tournament_rank'])];
        $return['players_coefficient'] = (isset($this->parameters['manual']) && isset($this->parameters['manual']['players_coefficient'])) ? floatval($this->parameters['manual']['players_coefficient']) : 0.05;
        $return['points_cutoffs'] = (isset($this->parameters['manual']) && isset($this->parameters['manual']['points_cutoffs']) && is_array($this->parameters['manual']['points_cutoffs'])) ? $this->parameters['manual']['points_cutoffs'] : array(
            array(0.0, 1.0),
            array(0.02, 0.9),
            array(0.2, 0.2),
            array(0.5, 0.0)
        );
        recursive_ksort($return['points_cutoffs']);
        if ($return['points_cutoffs'][0][0] != 0.0) {
            array_unshift($return['points_cutoffs'], array(0.0, 1.0));
        }
        if ($return['points_cutoffs'][count($return['points_cutoffs'])-1][1] != 0.0) {
            array_push($return['points_cutoffs'], array(1.0, 0.0));
        }
        foreach ($return['points_cutoffs'] as &$cutoff) {
            if (($cutoff[0] < 0.0) || ($cutoff[0] > 1.0)) {
                throw new ParametersException('Cutoff points need to be between 0.0 and 1.0: ' . $cutoff[0]);
            }
            $cutoff[0] = floatval($cutoff[0]);
            if (($cutoff[1] < 0.0) || ($cutoff[1] > 1.0)) {
                throw new ParametersException('Cutoff values need to be between 1.0 and 0.0: ' . $cutoff[1]);
            }
            $cutoff[1] = floatval($cutoff[1]);
        }
        unset($cutoff);
        for ($prev = 0; $prev < count($return['points_cutoffs']) - 1; $prev++) {
            $next = $prev + 1;
            if ($return['points_cutoffs'][$prev][0] >= $return['points_cutoffs'][$next][0]) {
                throw new ParametersException(
                    'Cutoff points need to be ascending: ' . $return['points_cutoffs'][$prev][0] . ', ' . $return['points_cutoffs'][$next][0]);
            }
            if ($return['points_cutoffs'][$prev][1] < $return['points_cutoffs'][$next][1]) {
                throw new ParametersException(
                    'Cutoff values need to be non-ascending: ' . $return['points_cutoffs'][$prev][1] . ', ' . $return['points_cutoffs'][$next][1]);
            }
        }
        return $return;
    }

    function get_position_percentage_from_position($position, $contestants) {
        return ($position - 1) / $contestants;
    }

    function get_percentage_from_position($position, $contestants, $cutoffs) {
        $position_percentage = $this->get_position_percentage_from_position($position, $contestants);
        for ($prev = 0; $prev < count($cutoffs) - 1; $prev++) {
            $next = $prev + 1;
            if (($cutoffs[$prev][0] <= $position_percentage) && ($cutoffs[$next][0] >= $position_percentage)) {
                $result = ($position_percentage - $cutoffs[$prev][0]) * ($cutoffs[$prev][1] - $cutoffs[$next][1]) / ($cutoffs[$prev][0] - $cutoffs[$next][0]) + $cutoffs[$prev][1];
                return $result;
            }
        }
        return 0.0;
    }

    function calculate_points() {
        $max_points = safe_ceil(max(
            $this->parameters['min_points'],
            (1 + 0.25 * ($this->parameters['type'] > 2)) * (max(0.15, $this->parameters['title_sum'] / $this->parameters['players']) * $this->parameters['tournament_weight'] + $this->parameters['players_coefficient'] * $this->parameters['contestants'] * $this->parameters['type'])
        ));
        $min_points = 1;
        $result = array("sum" => 0, "points" => array());
        for ($place = 1; $place <= $this->parameters['contestants']; $place++) {
            $percentage = $this->get_percentage_from_position($place, $this->parameters['contestants'], $this->parameters['points_cutoffs']);
            $points = safe_ceil(floatval($max_points) * $percentage);
            $result['points'][$place] = max($min_points, intval($points));
            $result['sum'] += $this->parameters['type'] * $result['points'][$place];
        }
        return $result;
    }

    function calculate_kmp_points() {
        $max_points = safe_ceil($this->parameters['contestants'] * 0.5);
        $min_points = 1;
        $result = array("sum" => 0, "points" => array(1 => $max_points));
        for ($place = 2; $place <= $this->parameters['contestants']; $place++) {
            $result['points'][$place] = max($min_points, $result['points'][$place-1]-1);
            $result['sum'] += $this->parameters['type'] * $result['points'][$place];
        }
        if ($this->parameters['title_sum'] / $this->parameters['players'] >= 2.5) {
            $result['points'][1] += 5;
            $result['points'][2] += 3;
            $result['points'][3] += 1;
            $result['sum'] += $this->parameters['type'] * 8;
        }
        return $result;
    }
}

class ApiPklV1 extends ApiPkl {}

class ApiPklV2 extends ApiPklV1 {

    function calculate_kmp_points() {
        // the line below works only because you can't play > 39 boards in KMP
        // please kill me if it ever changes
        $this->parameters['tournament_weight'] = 4;
        $this->parameters['min_points'] = 0;
        $intermediate = $this->calculate_points();
        $this->parameters['min_points'] = $intermediate['points'][1] + 10;
        return $this->calculate_points();
    }

}

class ApiPklV3 extends ApiPklV2 {}

?>