<?php
public static function Greeting()
  {
    $endMorning = mktime(11, 59, 59, date("m"), date("d"), date("Y"));
    $endAfternoon = mktime(17, 59, 59, date("m"), date("d"), date("Y"));
    $endNight = mktime(05, 59, 59, date("m"), date("d"), date("Y"));

    $today = mktime(date("H"), date("i"), date("s"), date("m"), date("d"), date("Y"));

    if ($today > $endAfternoon)
    {
      return 'Boa noite';
    }
    else if ($today > $endMorning)
    {
      return 'Boa tarde';
    }
    else
    {
      return 'Bom dia';
    }

    return 'dude, where are you?';
  }
?>