stats

#!/bin/bash
#
# Program 1 - stats
# Parker Howell
# CS 344
# Oct 9th, 2017
#

#echo "In stats"
#echo "Number of parameters: $#"
#echo "The parameters were: $@"

# trap to remove temp files
trap cleanError KILL INT HUP TERM
trap cleanExit EXIT

cleanError ()
{
	#echo "Cleaning temp files."
	rm -f datafile$$
	rm -f tempInput$$
	rm -f rowPrintData$$
	rm -f colAvgPrintData$$
	rm -f colMedPrintData$$
	exit 1
}

cleanExit ()
{
	rm -f datafile$$
	rm -f tempInput$$
	rm -f rowPrintData$$
	rm -f colAvgPrintData$$
	rm -f colMedPrintData$$
}


# test for arguments
# too few
if [ "$#" -lt 1 ]
then
	#echo "Need at least 1 parameter."
	echo "./stats {-rows|-cols} [file]" 1>&2
	exit 1


# too many 
elif [ "$#" -gt 2 ]
then
	#echo "Need fewer than 3 parameters."
	echo "./stats {-rows|-cols} [file]" 1>&2
	exit 1
fi


# just right	
# the if/elif check below is borowed from our assignment
# specification.

datafilepath="datafile$$"


# is input from stdin or a file?
# input from stdin
if [ "$#" = "1" ]
then
	#echo "Using stdin for input."
	cat > "$datafilepath"


#input from file
elif [ "$#" = "2" ]
then
	datafilepath=$2
		
	# check that input file exists
	if test -e "$datafilepath"
	then
		:  # had to add these :'s so wouldnt get error after
		   # commenting out the echos...
		#echo "The file exists."
	else
		echo "./stats - cannot read $2" 1>&2
		exit 1
	fi

	# check that input file is readable
	if test -r "$datafilepath"
	then 
		: 
		#echo "The file is readable."
	else
		echo "./stats - cannot read $2" 1>&2
		exit 1
	fi

fi
#echo "1-2 params used. :)"


# check for -r of -c option
if [[ $1 != -c* ]] && [[ $1 != -r* ]]; 
then		
	#echo "The first parameter needs a \"-c*\" or a \"-r*\"."	
	echo "./stats {-rows|-cols} [file]" 1>&2
	exit 1
fi


# if we want to calculate rows then we need to transpose the input
if [[ $1 = -r* ]]
then
	transposed="tempInput$$"
	# get the count of columns/"words" 
	colCount=$(head -n 1 "$datafilepath" | wc -w) 

	# then grab each col and write it to transposed file as a row
	# while ref: tldp.org/HOWTO/Bash-Prog-Intro-HOWTO-7.html
	COUNTER=1
	while [ ! $COUNTER -gt $colCount ];
	do
		# cut each col and replace newlines with tabs
		cut -f $COUNTER "$datafilepath" | tr '\n' '\t'
		# echo adds a newline at the end of the new row
		echo
		let COUNTER=COUNTER+1
	done >> "$transposed"
	#cat $transposed

	# set input to transposed file
	datafilepath=$transposed	
fi


# get the length of each col by counting newlines
rowCount=$(cat "$datafilepath" | wc -l)
#echo Rows: $rowCount


# get the number of cols by counting "words" in the first line of the head
colCount=$(head -n 1 "$datafilepath" | wc -w)
#echo Columns: $colCount


# get the median location. Works because of truncations and requirement
# that we choose the larger value when rowCount is even.
medLoc=$(expr $(expr $rowCount / 2) + 1)
#echo MedLoc: $medLoc


# loop through input and calculate the sum/average and get the median
COUNTER=1
while [ ! $COUNTER -gt $colCount ];
do
	# get a column and transfer it into a row for summing
	sumCol=$(cut -f $COUNTER "$datafilepath" | tr '\n' ' ')

	# sum a column. Reference: Bigloops from assigned reading: 1.4
	sum=0
	for i in $sumCol
	do
		sum=$(( $sum + $i ))
	done
	#echo $sum


	# get the average using formula: (a+(b/2)) / b  from assign. .pdf 
	avg=$(( $(( $sum + $(( $rowCount / 2  ))  )) / $rowCount ))
	#echo $avg


	# get the median. Grab a column, sort it numerically, then grab
	# the number at the medLoc position
	med=$(cut -f $COUNTER "$datafilepath" | sort -n | head -n $medLoc | tail -n 1 )
	#echo $med	


	# based on -r or -c option, save values for printing
	# if we are using rows
	if [[ $1 = -r* ]];
	then
		rowPrint="rowPrintData$$"
		echo -e "$avg\t$med" >> $rowPrint

	# else we are using columns
	else
		#echo Using cols...
		colAvgPrint="colAvgPrintData$$"
		colMedPrint="colMedPrintData$$"
		
		echo -e "$avg" >> $colAvgPrint
		echo -e "$med" >> $colMedPrint
	fi

	let COUNTER=COUNTER+1

done < $datafilepath


# print averages and medians
# if we are using rows
if [[ $1 = -r* ]];
then
	echo -e "Average\tMedian"
	cat "$rowPrint"


# else we are using colums
else
	# convert data to rows and print them
	echo "Averages:"
	cat "$colAvgPrint" | tr '\n' ' '
	echo
	echo "Medians:"
	cat "$colMedPrint" | tr '\n' ' '
	echo
fi