#!/bin/sh -u
# Sample solution to Unix Final Script (sloppy version)
#------------------------------------------------------------
# One line summary: Compile the larger of two C++ programs
#------------------------------------------------------------
# Syntax:
#    $0 [ sourcefilename ]
#------------------------------------------------------------
# Purpose: not required
#-------------------------------------------------------------
# Assignment Label: not required
#-------------------------------------------------------------

# Step 1 - 4 marks - correct header (syntax, interpreter, PATH, and umask)
# Set a standard search path and non-restrictive umask.
#
PATH=/bin:/usr/bin ; export PATH
umask 022

# Step 2 - 7 marks
# Exit the script if more than one argument is given.
#
if [ $# -gt 1 ]; then
	echo 1>&2 "$0: expecting one optional C++ source filename argument,"
	echo 1>&2 "found $# ($*)"
	exit 1
fi

# Step 3 - 5 marks
# Read the program name from the user if the argument is missing.
#
if [ $# -eq 1 ]; then
	prog="$1"
else
    	echo 1>&2 "Enter a C++ source file:" 
    	read prog || exit 2
fi

# Step 4 - 6 marks
# Exit if the pathname is an empty string (null string - no characters).
#
if [ -z "$prog" ]; then
	echo 1>&2 "$0: Empty C++ source program name - nothing done.  Bye!"
	exit 3
fi

# Step 5 - 6 marks
# Exit if the pathname is not a plain file.
#
if [ ! -f "$prog" ]; then
	echo 1>&2 "$0: C++ source '$prog' is missing, inaccessible,"
	echo 1>&2 "or not a plain file"
	exit 4
fi

# Step 6 - 6 marks
# Exit if the file is empty (zero size - contains no data).
#
if [ ! -s "$prog" ]; then
	echo 1>&2 "$0: C++ source file '$prog' is empty (zero size)"
	exit 5
fi

# Step 7 - 6 marks
# Add missing read permissions.
#
if [ ! -r "$prog" ]; then
	chmod ug+r "$prog" || exit 6
fi

# Step 8 - 3 marks
# Count the lines in the user-supplied file.
#
plines=$( wc -l <"$prog" )

# Step 9 - 3 marks
# Count the lines in the existing file.
#
flines=$( wc -l <"foo.cpp" )

# Step 10 - 4 marks
# Rename an existing output pathname.
#
if [ -e "happy" ]; then
	mv "happy" "happy.bak"
fi

# Step 11 - 6 marks
# Compile whichever file is bigger.
#
if [ "$plines" -gt "$flines" ] ; then
	g++ -o "happy" "$prog" || exit 8
else
	g++ -o "happy" "foo.cpp" || exit 8
fi