#!/bin/bash

set -e

if [ "$UID" -ne 0 ]; then
    >&2 echo 'Must be run as root'
    exit 1
fi

if [ -z "$1" ]; then
    >&2 echo "usage: $0 <SQUASHFS>"
    exit 1
fi

VERSION=$(unsquashfs -cat $1 /usr/lib/startos/VERSION.txt)
GIT_HASH=$(unsquashfs -cat $1 /usr/lib/startos/GIT_HASH.txt)
B3SUM=$(b3sum $1 | head -c 32)

if [ -n "$CHECKSUM" ] && [ "$CHECKSUM" != "$B3SUM" ]; then
    >&2 echo "CHECKSUM MISMATCH"
    exit 2
fi

mv $1 /media/startos/images/${B3SUM}.rootfs
ln -rsf /media/startos/images/${B3SUM}.rootfs /media/startos/config/current.rootfs

unsquashfs -n -f -d / /media/startos/images/${B3SUM}.rootfs boot

umount -R /media/startos/next 2> /dev/null || true
umount -R /media/startos/lower 2> /dev/null || true
umount -R /media/startos/upper 2> /dev/null || true

rm -rf /media/startos/lower /media/startos/upper /media/startos/next
mkdir /media/startos/upper
mount -t tmpfs tmpfs /media/startos/upper
mkdir -p /media/startos/lower /media/startos/upper/data /media/startos/upper/work /media/startos/next
mount /media/startos/images/${B3SUM}.rootfs /media/startos/lower
mount -t overlay \
  -olowerdir=/media/startos/lower,upperdir=/media/startos/upper/data,workdir=/media/startos/upper/work \
  overlay /media/startos/next
mkdir -p /media/startos/next/media/startos/root
mount --bind /media/startos/root /media/startos/next/media/startos/root
mkdir -p /media/startos/next/dev
mkdir -p /media/startos/next/sys
mkdir -p /media/startos/next/proc
mkdir -p /media/startos/next/boot
mount --bind /dev /media/startos/next/dev
mount --bind /sys /media/startos/next/sys
mount --bind /proc /media/startos/next/proc
mount --bind /boot /media/startos/next/boot

chroot /media/startos/next update-grub2

umount -R /media/startos/next
umount -R /media/startos/upper
umount -R /media/startos/lower
rm -rf /media/startos/lower /media/startos/upper /media/startos/next

sync

reboot