#!/bin/sh
set -e

pl="/var/cache/etckeeper/packagelist"

# Parent process is etckeeper
# (Only procps ps is currently supported, others will fail,
# so this may end up empty.)
ETCKEEPER_PID=$( ps --no-headers -o ppid "${PPID}" 2>/dev/null | sed 's/^ *//' )

# Find the parent of etckeeper and get the command line of the process
if ! [ -z "${ETCKEEPER_PID}" ]; then
	ETCKEEPER_PPID=$( ps --no-headers -o ppid "${ETCKEEPER_PID}" | sed 's/^ *//' )
	ETCKEEPER_PARENT_COMMAND_LINE=$( ps --no-headers -o args "${ETCKEEPER_PPID}" )
fi

get_changes () {
	if [ "$VCS" = git ]; then
		git diff --stat | grep '|' | cut -d'|' -f1 | cut -b2-
		git ls-files --exclude-standard --others
	fi
	if [ "$VCS" = hg ]; then
		hg status --no-status
	fi
	if [ "$VCS" = bzr ]; then
		bzr status -S | cut -b5-
	fi
	if [ "$VCS" = darcs ]; then
		# ignore ' file -> file' lines for moved files
		# trim ' -M +N rP' from change summary
		darcs whatsnew --summary | grep -v '^ .* -> ' | cut -d' ' -f2- | sed 's/ [-+r][0-9]\+//g;s/^\.\///'
		# lines beginning with 'a' show unversioned files
		darcs whatsnew --look-for-adds --boring --summary | grep '^a' | cut -d' ' -f2- | sed 's/^\.\///'
	fi
}

get_changed_packages () {
	if [ "$LOWLEVEL_PACKAGE_MANAGER" = dpkg ]; then
		get_changes | sed 's/^/\/etc\//;s/\s*$//' | xargs -d '\n' dpkg 2>/dev/null -S | cut -d':' -f1 | sed 's/, /\n/g'
	fi
	if [ "$LOWLEVEL_PACKAGE_MANAGER" = rpm ]; then
		# if output contains file path, file was not found
		get_changes | sed 's/^/\/etc\//;s/\s*$//' | xargs -d '\n' rpm --qf '%{NAME}\n' -qf | grep -v "/etc/"
	fi
	# is it even possible to use pacmatic without pacman?
	if [ "$LOWLEVEL_PACKAGE_MANAGER" = pacman -o "$LOWLEVEL_PACKAGE_MANAGER" = pacmatic ]; then
		get_changes | sed 's/^/\/etc\//;s/\s*$//' | xargs -d '\n' pacman 2>/dev/null -Qo | rev | cut -d' ' -f1-2 | rev | cut -d' ' -f1
	fi
	if [ "$LOWLEVEL_PACKAGE_MANAGER" = pkgng ]; then
		get_changes | sed 's/^/\/etc\//;s/\s*$//' | xargs -d '\n' pkg which --quiet | rev | cut -d'-' -f2- | rev
	fi
}

if etckeeper unclean; then
	if [ -z "${ETCKEEPER_PARENT_COMMAND_LINE}" ]; then
		message="committing changes in /etc after $HIGHLEVEL_PACKAGE_MANAGER run"
	else
		message="committing changes in /etc made by \"$ETCKEEPER_PARENT_COMMAND_LINE\""
	fi

	set +e
	if [ -e $pl.pre-install ] && [ "$(cat $pl.fmt 2>/dev/null || true)" = "$(etckeeper list-installed fmt)" ]; then
		(
			echo "$message"
			echo
			get_changed_packages | sort | uniq > $pl.found-pkgs
			if [ -s $pl.found-pkgs ]; then
				sed -i 's/^/^[-+]/;s/$/ /' $pl.found-pkgs
				etckeeper list-installed | diff -U0 $pl.pre-install - | tail -n+4 | egrep '^[-+]' | grep -f $pl.found-pkgs > $pl.found-packages
				if [ -s $pl.found-packages ]; then
					echo "Packages with configuration changes:"
					cat $pl.found-packages || true
					echo
				fi
			fi
			echo "Package changes:"
			etckeeper list-installed | diff -U0 $pl.pre-install - | tail -n+4 | egrep '^[-+]' || true
		) | etckeeper commit --stdin
	else
		etckeeper commit "$(printf "$message")"
	fi
	status=$?
	set -e

	if [ "$status" != 0 ]; then
		echo "warning: etckeeper failed to commit changes in /etc using $VCS" >&2
	fi
fi

rm -f $pl.pre-install $pl.fmt
rm -f $pl.found-pkgs $pl.found-packages