#!/bin/bash
#
# Original version by Marcel Sackermann 2017-03-06
# Patched by Markus Blatt on 2018-10-17 to support
# the patch for kernel version >= 4.18 by phonics
# from 2018-10-09
kv=$(uname -r | grep -Po '^[0-9]\.[0-9]+(\.[1-9]+)?')
IFS='.' read -ra kv_numbers <<< "$kv"
linux_dir="linux-$kv"
alx_driver_path="drivers/net/ethernet/atheros/alx"
dkms_dir="/usr/src/alx-$kv"
deb_dependencies="git patch dkms"

get_linux_source() {
  if [ ! -d $linux_dir ]; then
    
    echo "Downloading kernel source for $kv by git..."
    git clone --depth 1 -b "v$kv" git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git "linux-$kv"
    if [ $? != 0 ]; then
      echo "git failed to download the source. Check the output for information."
      exit 1
    else
      echo "Done"
      return 0
    fi
  else
    if [ ! -d $linux_dir/$alx_driver_path ]; then
      echo "Git refuses clone into an non empty directory but '$linux_dir' exists and does not contain the driver source that should be located at '$linux_dir/$alx_driver_path'. Please delete or move the directory yourself so git may download the source."
      exit 1
    fi
  fi
}

get_deps() {
  echo "Checking dependencies..."
  for i in $deb_dependencies; do
    which $i > /dev/null
    if [ $? != 0 ];then
      if [ -f /etc/debian_version ]; then
        echo "installing dependencies... ($deb_dependencies)"
        sudo apt-get install $deb_dependencies
        if [ $? != 0 ]; then
          echo "Could not install dependencies. Check the output for information."
          exit 1
        fi
      else
        echo "Please make sure you have the following dependencies installed: $deb_dependencies"
        exit 1
      fi
    fi
  done
  echo "Done"
  return 0
}

prepare_src() {
  echo "Preparing dkms module source..."
  patch="000-enable-alx-wol.patch"
  offset=8
  # newer patch for kernel 5.15 and up
  if [ "${kv_numbers[0]}" -ge 5 ] && [ "${kv_numbers[1]}" -ge 15 ]; then
    echo "Using 5.16 patch..."
    patch="000-enable-alx-wol-5.16.patch"
    offset=6
  # newer patch for kernel 5.10 and up
  elif [ "${kv_numbers[0]}" -ge 5 ] && [ "${kv_numbers[1]}" -ge 10 ]; then
    echo "Using 5.10 patch..."
    patch="000-enable-alx-wol-5.10.patch"
    offset=6
  # newer patch for kernel 5.4 and up
  elif [ "${kv_numbers[0]}" -ge 5 ] && [ "${kv_numbers[1]}" -ge 4 ]; then
    echo "Using 5.4+ patch..."
    patch="000-enable-alx-wol-5.4.x.patch"
    offset=6
  # newer patch for kernel 4.18 and up
  elif [ "${kv_numbers[0]}" -ge 4 ] && [ "${kv_numbers[1]}" -ge 18 ] || [ "${kv_numbers[0]}" -ge 5 ] && [ "${kv_numbers[1]}" -lt 4 ]; then
    echo "Using 4.18+ patch..."
    patch="000-enable-alx-wol-4.18.patch"
    offset=6
  # newer patch for kernel 4.9 and up
  elif [ "${kv_numbers[0]}" -ge 4 ] && [ "${kv_numbers[1]}" -ge 9 ] && [ "${kv_numbers[1]}" -lt 18 ]; then
    echo "Using 4.9+ patch..."
    patch="000-enable-alx-wol-4.9.patch"
    offset=5
  fi

  if [ -d "$dkms_dir/src" ]; then sudo rm -Rf $dkms_dir/src; fi

  sudo mkdir -p $dkms_dir/src &&
    sed "s|KERNEL_VERSION|$kv|g" dkms.conf | sudo tee $dkms_dir/dkms.conf > /dev/null &&
    sudo cp $linux_dir/$alx_driver_path/* $dkms_dir/src &&
    sudo patch -d $dkms_dir/src -V never -r - -t -s -N -p$offset < "$patch" &&
    echo "Done"
}

dkms_remove(){
  if /usr/sbin/dkms status | grep alx ; then
    echo "uninstalling dkms module"
    sudo /usr/sbin/dkms remove alx/$kv --all
  fi
}

dkms_add() {
  echo "Adding dkms module alx/$kv"
  sudo dkms add alx/$kv
  status=$?
  if [ $status != 0 ] && [ $status != 3 ]; then
    echo "something went wrong. Check the output for information."
  elif [ $status != 0 ]; then
    if [ $status = 3 ]; then
      echo "Seems the dkms module is already enabled. Don't worry about that error."
    fi
    echo "Done"
    return 0
  fi
}

get_deps && get_linux_source && prepare_src && dkms_remove && dkms_add && sudo dkms autoinstall alx/$kv && sudo update-initramfs -u
if [ "$?" != "0" ]; then
  echo "!!! there is some error"
else
  echo "all ok, now you may need reboot"
fi