#!/bin/sh
set -e

IMAGE_NAME="anthrill.iso"
ROOTFS_DIR="alpine-rootfs"
MNT_DIR="mnt"

# nix-shell vmtest.nix

if [ ! -f alpine-make-rootfs ]; then
    wget https://raw.githubusercontent.com/alpinelinux/alpine-make-rootfs/v0.8.1/alpine-make-rootfs \
        && echo '2b21327244d2d63082dd4780e22549221e298206  alpine-make-rootfs' | sha1sum -c \
        || exit 1
    chmod +x alpine-make-rootfs
fi


./alpine-make-rootfs \
    --branch v3.22 \
    --packages 'linux-lts linux-firmware grub efibootmgr mkinitfs e2fsprogs dosfstools bash' \
    --timezone 'Europe/Moscow' \
    "$ROOTFS_DIR"

rm -f "$ROOTFS_DIR/sbin/init"
install -Dm755 ../target/release/x86_64-linux-musl/init "$ROOTFS_DIR/sbin/init"

cat > "$ROOTFS_DIR/etc/fstab" <<EOF
# <file system>        <mount point>  <type>  <options>         <dump>  <pass>
/dev/sda2              /              ext4    defaults          0       1
/dev/sda1              /boot/efi      vfat    umask=0077        0       2
EOF


KERNEL_VERSION=$(ls "$ROOTFS_DIR/lib/modules/" | grep -E '^[0-9]+\.' | head -n1)
if [ -z "$KERNEL_VERSION" ]; then
    echo "Err: couldnt find kernel dir in $ROOTFS_DIR/lib/modules/"
    exit 1
fi

mkdir -p "$MNT_DIR/root" "$MNT_DIR/boot"

dd if=/dev/zero of="$IMAGE_NAME" bs=1M count=512
sfdisk "$IMAGE_NAME" <<EOF
label: gpt
device: $IMAGE_NAME
unit: sectors

start=2048, size=204800, type=C12A7328-F81F-11D2-BA4B-00A0C93EC93B, name="EFI System Partition"
start=206848, size=, type=0FC63DAF-8483-4772-8E79-3D69D8477DE4, name="Linux filesystem"
EOF

LOOP_DEV=$(sudo losetup --find --show --partscan "$IMAGE_NAME")
BOOT_PART="${LOOP_DEV}p1"
ROOT_PART="${LOOP_DEV}p2"


mkfs.vfat -F 32 "$BOOT_PART"
mkfs.ext4 "$ROOT_PART"


mount "$ROOT_PART" "$MNT_DIR/root"
mount "$BOOT_PART" "$MNT_DIR/boot"
cp -a "$ROOTFS_DIR"/* "$MNT_DIR/root/"
mkdir -p "$MNT_DIR/root/boot/efi"
mount --bind "$MNT_DIR/boot" "$MNT_DIR/root/boot/efi"

chroot "$MNT_DIR/root" mkinitfs "$KERNEL_VERSION"

mkdir -p "$MNT_DIR/root/boot/grub"
cat > "$MNT_DIR/root/boot/grub/grub.cfg" <<GRUBCFG
insmod part_gpt
insmod fat
insmod efi_gop
insmod efi_uga

set timeout=3
menuentry "Anthrill OS" {
    linux /vmlinuz-${KERNEL_VERSION} root=/dev/sda2 ro quiet
    initrd /initramfs-${KERNEL_VERSION}
}
GRUBCFG

grub-install --target=x86_64-efi \
    --efi-directory="$MNT_DIR/boot" \
    --boot-directory="$MNT_DIR/root/boot" \
    --removable \
    --no-nvram \
    --bootloader-id=anthrill

umount "$MNT_DIR/root/boot/efi"
umount "$MNT_DIR/boot"
umount "$MNT_DIR/root"
losetup -d "$LOOP_DEV"

echo "Running qemu"
qemu-system-x86_64 \
    -machine q35,accel=kvm:tcg \
    -cpu host \
    -m 1G \
    -bios /usr/share/edk2-ovmf/OVMF_CODE.fd \
    -drive file="$IMAGE_NAME",format=raw,if=virtio \
    -net nic -net user