HOST_NAME=$(hostname -s)
DAY=$(date +%u) # 1-7, MO is 1
WEEKLY_DAY=7 # SA->SO

NAS_MOUNT_POINT="$(realpath $HERE/../../..)" # Server/bin/backup
NAS_ROOT="$NAS_MOUNT_POINT/backups"

LOG_FILE_PATH="$NAS_MOUNT_POINT/Server/log/backup"
log_file_name="$LOG_FILE_PATH/$HOST_NAME-$(date '+%Y-%m-%d_%H%M%S')"
LOG_FILE="${log_file_name}.log"
LOG_KEEP_DAYS=14

RESTORE_PATH="$NAS_MOUNT_POINT/Server/restore"

BACKUP_MASTER_CHECK="/var/containers/vol/caddy"

NAS_HOSTNAME=synology
NAS_IP=10.4.2.20
NAS_SCRIPT=/volume1/nfs/Server/bin/backup/main.sh

PASSPHRASE=L1rfCXu8PHMQsGL0HJWwzQYpCT7f5VboislOTHMaEV
EXT=tgz.gpg
LIST_EXT=list

#DOCKER="/usr/bin/docker compose -f /var/docker/run/docker-compose.yml --ansi never"
SYNO_USB=/usr/syno/bin/synousbdisk
SYSTEMCTL_USER="/usr/bin/systemctl --user --machine=container@"
SYSTEMCTL="/usr/bin/systemctl"
PODMAN=" sudo -u container podman"
CONTAINER_EXEC_USER=" $PODMAN exec"
CONTAINER_SVC_UPDATE_USER=" $PODMAN auto-update"
CONTAINER_EXEC="podman exec"

LOG_RECIPIENT=hb242@pm.me
INFO=INFO
WARN=WARN
ERROR=ERROR
DEBUG=DEBUG
SUCCESS="*** success"
INF="---"
WRN=":::"
ERR="###"
DBG="==="

# ----- logging -----

# Log-Datei schreiben.
#
# $1 - Typ, z.B. INFO, WARN, ERROR, etc.
# $2 ff. - die Meldung, die ins Log geschreiben wird
#
log() {
    local type=$1
    #if [ "$type" == "ERROR" ]; then ERROR=0; fi
    shift 1
    echo "$(date '+%d.%m.%Y %H:%M:%S') - $type $@" | tee -a $LOG_FILE >/dev/null

} 

# Reduziertes Log für automatische Läufe
#
# Das Log wird am Ende des Laufs als Mail verschickt. Die Meldungen
# werden zusätzlich im Standard-Log protokolliert.
# Dieses log wird nur geschrieben, wenn $MAIL_LOG_FILE definiert ist.
#
# $1 - Typ, z.B. INFO, WARN, ERROR, etc.
# $2 ff. - die Meldung, die ins Log geschreiben wird
# 
mail_log() {
    local type=$1
    shift
    if [ "$MAIL_LOG_FILE" ]; then
        echo "$(date '+%d.%m.%Y %H:%M:%S') - $type $@" >> $MAIL_LOG_FILE
    fi
    log "$type" "$@"
}

# Reduziertes Log senden
#
send_mail_log() {
    local subject="$@"
    log $DEBUG "$DBG send_mail_log()"
    log $DEBUG "$DBG > $HERE/mail.sh $LOG_RECIPIENT \"[$HOST_NAME] $subject\" $MAIL_LOG_FILE"
    $HERE/mail.sh $LOG_RECIPIENT "[$HOST_NAME] $subject" $MAIL_LOG_FILE >>$LOG_FILE 2>&1
}

# Alte Logs löschen
#
# Dateien älter als $LOG_KEEP_DAYS Tage löschen
#
prune_logs() {
    log $DEBUG "$DBG prune_logs()"
    log $DEBUG "$DBG > find \"$LOG_FILE_PATH\" -type f -mtime +$LOG_KEEP_DAYS -delete"
    find "$LOG_FILE_PATH" -type f -mtime +$LOG_KEEP_DAYS -delete >>$LOG_FILE 2>&1
    if [ $? -ne 0 ]; then
        # Fehler nur protokollieren, kein Grund abzubrechen
        mail_log $ERROR "$ERR error deleting old log files."
    fi
}

# ----- db dump -----

#dump_mariadb() {
#    return 0
#    log $DEBUG "$DBG dump_mariadb( $@ )"
#    local dump_dir=$1
#    local mysqlconnect="--user=root --password=snafu"
#
#    log $DEBUG "$DBG > \$DOCKER exec mysql /usr/bin/mariadb --silent --user=xxx --password=xxx -e \"show databases\" -B"
#    for db in $($DOCKER exec mysql /usr/bin/mariadb --silent $mysqlconnect -e "show databases" -B 2>>$LOG_FILE | grep -v information_schema 2>>$LOG_FILE | grep -v performance_schema 2>>$LOG_FILE | sed -e 's/\r//' 2>>$LOG_FILE); do
#        log $DEBUG "$DBG   > \$DOCKER exec mysql /usr/bin/mariadb-dump --hex-blob --user=xxx --password=xxx --databases $db"
#        $DOCKER exec mysql /usr/bin/mariadb-dump --hex-blob $mysqlconnect --databases $db >$dump_dir/$db.sql 2>>$LOG_FILE
#        is_error $? false && return 1
#    done
#    return 0
#}

dump_postgresql() {
    local pg_container=$1
    local dump_dir=$2
    log $DEBUG "$DBG dump_postgresql( $@ )"
    delete_dir $dump_dir
    check_directory $dump_dir
    
