#!/bin/ksh
#
# $Id: mkmail,v 1.7 2001/05/18 21:03:28 vogelke Exp $
#
# NAME:
#    mkmail
#
# SYNOPSIS:
#    mkmail [-hmv] [--help] [--version] [-s subject] [-t to] [file]
#
# DESCRIPTION:
#    Read one or more files, add a mail header, write to stdout.
#    Relies on GNU date.
#
# OPTIONS:
#    -h, --help        print this message
#    -v, --version     print the version and exit
#    -s                specifies subject
#    -t                specifies recipient
#    -m                mail to myself
#  
# EXAMPLE:
#    mkmail 
#
# AUTHOR:
#    Based on Free Software Foundation configure scripts.
#
#    Karl Vogel <vogelke@dnaco.net>
#    Sumaria Systems, Inc.

PATH=/usr/local/bin:/bin:/usr/bin:/usr/sbin:/usr/ucb
export PATH
tag=`basename $0`

# ======================== FUNCTIONS =============================
#
# logmsg: prints a string to the system log.

logmsg () {
    logger -t $tag "$*"
}

# die: prints an optional argument to stderr and exits.
# warn: prints an optional argument to stderr.
#    A common use for "die" is with a test:
#         test -f /etc/passwd || die "no passwd file"
#    This works in subshells and loops, but may not exit with
#    a code other than 0.

die () {
    echo "$tag: error: $*" 1>&2
    exit 1
}

warn () {
    echo "$tag: warning: $*" 1>&2
}

# checkvar: reject invalid shell variable names.

checkvar () {
    case "`echo $1 | sed 's/[-a-zA-Z0-9_]//g'`" in
        "") ;;
        *)  die "$1: invalid feature name" ;;
    esac
}

# usage: prints an optional string plus part of the comment
#   header (if any) to stderr, and exits with code 1.

usage () {
    lines=`egrep -n '^# (NAME|AUTHOR)' $0 | sed -e 's/:.*//'`

    (
        case "$#" in
            0)  ;;
            *)  echo "usage error: $*"; echo ;;
        esac

        case "$lines" in
            "") ;;
            *)  set `echo $lines | sed -e 's/ /,/'`
                sed -n ${1}p $0 | sed -e 's/^#//g' |
                    egrep -v AUTHOR:
                ;;
        esac
    ) 1>&2

    exit 1
}

# version: prints the current version to stdout.

version () {
    lsedscr='s/RCSfile: //
    s/.Date: //
    s/,v . .Revision: /  v/
    s/\$//g'

    lrevno='$RCSfile: mkmail,v $ $Revision: 1.7 $'
    lrevdate='$Date: 2001/05/18 21:03:28 $'
    echo "$lrevno $lrevdate" | sed -e "$lsedscr"
    exit 0
}

# fqdn: call hostname, domainname

fqdn () {
    h=`hostname`

    case "$h" in
        *.*)  echo $h ;;
	*)    d=`domainname`; echo "$h.$d" ;;
    esac
}

# ======================== MAIN PROGRAM ==========================

# Defaults:
ac_prev=
ac_invalid="invalid option; use --help to show usage"
argv=

# Initialize some variables set by options.
s="Your subject here"
t=nobody@nowhere.com

for ac_option
do

    # If the previous option needs an argument, assign it.
    case "$ac_prev" in
        "") ;;
        *)  eval "$ac_prev=\$ac_option"; ac_prev=; continue ;;
    esac

    case "$ac_option" in
        -*=*) ac_optarg=`echo "$ac_option" |
                sed 's/[-_a-zA-Z0-9]*=//'` ;;
        *)    ac_optarg= ;;
    esac

    # main switch
    case "$ac_option" in
        -h | -help | --help | --hel | --he) usage ;;
        -m) t=myself ;;
        -s) ac_prev=s ;;
        -t) ac_prev=t ;;
    
        -v | -version | --version | --versio |\
        --versi | --vers)
            version ;;
    
        -*) die "$ac_option: $ac_invalid" ;;
        *)  argv="$argv $ac_option" ;;
    esac
done

case "$ac_prev" in
    "") ;;
    *)  die "missing arg to --`echo $ac_prev | sed 's/_/-/g'`" ;;
esac

#
# Real work starts here.  Test for specific features.
#

sub="$s"
to="$t"

#
# fdate = from-line date
# adate = ARPA-style date
# fhost = fully-qualified name of my host
#

case "$argv" in
    "") list="-" ;;
    *)  list="$argv" ;;
esac

case "$MAILHOST" in
    "") fhost=`fqdn` ;;
    *)  fhost="$MAILHOST" ;;
esac

case "$MAILUSER" in
    "") myname=`whoami` ;;
    *)  myname="$MAILUSER" ;;
esac

fdate=`gdate "+%a %b %d %T %Y"`
adate=`gdate --rfc-2822`

case "$to" in
    myself) to="$myname@`fqdn`" ;;
    *)  ;;
esac

#
# Print results.
#

cat <<EndHeader
From $myname@$fhost $fdate
Return-Path: <$myname@$fhost>
Date: $adate
`msgid -d $tag`
From: $myname@$fhost
To: $to
Subject: $sub

EndHeader

cat $list
echo
exit 0