#!/usr/bin/env bash
#
#   (If anyone knows a good freeze program, please let me know!  youssef@bu.edu)  S.Y.
#
MAJOR_REQ=2  #major version requirement (greater than or equal to)
MINOR_REQ=2  #if major version satisfied, minor version requirement (greater than or equal to)

VERBOSE=1                #leave it unset or set it to an empty string for non-verbose mode (no listing steps of building python)
BUILDOUTPUT='/dev/null'  #file for stdout redirection for wget, gunzip, tar, configure, make, make install; also stderr redirection for wget and make
                         #    use /dev/fd/0 to send back to stdout (maybe &1 works, too)
                         #    use /dev/null to suppress
DEBUG=$1                 #leave this unset or set it to an empty string for no extra debugging messages

#check python existence and version
GT=0         #0->false->don't have to do anything
HASPYTHON=0  #so user messages make sense (installing versus upgrading)
if python -V &> /dev/null; then
	test "$DEBUG" && echo -n 'Python found...'
	HASPYTHON=1
	MAJOR=`python -V 2>&1 | awk '{ print $2 }' | tr '.' ' ' | awk '{ print $1 }'`  #python -V outputs to stderr, so have to redirect to catch it
	MINOR=`python -V 2>&1 | awk '{ print $2 }' | tr '.' ' ' | awk '{ print $2 }'`
	if [ $MAJOR_REQ -gt $MAJOR ]; then
		test "$DEBUG" && echo " but version is too old (major version $MAJOR is too old)."
		GT=1
	elif [ $MAJOR_REQ -eq $MAJOR -a $MINOR_REQ -gt $MINOR ]; then
		test "$DEBUG" && echo " but version is too old (major version $MAJOR is OK, but minor version $MINOR is too old)."
		GT=1
	else
		test "$DEBUG" && echo " version $MAJOR.$MINOR is OK."
	fi
else
	test "$DEBUG" && echo 'Python not found.'
	GT=1
fi

#do the updating if necessary
if [ $GT -eq 1 ] && [ ! -d python/python/bin ]; then
#	echo ''
	echo "Pacman requires at least Python version $MAJOR_REQ.$MINOR_REQ."
	if [ $HASPYTHON -eq 1 ]; then
		echo "Your Python version, $MAJOR.$MINOR, is too old for Pacman."
	fi
#	echo -n "OK to install Python 2.2.3 locally now? [y or n]: "
#	read ANSWER
#	ANSWER='y'
	if [ 1 ]; then
#		test "$VERBOSE" && echo ''
#		test "$VERBOSE" && echo 'Downloading and installing Python...'
#		test "$VERBOSE" && echo '===================================='
		
		HERE=`pwd`
		if [ ! -d python ]; then  #I think this is unnecessary
			mkdir python          #''
		fi                        #''
		cd python                 #''
		
		#wget
		test "$VERBOSE" && echo -n 'Installing Python 2.4.1 locally... '
		test "$VERBOSE" && echo -n 'Downloading Python 2.4.1... '
#		if wget http://physics.bu.edu/pacman/python/Python-2.2.3.tgz &> $BUILDOUTPUT
		if wget http://physics.bu.edu/pacman/python/Python-2.4.1.tgz &> $BUILDOUTPUT
			then test "$VERBOSE" && echo 'download successful.'
			else test "$VERBOSE" && echo 'download failed.'; exit 1
		fi
		
		#gunzip
		test "$VERBOSE" && echo -n 'Unzipping... '
		if gunzip Python-2.4.1.tgz > $BUILDOUTPUT
			then test "$VERBOSE" && echo 'unzip successful.'
			else test "$VERBOSE" && echo 'unzip failed.'; exit 1
		fi
		
		#tar
		test "$VERBOSE" && echo -n 'Untarring... '
		if tar xf Python-2.4.1.tar > $BUILDOUTPUT
			then test "$VERBOSE" && echo 'untar successful.'
			else test "$VERBOSE" && echo 'untar failed.'; exit 1
		fi

		mkdir python  #I think this is unnecessary
		
		#configure
		test "$VERBOSE" && echo -n 'Configuring... '
		cd Python-2.4.1
		if ./configure --prefix="$HERE/python/python" > $BUILDOUTPUT
			then test "$VERBOSE" && echo 'configure successful.'
			else test "$VERBOSE" && echo 'configure failed.'; exit 1
		fi
		cd ..
		
		#make
		test "$VERBOSE" && echo -n 'Making Python 2.4.1... '
		cd Python-2.4.1
		if make &> $BUILDOUTPUT
			then test "$VERBOSE" && echo -n 'make successful.'
			else test "$VERBOSE" && echo 'make failed.'; exit 1
		fi
		
		#make install
		if make install > $BUILDOUTPUT
			then test "$VERBOSE" && echo 'make install successful.'
			else test "$VERBOSE" && echo 'make install failed.'; exit 1
		fi
		cd ..
		
		/usr/bin/env rm -r -f Python-2.4.1
		/usr/bin/env rm -f Python-2.4.1.tar
		
		echo 'Python 2.4.1 has been built locally.'
		echo 'Ready to use Pacman.'
	else
		if [ $HASPYTHON -eq 1 ]; then
			echo "Python version not updated."
		else
			echo "Python not installed."
		fi
		exit 1
	fi
elif [ $GT -eq 0 ]; then
	test "$DEBUG" && echo 'No action taken.'
else
	test "$DEBUG" && echo 'Using Python 2.4.1 from the Pacman installation area.'
fi

exit 0