<?php
declare(strict_types=1);

class UserRank
{
    # Prefix for memcache keys, to make life easier
    const PREFIX = 'percentiles_';


    /**
     * Returns a 101 row array (101 percentiles: 0-100),
     * with the minimum value for that percentile as the value for each row.
     *
     * BTW - ingenious
     */
    private static function build_table($MemKey, $Query)
    {
        $QueryID = G::$DB->get_query_id();

        G::$DB->prepare_query("
        DROP TEMPORARY TABLE IF EXISTS
          `temp_stats`
        ");
        G::$DB->exec_prepared_query();

        G::$DB->prepare_query("
        CREATE TEMPORARY TABLE `temp_stats`(
          `id` INT NOT NULL PRIMARY KEY AUTO_INCREMENT,
          `value` BIGINT NOT NULL
        );
        ");
        G::$DB->exec_prepared_query();

        G::$DB->prepare_query("
        INSERT INTO `temp_stats`(`value`) "
        . $Query
        );
        G::$DB->exec_prepared_query();

        G::$DB->prepare_query("
        SELECT
          COUNT(`id`)
        FROM
          `temp_stats`
        ");
        G::$DB->exec_prepared_query();
        list($UserCount) = G::$DB->next_record();

        $UserCount = (int) $UserCount;
        G::$DB->query("
        SELECT
          MIN(`value`)
        FROM
          `temp_stats`
        GROUP BY
          CEIL(`id` /($UserCount / 100));
        ");
        G::$DB->exec_prepared_query();

        $Table = G::$DB->to_array();
        G::$DB->set_query_id($QueryID);

        # Give a little variation to the cache length, so all the tables don't expire at the same time
        G::$Cache->cache_value($MemKey, $Table, 3600 * 24 * rand(800, 1000) * 0.001);

        return $Table;
    }


    /**
     * table_query
     */
    private static function table_query($TableName)
    {
        switch ($TableName) {
            case 'uploaded':
            $Query =  "
            SELECT
              `Uploaded`
            FROM
              `users_main`
            WHERE
              `Enabled` = '1' AND `Uploaded` > 0
            ORDER BY
              `Uploaded`;
            ";
            break;

            case 'downloaded':
            $Query =  "
            SELECT
              `Downloaded`
            FROM
              `users_main`
            WHERE
              `Enabled` = '1' AND `Downloaded` > 0
            ORDER BY
              `Downloaded`;
            ";
            break;

            case 'uploads':
            $Query = "
            SELECT
              COUNT(t.`ID`) AS `Uploads`
            FROM
              `users_main` AS um
            JOIN `torrents` AS t
            ON
              t.`UserID` = um.`ID`
            WHERE
              um.`Enabled` = '1'
            GROUP BY
              um.`ID`
            ORDER BY
              `Uploads`;
            ";
            break;

            case 'requests':
            $Query = "
            SELECT
              COUNT(r.`ID`) AS `Requests`
            FROM
              `users_main` AS um
            JOIN `requests` AS r
            ON
              r.`FillerID` = um.`ID`
            WHERE
              um.`Enabled` = '1'
            GROUP BY
              um.`ID`
            ORDER BY
              `Requests`;
            ";
            break;

            case 'posts':
            $Query = "
            SELECT
              COUNT(p.`ID`) AS `Posts`
            FROM
              `users_main` AS um
            JOIN `forums_posts` AS p
            ON
              p.`AuthorID` = um.`ID`
            WHERE
              um.`Enabled` = '1'
            GROUP BY
              um.`ID`
            ORDER BY
              `Posts`;
            ";
            break;

            case 'bounty':
            $Query = "
            SELECT
              SUM(rv.`Bounty`) AS `Bounty`
            FROM
              `users_main` AS um
            JOIN `requests_votes` AS rv
            ON
              rv.`UserID` = um.`ID`
            WHERE
              um.`Enabled` = '1'
            GROUP BY
              um.`ID`
            ORDER BY
              `Bounty`;
            ";
            break;

            case 'artists':
            $Query = "
            SELECT
              COUNT(ta.`ArtistID`) AS `Artists`
            FROM
              `torrents_artists` AS ta
            JOIN `torrents_group` AS tg
            ON
              tg.`id` = ta.`GroupID`
            JOIN `torrents` AS t
            ON
              t.`GroupID` = tg.`id`
            WHERE
              t.`UserID` != ta.`UserID`
            GROUP BY
              tg.`id`
            ORDER BY
              `Artists` ASC
            ";
            break;
        }

        return $Query;
    }


    /**
     * get_rank
     */
    public static function get_rank($TableName, $Value)
    {
        if ($Value === 0) {
            return 0;
        }

        $Table = G::$Cache->get_value(self::PREFIX.$TableName);
        if (!$Table) {
            # Cache lock!
            $Lock = G::$Cache->get_value(self::PREFIX.$TableName.'_lock');

            if ($Lock) {
                return false;
            } else {
                G::$Cache->cache_value(self::PREFIX.$TableName.'_lock', '1', 300);
                $Table = self::build_table(self::PREFIX.$TableName, self::table_query($TableName));
                G::$Cache->delete_value(self::PREFIX.$TableName.'_lock');
            }
        }

        $LastPercentile = 0;
        foreach ($Table as $Row) {
            list($CurValue) = $Row;

            if ($CurValue >= $Value) {
                return $LastPercentile;
            }

            $LastPercentile++;
        }

        # 100th percentile
        return 100;
    }


    /**
     * overall_score
     */
    public static function overall_score($Uploaded, $Downloaded, $Uploads, $Requests, $Posts, $Bounty, $Artists, $Ratio)
    {
        # We can do this all in 1 line, but it's easier to read this way
        if ($Ratio > 1) {
            $Ratio = 1;
        }

        $TotalScore = 0;
        if (in_array(false, func_get_args(), true)) {
            return false;
        }
        
        $TotalScore += $Uploaded * 15;
        $TotalScore += $Downloaded * 8;
        $TotalScore += $Uploads * 25;
        $TotalScore += $Requests * 2;
        $TotalScore += $Posts;
        $TotalScore += $Bounty;
        $TotalScore += $Artists;
        $TotalScore /= (15 + 8 + 25 + 2 + 1 + 1 + 1);
        $TotalScore *= $Ratio;
        
        return $TotalScore;
    }
}