#! /bin/zsh -f
# backup script
#     Usage: jbackup [config_file]
#     uses configuration file ~/.jbackup by default
#     You may override the configuration file by setting DOTJBACKUP or
#          providing a filename
# 
# Copyright (C) 2008 Joel J. Adamson
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
#

help_message () {
    if [[ "$1" = "NO_FILES" ]]; then
	printf "Error: no files to back up\n"
    elif [[ "$1" = "NO_DISK" ]]; then
	printf "Error: device %s not found\n" "$2"
    elif [[ "$1" = "NO_DESTINATION" ]]; then
	printf "Error: no backup destination specified\n"
    elif [[ "$1" = "RSYNC_ERROR" ]]; then
	printf "Error: rsync error \"%s\"" "$2"
    elif [[ "$1" = "NO_CONFIG" ]]; then
	printf "Error: no configuration found\n"
    elif [[ "$1" = "help" ]]; then
	:
    else
	printf "Unknown option\n"
    fi

cat -<<EOF
Usage: jbackup [config_file]
uses configuration file ~/.jbackup by default
You may override the configuration file by setting DOTJBACKUP or
  by providing a filename

EOF

    exit 1
}

parse_file () {
    . $1
    return $?
}

rsync_files () {
    trap "help_message RSYNC_ERROR" ZERR
    $RSYNC "$@"
}

if [[ "$1" = "--help" ]] || [[ "$1" = "help" ]] || [[ "$1" = "-h" ]]; then
    help_message help
fi

if [[ -e $HOME/.jbackup ]]; then 
    parse_file $HOME/.jbackup
elif [[ -e $DOTJBACKUP ]]; then
    parse_file $DOTJBACKUP
elif [[ -e $1 ]]; then
    parse_file $1
else
    help_message NO_CONFIG
fi

if [[ -z $DIRECTORIES ]] && [[ -z $FILES ]]; then
    help_message NO_FILES
elif [[ -z $DESTINATION ]]; then
    help_message NO_DESTINATION 
fi

if [[ -n "$DISK" ]] && [[ -n `grep "$DISK" /etc/mtab` ]]; then
    rsync_files $RS_FLAGS $DIRECTORIES $FILES $DESTINATION
else
    help_message NO_DISK $DISK
fi
exit $?