function calendarBasedReply() {
    var interval = 1;    //  if the script runs every minute; change otherwise
    var date = new Date();
    var timeFrom = Math.floor(date.valueOf() / 1000) - ((60 * interval) + 1);
    var threads = GmailApp.search('is:inbox after:' + timeFrom);
    var shouldMarkAsReadAfterReply = false
    var shouldAlwaysMarkAsRead = false
    date.setMinutes(date.getMinutes() - interval)
    Logger.log(timeFrom)
    if (threads.length <= 0) {
        console.info("no threads present, no reply needed")
        return
    }
    // Replace the calender id with the correct calendar ID
    var calendarId = 'placeholder@group.calendar.google.com'
    var events = Calendar.Events.list(calendarId, {
        timeMin: date.toISOString(),
        singleEvents: true,
        orderBy: 'startTime',
        maxResults: 3
    });

    for (var i = 0; i < threads.length; i++) {
        console.info("thread ", i, " is unread ", threads[i].isUnread())
        if (threads[i].isUnread()) {
          if (shouldAlwaysMarkAsRead){
            threads[i].markRead();
          }
            for (var i = 0; i < events.items.length; i++) {
                var event = events.items[i]
                var begin = new Date(event.start.dateTime)
                console.info("begin " + begin + " last message " + threads[i].getLastMessageDate())
                if (begin < threads[i].getLastMessageDate()) {
                  if (shouldMarkAsReadAfterReply){
                    threads[i].markRead();
                  }
                    threads[i].reply("", { htmlBody: event.description })
                    threads[i].markImportant()
                    break
                }
            }
        }
    }
}