#!/bin/bash

SERVICE="ogn2rcd"
SYSTEMD="/etc/systemd/system"
SERVICE_FILE="${SYSTEMD}/${SERVICE}.service"

echo ""
echo "Task: Check if destination is accessible from R-Pi"
if [ "$1" == "" ]
then
  DESTIN=radarcape
else
  DESTIN=$1
fi

ping -c 1 -q $DESTIN > /dev/null

if [ $? == 0 ]
then
  echo "${DESTIN} is reachable from this computer"
else
  echo "${DESTIN} is not reachable, please investigate."
  echo "If operating with different hostname, call script with ./ogn-install.sh <hostname>"
  echo "Or you may use IP address and call script with         ./ogn-install.sh <ip-address>"
  exit 1
fi

echo ""
echo "Task: Make sure only root can run our script"
if [ "$(id -u)" != "0" ]; then
   echo "This script must be run as root" 1>&2
   exit 1
fi

echo ""
echo "Task: Check if local system provides systemd services"
if [ ! -d "$SYSTEMD" ]; then
   echo "Folder ${SYSTEMD} missing, ensure you are on the right system"
   exit 1
fi

# nc (netcat) would be possible if destination is addressed with IP address, but socat provides name resolution
# in this case, use nc localhost 50001 > /dev/udp/192.168.1.38/50001
# multiple targets can be served with
# socat tcp:localhost:50001 - | tee >(socat - udp-sendto:radarcape.local:50001) >(socat - udp-sendto:target2:50001)

echo ""
echo "Task: Install socat"
apt-get update
apt-get install socat

echo ""
echo "Task: Stop and disable eventually running ogn2rcd service"

if [ "$(systemctl is-active ${SERVICE})" = "active" ]
then
    systemctl stop ${SERVICE}
fi
systemctl disable ${SERVICE} || true

echo ""
echo "Task: Generate systemd service which starts local script automatically after reboot"
cat > /etc/systemd/system/${SERVICE}.service <<-__EOF__
[Unit]
Description=Mirror TCP port 50001 to ${DESTIN}
After=network.target

[Service]
ExecStart=\
/usr/bin/socat -u tcp:localhost:50001 udp-sendto:${DESTIN}:50001
RestartSec=5
Restart=always

[Install]
WantedBy=multi-user.target
__EOF__

echo ""
echo "Task: Refresh systemd configuration and enter ogn2rcd.service to autostart"
systemctl daemon-reload
systemctl enable ${SERVICE}
systemctl start ${SERVICE}

echo ""
echo "Service ogn2rcd correctly installed and enabled"
echo "You now should enable external source \"Open Glider Net Local Receiver\""
echo "Monitor operation in Status -> Open Glider Net Local Receiver Connection"