#!/usr/bin/bash
#
# Copy the running system onto the C630's internal storage.
#
# Run this from the USB-booted image, on the laptop itself:
#
#   sudo ./install-to-disk.sh --dry-run     # show the plan, touch nothing
#   sudo ./install-to-disk.sh               # do it, after confirmation
#
# Why this rather than dd'ing the image at the internal drive:
#
#   * The internal UFS reports 4096-byte logical sectors. The disk image is
#     built with 512-byte sector geometry, so its GPT header and every
#     partition offset would land in the wrong place. Partitioning has to
#     happen natively, on the device, at its own sector size.
#
#   * There are no EFI variables on this machine — efibootmgr reports "EFI
#     variables are not supported on this system" — so nothing can register a
#     boot entry. GRUB has to sit at the removable-media path,
#     EFI/BOOT/BOOTAA64.EFI, where the firmware looks without being told.

set -euo pipefail

TARGET=/dev/sda
ESP_SIZE=1GiB
BOOT_SIZE=1GiB
ASSUME_YES=0
DRY_RUN=0

usage() {
    cat <<EOF
Usage: sudo $0 [options]

  --target DEV     Disk to install onto (default: ${TARGET})
  --esp-size SIZE  EFI system partition (default: ${ESP_SIZE})
  --boot-size SIZE /boot partition (default: ${BOOT_SIZE})
  --dry-run        Print the plan and exit without touching anything
  --yes            Skip the confirmation prompt
  -h, --help       This message

Everything on the target disk is destroyed.
EOF
}

while [ $# -gt 0 ]; do
    case "$1" in
        --target)    TARGET="$2"; shift 2 ;;
        --esp-size)  ESP_SIZE="$2"; shift 2 ;;
        --boot-size) BOOT_SIZE="$2"; shift 2 ;;
        --dry-run)   DRY_RUN=1; shift ;;
        --yes)       ASSUME_YES=1; shift ;;
        -h|--help)   usage; exit 0 ;;
        *) echo "unknown option: $1" >&2; usage >&2; exit 2 ;;
    esac
done

die() { echo "error: $*" >&2; exit 1; }
log() { printf '\n\033[1;34m==> %s\033[0m\n' "$*"; }

[ "$(id -u)" -eq 0 ] || die "must run as root"
[ -b "$TARGET" ]     || die "$TARGET is not a block device"

# nvme0n1 -> nvme0n1p1, sda -> sda1
partdev() { case "$TARGET" in *[0-9]) echo "${TARGET}p$1" ;; *) echo "${TARGET}$1" ;; esac; }
ESP_PART=$(partdev 1); BOOT_PART=$(partdev 2); ROOT_PART=$(partdev 3)

# --- refuse to eat the system we are running from ------------------------
RUNNING_ROOT="$(findmnt -no SOURCE /)"
RUNNING_DISK="/dev/$(lsblk -no pkname "$RUNNING_ROOT" 2>/dev/null || true)"
if [ "$RUNNING_DISK" = "$TARGET" ]; then
    die "$TARGET holds the running root filesystem ($RUNNING_ROOT). Boot the USB image and try again."
fi
while read -r mnt; do
    [ -n "$mnt" ] && die "$TARGET has a mounted partition at $mnt — unmount it first"
done < <(lsblk -nro MOUNTPOINT "$TARGET" | grep -v '^$' || true)

SIZE_H="$(lsblk -dno SIZE "$TARGET")"
SECTOR="$(blockdev --getss "$TARGET")"

cat <<EOF

  Target        ${TARGET}  (${SIZE_H}, ${SECTOR}-byte logical sectors)
  Running from  ${RUNNING_ROOT}

  ${ESP_PART}   ${ESP_SIZE}    fat32  ESP     -> /boot/efi
  ${BOOT_PART}  ${BOOT_SIZE}   ext4   boot    -> /boot
  ${ROOT_PART}  rest           ext4   fedora  -> /

