#!/bin/bash

export LC_ALL=C
export LANG=C
export LANGUAGE=C

if [ "$(id -u)" != "0" ]
then
  echo 'You must have root privileges to use this.'
  exit
fi

ping -c 1 8.8.8.8 > /dev/null 2>&1
if [ $? != 0 ]
then
  echo 'No connection to Internet. Can not continue.'
  exit
fi

echo ''
echo 'This is a script to install slimmed Ubuntu LTS.'

### CREATE ROOT PARTITION

echo ''
echo 'List of found disks:'
for D in $(ls /dev/sd[a-z])
do
  fdisk -l $D | head -2 | sed 's/^Disk //' | sed -z 's/sectors\n/sectors, /'
done
echo ''
echo 'Select a disk to install Ubuntu on, for example sda, sdb or sdc:'
read -i sd -e ROOTDISK
if [ ! -e /dev/$ROOTDISK ]
then
  echo ''
  echo "Device $ROOTDISK does not exist."
  exit
fi
echo ''
echo 'Here are existing partitions on this disk:'
fdisk -l /dev/$ROOTDISK | grep --color=never -E '^Device|^\/dev'
echo ''
echo 'Would you like to use whole disk for root partition?'
echo 'If so, print yes. This will create totally new partition table.'
echo "To use existing partition, print it's number, for example 2 :"
read -e PARTNUM;
if [ "$PARTNUM" = "yes" ]
then
  echo ''
  ROOTPART="$ROOTDISK"1
  dd if=/dev/zero of=/dev/$ROOTDISK count=2048
  (echo o; echo n; echo ""; echo ""; echo ""; echo ""; echo a; echo p; echo w) | fdisk /dev/$ROOTDISK
elif [ ! -e /dev/$ROOTDISK$PARTNUM ]
then
  echo ''
  echo 'Partition was not found.'
  echo 'Use cfdisk to manually create partition and rerun this installer.'
  exit
else
  ROOTPART=$ROOTDISK$PARTNUM
  dd if=/dev/zero of=/dev/$ROOTDISK seek=1 count=2047
  (echo a; echo $PARTNUM; echo p; echo w) | fdisk /dev/$ROOTDISK
fi

### FORMAT ROOT

yes | mkfs.ext4 "/dev/$ROOTPART"
mount "/dev/$ROOTPART" /mnt

### DOWNLOAD AND UNPACK UBUNTU BASE

cd /tmp
wget https://cdimage.ubuntu.com/ubuntu-base/releases/24.04/release/SHA256SUMS
TAR=$(cut -d '*' -f 2 SHA256SUMS | grep amd64 | tail -1)
wget https://cdimage.ubuntu.com/ubuntu-base/releases/24.04/release/$TAR
tar -xf $TAR -C /mnt
if [ $? -ne 0 ]
then
  echo 'Error: Can not download Ubuntu base archive.'
  umount "/dev/$ROOTPART"
  exit
fi

### CREATE SWAP, FSTAB AND RESOLV.CONF

echo "/dev/$ROOTPART / ext4 defaults 0 1" > /mnt/etc/fstab

fallocate -l 2G /mnt/swapfile
chmod 0600      /mnt/swapfile
mkswap          /mnt/swapfile
echo  '/swapfile none swap defaults 0 0' >> /mnt/etc/fstab

echo 'nameserver 9.9.9.9' > /mnt/etc/resolv.conf

### PREPARE TO CHROOT

mount --bind /dev /mnt/dev
mount --bind /tmp /mnt/tmp
mount --bind /run /mnt/run
mount -t proc proc /mnt/proc
mount -t sysfs none /mnt/sys
mount -t devpts -o noexec,nosuid devpts /mnt/dev/pts

### WRITE CHROOT SCRIPT
# What happens here:
#  unminimize base system
#  install minimal set of desktop needed packages
#  configure grub2
#  set hostname
#  add user
#  add a couple of sane fixes
#  add nonsnap firefox repository
#  configure user session

cat << 'EOF' > /mnt/continue_install
rm /etc/dpkg/dpkg.cfg.d/excludes
rm /etc/update-motd.d/60-unminimize
rm /usr/local/sbin/unminimize
rm /usr/bin/man
dpkg-divert --remove --no-rename /usr/bin/man

apt update
apt install --reinstall -y $(dpkg-query -S /usr/share/man | tr -d ',' | sed 's/\: \/usr.*$//')
apt upgrade -y

