<?php
setlocale(LC_ALL, "de_DE@euro", "de_DE", "de", "ge");
set_include_path(get_include_path() . PATH_SEPARATOR . "./lib/");

// Configs
require_once "config/participo.php";
require_once $config["basePath"] . "/config/cwsvJudo.config.php";

// Libs
require_once "participoLib/user.php";

participo::init($cwsvJudoConfig);

$pmelo = new PmElo();

class PmElo
{
    function __construct()
    {
        // starting/continuing a session
        session_start();

        // create 'pmelo' section in the sessions data
        if (!array_key_exists("pmelo", $_SESSION)) {
            $_SESSION["pmelo"] = [];
        }
        // - data storage for id-s of chosen fighters
        if (!array_key_exists("fighterIds", $_SESSION["pmelo"])) {
            $_SESSION["pmelo"]["fighterIds"] = [];
        }

        // load/recreate ranking data
        if (!is_file(self::$pmeloJson)) {
            $this->log["info"][] =
                "Couldn't find `" . self::$pmeloJson . "`. Create a new one!";
            file_put_contents(self::$pmeloJson, json_encode([]));
        }

        // init members
        $this->trainees = self::getTrainees();
        $this->rankings = $this->createRankings();
        $this->fighters = [];
        foreach ($_SESSION["pmelo"]["fighterIds"] as $id) {
            $this->fighters[$id] = $this->trainees[$id];
        }

        // @todo Can be split. Some actions need the members to be already filled, some could be done earlier.
        // check for action in post data
        if (array_key_exists("pmelo", $_POST)) {
            // setting the current fighters
            // - meaning: fighter list is automatically updated by posted fighters
            if (array_key_exists("fighterIds", $_POST["pmelo"])) {
                $_SESSION["pmelo"]["fighterIds"] =
                    $_POST["pmelo"]["fighterIds"];

                header("Location: pmelo");
            }

            if (array_key_exists("promote", $_POST["pmelo"])) {
                $promote = $_POST["pmelo"]["promote"];
                $this->promote(
                    $promote["promoteeId"],
                    $promote["promoteeRank"],
                    $promote["degradeeId"],
                    $promote["degradeeRank"]
                );

                header("Location: pmelo");
            }

        }

        // save the updated ranking
        // @todo should be in destructor
        self::saveRankings($this->rankings);
    }

    function __destruct()
    {
        // sad, the destructor is not allowed to use file_put_contents
    }

    // load all active trainees into a id=>User assoc array
    public static function getTrainees()
    {
        $traineeList = array_map(
            "User::fromDbArray",
            User::dbSelectWithAttribute(4)
        );
        $traineeAssocArray = [];
        foreach ($traineeList as $trainee) {
            $traineeAssocArray[$trainee->getId()] = $trainee;
        }
        return $traineeAssocArray;
    }

    // load ranking from json file
    public static function loadRankings()
    {
        return json_decode(file_get_contents(self::$pmeloJson));
    }

    // save a ranking to json file
    public static function saveRankings(array $rankings)
    {
        file_put_contents(self::$pmeloJson, json_encode($rankings));
    }

    // simple logger to a logging buffer
    function var_log(
        $variable,
        string $prefix = null,
        string $logChannel = "info"
    ) {
        if (!in_array($logChannel, ["info", "warning", "error"])) {
            $logChannel = "info";
        }
        $prefix = !empty($prefix) ? $prefix . ": " : "";
        $this->log[$logChannel][] = $prefix . var_export($variable, true);
    }

    // create the ranking for the current session (load saved ranking from file, remove old trainees, add new trainees)
    public function createRankings()
    {
        // load the last state of the ranking
        $loadedRanking = self::loadRankings();

        // check if the ranked trainees still are in training
        // - the ranking with
        $cleanRanking = [];
        // - trainees that aren't currently in the ranking for later inserting
        $toBeInsertedTrainees = $this->trainees;
        foreach ($loadedRanking as $id) {
            if (array_key_exists($id, $this->trainees)) {
                // userId is still in training, so append it to the cleaned up ranking
                $cleanRanking[] = $id;
                // trainees already in the ranking we won't have to insert manual
                unset($toBeInsertedTrainees[$id]);
            }
        }