EOF

if [ "$DRY_RUN" = 1 ]; then
    echo "dry run — nothing written"
    exit 0
fi

if [ "$ASSUME_YES" != 1 ]; then
    echo "This destroys everything on ${TARGET}."
    read -rp "Type the target device to confirm: " reply
    [ "$reply" = "$TARGET" ] || die "not confirmed"
fi

MNT=$(mktemp -d /tmp/c630-install.XXXXXX)
cleanup() { umount -R "$MNT" 2>/dev/null || true; rmdir "$MNT" 2>/dev/null || true; }
trap cleanup EXIT

# ---------------------------------------------------------------------------
log "Partitioning ${TARGET}"
# ---------------------------------------------------------------------------
# sgdisk works in the device's own sector size, which is the entire point of
# doing this here rather than in the image.
wipefs -a "$TARGET" >/dev/null
sgdisk --zap-all "$TARGET" >/dev/null
sgdisk \
    --new "1:0:+${ESP_SIZE}"  --typecode 1:ef00 --change-name 1:ESP \
    --new "2:0:+${BOOT_SIZE}" --typecode 2:8300 --change-name 2:boot \
    --new "3:0:0"             --typecode 3:8300 --change-name 3:root \
    "$TARGET" >/dev/null
partprobe "$TARGET" 2>/dev/null || true
udevadm settle
sgdisk --print "$TARGET"

# ---------------------------------------------------------------------------
log "Creating filesystems"
# ---------------------------------------------------------------------------
# Let mkfs.vfat take the device's 4096-byte sectors rather than forcing 512 —
# this firmware booted Windows off this disk, so it reads it natively.
mkfs.vfat -F 32 -n ESP "$ESP_PART" >/dev/null

# orphan_file and metadata_csum_seed are recent ext4 features some GRUB builds
# cannot read, and GRUB has to read /boot.
mkfs.ext4 -q -F -O ^orphan_file,^metadata_csum_seed -L boot   "$BOOT_PART"
mkfs.ext4 -q -F -O ^orphan_file,^metadata_csum_seed -L fedora "$ROOT_PART"

ROOT_UUID=$(blkid -s UUID -o value "$ROOT_PART")
BOOT_UUID=$(blkid -s UUID -o value "$BOOT_PART")
ESP_UUID=$(blkid -s UUID -o value "$ESP_PART")
echo "root=${ROOT_UUID} boot=${BOOT_UUID} esp=${ESP_UUID}"

mount "$ROOT_PART" "$MNT"
mkdir -p "$MNT/boot"
mount "$BOOT_PART" "$MNT/boot"
mkdir -p "$MNT/boot/efi"
mount "$ESP_PART" "$MNT/boot/efi"

# Copy one filesystem's worth of tree, hard links, ACLs and xattrs intact.
# rsync is not in the minimal image and tar is, so tar is the fallback rather
# than the exception. --xattrs-include='*' matters: without it tar drops
# security.selinux, and an unlabelled root does not boot.
copy_tree() {
    local src="$1" dst="$2"
    if command -v rsync >/dev/null; then
        # 24 is "some files vanished while transferring", which is normal when
        # copying a filesystem that is in use.
        rsync -aHAX -x --info=progress2 "$src/" "$dst/" || [ $? -eq 24 ]
        return
    fi

    # This copies a *live* root, so files legitimately change underneath us and
    # tar exits 1 to say so. The clock is also often wrong on this machine
    # (no working RTC), which makes every mtime look like it is in the future.
    # Neither is a reason to abandon the install — but exit 2 is.
    local st
    set +e
    tar --create --file - --one-file-system --numeric-owner \
        --warning=no-timestamp --warning=no-file-changed --warning=no-file-removed \
        --xattrs --xattrs-include='*' --acls --selinux -C "$src" . \
    | tar --extract --file - --numeric-owner \
        --warning=no-timestamp \
        --xattrs --xattrs-include='*' --acls --selinux -C "$dst"
    st=("${PIPESTATUS[@]}")
    set -e
    [ "${st[0]}" -le 1 ] || die "reading ${src} failed (tar exit ${st[0]})"
    [ "${st[1]}" -le 1 ] || die "writing ${dst} failed (tar exit ${st[1]})"
}

