#!/bin/bash

################################################################################
# Backup External Disk Script
# ---------------------------
#
# THIS SCRIPT IS WORK IN PROGRESS AND WILL PROBABLY BE REPLACED SOON!
#
# Author: Robin Meier - robin@meier.si
################################################################################

# Load configuration
script_dir=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
set -o allexport
source ${script_dir}/config/backup > /dev/null 2>&1
set +o allexport

# Import logging functionality
logfile=${script_dir}/log/backup.log
log_identifier="EXTERN"
source ${script_dir}/functions/logging.sh

# Exit if no env file is given
if [[ -z "$EXTERNAL_DISK_BACKUP_ENV_FILE" ]]; then
  exit 0
fi

set -o allexport
source $EXTERNAL_DISK_BACKUP_ENV_FILE
set +o allexport

log "External Disk Backup Started"

# Check if required env vars are set
if [[ -z "$BORG_REPO" || -z "$BORG_PASSPHRASE" || -z "$BORG_DEBIAN_DIRS" || -z "$BORG_ZFS_DIRS" ]]; then
  log "[ERROR] Required env var missing in $EXTERNAL_DISK_BACKUP_ENV_FILE"
  exit 42
fi

if [[ -z "$ZFS_ARRAY_NAME" ]]; then
  ZFS_ARRAY_NAME=zfs
fi

# Automated negative response to these questions
export BORG_RELOCATED_REPO_ACCESS_IS_OK=no
export BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK=no

# Error handling
trap 'echo $( date ) Backup interrupted >&2; exit 2' INT TERM

# Output current version
borg --version


# Backup debian
log "Creating debian backup"

borg create $BORG_OPTS         \
  --verbose                    \
  --filter AME                 \
  --list                       \
  --show-rc                    \
  --compression lz4            \
  --one-file-system            \
  --exclude-caches             \
  --exclude 'root/.cache'      \
  --exclude 'home/*/.cache/*'  \
  --exclude 'var/tmp/*'        \
  --exclude 'var/lib/docker/*' \
  ::'{hostname}-debian-{now}'  \
  $BORG_DEBIAN_DIRS

backup_exit_1=$?

log "Finished creating debian backup ($backup_exit_1)"


# Backup zfs array
log "Creating $ZFS_ARRAY_NAME backup"

borg create $BORG_OPTS                   \
  --verbose                              \
  --filter AME                           \
  --list                                 \
  --show-rc                              \
  --compression lz4                      \
  --exclude-caches                       \
  ::"{hostname}-${ZFS_ARRAY_NAME}-{now}" \
  $BORG_ZFS_DIRS

backup_exit_2=$?

log "Finished creating $ZFS_ARRAY_NAME backup ($backup_exit_2)"

backup_exit=$(( backup_exit_2 > backup_exit_1 ? backup_exit_2 : backup_exit_1 ))


# Prune no longer needed backups
log "Pruning debian backups from repository"

borg prune                                 \
    --list                                 \
    --glob-archives '{hostname}-debian-*'  \
    --show-rc                              \
    --keep-daily    7                      \
    --keep-weekly   4                      \
    --keep-monthly  6

prune_exit_1=$?

log "Finished pruning debian backups from repository ($prune_exit_1)"

log "Pruning $ZFS_ARRAY_NAME backups from repository"

borg prune                                           \
    --list                                           \
    --glob-archives "{hostname}-${ZFS_ARRAY_NAME}-*" \
    --show-rc                                        \
    --keep-daily    7                                \
    --keep-weekly   4                                \
    --keep-monthly  6

prune_exit_2=$?

log "Finished pruning $ZFS_ARRAY_NAME backups from repository ($prune_exit_2)"

prune_exit=$(( prune_exit_2 > prune_exit_1 ? prune_exit_2 : prune_exit_1 ))


# Compact repository
log "Compacting repository"

# TODO: Maybe first check if compacting is supported by the client? (Older versions)

borg compact

compact_exit=$?

log "Finished compacting repository ($compact_exit)"


# Calculate global exit code
global_exit=$(( backup_exit > prune_exit ? backup_exit : prune_exit ))
global_exit=$(( compact_exit > global_exit ? compact_exit : global_exit ))

if [ ${global_exit} -eq 0 ]; then
  log "Backup, Prune, and Compact finished successfully"
elif [ ${global_exit} -eq 1 ]; then
  log_echo "Backup, Prune, and/or Compact finished with warnings"
else
  log_echo "Backup, Prune, and/or Compact finished with errors"
fi


log "External Disk Backup Finished"

exit ${global_exit}