#!/usr/bin/env bash

script_name="$(basename $(realpath $0))"
working_dir="$(dirname $(realpath $0))"

conf_file="${working_dir}/conf/${script_name%%.*}.conf"

LOCK_DIR="/tmp/$(basename $0).$$.LOCK"
log_file="${LOCK_DIR}/${script_name%%.*}.log"



clean_up() {

   # Perform program exit housekeeping
   rm -rf "$LOCK_DIR"
   blank_line
   exit $1
}


echononl(){
   if $terminal ; then
      echo X\\c > /tmp/shprompt$$
      if [ `wc -c /tmp/shprompt$$ | awk '{print $1}'` -eq 1 ]; then
         echo -e -n "   $*\\c" 1>&2
      else
         echo -e -n "   $*" 1>&2
      fi
      rm /tmp/shprompt$$
   fi
}


fatal(){
   echo ""
   if $terminal ; then
      echo -e "   [ \033[31m\033[1mFatal\033[m ] $*"
   else
      echo -e "   [ Fatal ] $*"
   fi
   echo ""
   if $terminal ; then
      echo -e "             \033[1mScript terminated\033[m.."
   else
      echo -e "             Script terminated.."
   fi
   echo ""
   rm -rf $LOCK_DIR
   blank_line
   exit 1
}

error (){
   echo ""
   if $terminal ; then
      echo -e "   [ \033[31m\033[1mError\033[m ] $*"
   else
      echo "   [ Error ] $*"
   fi
   echo ""
}

warn (){
   if $LOGGING || $terminal ; then
      echo ""
      if $terminal ; then
         echo -e "   [ \033[33m\033[1mWarn\033[m ]  $*"
      else
         echo "   [ Warn ]  $*"
      fi
      echo ""
   fi
}

info (){
   if $LOGGING || $terminal ; then
      echo ""
      if $terminal ; then
         echo -e "   [ \033[32m\033[1mInfo\033[m ]  $*"
      else
         echo "   [ Info ]  $*"
      fi
      echo ""
   fi
}

ok (){
   if $LOGGING || $terminal ; then
      echo ""
      if $terminal ; then
         echo -e "   [ \033[32m\033[1mOk\033[m ]    $*"
      else
         echo "   [ Ok ]    $*"
      fi
      echo ""
   fi
}
echo_done() {
   if $terminal ; then
      echo -e "\033[75G[ \033[32mdone\033[m ]"
   fi
}
echo_ok() {
   if $terminal ; then
      echo -e "\033[75G[ \033[32mok\033[m ]"
   fi
}
echo_warn() {
   if $terminal ; then
      echo -e "\033[75G[ \033[33mwarn\033[m ]"
   fi
}
echo_failed(){
   if $terminal ; then
      echo -e "\033[75G[ \033[1;31mfailed\033[m ]"
   fi
}
echo_skipped() {
   if $terminal ; then
      echo -e "\033[75G[ \033[90m\033[1mskipped\033[m ]"
   fi
}
echo_wait(){
   if $terminal ; then
      echo -en "\033[75G[ \033[5m\033[1m...\033[m ]"
   fi
}

trim() {
    local var="$*"
    var="${var#"${var%%[![:space:]]*}"}"   # remove leading whitespace characters
    var="${var%"${var##*[![:space:]]}"}"   # remove trailing whitespace characters
    echo -n "$var"
}

blank_line() {
   if $terminal ; then
      echo ""
   fi
}


# ----------
# - Jobhandling
# ----------

# - Run 'clean_up' for signals SIGHUP SIGINT SIGTERM
# -
trap clean_up SIGHUP SIGINT SIGTERM

# - Create lock directory '$LOCK_DIR"
#
mkdir "$LOCK_DIR"


# ----------
# - Some checks ..
# ----------

# - Running in a terminal?
# -
if [[ -t 1 ]] ; then
   terminal=true
else
   terminal=false
fi


# ----------
# - Headline
# ----------

if $terminal ; then
   echo ""
   echo -e "\033[1m----------\033[m"
   echo -e "\033[32m\033[1mRunning script \033[m\033[1m$script_name\033[32m .. \033[m"
   echo -e "\033[1m----------\033[m"
   echo ""
fi


echononl "Enable IPv6 on this machine.."

output="$(ip -6 addr 2> $log_file)"
if [[ $? -ne 0 ]] ; then
   echo_failed
   error "Executing command 'ip -6 addr' failed!\n\nThe Error was:\n$(cat "$log_file")"
elif [[ -n "$output" ]] ; then
   echo_skipped
   warn "IPv6 is already enabled."
else
   sysctl -w net.ipv6.conf.all.disable_ipv6=0 > /dev/null 2> $log_file
   if [[ $? -ne 0 ]] ; then
      echo_failed
      error "Cannot set kernel parameter 'net.ipv6.conf.all.disable_ipv6'\n\nThe Error was:\n$(cat "$log_file")"
      clean_up 1
   fi

   sysctl -w net.ipv6.conf.default.disable_ipv6=0 > /dev/null 2> $log_file
   if [[ $? -ne 0 ]] ; then
      echo_failed
      error "Cannot set kernel parameter 'net.ipv6.conf.default.disable_ipv6'\n\nThe Error was:\n$(cat "$log_file")"
      clean_up 1
   fi

   sysctl -w net.ipv6.conf.lo.disable_ipv6=0  > /dev/null 2> $log_file
   if [[ $? -ne 0 ]] ; then
      echo_failed
      error "Cannot set kernel parameter 'net.ipv6.conf.default.disable_ipv6'\n\nThe Error was:\n$(cat "$log_file")"
      clean_up 1
   fi
   echo_ok
fi

# ----------
# One method to make this option persist is modifying /etc/sysctl.conf.
#
#  net.ipv6.conf.all.disable_ipv6=0
#  net.ipv6.conf.default.disable_ipv6=0
#  net.ipv6.conf.lo.disable_ipv6=0
#
# For the settings to take effect use:
#
#  sudo sysctl -p
#
# If IPv6 is still enabled after rebooting, you must create (with root 
# privileges) the file /etc/rc.local and fill it with:
#
#  #!/bin/bash
#  # /etc/rc.local
#
#  /etc/sysctl.d
#  /etc/init.d/procps restart
#
#  exit 0
#
# Now use chmod command to make the file executable:
#
# chmod 755 /etc/rc.local
# ----------

clean_up 0