#!/bin/sh
#
# Copyright (c) 2009 Nagios Plugins Development Team
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

set -e
set -u

prefix='/home/git'

PATH="$prefix/opt/git/bin:/bin:/usr/bin"
export PATH

gitnotify="$prefix/libexec/git-notify"
recipient='Nagios Plugins Commit List <nagiosplug-checkins@lists.sourceforge.net>'
maxcommits=100
maxdiffsize=$((300 * 1024))
gitweburl='http://repo.or.cz/w'
tempprefix='/dev/shm'
fourtyzeros=$(printf '%.40u' 0)
myself=${0##*/}

checkrefs()
{
	turn=$1

	git show-ref | while read object ref
	do
		refdir="$tempdir/${ref%/*}"
		reffile="$tempdir/$ref"

		if [ $turn -eq 2 -a -f "$reffile" ] \
		    && grep "^1 $object$" "$reffile" >'/dev/null'
		then	# The ref has not been modified.
			rm -f "$reffile"
		else
			mkdir -p "$refdir"
			echo "$turn $object" >>"$reffile"
		fi
	done
}

if [ $# -lt 1 ]
then
	echo >&2 "Usage: $myself <repository> ..."
	exit 1
fi

tempdir=$(mktemp -d "$tempprefix/$myself.XXXXXX")
tempfile=$(mktemp "$tempprefix/$myself.XXXXXX")
trap 'rm -rf "$tempdir" "$tempfile"' EXIT

for repository in "$@"
do
	cd "$repository"

	checkrefs 1
	if ! git remote update --prune >"$tempfile" 2>&1
	then
		cat >&2 "$tempfile"
		exit 1
	fi
	git fetch --quiet --tags
	checkrefs 2

	find "$tempdir" -type 'f' -print | while read reffile
	do
		ref=${reffile#$tempdir/}
		old=$(awk '$1 == "1" { print $2; exit }' "$reffile")
		new=$(awk '$1 == "2" { print $2; exit }' "$reffile")
		old=${old:-$fourtyzeros}
		new=${new:-$fourtyzeros}

		echo "$old" "$new" "$ref"
	done | $gitnotify \
	    -m "$recipient" \
	    -n "$maxcommits" \
	    -s "$maxdiffsize" \
	    -u "$gitweburl"

	cd "$OLDPWD"
done