#! /bin/sh
#
# mhmail -- simple mail program
#
# This code is Copyright (c) 2012, by the authors of nmh.  See the
# COPYRIGHT file in the root directory of the nmh distribution for
# complete copyright information.
#
# Emulation of compiled mhmail(1), with these differences:
# * Instead of silently not sending an empty message, notifies user
#   "mhmail: empty message not sent, use -body '' to force."
# * The compiled mhmail dropped a trailing newline from the -body argument.
# * Supports all post(8) (by default, without -profile) or send(1)
#   (with -profile) options.
# * Optionally (with -profile) obeys the users profile, including
#   AliasFile and send entries.
# * Adds -nosend option, which displays the draft but does not send it.
# * Drops support for undocumented -queue option.
#
# To do:
# * fix -resent with -profile
# * add -header-field name:body switch
# * add -attach file ... switch

usage='Usage: mhmail [addrs ... [switches]]
  switches are:
  -b(ody) text
  -c(c) addrs ...
  -f(rom) addr
  -su(bject) text
  -r(esent)
  -pr(ofile)
  -se(nd)
  -nose(nd)
  -v(ersion)
  -h(elp)
  and all post(8)/send(1) switches'

bindir=`dirname $0`
nmhbindir=`cd "${bindir}" && pwd`

if [ $# -eq 0 ]; then
  #### Emulate mhmail for reading mail.
  exec "${nmhbindir}"/inc
else
  #### Go through all the switches so we can build the draft.
  tolist=
  body=
  bodyarg=0
  cclist=
  ccarg=0
  from=
  fromarg=0
  subject=
  subjectarg=0
  resent=0
  postsendargs=
  switcharg=0
  use_send=0
  sendsw=1
  for arg in "$@"; do
    case "${arg}" in
      -*) switcharg=0
    esac

    case "${arg}" in
      #### Post and send won't accept -f -or -s because they'd be
      #### ambiguous, so no conflicts with them.  And they don't have
      #### -b, -c, or -r.  For the new switches that compiled mhmail
      #### didn't have:  let -p indicate mhmail -profile, not send
      #### -port.  -send masks the send(1) -send switch.
      -b|-bo|-bod|-body) bodyarg=1 ;;
      -c|-cc) ccarg=1 ;;
      -f|-fr|-fro|-from) fromarg=1 ;;
      -h|-he|-hel|-help) printf "%s\n" "${usage}"; exit ;;
      -nose|-nosen|-nosend) sendsw=0 ;;
      -p|-pr|-pro|-prof|-profi|-profil|-profile) use_send=1 ;;
      -resend) printf "mhmail: did you mean -resent instead of -resend?\n" 1>&2
         exit 1 ;;
      -r|-re|-res|-rese|-resen|-resent) resent=1 ;;
      -se|-sen|-send) sendsw=1 ;;
      -su|-sub|-subj|-subje|-subjec|-subject) subjectarg=1 ;;
      -v|-ve|-ver|-vers|-versi|-versio|-version)
         #### Cheat instead of using autoconf and make to fill in the version.
         "${nmhbindir}"/mhpath -v | sed 's/mhpath/mhmail/'; exit ;;
      -*) postsendargs="${postsendargs:+${postsendargs} }${arg}"; switcharg=1 ;;
      *) if [ ${bodyarg} -eq 1 ]; then
           body="${arg}
"; bodyarg=0
           #### Allow -body "" by using just a newline for the body.
           [ "${body}"x = x ]  &&  body='
'
         elif [ ${fromarg} -eq 1 ]; then
           from="${arg}"; fromarg=0
         elif [ ${subjectarg} -eq 1 ]; then
           subject="${arg}"; subjectarg=0
         elif [ ${switcharg} -eq 1 ]; then
           postsendargs="${postsendargs:+${postsendargs} }${arg}"
         elif [ ${ccarg} -eq 1 ]; then
           #### Never reset ccarg to 0, for compatibilty with compiled mhmail.
           cclist="${cclist:+${cclist}, }${arg}"
         else
           #### An address.
           tolist="${tolist:+${tolist}, }${arg}"
         fi
    esac
  done

