git-hook-append-ticket-num.sh

#!/bin/sh
#inspired by HellBrick

commit_msg_file=$1

detached_head='unnamed branch'
current_branch="$(git symbolic-ref HEAD 2>/dev/null)" ||
current_branch="$detached_head"
pipe_separated_system_branches="smartgit-temp|bitbucket-temp"

ticket=`echo $current_branch | awk -F '__' '{ print $NF }' | grep -P '^[0-9]+\$'`

if [ ! -z "$ticket" ]
then
    to_insert_prefix="issue::"
	old_ticket=`cat $commit_msg_file | awk -F "$to_insert_prefix" '{ print $NF }' | grep -Po '^[0-9]+'`
	echo "old ticket : $old_ticket" >&2
	to_replace=" ( $to_insert_prefix$old_ticket )"
    to_insert=" ( $to_insert_prefix$ticket )"

    # hook should replace ticket id if it is already inserted
    if [ -n "$old_ticket" ]
    then
		
		echo `sed "s/$to_replace/$to_insert/" $commit_msg_file` > $commit_msg_file

	else
		
        first_line=`head $commit_msg_file -n1`

        text="${first_line}${to_insert}"

        lines_count=$( cat $commit_msg_file | wc -l)

        if [ $lines_count -gt 1 ]
        then
            lines_after_first=`tail $commit_msg_file -n +2`
            text="${text}
${lines_after_first}"
        fi

        echo "$text" > $commit_msg_file

    fi
else
	should_fail=`echo $current_branch | grep -oP "(?:$pipe_separated_system_branches|$detached_head)"`
	if [ -z "$should_fail" ]
	then
		echo 'no ticket id in the branch name' >&2
		exit 1
	fi
fi