#!/usr/bin/env bash

#######################################################################################################################
##
## Script to full update the system
##
##   0. Pre checks
##   1. Generate new boot environment (BE)
##   2. Update and Salt highstate
##   3. Clean up
##
#######################################################################################################################


#######################################################################################################################
## Definitions
#######################################################################################################################

readonly TEMPDIR=$(mktemp -d /tmp/systemupdate.XXXXXX)
readonly LOCK_FILE="${TEMPDIR}/systemupdate.lock"

readonly TIMESTAMP=$(date +"%Y-%m-%d_%H-%M-%S")

readonly BTRFS_ROOT="/btrfs"
readonly CURRENT_SUBVOLUME=$(LC_ALL=C btrfs sub show / | LC_ALL=C grep 'Name' | cut -d: -f2 | awk '{$1=$1};1')
readonly NEW_SUBVOLUME="@root_${TIMESTAMP}"
readonly MOUNTPOINT='/mnt'

readonly EFI_DISK=$(findmnt -T /efi -o SOURCE | tail -n 1)
readonly ROOT_DISK=$(findmnt / -o SOURCE | cut -d"[" -f1 | tail -n 1)

readonly BE_HISTORY_COUNT=5


#######################################################################################################################
## Errorhandling
#######################################################################################################################

#----------------------------------------------------------------------------------------------------------------------
#   systemupdate failed
#----------------------------------------------------------------------------------------------------------------------
systemupdateFailed() {
  echo ""
  echo "┌──────────────────────────────────────────┐"
  echo "│  FAILED => clean up                      │"
  echo "└──────────────────────────────────────────┘"

  subtaskTitle "Unmount BE if mounted"
  unmountMountpoint

  subtaskTitle "Remove BE"
  removeBEFromTimestamp ${TIMESTAMP}

  rm -f ${LOCK_FILE}

  subtaskTitle "Finished with exit code 1"
  exit 1
}

# catch ^C and other signals and clean up
trap "echo -e '\n=> Interrupted with CTRL+C' >&2; systemupdateFailed" SIGINT SIGHUP SIGTERM SIGABRT


#######################################################################################################################
## Helper Functions
#######################################################################################################################

#----------------------------------------------------------------------------------------------------------------------
#   Subtask title output
#----------------------------------------------------------------------------------------------------------------------
subtaskTitle() {
  echo -e "\n=> $1"
}

#----------------------------------------------------------------------------------------------------------------------
#   Unmount ${MOUNTPOINT}
#----------------------------------------------------------------------------------------------------------------------
unmountMountpoint() {
  # if mountpoint exists -> umount
  [[ $(findmnt -M "${MOUNTPOINT}") ]] && umount -R "${MOUNTPOINT}"
}

#----------------------------------------------------------------------------------------------------------------------
#   Recursive subvolume delete
#----------------------------------------------------------------------------------------------------------------------
btrfsSubDelRecursive() {
  btrfs sub list -o "${BTRFS_ROOT}/${1}" | cut -d " " -f 9 | while read i; do
    btrfsSubDelRecursive "$i"
  done
  btrfs sub del "${BTRFS_ROOT}/${1}"
}

#----------------------------------------------------------------------------------------------------------------------
#   Remove BE from timestamp
#----------------------------------------------------------------------------------------------------------------------
removeBEFromTimestamp() {
  # remove all subvolume with this timestamp
  for f in $(btrfs sub list -o /btrfs | cut -d " " -f 9 | grep "@root"); do
    if [[ "$f" =~ "$1" ]]; then
      btrfsSubDelRecursive "$f"
    fi
  done
}


#######################################################################################################################
## Main
#######################################################################################################################

echo "┌──────────────────────────────────────────┐"
echo "│  0. Pre checks                           │"
echo "└──────────────────────────────────────────┘"
subtaskTitle "Check if another systemupgrade is in progress"
if [ -f ${LOCK_FILE} ]; then
  echo "[ERROR] Another systemupgrade is in progress (lockfile: ${LOCK_FILE}) => exit" >&2
  exit 1
fi

subtaskTitle "Check if ${MOUNTPOINT} exists"
if [ ! -d ${MOUNTPOINT} ]; then
  mkdir -p "${MOUNTPOINT}"
fi

subtaskTitle "Check if ${MOUNTPOINT} is already a mountpoint"
if [[ $(findmnt -M "${MOUNTPOINT}") ]]; then
  echo "[ERROR] ${MOUNTPOINT} is already a mountpoint => exit" >&2
  exit 1
fi

subtaskTitle "Checks finished and update can start"

