<?php

$result = mysqli_query($mysqli, "SELECT config_timezone FROM settings WHERE company_id = 1");
$row = mysqli_fetch_array($result);
$_SESSION['session_timezone'] = $row['config_timezone'];

// Set PHP timezone
date_default_timezone_set($_SESSION['session_timezone']);

// Calculate UTC offset and store it in session
$session_datetime = new DateTime('now', new DateTimeZone($_SESSION['session_timezone']));
$_SESSION['session_utc_offset'] = $session_datetime->format('P');

// Use the stored timezone and offset
$session_timezone = $_SESSION['session_timezone'];
date_default_timezone_set($session_timezone);

// Set MySQL session time zone
mysqli_query($mysqli, "SET time_zone = '{$_SESSION['session_utc_offset']}'");