  #### Check for at least one address and -from.
  if [ "${tolist}"x = x ]; then
    printf "mhmail: usage: mhmail addrs ... [switches]\n"
    exit 1
  fi
  if [ "${from}"x = x ]; then
    nmhlibdir=`${nmhbindir}/mhparam libdir`/
    #### If nmhlibdir isn't right, assume that the nmh lib dir is on the PATH.
    [ -x "${nmhlibdir}ap" ]  ||  nmhlibdir=
    from=`${nmhlibdir}ap -format '%(localmbox)' 0`
  fi

  #### Build header.
  [ ${resent} -eq 0 ]  &&  prefix=  ||  prefix='Resent-'
  header="${prefix}To: ${tolist}
"
  [ "${cclist}"x = x ]  ||  header="${header}${prefix}Cc: ${cclist}
"
  [ "${subject}"x = x ]  ||  header="${header}${prefix}Subject: ${subject}
";
  [ "${from}"x = x ]  ||  header="${header}${prefix}From: ${from}
";

  #### Set up a file to supply as a draft to send/post.  And set a
  #### trap to remove it.  send moves the file to a backup, so it will
  #### remove that, too.
  umask 077
  tmpdir="${MHTMPDIR:-${TMPDIR:-${TMP:-`${nmhbindir}/mhpath +`}}}"
  tmpfil="${tmpdir}/mhmail$$"
  tmpfilbackup="${tmpdir}/[,#]mhmail$$"
  trap 'rm -f '"${tmpfil}"' '"${tmpfilbackup}" EXIT

  if [ ${resent} -eq 0 ]; then
    #### Add blank line after header if not resending.
    header="${header}
"
  else
    if [ ${use_send} -eq 0 ]; then
      postsendargs="${postsendargs:+${postsendargs} }-dist"
    else
      mhdist=1; export mhdist
      mhaltmsg=${tmpfil}; export mhaltmsg
      #### This doesn't work, I'm not sure about mhaltmsg.
      printf "mhmail: -resent not currently supported with -profile\n"
      exit 1
    fi
  fi

  if [ "${body}"x = x ]; then
    #### First put message header in the file.  cat >> handles blank
    #### lines better than body=`cat`.
    printf "%s" "${header}" > "${tmpfil}" || exit 1

    tmpfile_size_before=`wc -c "${tmpfil}"`
    #### Now grab the body from stdin.
    cat >>"${tmpfil}"
    tmpfile_size_after=`wc -c "${tmpfil}"`

    #### Don't allow an empty body (from stdin).  Use string
    #### comparison so we don't have to strip the filename, etc.
    if [ "${tmpfile_size_before}" = "${tmpfile_size_after}" ]; then
      printf "mhmail: empty message not sent, use -body '' to force.\n" 1>&2
      exit 1
    fi

    #### Add trailing newline to body if it doesn't have one.
    [ `printf "${body}" | tail -n 1 | wc -l` -ne 1 ]  &&  body="${body}
"
  else
    #### Put message header and body in the file.
    printf "%s" "${header}${body}" > "${tmpfil}" || exit 1
  fi

  if [ ${sendsw} -eq 0 ]; then
    cat "${tmpfil}"
  else
    if [ ${use_send} -eq 0 ]; then
      post_or_send=`${nmhbindir}/mhparam postproc`
    else
      post_or_send="${nmhbindir}/send"
    fi

    if "${post_or_send}" "${tmpfil}" ${postsendargs}; then
      exit
    else
      printf "Letter saved in dead.letter\n"
      #### exec skips the trap set above.
      exec mv "${tmpfil}" dead.letter
    fi
  fi
fi