query("tank_history", "SELECT date_time, current_liters FROM history WHERE tank_id = $tank_id AND date_time >= NOW() - INTERVAL 1 DAY ORDER BY date_time ASC");
// $labels = ["08:00", "10:00", ...];
// $values = [5000, 4800, ...];
$tank = $db->query("tanks", "SELECT * FROM tanks WHERE record_id = $tank_id");
$tank = $tank->fetch_assoc();
$name = $tank['name'];
$radius = $tank['radius_mm'];
$length = $tank['length_mm'];
$tank_type = $tank['tank_type'];
$add_to_distance = $tank['add_to_distance'];
// 1. Get the raw logs for the last 24 hours in ONE query
// We group by the date and hour to get one entry per hour
$sql = "SELECT * FROM tank_level_log
WHERE tank_id = $tank_id
AND date_time_measured >= NOW() - INTERVAL 24 HOUR
GROUP BY DATE(date_time_measured), HOUR(date_time_measured)
ORDER BY date_time_measured ASC";
$logs_res = $db->query("tank_level_log", $sql);
$labels = [];
$values = [];
$func = new functions();
while ($log = $logs_res->fetch_assoc()) {
$distance = $log['distance'] ?? 0;
// Perform your volume calculation
$calc = $func->calculate_horizontal_cylinder_volume(
$radius,
($radius * 2) - ($distance + $add_to_distance),
$length
);
// Format the time for the graph (e.g., "14:00")
$labels[] = date("H:i", strtotime($log['date_time_measured']));
$values[] = round($calc['fluid_volume_liters']);
}
// Convert to JSON for the Javascript Chart
$js_labels = json_encode($labels);
$js_values = json_encode($values);
?>
HIGHEST LEVEL
LOWEST LEVEL