#!/bin/sh
# http://mg.pov.lt/blog/sysadmin-diary.html is the closest this thing has to
# documentation.
version=1.0
changelog=/root/Changelog

if [ x"$1" = x-h ] || [ x"$1" = x--help ]; then
    echo "Usage: $0 [filename] [message]"
    echo "Opens an admin change log file (default: /root/Changelog) in vi"
    echo "or appends a timestamped message to the end and prints it."
    exit
fi

if [ x"$1" = x--version ]; then
    echo "new-changelog-entry version $version"
    echo "Written by Marius Gedminas <marius@gedmin.as>"
    exit
fi

if test -n "$1" && test -f "$1"; then
    changelog=$1
    shift

    case "$changelog" in
        *hangelog*)
            ;;
        *)
            echo "Cowardly refusing to edit $changelog since it doesn't mention Changelog in the filename" 1>&2
            exit 1
            ;;
    esac
fi

swapfile="`dirname $changelog`/.`basename $changelog`.swp"

if [ -f $swapfile ]; then
    echo "Someone is currently editing $changelog ($swapfile exists)" 1>&2
    exit 1
fi

if ! [ -w $changelog ] && [ `id -u` -ne 0 ]; then
    exec sudo "$0" "$changelog" "$@"
fi

if [ -f $changelog ]; then
    # append an empty line if it is not there
    test -n "`tail -n 1 $changelog`" && echo >> $changelog
fi

msg="$*"

# append a header
cat >> $changelog <<END
`date +'%Y-%m-%d %H:%M %z'`: ${SUDO_USER:-$USER}
  $msg
END
test -z "$msg" \
  && exec vim $changelog +$ \
  || tail $changelog