relative date

relative_date.php

<?
# relative_date
# usage: relative_date("2009-09-09 9:09:09") => "9 minutes ago"
# just now, 25 seconds ago... yesterday, 5 days ago, 3 months ago

function pluralize($count,$word) {
  if($count == 0) {
    return "no ".$word."s";
  } else if($count == 1) {
    return "1 ".$word;
  } else {
    return floor($count)." ".$word."s";
  }
}

function date_diff($interval, $date1, $date2) {
  
  $date1 = strtotime($date1);
  $date2 = strtotime($date2);
  $seconds = $date2 - $date1;

  if ($seconds < 0) {
    $tmp = $date1;
    $date1 = $date2;
    $date2 = $tmp;
    $seconds = 0-$seconds;
  }

  if ($interval =='y' || $interval=='m') {
    $date1 = date("Y-m-d h:i:s", $date1);
    $date2=  date("Y-m-d h:i:s", $date2);
  }

  switch($interval) {
    case "y":
      list($year1, $month1, $day1) = split('-', $date1);
      list($year2, $month2, $day2) = split('-', $date2);
      $time1 = (date('H',$date1)*3600) + (date('i',$date1)*60) + (date('s',$date1));
      $time2 = (date('H',$date2)*3600) + (date('i',$date2)*60) + (date('s',$date2));
      $diff = $year2 - $year1;

      if($month1 > $month2) {
        $diff -= 1;
      } elseif($month1 == $month2) {
        if($day1 > $day2) {
        $diff -= 1;
        } elseif($day1 == $day2) {
          if($time1 > $time2) {
            $diff -= 1;
          }
        }
      }
      break;
    case "m":
      list($year1, $month1, $day1) = split('-', $date1);
      list($year2, $month2, $day2) = split('-',$date2);
      $time1 = (date('H',$date1)*3600) + (date('i',$date1)*60) + (date('s',$date1));
      $time2 = (date('H',$date2)*3600) + (date('i',$date2)*60) + (date('s',$date2));
      $diff = ($year2 * 12 + $month2) - ($year1 * 12 + $month1);
      if($day1 > $day2) {
        $diff -= 1;
      } elseif($day1 == $day2) {
        if($time1 > $time2) {
          $diff -= 1;
        }
      }
      break;
    case "w":
      $diff = floor($seconds / 604800);
      break;
    case "d":
      $diff = floor($seconds / 86400);
      break;
    case "h":
      $diff = floor($seconds / 3600);
      break;
    case "i":
      $diff = floor($seconds / 60);
      break;
    case "s":
      $diff = $seconds;
      break;
  }

  return $diff;
}

function relative_date($date_added) {
  
  $now = date('Y-m-d H:i:s');
  $hours_ago = date_diff('h',$now,$date_added);
  
  if($hours_ago<1) {
    $min_ago = date_diff('i',$now,$date_added);
    if($min_ago < 1) {
      $sec_ago = date_diff('s',$now,$date_added);
      if($sec_ago < 1) {
        $ago = "just now";
      } else {
        $ago = pluralize($sec_ago,"second")." ago";
      }
    } else {
      $ago = pluralize($min_ago,"minute")." ago";
    }
  } elseif($hours_ago>743) {
    $months_ago = date_diff('m',$now,$date_added);
    $ago = pluralize($months_ago,"month")." ago";
  } elseif($hours_ago>23) {
    $days_ago = date_diff('d',$now,$date_added);
    if($days_ago == 1) {
      $ago = "yesterday";
    } else {
      $ago = $days_ago." days ago";
    }
  } else {
    $ago = pluralize($hours_ago,"hour")." ago";
  }
  
  return $ago;
}

?>