#!/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"


# ----------
# Base Function(s)
# ----------

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
   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_failed(){
   if $terminal ; then
      echo -e "\033[75G[ \033[1;31mfailed\033[m ]"
   fi
}
echo_skipped() {
   if $terminal ; then
      echo -e "\033[75G[ \033[33m\033[1mskipped\033[m ]"
   fi
}
echo_wait(){
   if $terminal ; then
      echo -en "\033[75G[ \033[5m\033[1m...\033[m ]"
   fi
}

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

detect_os () {

   if $(which lsb_release > /dev/null 2>&1) ; then

      os_dist="$(lsb_release -i | awk '{print tolower($3)}')"
      os_version="$(lsb_release -r | awk '{print tolower($2)}')"
      os_codename="$(lsb_release -c | awk '{print tolower($2)}')"

      if [[ "$os_dist" = "debian" ]]; then
         if $(echo "$os_version" | grep -q '\.') ; then
            os_version=$(echo "$os_version" | cut --delimiter='.' -f1)
         fi
      fi

   elif [[ -e "/etc/os-release" ]]; then

      . /etc/os-release

      os_dist=$ID
      os_version=${VERSION_ID}

   fi

   # remove whitespace from os_dist and os_version
   os_dist="${os_dist// /}"
   os_version="${os_version// /}"

}

# ----------
# - 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

# - Detedt Os
# -
detect_os
if [[ "${os_dist,,}" != ubuntu ]] ; then
	fatal "Linux Distribution '${os_dist}' is NOT supported (only Ubuntu). Exiting now ..!"
fi

# - Give your default values here
# -
LOGGING=false
BATCH_MODE=false



# ==========
# - Begin Main Script
# ==========

# ----------
# - 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"
fi


# ----------
# - Some pre-script tasks ..
# ----------

if $terminal ; then
   echo ""
   echo ""
   echo -e "   \033[1mDoing some pre-script tasks ..\033[m"
   echo ""
fi

echononl "Detecting not fully deinstalled kernel packages (rc).."

rc_kernel_pakages="$(dpkg -l linux* | grep -E "^rc" | awk '{print$2}')"

if [[ $? -eq 0 ]] ; then
	echo_ok
elif [[ -z "$rc_kernel_pakages" ]]; then
   echo_ok
else
	echo_failed
	fatal "Detecting not fully deinstalled kernel packages failed."
fi

blank_line
echononl "Get actual used kernel version.."
kernel_version="$(uname -r | grep -o -E "^[[:digit:]]{1}\.[[:digit:]]{1,3}\.[[:digit:]]{1,3}\-[[:digit:]]{1,3}")"
if [[ $? -eq 0 ]] && [[ -n "$kernel_version" ]]; then
   echo_ok
else
   echo_done
fi
   

echononl "Detecting old not used kernels.."
if [[ -f "/var/run/reboot-required" ]]; then
   unused_kernel_pakages=""
   warn "Reboot befor removing unused kernels.."
   echo_skipped
else
   unused_kernel_pakages="$(dpkg -l linux* | grep -E "^ii" | awk '{print$2}' | grep -v "$kernel_version" | grep -E "linux\-(image|modules|headers).*\-[[:digit:]]{1}\.[[:digit:]]{1,3}\.[[:digit:]]{1,3}\-[[:digit:]]{1,3}")"
   if [[ $? -eq 0 ]] ; then
      echo_ok
   elif [[ -z "$unused_kernel_pakages" ]]; then
      echo_ok
   else
      echo_failed
      fatal "Detecting old unused kernel packages failed."
   fi
fi



if $terminal && ! $BATCH_MODE ; then
	echo ""
	echo ""
	echo -e "   \033[32m\033[1mThe following Packages are detected for removing:\033[m"
	echo ""

   echo -e "   \033[1mNot fully deinstalled Packages:\033[m"

   if [[ -z "$rc_kernel_pakages" ]]; then
      echo -e "      \033[33m- No Packages found -\033[m"
   else
      for _package in $rc_kernel_pakages ; do
         echo -e "      ${_package}"
      done
   fi

   echo ""
   echo -e "   \033[1mUnused kernel packages:\033[m"
   if [[ -z "$unused_kernel_pakages" ]]; then
      echo -e "      \033[33m- No Packages found -\033[m"
   else
      for _package in $unused_kernel_pakages ; do
         echo -e "      ${_package}"
      done
   fi

   if [[ -z "$rc_kernel_pakages" ]] && [[ -z "$unused_kernel_pakages" ]] ; then
      info "No package for deletion found."
      clean_up 0
   fi

    echo ""

   if [[ -n "$rc_kernel_pakages" ]]; then
      echononl "Remove not fully deinstalled kernel packages? [\033[1myes/no\033[m]: "
      read OK
      while [[ "${OK,,}" != "yes" ]] && [[ "${OK,,}" != "no" ]] ; do
         echononl "\033[33mWrong entry!\033[m [\033[1myes/no\033[m]: "
         read OK
      done
      [[ "${OK,,}" = "yes" ]] || rc_kernel_pakages=""
   fi

   if [[ -n "$unused_kernel_pakages" ]]; then
      echononl "Remove unsed kernel packages? [\033[1myes/no\033[m]: "
      read OK
      while [[ "${OK,,}" != "yes" ]] && [[ "${OK,,}" != "no" ]] ; do
         echononl "\033[33mWrong entry!\033[m [\033[1myes/no\033[m]: "
         read OK
      done
      [[ "${OK,,}" = "yes" ]] || unused_kernel_pakages=""
   fi

fi

blank_line
echononl "Removing not fully deinstalled kernel packages.."
if [[ -z "$rc_kernel_pakages" ]] ; then
   echo_skipped
else
   echo_wait
   apt-get remove --purge -y $rc_kernel_pakages > $log_file 2>&1
   if [[ $? -eq 0 ]] ; then
      echo_ok
   else
      echo_failed
      error "$(cat "$log_file")"
      fatal "Removing not fully deinstalled kernel packages failed."
   fi
fi

echononl "Removing unsed kernel packages.."
if [[ -z "$unused_kernel_pakages" ]] ; then
   echo_skipped
else
   echo_wait
   apt-get remove --purge -y $unused_kernel_pakages > $log_file 2>&1
   if [[ $? -eq 0 ]] ; then
      echo_ok
   else
      echo_failed
      error "$(cat "$log_file")"
      fatal "Removing unused kernel packages failed."
   fi
fi

echononl "Update grub boot manager.."
update-grub > $log_file 2>&1
if [[ $? -eq 0 ]] ; then
	echo_ok
else
	echo_failed
	error "$(cat "$log_file")"
fi

blank_line
clean_up 0