Added Vacation Reporter

VacationReporter.gs

var teamMembers = ['Christian Strunk','Kirill Khaidukov'];
var googleCalendar = google.calendarWhosOut;
var slackInputHook = slack.inputHook.sam;

function sendVacationReportForTomorrow() {  
  var url = slackInputHook;
  var payload = {    
     "text" : todayReport(),// <-- required parameter
     "mrkdwn": true,
  }
  sendToSlack_(url,payload)
}

function todayReport() {
  var date = new Date();
  var muha = fetchCalendarEventsForMembers(teamMembers,date);
  return Utilities.formatString("*%s:*\n%s",formatDateToHuman(muha.date),formatterWhosOutArray(muha.whosout));
}
                                
function formatterWhosOutArray(array) { 
  text = '';
  separator = '\n';
  for(var i=0; i < array.length; i++) {
    var whosout = array[i];
    text = text + formatterWhosOut(whosout) + separator;
  }
  return text;
}
/*
 * formatterWhosOut
 * whosout: {member:string,type:string}
 * returning string
 */
function formatterWhosOut(whosout) {
  return Utilities.formatString("• _%s_: *%s*", whosout.member,whosout.type);
}

function formatterDate(date) {
  return Utilities.formatDate(date, "GMT+2", "E dd/MM/yyyy");
}

function formatDateToHuman(date) {
  var dateDate = date.getDate();
  var today = new Date().getDate();
  var tomorrow = new Date().setDate(today + 1);
  if(dateDate == today) {
    return 'Today';
  } else if(dateDate == tomorrow) {
    return 'Tomorrow';
  }
  return formatterDate(date); 
}

function getWhosOutCalendar() {
  return CalendarApp.getCalendarById(google.calendarWhosOut); 
}

function fetchCalendarEventsForMembersAndDates(members,startDate,endDate) {
  var days = dayDiv(startDate,endDate);
  return fetchCalendarEventsForMembersAndDateAndAmountOfDays(members,startDate,days);
}

function fetchCalendarEventsForMembersAndDateAndAmountOfDays(members,startDate,amountOfDays) {
  var array = [];
  for(var i=0; i<amountOfDays; i++) {
    var currentDate = new Date();
    currentDate.setDate(currentDate.getDate() + i);
    array.push(fetchCalendarEventsForMembers(members,currentDate));
  }
  return array;
}

function fetchCalendarEventsForMembers(members,date) {
  var events = fetchCalendarEvents(date);
  var filteredToRelevantEvents = filterToRelevantTeamMembers(events,members);
  
  return {date:date, whosout: filteredToRelevantEvents};
}

function fetchCalendarEvents(date) {
 var returnEvents = []
 var calendar = getWhosOutCalendar()
  var events = calendar.getEventsForDay(date);
  for(j = 0; j < events.length; j++) {
    var event = events[j]
    returnEvents.push(event);
  }
  return returnEvents;
}

function filterToRelevantTeamMembers(events,members) {
 var membersHasEvent = [];
  for(e = 0; e < events.length; e++) {
    event = events[e];
    for(m = 0; m < members.length; m++) {
      member = members[m];
      var regex = new RegExp(member,'g');
      var title = event.getTitle()
      if(title.match(regex)) {
        if(title.match(new RegExp('.*Home Office.*','g'))) {
           membersHasEvent.push({'member': member,'type': 'HomeOffice'});
        } else {
          membersHasEvent.push({'member': member,'type': 'Vacation'});
        }
      }
    }
  }
  return membersHasEvent;
}

function dayDiv(startDate,endDate) {
  return Math.round((startDate-endDate)/(1000*60*60*24));
}

function sendToSlack_(url,payload) {
   var options =  {
    "method" : "post",
    "contentType" : "application/json",
    "payload" : JSON.stringify(payload)
  };
  return UrlFetchApp.fetch(url, options)
}