<?php
declare(strict_types=1);

require_once __DIR__ . '/../../../modules/shared/db.php';
require_once __DIR__ . '/../../../modules/shared/auth/service.php';
require_once __DIR__ . '/../../../modules/erp/bestellungen/service.php';

header('Content-Type: text/event-stream; charset=utf-8');
header('Cache-Control: no-cache, no-transform');
header('Connection: keep-alive');
header('X-Accel-Buffering: no');

ignore_user_abort(true);
set_time_limit(0);

if (function_exists('apache_setenv')) {
    @apache_setenv('no-gzip', '1');
}
@ini_set('zlib.output_compression', '0');

$env = expand_env_values(parse_env_file(__DIR__ . '/../../../.env'));

try {
    $pdo = connect_database($env);
} catch (Throwable $e) {
    http_response_code(500);
    echo 'Database connection failed';
    exit;
}

auth_bootstrap_session();
$currentUser = auth_current_user($pdo);
if ($currentUser === null) {
    http_response_code(401);
    echo 'Unauthorized';
    exit;
}

session_write_close();

while (ob_get_level() > 0) {
    ob_end_flush();
}

$sendEvent = static function (string $eventName, array $payload): void {
    echo 'event: ' . $eventName . "\n";
    echo 'data: ' . json_encode($payload, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES) . "\n\n";
    flush();
};

$lastHeartbeatAt = time();
$state = [];
foreach (get_sales_order_realtime_snapshot($pdo) as $row) {
    $state[(int) $row['id']] = (string) $row['updated_at'];
}

echo ": connected\n\n";
flush();

while (!connection_aborted()) {
    try {
        $snapshot = get_sales_order_realtime_snapshot($pdo);
        $nextState = [];

        foreach ($snapshot as $row) {
            $orderId = (int) ($row['id'] ?? 0);
            if ($orderId <= 0) {
                continue;
            }

            $updatedAt = (string) ($row['updated_at'] ?? '');
            $nextState[$orderId] = $updatedAt;

            if (!array_key_exists($orderId, $state)) {
                $sendEvent('bestellungen.changed', [
                    'kind' => 'created',
                    'orderId' => $orderId,
                    'updatedAt' => $updatedAt,
                ]);
                continue;
            }

            if ($state[$orderId] !== $updatedAt) {
                $sendEvent('bestellungen.changed', [
                    'kind' => 'updated',
                    'orderId' => $orderId,
                    'updatedAt' => $updatedAt,
                ]);
            }
        }

        $state = $nextState;

        if ((time() - $lastHeartbeatAt) >= 15) {
            echo ": ping\n\n";
            flush();
            $lastHeartbeatAt = time();
        }

        usleep(2000000);
    } catch (Throwable $e) {
        echo ": error\n\n";
        flush();
        try {
            $pdo = connect_database($env);
            $state = [];
            foreach (get_sales_order_realtime_snapshot($pdo) as $row) {
                $state[(int) $row['id']] = (string) $row['updated_at'];
            }
        } catch (Throwable $reconnectError) {
            // Keep the connection open and try again on the next loop.
        }
        usleep(5000000);
    }
}