#!/bin/sh
main(){

  #get sudo
  if test "${nosudo-false}" != true -a `id -u` != 0; then
    echo "we're going sudo..." >&2
    exec sudo -E "$0" "$@"
    exit 23 # go to hell
  fi
  set -euf
  #
  SUBNET4=${SUBNET4:-10.243}
  SUBNET6=${SUBNET6:-42}
  TEMPDIR=${TEMPDIR:-auto}
  TINCDIR=${TINCDIR:-auto}
  exists() { type "$1" >/dev/null 2>/dev/null; }

  if exists hostname ;then SYSHOSTN=${HOSTNAME:-$(hostname)}
  elif exists uci    ;then SYSHOSTN=$(uci get system.@system[0].hostname)
  elif [ -e /etc/hostname ]   ;then SYSHOSTN=$(cat /etc/hostname)
  else                              SYSHOSTN="unknown"
  fi

  #overwrite `found` hostname
  HOSTN=${HOSTN:-$SYSHOSTN}
  NETNAME=${NETNAME:-retiolum}
  MASK4=${MASK4:-16}
  MASK6=${MASK6:-16}
  RMASK=${RMASK:-255.255.0.0}
  URL=${URL:-http://euer.krebsco.de/retiolum/hosts.tar.gz}
  SURL=${SURL:-http://euer.krebsco.de/retiolum/supernodes.tar.gz}

  IRCCHANNEL=${IRCCHANNEL:-"#krebs_incoming"}
  IRCSERVER=${IRCSERVER:-"irc.freenode.net"}
  IRCPORT=${IRCPORT:-6667}

  OS=${OS:-0}
  TELNET=${TELNET:-}

  IP4=${IP4:-0}
  IP6=${IP6:-0}

  RAND4=1
  RAND6=1


  if [ $IP4 -eq 0 ]; then
    RAND4=1
  elif ! check_ip_valid4 $IP4; then
    echo 'ip4 is invalid'
    exit 1
  fi
  if [ $IP6 -eq 0 ]; then
    RAND6=1
  elif ! check_ip_valid6 $IP6; then
    echo 'ip6 is invalid'
    exit 1
  fi

  #find OS
  if [ $OS -eq 0 ]; then
    find_os
  fi
  if [ -z "$TELNET" ]; then
    find_telnet
  fi
  #check if everything is installed
  if ! exists awk ; then
    echo "Please install awk"
    exit 1
  fi

  if ! exists curl ; then
    if ! exists wget ; then
      echo "Please install curl or wget"
      exit 1
    else
      LOADER='wget -O-'
      HEAD_LOADER="$LOADER --spider"
    fi
  else
    LOADER=curl
    HEAD_LOADER="$LOADER -I"
  fi

  if ! $HEAD_LOADER $SURL >/dev/null 2>/dev/null ;then
    echo "Cannot find supernode package, check if your internet is working"
    exit 1
  fi

  #check if everything is installed
  if [ $OS = 'android' ]; then
    if ! test -e /data/data/org.poirsouille.tinc_gui/files/tincd; then
      echo "Please install tinc-gui"
      exit 1
    else
      TINCBIN=/data/data/org.poirsouille.tinc_gui/files/tincd
      DEV="/dev/tun"
      if [ $TINCDIR = 'auto' ]; then TINCDIR="/usr/local/etc/tinc" ;fi
      if [ $TEMPDIR = 'auto' ]; then TEMPDIR="/storage/sdcard0/tinc-fu" ;fi
      mount -o remount,rw /
      mount -o remount,rw /system
    fi
  elif [ $OS = 'osx' ]; then
    if ! exists tincd >/dev/null; then
      echo "Please install tinc"
      exit 1
    else
      TINCBIN=tincd
      DEV="/dev/net/tun"
      if [ $TINCDIR = 'auto' ]; then TINCDIR="/usr/local/etc/tinc" ;fi
      if [ $TEMPDIR = 'auto' ]; then TEMPDIR="/tmp/tinc-install-fu" ;fi
    fi
  else
    if ! exists tincd >/dev/null; then
      echo "Please install tinc"
      exit 1
    else
      TINCBIN=tincd
      DEV="/dev/net/tun"
      if [ $TINCDIR = 'auto' ]; then TINCDIR="/etc/tinc" ;fi
      if [ $TEMPDIR = 'auto' ]; then TEMPDIR="/tmp/tinc-install-fu" ;fi
    fi
  fi

