#!/bin/sh
#
# Cyril Romain 2006
# Script that bakes the used flags on a per package basis in a package.use hierarchy tree

PKGUSE=/etc/portage/package.use

# check that package.use does not already exist as a file 
# note: portage >=2.1 accept package.use to be a directory
[ -f $PKGUSE ] && (echo "$PKGUSE already exists but as a file. Please update to portage 2.1 or above and make it a directory." ; exit 1)

usage()
{
	echo "Usage: `basename $0` [OPTION] packages"
	echo "Try '`basename $0` --help' for more information."
	exit $E_OPTERROR 
}

# Exit and explain usage, if no argument(s) given.
[ $# -eq 0 ] && usage

# add a package to the package.use directory
#  $1 the full package name to bake (e.g.' dev-lang/python')
function add_package()
{
	# if the package is not in the package.use directory
	is_installed=`equery u $1 2> /dev/null`
	if [ "$is_installed" ] ; then 
		# bake the used flags of the package
		Iflags=`echo $is_installed | sed 's/[-+]\([-+]\)/\1/g' | sed 's/+//'`
		bakeuse $1 $Iflags
	else
		# bake the ready-to-use USE flags of the package
		emergeFind=`emerge -pv --columns $1`
		if [ "`echo $emergeFind | grep Error`" ] ; then 
			echo "Bad package name: $1"
		else
			available_flags=`echo $emergeFind | grep $1 | egrep -o 'USE="[^"]*' | sed 's/USE="//' | sed 's/[*%]//g'`
			bakeuse $1 $available_flags
		fi
	fi
}

# bake the use flags of one package
#  $1 the full package name to bake (e.g.' dev-lang/python')
#  $2, $3, ..., $n the list of USE flags
function bakeuse()
{
	mkdir -p $PKGUSE/$1
	echo "Add/update the package.use directory with $1"
	echo $@ > $PKGUSE/$1/package.use
}

# bake the use flags of all installed packages
function bakeuse_installed()
{
	installed_packages=`emerge -pev --columns world | awk '{ if ($1 ~ /\[ebuild/) print $4 }'`
	for p in $installed_packages ; do
		Iflags=`equery u $p | sed 's/[-+]\([-+]\)/\1/g' | sed 's/+//'`
		bakeuse $p $Iflags
	done
}

# check for USE flag conflict - i.e. per-package vs global settings - of installed package
function bake_check()
{
	installed_packages=`emerge -pev --columns world | awk '{ if ($1 ~ /\[ebuild/) print $4 }'`
	for p in $installed_packages ; do
		flags=`equery u $p`
		for i in $flags; do
			globalOveride=`echo $i | grep '+-'` && echo "Warning: $p has $globalOveride" 
		done
	done
}

main()
{
	while getopts ":bc-:" Option
	do
		case $Option in
			b ) echo "Bake the USE flags of all installed package."
				bakeuse_installed;;
			c ) echo "Check for conflict between per-package and global USE flags."
				bake_check;;
			- ) 
				case $OPTARG in
					bake ) echo "Bake the USE flags of all installed package."
						bakeuse_installed;;
					check) echo "Check for conflict between per-package and global USE flags."
						bake_check;;
					help ) echo "Usage: `basename $0` [OPTION] packages"
						echo "Example: `basename $0` dev-lang/lua dev-lang/erlang"
						echo
						echo "Options:"
						echo "  --bake (-b short option): to bake the USE flags of all installed package."
						echo "  --check (-c short option): to check for conflict between per-package anf global USE flags."
						echo "  --help to display this help."
						return 0;;
					*    ) echo "Illegal option chosen --$OPTARG"
						usage
						return 1;;   # DEFAULT
				esac;;
			* ) echo "Illegal option chosen $OPTARG"
				usage
				return 1;;   # DEFAULT
		esac
	done
	shift $(($OPTIND - 1))

	# add packages given in arguments
	while [ -n "$1" ] ; do
		add_package $1
		shift
	done
}

main $*
exit 0