public function overlap(DayTime $b)
{
// Seconds from commencement of the week;
$selfMinutes = $this->getDay() * self::MINUTES_IN_DAY + $this->getHour() * self::MINUTES_IN_HOUR + $this->getMinute();
$bMinutes = $b->getDay() * self::MINUTES_IN_DAY + $b->getHour() * self::MINUTES_IN_HOUR + $b->getMinute();
if ($selfMinutes > $bMinutes) {
// I start before the other does
return min($bMinutes + $b->getDuration(), $selfMinutes + $this->getDuration()) - $selfMinutes;
}
// Does this DayTime end overlap with the $b period?
if ($selfMinutes + $this->getDuration() < $bMinutes) {
// No overlap - return 0;
return 0;
}
$selfEnd = $selfMinutes + $this->getDuration();
$bEnd = $bMinutes + $b->getDuration();
if ($selfEnd < $bEnd) {
// I end before $b ends
return $bMinutes + ($bEnd - $selfEnd);
}
return $b->getDuration();
}
