#! /bin/sh
# Run with no arguments for usage.
# Note that you need netcat installed.

# Copyright (C) 2007 Hans Fugal <hans@fugal.net>
# All rights reserved.
# 
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
# 3. The name of the author may not be used to endorse or promote products
#    derived from this software without specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

host=localhost
port=5500

if [ $# -lt 2 ]; then
    cat <<EOF
usage: $0 lat lon [host [port]]
Latitude and Longitude are in degrees, with south and west negative.
Default host is $host, default port is $port.
EOF
    exit 1
fi

lat=$(($1 * 100))
lon=$(($2 * 100))
[ -z "$3" ] || host=$3
[ -z "$4" ] || port=$4

ns=N
if [ $lat -lt 0 ]; then
    ns=S 
    lat=$((-$lat))
fi
ew=E
if [ $lon -lt 0 ]; then
    ew=W
    lon=$((-$lon))
fi

# note, because of a bug in terrasync we need exactly 6 characters in the
# second field (which is otherwise unused for TerraSync)
msg="\$GPGGA,123456,$lat,$ns,$lon,$ew"
echo $msg | nc -q 1 -u $host $port