#!/bin/bash
#################################
# Bash script to complement bug #13616
# this will grab the current USE from emerge info

# Copyright Gentoo Linux 
# Written By John Mylchreest <johnm@gentoo.org>
#################################

PKG_DIR="/var/db/pkg/"
PACKAGE_USE_FILE="/etc/portage/package.use"
CURRENT_FLAGS="$(emerge info | grep USE | sed 's:"::g' | sed 's:USE=::g')"

if [ ! "$(whoami)" == "root" ] ; then
	echo "This script must be ran as root"
	exit 0
fi

if [ -f "${PACKAGE_USE_FILE}" ] ; then
	echo "Moving ${PACKAGE_USE_FILE} to ${PACKAGE_USE_FILE}.orig"
	mv ${PACKAGE_USE_FILE} ${PACKAGE_USE_FILE}.orig
fi

echo "Searching packages currently installed for variation on USE flags, This will take a LONG time..."

for x in $(grep -F -R "" ${PKG_DIR}/*/*/USE)
do
	PKG_TMP=$(echo ${x} | cut -f1 -d: | sed "s:${PKG_DIR}\/::g" | sed "s:-[0-9].*::g")
	if [ -n "$(echo ${PKG_TMP} | grep "/")" ] ; then
		if [ -n "${PACKAGE_USE}" ] ; then
			echo "	Found ${PACKAGE_NAME}->'${PACKAGE_USE}'"
			$(echo "${PACKAGE_NAME} ${PACKAGE_USE}" | sed 's:  : :g' >> ${PACKAGE_USE_FILE})
		fi
		
		PACKAGE_NAME=${PKG_TMP}
		PACKAGE_USE=""
		
		echo "Checking: ${PACKAGE_NAME}"
	else
		[ -z "$(echo " ${CURRENT_FLAGS}" | grep " ${PKG_TMP}" 2> /dev/null)" ] && PACKAGE_USE="${PACKAGE_USE} ${PKG_TMP}"
	fi
done

echo "Finished, please check ${PACKAGE_USE_FILE} for correctness"