<?php
date_default_timezone_set("Europe/London");
$sqlh = new PDO("mysql:host=127.0.0.1;dbname=wifi", "", ""); //connect to MySQl - add values
$devices = array();
$date = "2015_02_23";
$macs = $sqlh->query("SELECT mac,COUNT(seen_epoch) FROM meraki_$date group by mac having count(seen_epoch)>10 LIMIT 10;"); //get list of macs from db
while($mac = $macs->fetch(PDO::FETCH_ASSOC)) { //loop over mac addresses
    $first_seen = "";
    $last_seen = "";
    $sql_string = "SELECT seen_time,seen_epoch,last_seen,mac FROM meraki_$date WHERE mac='" . $mac['mac'] . "' ORDER BY seen_epoch ASC;"; //get all records for each mac
    $records = $sqlh->query($sql_string);
    while($record = $records->fetch(PDO::FETCH_ASSOC)) { //loop over records
        if(date("G", $record['seen_epoch']) < 7) { //Values before 7am are assumed not to be actual visitors
            continue; //continue to next iteration of loop without taking further action
        }
        if($first_seen == "") { //if begining of a new visit - record start time
            $first_seen = $record['seen_epoch'];
        }
        if($record['last_seen'] < 3600) { // if less than 1 hour since previous entry then assume continuing visit
            $last_seen = $record['seen_epoch'];
        } else {
            $visit['arrival'] = $first_seen; //Add arrival & departure times to array
            $visit['depart'] = $last_seen;
            $visits[] = $visit; //Add visit to array of visits
            $first_seen == ""; //reset visit start time
        }
        $mac = $record['mac'];//record device mac address
    }
    $visit['arrival'] = $first_seen;
    $visit['depart'] = $last_seen;
    $visits[] = $visit;
    $first_seen == "";
    $devices[] = $visits;
}
print_r($devices);
foreach($devices as $addr => $row) {
    foreach($row as $visit) {
        $arrival = date("r", $visit['arrival']);
        $departure = date("r", $visit['depart']);
        echo ("Device $addr arrived at $arrival and left at $departure<p />");
    }
}
?>