# Create lock file
touch ${LOCK_FILE} || systemupdateFailed


echo ""
echo "┌──────────────────────────────────────────┐"
echo "│  1. Generate new boot environment (BE)   │"
echo "└──────────────────────────────────────────┘"

subtaskTitle "Create snapshot of current running system"
btrfs subvolume snapshot / ${BTRFS_ROOT}/${NEW_SUBVOLUME} || systemupdateFailed

subtaskTitle "Mount new BE to ${MOUNTPOINT}"
mount -o noatime,nodiratime,discard=async,space_cache=v2,subvol="${NEW_SUBVOLUME}" "${ROOT_DISK}" "${MOUNTPOINT}" || systemupdateFailed
mount -o noatime,nodiratime,discard=async,space_cache=v2,subvol=@home "${ROOT_DISK}" "${MOUNTPOINT}/home" || systemupdateFailed
mount -o noatime,nodiratime,discard=async,space_cache=v2,subvol=@podman "${ROOT_DISK}" "${MOUNTPOINT}/opt/podman" || systemupdateFailed
mount -o noatime,nodiratime,discard=async,space_cache=v2,subvol=@mysql "${ROOT_DISK}" "${MOUNTPOINT}/var/lib/mysql" || systemupdateFailed
mount -o noatime,nodiratime,discard=async,space_cache=v2,subvol=/ "${ROOT_DISK}" "${MOUNTPOINT}/btrfs" || systemupdateFailed

mount -o nodev,nosuid,noexec "${EFI_DISK}" "${MOUNTPOINT}/efi" || systemupdateFailed
mount -t proc /proc "${MOUNTPOINT}/proc/" || systemupdateFailed
mount -t sysfs /sys "${MOUNTPOINT}/sys/" || systemupdateFailed
mount -o bind /sys/firmware/efi/efivars "${MOUNTPOINT}/sys/firmware/efi/efivars/" || systemupdateFailed
mount -o bind /dev "${MOUNTPOINT}/dev/" || systemupdateFailed
mount -o bind /run "${MOUNTPOINT}/run/" || systemupdateFailed

subtaskTitle "New BE mounted"

echo ""
echo "┌──────────────────────────────────────────┐"
echo "│  2. Update and Salt highstate            │"
echo "└──────────────────────────────────────────┘"

subtaskTitle "Update Saltstack"

chroot "${MOUNTPOINT}" /bin/bash -c "git -C /srv/salt pull" || systemupdateFailed
chroot "${MOUNTPOINT}" /bin/bash -c "git -C /srv/pillar pull" || systemupdateFailed

subtaskTitle "Update bootloader configs"
chroot "${MOUNTPOINT}" /bin/bash -c "salt-call state.sls system.bootloader" >/dev/null || systemupdateFailed

subtaskTitle "Alpine repositories & keyring update"
chroot "${MOUNTPOINT}" /bin/bash -c "apk update" || systemupdateFailed

subtaskTitle "Alpine packages update"
chroot "${MOUNTPOINT}" /bin/bash -c "apk upgrade" || systemupdateFailed

subtaskTitle "Salt highstate"
chroot "${MOUNTPOINT}" /bin/bash -c "salt-call state.highstate" >/dev/null || systemupdateFailed

subtaskTitle "Generate new initial ramdisk"
chroot "${MOUNTPOINT}" /bin/bash -c "mkinitfs $(uname -r)" || systemupdateFailed

subtaskTitle "Update motd"
chroot "${MOUNTPOINT}" /bin/bash -c "/usr/local/noveria/bin/generate_motd" || systemupdateFailed

subtaskTitle "Update GRUB"
chroot "${MOUNTPOINT}" /bin/bash -c "grub-install --target=x86_64-efi --efi-directory=/efi --bootloader-id=alpine" || systemupdateFailed
chroot "${MOUNTPOINT}" /bin/bash -c "/usr/local/noveria/bin/noveriablcgen --noconfirm" || systemupdateFailed

subtaskTitle "Update finished"

subtaskTitle "Unmount BE"
unmountMountpoint

echo ""
echo "┌──────────────────────────────────────────┐"
echo "│  3. Clean Up                             │"
echo "└──────────────────────────────────────────┘"

subtaskTitle "Clean up finished"

# Remove lock file
rm -f ${LOCK_FILE}