// theDt - the business object of the date field (i.e. BOA, BO.F_Date1)
app.getSharedData().getWeekNumberFromDate = function(theDt) {
if(theDt !== "") {

// Create a copy of this date object
var t = new Date(theDt);

// ISO week date weeks start on monday so correct the day number
var dayNr = (t.getDay() + 6) % 7;

// Set the target to the thursday of this week so the target date is in the right year
t.setDate(t.getDate() - dayNr + 3);

// ISO 8601 states that week 1 is the week with january 4th in it
var jan4 = new Date(t.getFullYear(), 0, 4);

// Number of days between target date and january 4th
var dayDiff = (t - jan4) / 86400000;

// Calculate week number: Week 1 (january 4th) plus the number of weeks between target date and january 4th
var weekNr = 1 + Math.ceil(dayDiff / 7);
return weekNr; 
} else {
return "";
}
}

app.getSharedData().daysInThisMonth = function( date ) {

var calendarObj = new Array();

calendarObj.push({month: 0, days: 31});
calendarObj.push({month: 1, days: 28});
calendarObj.push({month: 2, days: 31});
calendarObj.push({month: 3, days: 30});
calendarObj.push({month: 4, days: 31});
calendarObj.push({month: 5, days: 30});
calendarObj.push({month: 6, days: 31});
calendarObj.push({month: 7, days: 31});
calendarObj.push({month: 8, days: 30});
calendarObj.push({month: 9, days: 31});
calendarObj.push({month: 10, days: 30});
calendarObj.push({month: 11, days: 31});

// Get the "non-Leap Year" number of days in the current month.
var month = date.getMonth(); // Returns [0-11]
var days = get( calendarObj, month ).days;

// Add one day to February, if this is a Leap Year.
if( month === "1" && app.getSharedData().isLeapYear( date ) ) {
days++;
}

return days;
}

// dateObj1 - The date field (i.e. BO.F_Date)
// numOfHours - The number of hours to add
app.getSharedData().addHoursToDate = function(dateObj1, numOfHours) {
    var d1 = dateObj1.getValue(); //get first date

    var d1_milli = d1.getTime();
    return new Date(Math.ceil(d1_milli + (1000 * 60 * 60 * numOfHours)));
}

// dateObj1 - The date field (i.e. BO.F_Date)
// numOfDays - The number of days to add
app.getSharedData().addDaysToDate = function(dateObj1, numOfDays) {
    var d1 = dateObj1.getValue(); //get first date

    var d1_milli = d1.getTime();
    return new Date(Math.ceil(d1_milli + (1000 * 60 * 60 * 24 * numOfDays)));
}

app.getSharedData().isHoliday = function(d) {
  var r = false;
  var holidays = ["01-01","02-18","04-19","05-20","08-05","09-02"]; //set your holidays

  //check if any of the days is a holiday
  for(var holiday in holidays) {
    var h = new Date(get(holidays, holiday)+"-2020");

    if(d.getMonth() == h.getMonth() && d.getDay() == h.getDay()) {
      r = true;
    }
  }
  return r;
}

// dateObj1 - The date field (i.e. BO.F_Date)
// numOfDays - The number of working days to add
app.getSharedData().addWorkingDaysToDate = function(dateObj1, numOfDays) {

    var sd = dateObj1.getValue(); //get first date
    var ed = dateObj1.getValue();
    var counter = numOfDays;
    var millisecondsPerDay = 86400 * 1000;
    while (counter > 0) {
      ed = new Date(Math.ceil(ed.getTime() + millisecondsPerDay));
      var theDay = ed.getDay();

    //dont count sat and sunday and holidays
        if(theDay !== 0 && theDay !==6 && !app.getSharedData().isHoliday(ed)) {
            counter--;
        }    
    }

    return ed;    
}

// dateObj1 - The date field (i.e. BO.F_Date)
// numOfDays - The number of days to subtract
app.getSharedData().subtractDaysFromDate = function(dateObj1, numOfDays) {
    var d1 = dateObj1.getValue(); //get first date
    var d1_milli = d1.getTime();
    return new Date(Math.ceil(d1_milli - (1000 * 60 * 60 * 24 * numOfDays)));
}

// dateObj1 - The date field (i.e. BO.F_Date)
// numOfDays - The number of working days to subtract
app.getSharedData().subtractWorkingDaysFromDate = function(dateObj1, numOfDays) {
    var d1 = dateObj1.getValue(); //get first date
  var d2 = dateObj1.getValue();
    var counter = numOfDays;
    var millisecondsPerDay = 86400 * 1000;
    while (counter > 0) {
        d2 = new Date(Math.ceil(d2.getTime() - millisecondsPerDay));
    var theDay = d2.getDay();
    //dont count sat and sunday
        if(theDay !== 0 && theDay !==6) {
            counter--;
        }
    }
    return d2;    
}

// dateAD: the date to convert
app.getSharedData().convertToBuddhistDate = function(dateAD){
    var dateBE = new Date(dateAD);
    dateBE.setFullYear(dateAD.getFullYear() + 543);
    return dateBE;
}

// birthDay - the date to calculate the age from
app.getSharedData().getAgeFromBirthDate = function(birthDay) {
  
 // 1557600000 is 24 * 3600 * 365.25 * 1000 Which is the length of a year
 // the length of a year is 365 days and 6 hours which is 0.25 day.
  // double tilde converts float to integer
  return ~~((Date.now() - birthDay) / (31557600000));

}

app.getSharedData().isDateAfterToday(BO.F_Date1, "The date must be after today.");

 app.getSharedData().isDateAfterToday(BO.F_Date1, "The date must be after today.");

app.getSharedData().compareDatesByDays(BO.F_Date2, BO.F_Date3, 14, "The date must be 14 days past D1.");

app.getSharedData().workingDaysBetweenDates = function(startDt, endDt, includeWeekends, excludeHolidays) {
   // Validate input
   if (endDt < startDt)
       return 0;

   // Calculate days between dates
   var millisecondsPerDay = 86400 * 1000; // Day in milliseconds
   startDt.setHours(0,0,0,1);  // Start just after midnight
   endDt.setHours(23,59,59,999);  // End just before midnight
   var diff = endDt.getTime() - startDt.getTime();  // Milliseconds between datetime objects    
   var days = Math.ceil(diff / millisecondsPerDay);   

   if(!includeWeekends) {
       // Subtract two weekend days for every week in between
       var weeks = Math.floor(days / 7);
       var days = days - (weeks * 2);

       // Handle special cases
       var startDay = startDt.getDay();
       var endDay = endDt.getDay();

       // Remove weekend not previously removed.   
       if (startDay - endDay > 1)        
            days = days - 2;     

       // Remove start day if span starts on Sunday but ends before Saturday
       if (startDay === 0 && endDay !== 6)
            days = days - 1  

       // Remove end day if span ends on Saturday but starts after Sunday
      if (endDay === 6 && startDay !== 0)
           days = days - 1  
    }
   
   //remove any holidays that might be in the range
   if(excludeHolidays !== null) {
       for(var h=0; h<excludeHolidays.length;h++) {
           var th = get(excludeHolidays, h).d.getTime();
           
           if(th < endDt.getTime() && th > startDt.getTime()) {
                days--;
            }
        }
    }
   return days;