#!/bin/bash

# post-merge hook for Debian systems
#
# 1. copy to .git/hooks
# 2. to test run "git pull -q"
# 3. create cronjob, which runs "git pull -q" in your ${icvpn} dir
#

icvpndir=/etc/tinc/icvpn/
tinccfg=tinc.conf
export icvpndir tinccfg

PATH="/sbin:/bin:/usr/sbin:/usr/bin"
tmpfile=$(mktemp)
export PATH tmpfile

# get changed files
changed_files="$(git diff-tree -r --name-only --no-commit-id ORIG_HEAD HEAD)"

# run $2 if $1 matches changed files
check_run() {
	echo "$changed_files" | grep --quiet "$1" && eval "$2"
}

# generate ${tinccfg}
gen_conf() {
	test -w ${icvpndir}/${tinccfg} || \
		{ echo "ERR: ${tinccfg} (${icvpndir}/${tinccfg}) is not writeable, exiting." >&2; exit 1; }

	# remove all ConnectTo Statements
	grep -v 'ConnectTo' ${icvpndir}/${tinccfg} > ${tmpfile}
	# add ConnectTo Statements for all hosts
	for host in ${icvpndir}/hosts/[a-zA-Z]*; do
		echo "ConnectTo = ${host##*/}" >> ${tmpfile}
	done

	test -s ${tmpfile} || \
		{ echo "ERR: generated config was empty, zeh sky is falling, exiting." >&2; exit 2; }

	num_connectto=$(grep -s ConnectTo ${tmpfile} | wc -l)
	[ ${num_connectto} -gt 20 ] || \
		{ echo "ERR: generated config has ${num_connectto} <= 20 ConnectTo lines, safety 1st, exiting." >&2; exit 30; }
	num_all=$(cat ${tmpfile} | wc -l)
	[ ${num_all} -gt 25 ] || \
		{ echo "ERR: generated config has ${num_all} <= 25 lines, safety 1st, exiting." >&2; exit 31; }

	cp -f ${icvpndir}/${tinccfg} ${icvpndir}/${tinccfg}.old
	cat ${tmpfile} > ${icvpndir}/${tinccfg}

	invoke-rc.d tinc reload icvpn
}

check_run hosts/[a-zA-Z] gen_conf

rm -f ${tmpfile}
exit 0