#!/bin/sh

COMMIT_MSG_FILE=$1
COMMIT_SOURCE=$2
SHA1=$3

# Merging branch (could use GIT_MERGE file)
if grep -q "Merge branch "; then
	exit
fi

# Amending
if [ ! -z "$SHA1" ]; then
	exit
fi

PREFIX=$(git log -n 5 --pretty=%B | grep ": " | cut -d " " -f1 | head -n 1)

if -z "$PREFIX"; then
	exit
fi

sed -i "1i $PREFIX " "$COMMIT_MSG_FILE"