#!/bin/bash

# Quick and dirty script to install the package changed
# last in a recently changed overlay.

#   Copyright 2015 Sławomir Nizio
#
#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.

if [[ -e /sabayon/bin/buildrc ]]; then
	. /sabayon/bin/buildrc || exit 2
else
	echo "Warning: buildrc not found" >&2
fi

overlays_dir=${1:-/var/lib/layman}

conventions="sabayon-distro:sabayon sabayon:for-gentoo"
for c in ${conventions}; do
	o1=${c%:*}
	o2=${c#*:}
	if [[ -e ${overlays_dir}/${o1} && -e ${overlays_dir}/${o2} ]]; then
		break
	fi
done

o1_name=sabayon-distro
o2_name=sabayon

post=/.git/index
ind1=${overlays_dir}/${o1}${post}
ind2=${overlays_dir}/${o2}${post}

if [[ ! -e ${ind1} || ! -e ${ind2} ]]; then
	echo "Either ${ind1} or ${ind2} not found (or even both)!" >&2
	exit 1
fi

if [[ ${ind1} -nt ${ind2} ]]; then
	newer=${o1}
	name=${o1_name}
else
	newer=${o2}
	name=${o2_name}
fi

echo "taking from ${newer}"
changes=$(git --work-tree="${overlays_dir}/${newer}" \
	--git-dir="${overlays_dir}/${newer}/.git"	\
	diff-tree --name-status -r --no-commit-id HEAD) || exit 1

echo "changes for the last commit:"
echo "${changes}"

# This can be made by one command but well, lol.
pkg_changes=$(echo "${changes}" | grep -v "^D" \
	| sed -r -e 's/^[a-zA-Z0-9]+[[:space:]]*//' -e 's:^([^/]+/[^/]+).*:\1:' \
	| sort -u | grep -E '^(virtual/|[^/]+-)' | awk "{print \$1 \"::${name}\"}")

echo "packages to install:"
echo "${pkg_changes}"
set -f
emerge -av ${pkg_changes}