PHP - Time Based Account

<header>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.5.1/jquery.min.js"></script>
<script src="Time/detect_timezone.js"></script>
<script src="Time/jquery.detect_timezone.js"></script>
<script>
$(document).ready(function(){
  $('#tzvalue').set_timezone({'default' : 'America/Los_Angeles'});
});
</script>
</header>

       $tablesum ++;
        $guestsum += $row->reservation_pax;
<?php echo $guestsum;?>&nbsp;&nbsp;<?php echo _guest_summary;?>

<!-- Begin reservation table data -->
<br/>
<table class="global resv-table-small" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
		
		<?php
		echo "<td class='noprint'> </td>";
		echo "<td>Time</td>";
		echo "<td>Guests/Type</td>";
		echo "<td>Name</td>";
		echo "<td>Special Instructions/Notes</td>";
		echo "<td class='noprint'>Table</td>";
		echo "<td class='noprint'>Status</td>";
		echo "<td class='noprint'>Created</td>";
		echo "<td class='noprint'>Details/Delete</td>";

	echo "</tr>";
		
		// Clear reservation variable
		$reservations ='';
		
		if ($_SESSION['page'] == 1) {
			$reservations =	querySQL('all_reservations');
		}else{
			$reservations =	querySQL('reservations');
		}
		
		// reset total counters
		$tablesum = 0;
		$guestsum = 0;
			
		if ($reservations) {
			
			//start printing out reservation grid
			foreach($reservations as $row) {
				// reservation ID
				$id = $row->reservation_id;
				$_SESSION['reservation_guest_name'] = $row->reservation_guest_name;
				// check if reservation is tautologous
				$tautologous = querySQL('tautologous');
				
			echo "<tr id='res-".$id."'>";
			echo "<td";
			// daylight coloring
			if ($row->reservation_time > $daylight_evening){
				echo " class='evening noprint'";
			}else if ($row->reservation_time > $daylight_noon){
				echo " class='afternoon noprint'";
			}else if ($row->reservation_time < $daylight_noon){
				echo " class='morning noprint'";
			}
			
			echo " style='width:10px !important; padding:0px;'>&nbsp;</td>";
			echo "<td id='tb_time'";
			// reservation after maitre message
			if ($row->reservation_timestamp > $maitre['maitre_timestamp'] && $maitre['maitre_comment_day']!='') {
				echo " class='tautologous' title='"._sentence_13."' ";
			}
			echo ">";
			echo "<strong>".formatTime($row->reservation_time,$general['timeformat'])."</strong></td>";
			echo "<td id='tb_pax'><strong class='big'>".$row->reservation_pax."</strong>&nbsp;&nbsp;<span class='noprint'>";
			printType($row->reservation_hotelguest_yn);
				//echo "<img src='images/icons/user-silhouette.png' class='middle'/>";
			echo "</span></td><td style='width:10%' id='tb_name'><span class='noprint'>".printTitle($row->reservation_title)."</span><strong> <a id='detlbuttontrigger' href='ajax/guest_detail.php?id=".$id."'"; 
			// color guest name if tautologous
			if($tautologous>1){echo" class='tautologous tipsy' title='"._tautologous_booking."'";}
			echo ">".$row->reservation_guest_name."</a></strong>";
			
			// old reservations symbol
			if( (strtotime($row->reservation_timestamp) + $general['old_days']*86400) <= time() ){
				echo "<img src='images/icons/clock-bolt.png' class='help tipsyold middle smicon' title='"._sentence_11."' />";
			}
			// recurring symbol
			if ($row->repeat_id !=0) {
	            echo "&nbsp;<img src='images/icons/loop-alt.png' alt='"._recurring.
					 "' title='"._recurring."' class='tipsy' border='0' >";
	        }
	
			echo"</td><td style='width:10%' id='tb_note'>";
				if ($_SESSION['page'] == 1) {
			 		echo $row->outlet_name;
			 	}else{
					echo $row->reservation_notes;
				}
			echo "</td>";
			
			if($_SESSION['wait'] == 0){
				echo "<td class='big tb_nr' style='width:85px;' id='tb_table'><img src='images/icons/table_II.png' class='tipsy leftside noprint' title='"._table."' /><div id='reservation_table-".$id."' class='inlineedit'>".$row->reservation_table."</div></td>";
			}
			echo "<td class='noprint'><div>";
				getStatusList($id, $row->reservation_status);
			echo "</div></td>";
			echo "<td class='noprint'>";
			echo "<small>".$row->reservation_booker_name." | ".humanize($row->reservation_timestamp)."</small>";
			echo "</td>";
			echo "<td class='noprint'>";
			// MOVE BUTTON
			//	echo "<a href=''><img src='images/icons/arrow.png' alt='move' class='help' title='"._move_reservation_to."'/></a>";
			
