Google App Script - Personal Calendar Sync

cal_sync.js

function sync() {
  var secondaryCalIds = [];
  secondaryCalIds.push("[email protected]");
  secondaryCalIds.push("[email protected]");
  var primaryEventTitle = "Personal Appointment";
  var eventBufferMinutes = 20;
  var eventBufferMs = eventBufferMinutes * 60 * 1000;
  var visiblity = CalendarApp.Visibility.PUBLIC;
  var color = CalendarApp.EventColor.YELLOW;

  var today = new Date();
  var endDate = new Date();
  endDate.setDate(today.getDate() + 28); // how many days in advance to monitor and block off time
  var secondaryEvents = [];
  for (cid in secondaryCalIds) {
    var secondaryCal = CalendarApp.getCalendarById(secondaryCalIds[cid]);
    var srcEvents = secondaryCal.getEvents(today, endDate)
    var secondaryEvents = secondaryEvents.concat(srcEvents);
    Logger.log('Number of source events: ' + srcEvents.length + ' (' + secondaryCalIds[cid] + ')');
  }

  // create filtered list of existing primary calendar events that were previously created from the secondary calendar
  var primaryCal = CalendarApp.getDefaultCalendar();
  var primaryEventsAll = primaryCal.getEvents(today, endDate); // all primary calendar events
  var primaryEvents = []; // to contain primary calendar events that were previously created from secondary calendar
  for (pev in primaryEventsAll) {
    var primaryEvent = primaryEventsAll[pev];
    if (primaryEvent.getTitle() == primaryEventTitle) {
      primaryEvents.push(primaryEvent);
    }
  }
  Logger.log('Total number of target events: ' + primaryEventsAll.length);
  Logger.log('Number of managed target events: ' + primaryEvents.length);

  // process all events in secondary calendar
  var statsCreated = 0, statsDeleted = 0;
  var updatedPrimaryEventIds = []; // to contain primary calendar events that were updated from secondary calendar
  for (sev in secondaryEvents) {
    secondaryEvent = secondaryEvents[sev];

    // include buffer around personal appoint (i.e. travel time)
    var secondaryStart = new Date(secondaryEvent.getStartTime().getTime() - eventBufferMs);
    var secondaryEnd = new Date(secondaryEvent.getEndTime().getTime() + eventBufferMs);

    // if the secondary event has already been blocked in the primary calendar, update it
    updated = false;
    for (existingId in primaryEvents) {
      var primaryEvent = primaryEvents[existingId];
      if ((primaryEvent.getStartTime().getTime() == secondaryStart.getTime()) && (primaryEvent.getEndTime().getTime() == secondaryEnd.getTime())) {
        primaryEvent.setDescription(secondaryEvent.getTitle() + '\n\n' + secondaryEvent.getDescription());
        primaryEvent.setVisibility(visiblity);
        primaryEvent.setColor(color);
        updatedPrimaryEventIds.push(primaryEvent.getId());
        Logger.log('EVENT UPDATED - id: ' + primaryEvent.getId() + ' (' + secondaryEvent.getTitle() + ')');
        updated = true;
        break;
      }
    }
    if(updated) {
      continue;
    }

    // skip all day, multi-day, or weekend events
    var startDay = secondaryEvent.getStartTime().getDay();
    var endDay = secondaryEvent.getEndTime().getDay();
    if(secondaryEvent.isAllDayEvent() /*|| startDay != endDay */|| startDay == 0 || startDay == 6) {
      continue;
    }

    // create a new event based on the secondary event
    var newEvent = primaryCal.createEvent(primaryEventTitle, secondaryStart, secondaryEnd, {description:secondaryEvent.getTitle() + '\n\n' + secondaryEvent.getDescription()});
    newEvent.setVisibility(visiblity);
    newEvent.setColor(color);
    newEvent.removeAllReminders();
    statsCreated = statsCreated + 1;
    Logger.log('EVENT CREATED - id: ' + newEvent.getId() + ' (' + secondaryEvent.getTitle() + ')');
  }

  // if a primary event previously created no longer exists in the secondary calendar, delete it
  for (pev in primaryEvents) {
    if (updatedPrimaryEventIds.indexOf(primaryEvents[pev].getId()) == -1) {
      var pevIdToDelete = primaryEvents[pev].getId();
      Logger.log(pevIdToDelete + ' deleted');
    Logger.log('EVENT DELETED - id: ' + pevIdToDelete + '');
      statsDeleted = statsDeleted + 1;
    }
  }

  Logger.log('Events created: ' + statsCreated);
  Logger.log('Events updated: ' + updatedPrimaryEventIds.length);
  Logger.log('Events deleted: ' + statsDeleted);
}