#!/usr/bin/env bash

REALPATH="$(realpath $0)"
BASEDIR="${REALPATH%/*}"

if [[ "${1}" == "start" ]]; then
  rm $BASEDIR/var/*.conf &>/dev/null         # Create separate .conf files in var/ from etc/tunnelkeeper.conf
  awk -v "dir=$BASEDIR/var" '
    /^\[/ {sec=$1}
    !/^\[/ {print >> dir"/"sec".conf"}' < $BASEDIR/etc/tunnelkeeper.conf &>/dev/null
fi

SSHCONF="$BASEDIR/var/[ssh].conf"
TKCONF="$BASEDIR/var/[settings].conf"

function ruroot () {
  if [[ $UID -ne 0 ]]; then
    echo "You must be root to do this"
    exit
  fi
}

DEBUGLEVEL=$(grep -i -m1 "debug" $TKCONF | grep -o [0-9])
case "$DEBUGLEVEL" in
  2) dbgopt='-v';;
  3) dbgopt='-vvv';;
  *) dbgopt='';;
esac

function dbg () {
  [[ $DEBUGLEVEL != "0" ]] && logger -t tunnelkeeper
}

case "$1" in
  FORKSTART )
    touch "$BASEDIR/var/${2}.connected"
    while [[ -e "$BASEDIR/var/${2}.connected" ]]; do
      ssh -F "${SSHCONF}" $dbgopt -N $2 2>&1 | dbg
      sleep 5
    done
  ;;
  FORKKILL ) kill $(sudo netstat -tnlp | grep "127[0-9\.]*:${2}" | grep -o '[0-9]*/ssh' | grep -o '[0-9]*') &>/dev/null ;;
  FORKDEL ) rm "$BASEDIR/var/${2}.connected" ;;
  start)
    [[ -e "$BASEDIR/var/tunnelkeeper.pid" ]] && exit
    echo $$ > "$BASEDIR/var/tunnelkeeper.pid"
    cat "$SSHCONF" | awk '/^Host / {print $2}' | xargs -I% -P0 $0 FORKSTART % &
  ;;
  stop)
    rm "$BASEDIR/var/tunnelkeeper.pid"
    cat "$SSHCONF" | awk '/^Host / {print $2}' | sed 's/^Host //' | xargs -I% -P0 $0 FORKDEL %
    cat "$SSHCONF" | grep -o 'LocalForward [0-9]* ' | grep -o '[0-9]*' | xargs -I% -P0 $0 FORKKILL %
  ;;
  restart) $0 stop; sleep 2; $0 start ;;
  install )
    ruroot
    mkdir -p /opt/tunnelkeeper/var
    mkdir -p /opt/tunnelkeeper/etc
    if [[ "$BASEDIR" != '/opt/tunnelkeeper/' ]]; then
      cp -n "$BASEDIR/etc/tunnelkeeper.conf" /opt/tunnelkeeper/etc/
      cp "$REALPATH" "/opt/tunnelkeeper/tunnelkeeper"
    fi
    ln -f -s /opt/tunnelkeeper/tunnelkeeper /usr/local/bin/tunnelkeeper
    echo "[Unit]
Description=TunnelKeeper SSH tunnel utility.
After=network.target
[Service]
User=root
Group=root
Type=forking
ExecStart=/opt/tunnelkeeper/tunnelkeeper start
ExecStop=/opt/tunnelkeeper/tunnelkeeper stop
RestartSec=15
Restart=always
[Install]
WantedBy=multi-user.target" > /lib/systemd/system/tunnelkeeper.service
    systemctl daemon-reload
    systemctl enable tunnelkeeper.service
    echo -e "\nTunnelKeeper service installed.\n"
  ;;
  uninstall )
    ruroot
    systemctl disable tunnelkeeper.service
    rm /usr/local/bin/tunnelkeeper
    rm /lib/systemd/system/tunnelkeeper.service
    systemctl daemon-reload
    rm -rf /opt/tunnelkeeper
    echo -e "\nTunnelKeeper service uninstalled.\n"
  ;;
  list )
    echo "---"
    find "$BASEDIR/var/" -name '*.connected' | sed 's/^.*\///g; s/\.connected//g'
    echo "---"
  ;;
  config )
    ruroot
    vi "$BASEDIR/etc/tunnelkeeper.conf"
  ;;
   * )
    echo -e "\nUsage: $(basename $0) start|stop|restart|install|uninstall|config|list\n"
  ;;
esac