#!/bin/bash

### installer for nanodesk
### By: DeltaLima 2023
### 
### this is just a hobby, nothing serious. i know the debian installer and other
### exist, but i wanted to try some handcrafted installation.


CHROOTCMD="chroot /mnt/"

message () {
  echo "== " $1
}

error () {
  message "ERROR!"
  exit 1
}

finish () {
  message "removing installer files from target"
  $CHROOTCMD /usr/bin/rm -Rf /root/install_nanodesk.sh /root/kernel_deb || error
  message "removing live-packages from target"
  $CHROOTCMD /usr/bin/apt -y purge 'live-boot*' 'live-tools*'
  message "autoremove unneeded dependencies"
  $CHROOTCMD /usr/bin/apt -y autoremove
  message "we are now ready to boot from $target"
  exit 0
}

if [ "$1" == "--help" ] || [ -z "$1" ] 
then
  echo "Usage: $0 [OPTION] TARGETDEVICE
Example: $0 /dev/sda1

TARGETDEVICE: blockdevice already formatted with filesystem like ext4

Options:
  --help: Show this helptext

  $0 trys to install grub into the mbr of the given targetdevice.
  We simply cut the last character away from the targetdevice,
  so /dev/sda1 gets /dev/sda, where grub will be installed."
  exit 1
fi

target="$1"
if [ ! -b "$target" ]
then
  message "$target does not exist or is not a blockdevice."
  error
fi

message "Make sure you have a linux compatible filesystem at $target"
message "!! The installer immediately begins to write things to disk !!"
message "!! The installer only works reliable with legacy BIOS boot  !!"
message
message "I will mount $target to /mnt/. I try to install grub to ${target::-1}"
message
message "Are you sure to install nanodesk to $target?"
message "To continue type 'YES' and enter, to cancel type anything else or CTRL+C"

read -p "> " DOINSTALL
test "$DOINSTALL" == "YES" || error

message "... GOOD LUCK!"
message "mounting $target to /mnt/"
mount $target /mnt || error

message "copy systemfiles"
rsync -aHx / /mnt/ || error

message "bind mount dev proc sys"
for m in dev proc sys
do
	mount -o bind /$m /mnt/$m || error
done

message "creating /boot directory"
mkdir -p /mnt/boot/ || error

message "create tmp script for reinstalling grub and kernel"
echo "DEBIAN_FRONTEND=noninteractive
export DEBIAN_FRONTEND
/usr/bin/apt --yes purge 'linux-image-*' 'grub-*'
#/usr/bin/apt --yes install 'linux-image-amd64' 'grub-pc'
/usr/bin/dpkg -i /root/kernel_deb/*.deb" > /mnt/tmp/reinstall_kernel.sh

message "install kernel and grub"
$CHROOTCMD /bin/bash /tmp/reinstall_kernel.sh || error

message "grub-install $target"
$CHROOTCMD grub-install ${target::-1} || error

message "create initramfs"
$CHROOTCMD /usr/sbin/update-initramfs.orig.initramfs-tools -k all -c || error

message "update-grub"
$CHROOTCMD /usr/sbin/update-grub || error

message "create fstab"
echo "UUID=$(blkid -o value -s UUID $target) / $(blkid -o value -s TYPE $target) defaults 0 1" >> /mnt/etc/fstab

message "activating swap if present in fstab"
SWAP="$(blkid -o list | grep swap | awk '{print $5}')"
test -n "$SWAP" && echo "UUID=$SWAP none swap defaults 0 0" >> /mnt/etc/fstab 

message "Cleanup and create own [U]ser or [K]eep everything as it is?"
read -p "> " USERSTEP

STEPFINISH=0
while [ $STEPFINISH != 1 ]
do
  case $USERSTEP in
    u|U)
      message "please change root pw"
      $CHROOTCMD /usr/bin/passwd root || error

      message "deleting user 'debian'"
      $CHROOTCMD /usr/bin/id -u debian && $CHROOTCMD /usr/sbin/userdel -f debian || error

      message "removing user 'debian' from sudoers"
      $CHROOTCMD /usr/bin/sed -i '/^debian/d' /etc/sudoers || error

      message "please enter a name for a new user"
      read -p "> " NEWUSER
      $CHROOTCMD /usr/sbin/adduser $NEWUSER || error

      message "adding $NEWUSER to sudo group"
      $CHROOTCMD /usr/sbin/usermod -G sudo $NEWUSER || error
      $CHROOTCMD /usr/bin/ln -s -f /usr/share/nanodesk/pixmaps/nanodesk-installed.xpm /usr/share/nanodesk/pixmaps/nanodesk.xpm || error
      $CHROOTCMD /usr/bin/ln -s -f /usr/share/nanodesk/pixmaps/nanodesk-bw-installed.xpm /usr/share/nanodesk/pixmaps/nanodesk-bw.xpm || error
      
      STEPFINISH=1
      
      ;;
    k|K)
      finish
      ;;
  esac
done

finish