# ---------------------------------------------------------------------------
log "Copying the root filesystem"
# ---------------------------------------------------------------------------
# One filesystem only, so /boot, /boot/efi and the pseudo-filesystems are all
# skipped here and dealt with separately (or not at all).
copy_tree / "$MNT"

log "Copying /boot"
copy_tree /boot "$MNT/boot"

log "Copying the ESP"
# vfat carries no ownership, permissions or xattrs, so do not ask for any.
cp -r /boot/efi/. "$MNT/boot/efi/"

# ---------------------------------------------------------------------------
log "Pointing the new system at itself"
# ---------------------------------------------------------------------------
cat > "$MNT/etc/fstab" <<EOF
UUID=${ROOT_UUID}  /          ext4  defaults              1 1
UUID=${BOOT_UUID}  /boot      ext4  defaults              1 2
UUID=${ESP_UUID}   /boot/efi  vfat  umask=0077,shortname=winnt 0 2
EOF

# Every place the old root UUID appears has to become the new one, or the
# installed system quietly boots the USB stick's root — or nothing at all.
OLD_ROOT_UUID=$(blkid -s UUID -o value "$RUNNING_ROOT")
OLD_BOOT_UUID=$(findmnt -no UUID /boot 2>/dev/null || true)

for f in "$MNT"/boot/loader/entries/*.conf; do
    [ -e "$f" ] || continue
    sed -i "s/${OLD_ROOT_UUID}/${ROOT_UUID}/g" "$f"
    echo "  $(basename "$f")"
done

[ -f "$MNT/etc/kernel/cmdline" ] &&
    sed -i "s/${OLD_ROOT_UUID}/${ROOT_UUID}/g" "$MNT/etc/kernel/cmdline"

if [ -n "$OLD_BOOT_UUID" ]; then
    sed -i "s/${OLD_BOOT_UUID}/${BOOT_UUID}/g" "$MNT/boot/grub2/grub.cfg"
    for g in "$MNT"/boot/efi/EFI/*/grub.cfg; do
        [ -e "$g" ] && sed -i "s/${OLD_BOOT_UUID}/${BOOT_UUID}/g" "$g"
    done
fi

# No EFI variables on this machine, so the firmware will only find a bootloader
# at the removable-media path. Make sure one is there.
mkdir -p "$MNT/boot/efi/EFI/BOOT"
if [ -f "$MNT/boot/efi/EFI/fedora/grubaa64.efi" ]; then
    cp "$MNT/boot/efi/EFI/fedora/grubaa64.efi" "$MNT/boot/efi/EFI/BOOT/BOOTAA64.EFI"
fi

# A fresh identity, so the installed system is not a clone of the stick — two
# machines sharing one machine-id confuses DHCP leases and journal collection.
# The removal matters: systemd-machine-id-setup keeps an existing valid id, and
# one was just copied off the stick, so without this it is a no-op.
#
# Writing a real id rather than leaving the file empty also keeps systemd from
# treating the next boot as a first boot and prompting on the console for
# locale and passwords — which, on a machine reached over ssh, would look
# exactly like a hang.
rm -f "$MNT/etc/machine-id"
systemd-machine-id-setup --root="$MNT" >/dev/null 2>&1 ||
    uuidgen | tr -d - > "$MNT/etc/machine-id"

# The root partition already fills the disk, so there is nothing to grow.
mkdir -p "$MNT/var/lib/c630" && touch "$MNT/var/lib/c630/growfs-done"

sync
log "Done"
cat <<EOF

Installed to ${TARGET}. Reboot and pick the internal drive from the boot menu
(Fn+F12), or remove the USB stick.

  root  ${ROOT_UUID}
  boot  ${BOOT_UUID}
  esp   ${ESP_UUID}

EOF