        // get the ids of the to be inserted trainees sorted by the birthday
        $newTraineesIds = array_map(function ($u) {
            return $u->getId();
        }, $toBeInsertedTrainees);
        usort($newTraineesIds, function ($lhs, $rhs) {
            return $this->trainees[$lhs]->getStrBirthday() <
                $this->trainees[$rhs]->getStrBirthday()
                ? -1
                : ($this->trainees[$lhs]->getStrBirthday() >
                $this->trainees[$rhs]->getStrBirthday()
                    ? 1
                    : 0);
        });

        // now we do a mergesort (step)
        $updatedRanking = [];
        $idxNewTrainees = count($newTraineesIds) - 1;
        $idxRanking = count($cleanRanking) - 1;
        // - while we can merge, we merge
        while ($idxRanking >= 0 && $idxNewTrainees >= 0) {
            if (
                $this->trainees[$cleanRanking[$idxRanking]]->getDateOfBirth() >
                $this->trainees[
                    $newTraineesIds[$idxNewTrainees]
                ]->getDateOfBirth()
            ) {
                array_unshift($updatedRanking, $cleanRanking[$idxRanking]);
                $idxRanking -= 1;
            } else {
                array_unshift(
                    $updatedRanking,
                    $newTraineesIds[$idxNewTrainees]
                );
                $idxNewTrainees -= 1;
            }
        }
        while ($idxRanking >= 0) {
            array_unshift($updatedRanking, $cleanRanking[$idxRanking]);
            $idxRanking -= 1;
        }
        while ($idxNewTrainees >= 0) {
            array_unshift($updatedRanking, $newTraineesIds[$idxNewTrainees]);
            $idxNewTrainees -= 1;
        }
        return $updatedRanking;
    }

    private function promote(
        int $promoteeId,
        int $promoteeRank,
        int $degradeeId,
        int $degradeeRank
    ) {
        // input sanitation
        filterId($promoteeId);
        filterId($promoteeRank);
        filterId($degradeeId);
        filterId($degradeeRank);
        // check if both id are in the current fighter list
        if (
            array_key_exists($promoteeId, $this->fighters) &&
            array_key_exists($degradeeId, $this->fighters)
        ) {
            // check their current rank
            if (
                $this->rankings[$promoteeRank] == $promoteeId &&
                $this->rankings[$degradeeRank] == $degradeeId
            ) {
                // @todo check if they are rank neighbors in the fighter list
                if (true) {
                    // do the actual switch
                    $this->rankings[$promoteeRank] = $degradeeId;
                    $this->rankings[$degradeeRank] = $promoteeId;

                    $this->saveRankings($this->rankings);
                }
            }
        }
        // save the updated ranking
        $this->saveRankings($this->rankings);
    }
    // promotion means switching the position with another user
    // id-s would already be sufficient, rank is just for controlling
    public static function htmlPromoteButton(
        int $promoteeId,
        int $promoteeRank,
        int $degradeeId,
        int $degradeeRank
    ) {
        return "<form action=\"pmelo\" method=\"post\">" .
            "<input type= \"hidden\" name=\"pmelo[promote][promoteeId]\" value=\"" . $promoteeId . "\" />" .
            "<input type= \"hidden\" name=\"pmelo[promote][promoteeRank]\" value=\"" . $promoteeRank . "\" />" .
            "<input type= \"hidden\" name=\"pmelo[promote][degradeeId]\" value=\"" . $degradeeId . "\" />" .
            "<input type= \"hidden\" name=\"pmelo[promote][degradeeRank]\" value=\"" . $degradeeRank . "\">" .
            "<input class=\"btn\" type=\"submit\" value=\"^\">".
        "</form>";
    }

    public $log = ["error" => [], "warning" => [], "info" => []];
    public $fighters = null;
    public $trainees = null;
    // list of id-s in the order of the current ranking
    public $rankings = null;

    static $pmeloJson = "./pmeloRanking.json";
}