<?php
function sendIcalEvent($from_name, $from_address, $to_name, $to_address, $startTime, $endTime, $subject, $description, $location)
{
    $domain = 'exchangecore.com';

    //Create Email Headers
    $mime_boundary = "----Meeting Booking----".MD5(TIME());

    $headers = "From: ".$from_name." <".$from_address.">\n";
    $headers .= "Reply-To: ".$from_name." <".$from_address.">\n";
    $headers .= "MIME-Version: 1.0\n";
    $headers .= "Content-Type: multipart/alternative; boundary=\"$mime_boundary\"\n";
    $headers .= "Content-class: urn:content-classes:calendarmessage\n";
    
    //Create Email Body (HTML)
    $message = "--$mime_boundary\r\n";
    $message .= "Content-Type: text/html; charset=UTF-8\n";
    $message .= "Content-Transfer-Encoding: 8bit\n\n";
    $message .= "<html>\n";
    $message .= "<body>\n";
    $message .= '<p>'.$to_name.',</p>';
    $message .= '<p>'.$description.'</p>';
    $message .= "</body>\n";
    $message .= "</html>\n";
    $message .= "--$mime_boundary\r\n";

	//Europe/Paris
	//X-WR-TIMEZONE:Europe/Bucharest
	//'TZID:Eastern Time' . "\r\n" .
	
    $ical = 'BEGIN:VCALENDAR' . "\r\n" .
    'PRODID:-//Microsoft Corporation//Outlook 10.0 MIMEDIR//EN' . "\r\n" .
    'VERSION:2.0' . "\r\n" .
    'METHOD:REQUEST' . "\r\n" .
    'BEGIN:VTIMEZONE' . "\r\n" .
    'X-WR-TIMEZONE:Europe/Bucharest' . "\r\n" .
    'BEGIN:STANDARD' . "\r\n" .
    'DTSTART:20091101T020000' . "\r\n" .
    'RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=1SU;BYMONTH=11' . "\r\n" .
    'TZOFFSETFROM:-0400' . "\r\n" .
    'TZOFFSETTO:-0500' . "\r\n" .
    'TZNAME:EST' . "\r\n" .
    'END:STANDARD' . "\r\n" .
    'BEGIN:DAYLIGHT' . "\r\n" .
    'DTSTART:20090301T020000' . "\r\n" .
    'RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=2SU;BYMONTH=3' . "\r\n" .
    'TZOFFSETFROM:-0500' . "\r\n" .
    'TZOFFSETTO:-0400' . "\r\n" .
    'TZNAME:EDST' . "\r\n" .
    'END:DAYLIGHT' . "\r\n" .
    'END:VTIMEZONE' . "\r\n" .	
    'BEGIN:VEVENT' . "\r\n" .
    'ORGANIZER;CN="'.$from_name.'":MAILTO:'.$from_address. "\r\n" .
    'ATTENDEE;CN="'.$to_name.'";ROLE=REQ-PARTICIPANT;RSVP=TRUE:MAILTO:'.$to_address. "\r\n" .
    'LAST-MODIFIED:' . date("Ymd\TGis") . "\r\n" .
    'UID:'.date("Ymd\TGis", strtotime($startTime)).rand()."@".$domain."\r\n" .
    'DTSTAMP:'.date("Ymd\TGis"). "\r\n" .
    'DTSTART;TZID="Eastern Time":'.date("Ymd\THis", strtotime($startTime)). "\r\n" .
    'DTEND;TZID="Eastern Time":'.date("Ymd\THis", strtotime($endTime)). "\r\n" .
    'TRANSP:OPAQUE'. "\r\n" .
    'SEQUENCE:1'. "\r\n" .
    'SUMMARY:' . $subject . "\r\n" .
    'LOCATION:' . $location . "\r\n" .
    'CLASS:PUBLIC'. "\r\n" .
    'PRIORITY:5'. "\r\n" .
    'BEGIN:VALARM' . "\r\n" .
    'TRIGGER:-PT15M' . "\r\n" .
    'ACTION:DISPLAY' . "\r\n" .
    'DESCRIPTION:Reminder' . "\r\n" .
    'END:VALARM' . "\r\n" .
    'END:VEVENT'. "\r\n" .
    'END:VCALENDAR'. "\r\n";
    $message .= 'Content-Type: text/calendar;name="meeting.ics";method=REQUEST\n';
    $message .= "Content-Transfer-Encoding: 8bit\n\n";
    $message .= $ical;

    $mailsent = mail($to_address, $subject, $message, $headers);
	echo $mailsent;
    return ($mailsent)?(true):(false);
}

$from_name = "Administrateur";        
$from_address = "Nathalie.Janez@onsemi.com";        
$to_name = "Patrice";        
$to_address = "patrice.delpy@onsemi.com";        
$startTime = "01/04/2015 10:00:00";        
$endTime = "01/04/2015 10:20:00";        
$subject = "Réservation d'un massage";        
$description = "Tu viens de réserver une ou plusieurs séances à la date suivante:";  
 $description .= "\n";      
 $description .= "\n";      
 $description .= "blabla";      
$location = "Salle de repos";
sendIcalEvent($from_name, $from_address, $to_name, $to_address, $startTime, $endTime, $subject, $description, $location);

// convert it to the 'internal' time zone
//$Date->setTimezone( new DateTimeZone( 'Europe/Amsterdam' ) );

// ...

//echo "BEGIN:VEVENT\n";
//echo "DTSTART;TZID=W. Europe Standard Time:" . $Date->format( 'Ymd\THis' ) . "\n"
//X-WR-TIMEZONE:Europe/Bucharest
//TZID:America/New_York
?>