#!/bin/sh -u
#  $0 pathname
# Compile a program (the only argument) as C or C++ based on its contents.
# Display the errors/warnings with line numbers.
# -IAN!  idallen@ncf.ca

# This is standard for shell scripts in this course.
#
export PATH=/bin:/usr/bin
umask 022

# 6 marks
# Validate the number of arguments; issue a good error message.
#
if [ $# -ne 1 ]; then
	echo 1>&2 "$0: Expecting 1 argument; found $# ($*)"
	exit 1
fi

# 2 marks
# Transfer the argument to a named variable for better readability.
#
cprog="$1"

# Verify that the argument is a non-empty, readable file.
#
# 5 marks
if [ ! -f "$cprog" ]; then
	echo 1>&2 "$0: '$cprog' is not a file"
	exit 1
fi
# 5 marks
if [ ! -r "$cprog" ]; then
	echo 1>&2 "$0: '$cprog' is not readable"
	exit 1
fi
# 5 marks
if [ ! -s "$cprog" ]; then
	echo 1>&2 "$0: '$cprog' is empty"
	exit 1
fi

# 2 marks
# Create an error file.  Start by putting the date into it.
#
date >myerrs.txt || exit $?

# 8 marks
# Select the C compiler if a string is found indicating a C program.
#
if grep '<stdio' "$cprog" >/dev/null ; then
	gcc -o mycout -Wall "$cprog" 2>>myerrs.txt
fi

# 8 marks
# Select the C++ compiler if the following string is *not* found.
#
if ! grep 'printf(' "$cprog" >/dev/null ; then
	g++ -o mycppout -Wall "$cprog" 2>>myerrs.txt
fi

# 9 marks
# Remove an error file containing no errors.
# Rename and display with line numbers any errors.
#
if [ $(wc -l <myerrs.txt) -lt 2 ] ; then
	rm myerrs.txt
else
	mv myerrs.txt myerrs.dat
	cat -n myerrs.dat
	chmod 660 myerrs.dat
fi