  #generate full subnet information for v4

  #test if tinc directory already exists
  if test -e $TINCDIR/$NETNAME; then
    echo "tinc config directory $TINCDIR/$NETNAME does already exist. (backup and) delete config directory and restart"
    exit 1
  fi

  #get tinc-hostfiles
  mkdir -p $TEMPDIR/hosts
  $LOADER $URL | tar zx -C $TEMPDIR/hosts/

  #check for free ip
  #version 4
  until check_ip_taken $IP4; do
    if [ $RAND4 -eq 1 ]; then
      IP4="$SUBNET4.$(( $(head /dev/urandom | tr -dc "123456789" | head -c3) %255)).$(( $(head /dev/urandom | tr -dc "123456789" | head -c3) %255))"
    else
      printf 'choose new ip: '
      read IP4
      while !  check_ip_valid4 $IP4; do
        printf 'the ip is invalid, retard, choose a valid ip: '
        read IP4
      done
    fi
  done

  #version 6
  until check_ip_taken $IP6; do
    if [ $RAND6 -eq 1 ]; then
      NETLENGTH=$(expr $(expr 128 - $MASK6) / 4)
      IP6="$SUBNET6$(head /dev/urandom | tr -dc "0123456789abcdef" | head -c$NETLENGTH | sed 's/..../:&/g')" #todo: generate ip length from hostmask
    else
      printf 'ip taken, choose new ip: '

      read IP6
      while !  check_ip_valid6 $IP6; do
        printf 'the ip is invalid, retard, choose a valid ip: '
        read IP6
      done
    fi
  done


  #check for free hostname
  get_hostname $HOSTN


  #create the configs
  mkdir -p $TINCDIR/$NETNAME
  cd $TINCDIR/$NETNAME

  if [ $OS = 'openwrt' ]; then
    mkdir hosts
    $LOADER $SURL | tar xz -C hosts/
  else
    mv $TEMPDIR/hosts ./
  fi

  rm -r $TEMPDIR || echo "$TEMPDIR does not exist, skipping removal"

  echo "Subnet = $IP4" > hosts/$HOSTN
  echo "Subnet = $IP6" >> hosts/$HOSTN

  cat>tinc.conf<<EOF
Name = $HOSTN
Device = $DEV

#newer tinc features
LocalDiscovery = yes
AutoConnect = 3

#ConnectTos
ConnectTo = slowpoke
ConnectTo = pigstarter
ConnectTo = pico
EOF

  host2subnet $MASK4
  
  #check if ip is installed
  if exists ip >/dev/null; then
    echo 'dirname="`dirname "$0"`"' > tinc-up
    echo '' >> tinc-up
    echo 'conf=$dirname/tinc.conf' >> tinc-up
    echo '' >> tinc-up
    echo 'name=$(sed -n "s|^ *Name *= *\([^ ]*\) *$|\\1|p" $conf)' >> tinc-up
    echo '' >> tinc-up
    echo 'host=$dirname/hosts/$name' >> tinc-up
    echo '' >> tinc-up
    echo 'ip link set $INTERFACE up' >> tinc-up
    echo '' >> tinc-up
    echo "addr4=\$(sed -n \"s|^ *Subnet *= *\\($SUBNET4[.][^ ]*\\) *\$|\\\\1|p\" \$host)" >> tinc-up
    echo 'ip -4 addr add $addr4 dev $INTERFACE' >> tinc-up
    echo "ip -4 route add $FULLSUBNET/$MASK4 dev \$INTERFACE" >> tinc-up
    #TODO: variable for network announced
    echo "ip -4 route add 172.22.0.0/15 dev \$INTERFACE" >> tinc-up
    echo '' >> tinc-up
    echo "addr6=\$(sed -n \"s|^ *Subnet *= *\\($SUBNET6[:][^ ]*\\) *\$|\\\\1|p\" \$host)" >> tinc-up
    echo 'ip -6 addr add $addr6 dev $INTERFACE' >> tinc-up
    echo "ip -6 route add $SUBNET6::/$MASK6 dev \$INTERFACE" >> tinc-up
  else
    echo 'dirname="`dirname "$0"`"' > tinc-up
    echo '' >> tinc-up
    echo 'conf=$dirname/tinc.conf' >> tinc-up
    echo '' >> tinc-up
    echo 'name=$(sed -n "s|^ *Name *= *\([^ ]*\) *$|\\1|p" $conf)' >> tinc-up
    echo '' >> tinc-up
    echo 'host=$dirname/hosts/$name' >> tinc-up
    echo '' >> tinc-up
    echo "addr4=\$(sed -n \"s|^ *Subnet *= *\\($SUBNET4[.][^ ]*\\) *$|\\\\1|p\" \$host)" >> tinc-up
    echo 'ifconfig $INTERFACE $addr4' >> tinc-up
    echo "route add -net $FULLSUBNET netmask $RMASK dev \$INTERFACE " >> tinc-up
  fi
  
  #fix permissions
  chmod +x tinc-up
  chown -R 0:0 .
  
