web/public/api/race/results.php

<?php $app = require '../../../app/inc.php';
/**
 * We originally wanted to use SSE for this, but the hosting provider
 * did not support that so we resorted to simple polling instead
 * 
 * This page compiles a set of times and sends it if the provided hash of 
 * the data is not equal.
 */

use App\Teamtable\TeamMapper;
use App\Timetable\TimeMapper;

$team_mapper = new TeamMapper($app->database->conn);
$time_mapper = new TimeMapper($app->database->conn);

$prev_hash = filter_input(INPUT_GET, 'h');

$teams    = [];
$team_map = [];
$times    = [];
$time_ref = NULL;

foreach ($time_mapper->getAll() as $time)
{
    if (!isset($teams[$time->team_id]))
    {
        $teams[$time->team_id] = $team_mapper->get($time->team_id);
    }
    $team = $teams[$time->team_id];

    if (!isset($team_map[$team->id]))
    {
        $team_map[$team->id] = [
            "name"    => htmlspecialchars($team->name),
            "company" => htmlspecialchars($team->company),
            "rounds"  => htmlspecialchars($team->rounds),
        ];
    }

    if ($time_ref === NULL)
    {
        $time_ref = $time->date->getTimestamp();
    }

    $row = [
        "id"   => $team->id,
        "time" => ($time->date->getTimestamp() - $time_ref)
    ];

    array_push($times, $row);
}

$data = [
    "map" => [
        "team" => $team_map,
        "time_reference" => $time_ref
    ],
    "times" => $times
];

$hash = hash('crc32', serialize($data));

if ($prev_hash !== $hash)
{
    $app->api([
            "hash" => $hash,
            "data" => $data
        ]);
}
// return nothing
http_response_code(204);