DEBIAN_FRONTEND=noninteractive apt install -y \
  apt-utils dialog locales man-db keyboard-configuration systemd init grub2 \
  initramfs-tools linux-base linux-generic linux-image-generic zstd tzdata  \
  fdisk iproute2 inetutils-ping network-manager wget pulseaudio alsa-utils  \
  bc less nvi ncal sed pciutils xserver-xorg xinit x11-xserver-utils xterm fluxbox

dpkg-reconfigure tzdata

echo ''
echo 'Would you like to set specific boot options for GRUB?'
echo 'If so, print them here. Leave the line blank if no specific options needed.'
read GRUBOPTS

sed -i -e 's/^GRUB_CMDLINE_LINUX_DEFAULT=.*$/GRUB_CMDLINE_LINUX_DEFAULT="'"$GRUBOPTS"'"/' \
       -e 's/^GRUB_TIMEOUT_STYLE=.*$/GRUB_TIMEOUT_STYLE=menu/' \
       -e 's/^GRUB_TIMEOUT=0/GRUB_TIMEOUT=1/' \
       -e 's/^\#GRUB_TERMINAL=.*$/GRUB_TERMINAL=console/' /etc/default/grub
grub-mkconfig -o /boot/grub/grub.cfg
grub-install $(head -1 /etc/fstab | cut -d ' ' -f 1 | rev | cut -c 2- | rev)

echo ''
echo 'Set hostname:'
read -i "ubuntu" -e HOSTNAME
echo "$HOSTNAME" > /etc/hostname

echo ''
echo 'Set locale for X11. Console locale will remain en_US:'
read -i "ru_RU" -e LOCALE
if [ "$LOCALE" = "en_US" ]
then
  LOCALE=''
fi
locale-gen en_US.UTF-8 ${LOCALE:+$LOCALE.UTF-8}
localectl set-locale en_US.UTF-8

echo ''
echo 'Set root password:'
passwd
echo ''
echo 'Choose name for regular user:'
read USER
if [ -z "$USER" ]
then
  echo 'Empty name. User will not be created.'
  echo ''
else
  useradd -g root -G operator,sudo -s /bin/bash -m $USER
  passwd -d $USER 1> /dev/null
  echo ''
  echo 'Add tty autologin for this user?'
  read -i "yes" -e ANS
  if [ "$ANS" = "yes" ]
  then
    mkdir /etc/systemd/system/getty\@.service.d
    (echo '[Service]'
     echo 'ExecStart='
     grep '^ExecStart=' /usr/lib/systemd/system/getty\@.service | sed "s/--noclear/--noclear --autologin $USER/" ) \
          > /etc/systemd/system/getty\@.service.d/autologin.conf
  fi
fi

rmdir /*.usr-is-merged
echo 'APT::AutoRemove::SuggestsImportant "false";' > /etc/apt/apt.conf.d/99autoremove # fix autoremoving
echo 'kernel.dmesg_restrict=0' >> /etc/sysctl.conf # allow user to read dmesg

echo 'set ruler'      >> /etc/vi.exrc
echo 'set autoindent' >> /etc/vi.exrc
echo 'set noflash'    >> /etc/vi.exrc

echo 'Section "InputClass"
        Identifier "libinput touchpad catchall"
        Option "Tapping" "on"
EndSection' > /etc/X11/xorg.conf.d/20-touchpad.conf

echo 'network:
 renderer: NetworkManager' > /etc/netplan/config.yaml

wget -O /etc/apt/keyrings/packages.mozilla.org.asc https://packages.mozilla.org/apt/repo-signing-key.gpg
echo "deb [signed-by=/etc/apt/keyrings/packages.mozilla.org.asc] https://packages.mozilla.org/apt mozilla main" \
     > /etc/apt/sources.list.d/mozilla.list
echo -e 'Package: *\nPin: origin packages.mozilla.org\nPin-Priority: 1000' > /etc/apt/preferences.d/mozilla
apt update

if [ "$LOCALE" ]
then
  echo "export LANG=$LOCALE.UTF-8" >> /home/$USER/.xinitrc
  KB=$(echo $LOCALE | sed 's/_.*$//')
  echo "setxkbmap -layout 'us,$KB' -option 'grp:lwin_toggle,grp_led:scroll'" \
				   >> /home/$USER/.xinitrc
fi
echo 'xset r rate 250 34'          >> /home/$USER/.xinitrc
echo 'exec fluxbox'                >> /home/$USER/.xinitrc
chown $USER /home/$USER/.xinitrc

EOF

### RUN INSTALLATION INSIDE CHROOT

chroot /mnt /bin/bash -c "/bin/bash /continue_install"

rm /mnt/continue_install

echo ''
echo 'Installation done.'
echo 'Now you can reboot to installed system or continue by chroot /mnt .'