#!/bin/bash
# we depend on a properly build rootfs
if [ "$EUID" -ne 0 ]
then echo "Please run as root"
    exit
fi


CHIBRAX_MOUNT_POINT="/tmp/chibraxMountPoint"

rm -f disk.img

#create a 8Gb iso
dd if=/dev/zero of=disk.img bs=1024k seek=$((1000 * 8)) count=0

#creating a msdos image for mbr boot
parted disk.img mklabel msdos
parted disk.img mkpart primary ext4 0% 100%
START_SECTOR=$(file disk.img | cut -d',' -f 8 | cut -d' ' -f3)
echo "Start sector :" $START_SECTOR
OFFSET=$((512*$START_SECTOR))

echo $OFFSET > diskoffset

losetup --offset $OFFSET -f disk.img
LOOP=$(losetup -a | grep -v deleted | cut -d':' -f 1)

losetup -f disk.img
LOOP_ROOT=$(losetup -a | grep -v deleted | grep -v ${LOOP} | cut -d':' -f 1)

mkdir $CHIBRAX_MOUNT_POINT -p

mkfs.ext4 ${LOOP}
mount ${LOOP} $CHIBRAX_MOUNT_POINT

echo "rebuilding C++ hooks"
./clibs.sh
echo "done"

echo "coping rootfs"
cp rootfs/* $CHIBRAX_MOUNT_POINT -r
echo "done"

echo "installing grub"
mount --rbind /dev /mnt/mychroot/dev
mount --make-rslave /mnt/mychroot/dev
mount -t proc /proc /mnt/mychroot/proc
mount --rbind /sys /mnt/mychroot/sys
mount --make-rslave /mnt/mychroot/sys
mount --rbind /tmp /mnt/mychroot/tmp

chroot $CHIBRAX_MOUNT_POINT grub-install --target=i386-pc ${LOOP_ROOT} --modules=part_msdos
chroot $CHIBRAX_MOUNT_POINT grub-mkconfig -o /boot/grub/grub.cfg

umount /mnt/mychroot/dev
umount /mnt/mychroot/proc
umount /mnt/mychroot/sys
umount /mnt/mychroot/tmp

PARTUUID=$(lsblk $LOOP --fs | awk '{print $4}' | grep -v LABEL)

echo "menuentry 'Chibrax OS' {"                                        >> $CHIBRAX_MOUNT_POINT/boot/grub/grub.cfg
echo "    set root='hd0,msdos1'"                                       >> $CHIBRAX_MOUNT_POINT/boot/grub/grub.cfg
echo "    linux /boot/vmlinuz rootfstype=ext4 root=/dev/sda1 rw quiet" >> $CHIBRAX_MOUNT_POINT/boot/grub/grub.cfg
echo "}"                                                               >> $CHIBRAX_MOUNT_POINT/boot/grub/grub.cfg

umount $CHIBRAX_MOUNT_POINT
losetup -d $LOOP_ROOT
losetup -d $LOOP
#built by root but used by any, usefull to run the vm without root privileges
chmod 757 disk.img