#!/bin/bash
#
# git-add-byline - edit a commit message and add "Tested|Acked|...-by:" line
#                  (works for non-HEAD patches).
#
# Copyright (C) 2009, 2010 Karel Zak <kzak@redhat.com>
#
# This file 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 2 of the License, or
# (at your option) any later version.
#
# This file 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.

CID="$1"
BYLINE="$2"

if [ -z "$CID" ]; then
	echo "Usage: $0 <commit> <byline>"
	exit 1
fi

MYBRANCH=$(git branch | gawk '/^\* / { print $2 }')
TMPBRANCH="tmp.$$"

git checkout -f -b "$TMPBRANCH" "$CID"

git log --pretty=format:"%s%n%n%b" HEAD^..HEAD | grep -q -E '\-by: .*@'
if [ $? == 1 ]; then
	(git log --pretty=format:"%s%n%n%b" HEAD^..HEAD && echo "$BYLINE") | \
	   git commit --amend -F -
else
	git log --pretty=format:"%s%n%n%b" HEAD^..HEAD | \
	    awk -v tag="$BYLINE" '/\-by:/{if(last~/^[[:blank:]]*$/){print tag}}{last=$1;print $0}' | \
	    git commit --amend -F - 
fi

git rebase --onto "$TMPBRANCH" "$CID" "$MYBRANCH"
git branch -d "$TMPBRANCH"

echo "done."