php get closest timestamp but less than current timestamp - php

Question

I'm working with timestamp in an array as value, for example :
1455874500 : 19/02/2016 09h35
1455879600 : 19/02/2016 11h00
1455921300 : 19/02/2016 22h35
And the thing I would like to do is to get the closest timestamp from my array BUT if this timestamp is higher than the current timestamp (closest > current timestamp), get the lower value.
Here is an example to illustrate my point, it's 19/02/2016 10h58, I don't want to get 1455879600 (19/02/2016 11h00) but 1455874500 (19/02/2016 09h35) AND then, when it is 19/02/2016 11h00, get 1455879600.
I've been working on this code :
function find_closest($id, $date_now){
global $cnx;
$sql = "select position_history from worksheets WHERE id = $id LIMIT 1";
$stmt = $cnx->prepare($sql);
try {
$stmt->execute();
$result = $stmt->fetch(PDO::FETCH_OBJ);
}
catch (PDOException $e) {
echo $e->getMessage();
}
$pos_lane = unserialize($result->position_history);
$i=0;
$array = array();
foreach ($pos_lane as $item) {
// $exp[2] : timestamp
$exp = explode("|", $pos_lane[$i]);
$array[$exp[1]] = $exp[2];
$i++;
}
$mostrecent = "0";
foreach($array as $timestampmove)
{
if ($timestampmove > $mostrecent && $timestampmove < $date_now) {
$mostrecent = $timestampmove;
}
}
$closeto = array_search($mostrecent,$array);
return $closeto;
}
which aim to select the most recent timestamp BEFORE today but it does not seem to work as I want...
Maybe you have a better solution for me?
thank you !

Answer 1

Why not make it simpler and have the original sql query do the work for you?
$sql = "select MAX(position_history) from worksheets WHERE id = $id and position_history < now() LIMIT 1";

Answer 2

You may try the following:
foreach ($pos_lane as $item) {
// $exp[2] : timestamp
$exp = explode("|", $pos_lane[$i]);
$array[$exp[1]] = (int) $exp[2]; // <<< cast to int
$i++;
}
$mostrecent = 0;
$closeto = null;
foreach($array as $key => $timestampmove)
{
if ($timestampmove < $date_now) { // <<< make sure $date_now is a Unix timestamp
if ($mostrecent < $timestampmove) {
$mostrecent = $timestampmove;
$closeto = $key;
}
}
}
return $closeto;