//function that checks if a holiday lands on saturday/sunday and so we can move them to a friday/monday respectively
    private function getObservedDate($holidayDate){

        $dayofweek = date("w", strtotime($holidayDate));

        if ($dayofweek == 6) $holidayDate = date('m/d/Y', strtotime("$holidayDate - 1 days")); //saturday moves to friday
        else if ($dayofweek == 0)  $holidayDate = date('m/d/Y', strtotime("$holidayDate + 1 days"));  //sunday moves monday

        return $holidayDate;
    }


    //function that calculates the holidays for any given year
    private function getFederalHolidaysForYear($year){

        $NY = $this->getObservedDate( date('m/d/Y', strtotime("1/1/$year")) ); //new years day

        $MLK = $this->getObservedDate( date('m/d/Y', strtotime("third monday of january $year")) );  //martin luther king day

        $PD = $this->getObservedDate( date('m/d/Y', strtotime("third monday of february $year")) ); ; //presidents day

        $MDay = $this->getObservedDate( date('m/d/Y', strtotime("last monday of May $year")) ); //memorial day  

        $IDay = $this->getObservedDate( date('m/d/Y', strtotime("7/4/$year")) );  // independence day

        $LD = $this->getObservedDate( date('m/d/Y', strtotime("first monday of september $year")) ); //labor day

        $VD = $this->getObservedDate( date('m/d/Y', strtotime("11/11/$year")) ); //veterans day

        $ColD =$this->getObservedDate( date('m/d/Y', strtotime("second monday of october $year")) ); //columbus day   

        $TG = $this->getObservedDate( date('m/d/Y', strtotime("last thursday of november $year")) ); // thanksgiving       

        $CD = $this->getObservedDate( date('m/d/Y', strtotime("12/25/$year")) );  //christmas day 

        $nonWorkingDays = array();

        array_push($nonWorkingDays, $NY, $MLK, $PD, $MDay, $IDay, $LD, $ColD, $VD, $TG, $CD);

        return $nonWorkingDays;
    }