#!/bin/sh
# run like this: ocaml-rebuild.sh [-h|--help|-f|--force] [emerge_options]

emerge="$(type -P emerge) --ignore-default-opts"
portageq="$(type -P portageq)"
egrep="$(type -P egrep)"

if [ "$1" = "-h" ] || [ "$1" = "--help" ] ; then
	echo "usage: ocaml-rebuild.sh [-h | --help | -f | --force)] [emerge_options]"
	echo "With -f|--force, the packages will first be unmerged and then emerged"
	echo "with the given options to ensuree correct dependancy analysis."
	echo "Otherwise emerge is run with the --pretend flag and the given"
	echo "options."
	echo "It is recommended to keep the list of rebuilt packages printed"
	echo "in pretend mode in case something go wrong"
	exit 1
fi

if [ "$1" = "-f" ] || [ "$1" = "--force" ] ; then
	pretend=0
	shift
else
	pretend=1
	echo "Running in pretend mode, will only show which actions would be taken ..."
fi

installed="$($portageq match / '')"

echo "Searching installed packages for ocaml dependencies."
echo "Please be patient; this will take a while ..."

depends=
for i in $installed ; do
	LC_ALL=C # grep performance completely sucks with UTF-8
	depstring="$($portageq metadata / installed $i DEPEND)"
	if echo $depstring | $egrep -l 'dev-lang/ocaml|dev-ml/findlib' > /dev/null ; then
		depends="$depends $i"
	fi
done

echo "Building a list of packages to reinstall ..."

toclean=
tobuild=
for dep in $depends ; do
	slot="$($portageq metadata / installed $dep SLOT)"
	tobuild=">=$dep:$slot $tobuild"
	toclean="=$dep:$slot $toclean"
done

if [ "$toclean" != "" ] ; then
	if [ $pretend -eq 1 ] ; then
		$emerge --pretend $@ $tobuild
	else
		echo "Cleaning $toclean ..."
		$emerge --unmerge $toclean
		echo "Building $tobuild ..."
		$emerge $@ $tobuild
	fi
else
	echo "Nothing to update"
fi

echo "All done!"