#!/bin/sh
#
# batch-subject-editor - helper script to change subject lines with mutt
#
# Based on an idea by David Champion <dgc at uchicago.edu>
#
# Copyright © 2008 martin f. krafft <madduck@madduck.net>
# Released under the terms of the Artistic Licence 2.0
#
set -eu

if [ -z "${__RLWRAPPED:-}" ] && [ -x $(command -v rlwrap) ]; then
  __RLWRAPPED=true exec rlwrap "$0" "$@"
fi

printf 'Enter new subject: ' >/dev/tty
read subj </dev/tty

if [ -z "${subj:-}" ]; then
  echo No subject specified. >&2
  exit 1
fi

SED_DELIM=,
subj=$(echo "$subj" | sed -re "s${SED_DELIM}\\\&g")

RE_REPLY='((re|aw|antwort)([[(]?[[:digit:]]+[)]]?)?):[[:space:]]*'
RE_SUBJ_PREFIX="^Subject:[[:space:]]*(${RE_REPLY})*"
RE_SUBJ='.*'
EDITOR="sed -i -re \"s${SED_DELIM}(${RE_SUBJ_PREFIX})${RE_SUBJ}${SED_DELIM}\\\1$subj${SED_DELIM}i\""

printf "set editor='${EDITOR} %s'"