# A program that uses the last utility to determine the time that
# each student is logged on for the current month
# This program can be invoked by passing the students username as
# an arguement, which returns the logged time for that student;
# or the program can be invoked with no arguments to retrieve a
# list of all users' logged time


# check to see if the program has been invoked with arguements
# if yes, use those username, if no use the entire class list

if [ -z "$*" ];then
        users="`last | sort | sed -e 's/^\([a-z][a-z0-9]*\).*$/\1/' | uniq`"
else
        users="$*"
fi

# loop through the list to retrieve logged times
for n in $users; do

        days="`last | grep $n | grep -v 'still logged in' | grep -v 'gone - no logout' | grep '+' | sed -e 's/^.*(\(.*\)).*$/\1/' | cut -d':' -f1`"

        hours="`last | grep $n | grep -v 'still logged in' | grep -v 'gone - no logout' | sed -e 's/^.*(\(.*\)).*$/\1/' | cut -d':' -f1`"

        minutes="`last | grep $n | grep -v 'still logged in' | grep -v 'gone - no logout'| sed -e 's/^.*(\(.*\)).*$/\1/' | cut -d':' -f2`"

        # loop through the list of hours, removing leading zeros
        # and adding the remaining numbers together
        for h in $hours;do

                # check for '+' in case there's more than 24 hours
                chk=`echo $h | grep '+' | wc -l`

                #totaldays=0
                #days=0

                if [ $chk -eq 0 ]; then
                        # not more than 24 hours
                        h="`echo $h | sed -e 's/^0\([1-9][0-9]*\)/\1/'`"
                else

                        # get the number of days, then add it up as d
                        days="`echo $h | cut -d '+' -f1 | sed -e 's/^0\([1-9][0-9]*\)/\1/'`"
                        let totaldays=$totaldays+$days

                        # use the logic above to get h
                        h="`echo $h | cut -d '+' -f2 | sed -e 's/^0\([1-9][0-9]*\)/\1/'`"
                fi

                # add the hours extracted to totalhrs
                let totalhrs=$totalhrs+$h
                let totaldays=$totaldays+0
        done

        # loop through the list of minutes, removing leading zeros
        # and adding the remaining numbers together
        for m in $minutes;do
                m="`echo $m | sed -e 's/^0\([1-9][0-9]*\)/\1/'`"
                let totalmin=$totalmin+$m
        done


        # devide totalminutes by 60 to extract the number of hours
        # add hours extracted to hrs and leave the remaining minutes in min
        hrs=$(($totalmin/60))
        min=$(($totalmin-$(($hrs*60))))

        # add totalhrs to hrs
        hrs=$(($hrs+$totalhrs))

        # devide hrs by 24 to extract days from hrs, then add totaldays to get final number of  days
        days=$(($hrs/24))
        hrs=$(($hrs-$(($days*24))))
        days=$(($days+$totaldays))

        for ((nn=0; nn<$days; nn++ ));do
                dbar=$dbar"@"
        done

        for ((nnn=0; nnn<$hrs; nnn++)); do
                hbar=$hbar"#"
        done

        for ((nnnn=0; nnnn<$min; nnnn=nnnn+10 )); do
                mbar=$mbar"."
        done

        echo "-----------------+------+"

        bar="$dbar $hbar $mbar"

        printf " %-8s | %-2s : %-2s : %-2s | %-2s %-2s %-2s \n" $n $days $hrs $min $dbar $hbar $mbar

        #echo "$n | $days days : $hrs hours : $min min | $dbar $hbar $mbar"
        #echo "$n | $h"

        bar=""
        hbar=""
        dbar=""
        mbar=""
        totalmin=0
        totalhrs=0
        totaldays=0
        days=0
        hrs=0
        min=0
done