#!/bin/bb

is_internal()
{
	[ -z "$1" ] && return 1
	case $(command -v $1) in
		*/*) rc=1 ;;
		*) rc=0 ;;
	esac
	return $rc
}

run_command()
{
	local dryrun=
	[ $DRYRUN -eq 1 ] && dryrun=echo
	$dryrun "$@"
}

for cmd in cp ln; do
	if ! is_internal $cmd; then
		echo "Please rebuild busybox and include the $cmd command."
		exit 1
	fi
done

if [ -L /bin -a -L /sbin ]; then
	echo "It appears that the /usr merge has already been done on this system."
	exit 0
fi

DRYRUN=1
HELP=0
while [ $# -gt 0 ]; do
	case $1 in
		--dryrun|--dry-run) DRYRUN=1 ;;
		-h|--help) HELP=1 ;;
	esac
	shift
done

if [ $HELP -eq 1 ]; then
	echo "$(basename $0) -h \| --help - displays this message"
	echo "$(basename $0) --dryrun \| --dry-run  - show what would be done"
	exit 0
fi

# copy binaries
for dir in /bin /sbin /usr/sbin; do
	run_command cp -a $dir/* /usr/bin
done

# copy libraries
for dir in /lib*; do
	[ -L $dir ] && continue
	run_command cp -a $dir/* /usr$dir
done

# Create the /usr merge compatibility symlinks
for dir in /bin /sbin; do
run_command rm -rf $dir
run_command ln -s usr/bin $dir
done
run_command rm -rf /usr/sbin
run_command ln -s bin /usr/sbin
for dir in /lib*; do
	run_command rm -rf $dir
	run_command ln -s usr$dir $dir
done