#!/bin/bash
#
# Destroys /dev/sda
#
set -e

[[ -z $1 ]] && echo target hostname? && exit 1
sshhost=$1

[[ ! -f slackstart.conf ]] && echo setup slackstart.conf first && exit 1
. ./slackstart.conf
[[ -z $mirror ]] && echo define \$mirror in slackstart.conf && exit 1
[[ -z $pubkeys ]] && echo define \$pubkeys in slackstart.conf && exit 1

[[ ! -x `which fdisk` ]] && echo fdisk not found && exit 1
[[ ! -x `which sfdisk` ]] && echo sfdisk not found && exit 1
[[ ! -x `which head` ]] && echo head not found && exit 1
[[ ! -x `which awk` ]] && echo awk not found && exit 1

function diskprep {

total=`fdisk -l /dev/sda | head -1 | awk '{print $7}'`

#2048 * 512 = 1048576
echo -n writing sda.sfdisk...
cat > sda.sfdisk <<EOF && echo done
label: dos
label-id: 0x8ae$((RANDOM % 10))$((RANDOM % 10))3cc
device: sda
unit: sectors

/dev/sda1 : start=2048, size=$((total-1048576-2048)), type=83, bootable
/dev/sda2 : start=$((total-1048576)), size=1048576, type=ef
EOF

echo -n applying sda.sfdisk...
sfdisk /dev/sda < sda.sfdisk

echo
echo -n partprobe...
partprobe /dev/sda && echo done
echo

fdisk -l /dev/sda
echo
echo everything fine? \(y/n\)
echo
read input
[[ $input != y ]] && exit 1
unset input

#self verbose
echo formatting sda1
mkfs.ext4 -F /dev/sda1

mkdir -p lala/
mount /dev/sda1 lala/
mkdir lala/proc/
mount -o bind /proc lala/proc
}


function sysboot {

echo -n writing lala/etc/fstab...
cat > lala/etc/fstab <<-EOF && echo done
/dev/sda1        /                ext4        defaults         1   1
devpts           /dev/pts         devpts      gid=5,mode=620   0   0
proc             /proc            proc        defaults         0   0
tmpfs            /dev/shm         tmpfs       defaults         0   0
EOF
echo ''

echo -n HOSTNAME $sshhost...
echo $sshhost > lala/etc/HOSTNAME && echo done
echo ''

echo -n ssh pubkeys...
mkdir -p lala/root/.ssh/
cat > lala/root/.ssh/authorized_keys <<EOF && echo done
$pubkeys
EOF
chmod 700 lala/root/.ssh/
chmod 600 lala/root/.ssh/authorized_keys

#we want to trust he right curve algo on first connection
echo -n edwards only...
mv -i lala/etc/ssh/sshd_config lala/etc/ssh/sshd_config.dist
grep -vE '^[[:space:]]*(#|$)' lala/etc/ssh/sshd_config.dist > lala/etc/ssh/sshd_config
cat >> lala/etc/ssh/sshd_config <<EOF && echo done

HostKey /etc/ssh/ssh_host_ed25519_key

EOF

#
# BIOS
#
echo PREPARING BIOS BOOT
echo ''

echo -n preparing lilo.conf...
sed -rn '1,/^vga/p' lala/etc/lilo.conf_example > lala/etc/lilo.conf.clean
sed -r '
	/^[[:space:]]*(#|$)/d;
	/^timeout =/d;
	/^vga =/d;
	' lala/etc/lilo.conf.clean > lala/etc/lilo.conf
cat >> lala/etc/lilo.conf <<EOF && echo done
timeout = 50
vga = 791
image = /boot/vmlinuz
        label = "Linux"
        read-only
EOF
echo running lilo into chroot
chroot lala/ /sbin/lilo

echo -n un-mounting lala recursively...
umount -R lala/ && echo done
echo ''

#
# EFI
#
echo PREPARING EFI BOOT
echo ''

echo creating vfat
mkfs.vfat /dev/sda2 && echo done

echo -n mounting EFI...
mkdir -p efi/
mount /dev/sda2 efi/ && echo done
mkdir -p efi/EFI/boot/

echo -n copying efi/EFI/boot/BOOTX64.EFI...
cp BOOTX64.EFI efi/EFI/boot/ && echo done

echo -n writing efi/EFI/boot/grub.cfg...
cat > efi/EFI/boot/grub.cfg <<EOF && echo done
set default=0
set timeout=5

menuentry "Linux" {
	insmod ext2
	set root=(hd0,msdos1)
	linux /boot/vmlinuz root=/dev/sda1 ro ipv6.disable=1 vt.default_utf8=0 mitigations=off
}
EOF

echo -n un-mounting EFI...
umount efi/ && echo done
cat <<EOF

we are all good.  you are ready to reboot
(unless you made some changes to that script and wanna keep a copy of it)

	mount /dev/sda1 lala/
	cp slackstart.bash lala/
	cp slackstrap.bash lala/
	umount lala/

EOF

echo
}

if [[ $1 = -h ]]; then
	echo 'usage: ${0##*/} <target hostname> [boot|full]'
elif [[ $2 = boot ]]; then
	sysboot
elif [[ $2 = full ]]; then
	diskprep
	./slackstrap.bash lala/ $mirror full
	sysboot
else
	diskprep
	./slackstrap.bash lala/ $mirror
	sysboot
fi