  #generate keys with tinc
  if exists tinc ; then
    yes | tinc -n $NETNAME generate-keys
  else
    yes | $TINCBIN -n $NETNAME -K
  fi
  
  if [ $OS = 'android' ]; then
    mkdir /etc/tinc
    cd /
    mv $TINCDIR/$NETNAME /etc/tinc/
    cd /etc/tinc/$NETNAME
  fi
  #write to irc-channel
  NICK="${HOSTN}_$(head /dev/urandom | tr -dc "0123456789" | head -c3)"
  
  (   echo "NICK $NICK";
  echo "USER $NICK $IRCSERVER bla : $NICK";
  echo "JOIN $IRCCHANNEL";
  sleep 23;
  echo "PRIVMSG $IRCCHANNEL : This is $HOSTN";
  sed "s/^\(.*\)/PRIVMSG $IRCCHANNEL : \1/" hosts/$HOSTN;
  sleep 5; ) | $TELNET $IRCSERVER $IRCPORT
  
  
  # finish what you have begun!
  tincd -n $NETNAME
}


#convert hostmask to subnetmask only version 4
host2subnet()
{
  NEEDDOTSINSUB=$(expr 3 - $( echo $SUBNET4 | tr -C -d . | wc -c))
  case $NEEDDOTSINSUB in
    3) FULLSUBNET=$SUBNET4.0.0.0 ;;
    2) FULLSUBNET=$SUBNET4.0.0 ;;
    1) FULLSUBNET=$SUBNET4.0 ;;
    0) FULLSUBNET=$SUBNET4 ;;
    *) echo "cannot read subnet" && exit 1;;
    esac
}

#check if ip is valid ipv4 function
check_ip_valid4()
{
  if [ "$(echo $1 | awk -F"\." ' $0 ~ /^([0-9]{1,3}\.){3}[0-9]{1,3}$/ && $1 <=255 && $2 <= 255 && $3 <= 255 && $4 <= 255 ' 2>/dev/null)" == "$1" ] && [ ${1:0:${#SUBNET4}} == $SUBNET4 ]
  then
    return 0
  else
    return 1
  fi
}

#check if ip is valid ipv6 function
check_ip_valid6()
{
  if [ "$(echo $1 | awk -F"." ' $0 ~ /^([0-9a-fA-F]{1,4}\:){7}[0-9a-fA-F]{1,4}$/' 2>/dev/null)" == $1 ] && [ ${1:0:${#SUBNET6}} == $SUBNET6 ]
  then
    return 0
  else
    return 1
  fi
}

#check if ip is taken function
check_ip_taken()
{
  if grep -q -r -E "$1(#|/)" $TEMPDIR/hosts/ ;then
    return 1
  else
    return 0
  fi
}

#if hostname is taken, count upwards until it isn't taken function
get_hostname()
{
  TSTFILE=$TEMPDIR/hosts/$1
  LCOUNTER=0
  if test -e $TSTFILE; then
    while test -e $TSTFILE; do
      : $((LCOUNTER+=1))
      TSTFILE=$TEMPDIR/hosts/$1$LCOUNTER
    done
    HOSTN=$1$LCOUNTER
  else
    HOSTN=$1
  fi
}

#os autodetection
find_os()
{
  if grep -qe 'Linux' /etc/*release 2>/dev/null || grep -qe 'Linux' /etc/issue 2>/dev/null; then
    OS='linux'
  elif test -e /etc/preferred-apps/google.xml; then
    OS='android'
  elif test -e /etc/openwrt_release; then
    OS='openwrt'
  elif uname -s | grep -qi 'darwin'; then
    OS='osx'
  else
    echo "Cannot determine your operating system, falling back to Linux"
    OS='linux'
  fi
}

find_telnet(){
  if exists telnet >/dev/null;then
    TELNET="`command -v telnet`"
  elif exists busybox >/dev/null;then
    TELNET="`command -v busybox` telnet"
  else
    echo "cannot find telnet binary, please install either telnet-client or busybox"
    echo "bailing out!"
    exit 1
  fi
}
main