			// WAITLIST ALLOW BUTTON
			if($_SESSION['wait'] == 1){
				$leftspace = leftSpace(substr($row->reservation_time,0,5), $availability);
				if($leftspace >= $row->reservation_pax && $_SESSION['outlet_max_tables']-$tbl_availability[substr($row->reservation_time,0,5)] >= 1){	    
					echo"&nbsp;<a href='#' name='".$id."' class='alwbtn'><img src='images/icons/check-alt.png' name='".$id."' alt='"._allow."' class='help' title='"._allow."'/></a>&nbsp;&nbsp;";
				}
			}
			// EDIT/DETAIL BUTTON
			echo "<a href='?p=102&resID=".$id."'><img src='images/icons/pen-fill.png' alt='"._detail."' class='help' title='"._detail."'/></a>&nbsp;&nbsp;";
			// DELETE BUTTON
			if ( current_user_can( 'Reservation-Delete' ) && $q!=3 ){
		    	echo"<a href='#modalsecurity' name='".$row->repeat_id."' id='".$id."' class='delbtn'>
					<img src='images/icons/delete.png' alt='"._cancelled."' class='help' title='"._delete."'/></a>";
			}
		echo"</td></tr>";
		$tablesum ++;
		$guestsum += $row->reservation_pax;
			}
		}
		?>
	</tbody>
	<tfoot>

		<tr style="border:1px #000;">
			<td class=" noprint"></td><td></td>
			<td colspan="2" class="bold"><?php echo $guestsum;?>&nbsp;&nbsp;<?php echo _guest_summary;?></td>
			<td></td>
			<td colspan="2" class="bold"><?php echo $tablesum;?>&nbsp;&nbsp;<?php echo _tables_summary;?></td>
			<?php
			if($_SESSION['wait'] == 0){
				//echo "<td></td>";
			}
			?>
		</tr>
	</tfoot>
</table>
<!-- End reservation table data -->

I'm working on a project that has a lot of different timezone options, and all I have from the users is their UTC offset.

After weeks of doing tweaks, I come to new issues every time I add something, one would think it would be a lot easier to just get the correct time and day :)

The latest issue is that when I try to rewrite a date to a better fomat, it disregards the GMT offset. Like this:

4/14/19, 12:00 PM GMT+2 (=$date) becomes ... 14-04-2019 10:00 when using this code:

$bp_date_to_format = date_create_from_format('Y-m-d\TH:i:sP', $date);
echo date_format($bp_date_to_format, 'd-m-Y H:i');

I figured it would just rewrite the format, keeping the exact time. It isn't.

We do have all these sorts of localization functions as well, but because there doesn't seem to be one single standard (each 3rd party API connection we have uses its own default datetime format so it seems).

        // Remove UTC Text
        $UTC_offset = str_replace('UTC', '', $timezone);

        // Get Offset in Minutes
        if (stripos($UTC_offset, ':') !== false) {
            // Calculate seconds from offset
            list($hours, $minutes) = explode(':', $offset);
            $seconds = $hours * 60 * 60 + $minutes * 60;
        } else {
            $seconds = $UTC_offset * 60 * 60;
        }

        // Get User timezone name from seconds
        $timezone = timezone_name_from_abbr('', $seconds, 1);
        if ($timezone === false) {
            $timezone = timezone_name_from_abbr('', $seconds, 0);
        }
        // Set new TZ
        return date_default_timezone_set($timezone);

Isn't there any "one way"solution that can be used? It's confusing to say the least.

Cheers.

// STEP #1 = DEFINE THE DESIRED DATE/TIME DIFFERENCE INTERVAL DESIRED FOR QUERIES

$timeinterval = '60'; // Interval is in MINUTES and can be changed as desired

// STEP #2 = GET THE CURRENT LOCAL SERVER DATE/TIME
// as YYYY-MM-DD HH:MN:SE

$serverdatetime = date('Y-m-d H:i:s'); // My local Server Date & time

// STEP #3 = CALCULATE THE ***PAST** (OLDER) DATE/TIME LIMIT BASED ON $timeinterval (Minutes)
// as YYY-MM-DD HH:MN:SE

$pastdatetime = [stuckinarut here] <- 60 MINUTES prior to current Server Date/Time

// STEP #4 = MySQL QUERY (`submitted` column is auto-timestampped on record insertions)

$sql="[columnsblahblah] FROM mydb WHERE `submitted` >= $pastdatetime";

$num_of_ids = 10000; //Number of "ids" to generate.
$i = 0; //Loop counter.
$n = 0; //"id" number piece.
$l = "AAA"; //"id" letter piece.

while ($i <= $num_of_ids) { 
    $id = $l . sprintf("%04d", $n); //Create "id". Sprintf pads the number to make it 4 digits.
    echo $id . "<br>"; //Print out the id.

    if ($n == 9999) { //Once the number reaches 9999, increase the letter by one and reset number to 0.
        $n = 0;
        $l++;
    }

    $i++; $n++; //Letters can be incremented the same as numbers. Adding 1 to "AAA" prints out "AAB".
}