    # users and roles
    log $DEBUG "$DBG > \$CONTAINER_EXEC_USER -u=postgres $pg_container pg_dumpall --globals-only"
    $CONTAINER_EXEC_USER -u=postgres $pg_container pg_dumpall --globals-only > $dump_dir/_globals.sql 2>>$LOG_FILE

    log $DEBUG "$DBG \$CONTAINER_EXEC_USER -u=postgres $pg_container psql -t -c \"select datname from pg_database where not datistemplate\""
    for db in $($CONTAINER_EXEC_USER -u=postgres $pg_container psql -t -c "select datname from pg_database where not datistemplate" 2>>$LOG_FILE); do 
        log $DEBUG "$DBG   > \$CONTAINER_EXEC_USER -u=postgres $pg_container pg_dump --create $db"
        $CONTAINER_EXEC_USER -u=postgres $pg_container pg_dump --create $db > $dump_dir/$db.sql 2>>$LOG_FILE
        is_error $? false && return 1
    done
    return 0
}

# ----- helper functions -----

# Für Backup und Export muss das Script mit root-Rechten
# ausgeführt werden.
# 
check_root() {
    if [ "$(id -u)" -ne 0 ]; then
        log $ERROR "$ERR script must be run as superuser."
        echo "****"
        echo "***** script must be run as superuser! *****"
        echo "****"
        exit 100
    fi
}

start_containers() {
    local let rc=0 
    log $DEBUG "$DBG start_containers()"
#    if [ -f /var/docker/run/docker-compose.yml ]; then
#      log $DEBUG "$DBG > \$DOCKER up -d"
#      $DOCKER up -d >>$LOG_FILE 2>&1
#      let rc=rc+$?
#    fi
    if [ -d /var/containers ]; then
        do_start_stop_containers start
        let rc=rc+$?
    fi
    return $rc
}

stop_containers() {
    local let rc=0
    log $DEBUG "$DBG stop_containers()"
#    if [ -f /var/docker/run/docker-compose.yml ]; then
#      log $DEBUG "$DBG > \$DOCKER down"
#      $DOCKER down >>$LOG_FILE 2>&1
#      let rc=rc+$?
#    fi
    if [ -d /var/containers ]; then
        do_start_stop_containers stop
        let rc=rc+$?
    fi
    return $rc
}

do_start_stop_containers() {
    local cmd=$1
    local let rc=0
    log $DEBUG "$DBG do_start_stop_containers() $cmd"
    if [ ! -z "$ROOT_CONTAINERS" ]; then
        log $DEBUG "$DBG > $SYSTEMCTL $cmd $ROOT_CONTAINERS"
        $SYSTEMCTL $cmd $ROOT_CONTAINERS >>$LOG_FILE 2>&1 
        let rc=rc+$?
    fi
    if [ ! -z "$USER_CONTAINERS" ]; then
        log $DEBUG "$DBG > $SYSTEMCTL_USER $cmd $USER_CONTAINERS"
        $SYSTEMCTL_USER $cmd $USER_CONTAINERS >>$LOG_FILE 2>&1 
        let rc=rc+$?
    fi      
    return $rc
}

update_services() {
    log $DEBUG "$DBG update_services()"
    mail_log $INFO "$INF    update services"
    local upd=$($CONTAINER_SVC_UPDATE_USER 2>&1 | tee -a $LOG_FILE | egrep 'registry\s+true' | sed 's/^.* \([^[:space:]]*\/[^[:space:]]*\).*$/\1/g')
    check_pipe_rc ${PIPESTATUS[@]}
    local rc=$?
    for i in $upd; do
        mail_log $INFO "$INF      $i"
    done
    return $rc
}

check_services() {
    log $DEBUG "$DBG check_services()"
    mail_log $INFO "$INF    check services"
    $HERE/check.sh >>$LOG_FILE 2>&1
    return $?
}

# Zugriffsrechte für Logs und Backups setzen
#
fix_acls() {
    log $DEBUG "$DBG fix_acls()"

    log $DEBUG "$DBG > chmod -R a+r $NAS_ROOT"
    chmod -R a+r $NAS_ROOT >>$LOG_FILE 2>&1
    log $DEBUG "$DBG > chmod -R a+r $LOG_FILE_PATH"
    chmod -R a+r $LOG_FILE_PATH >>$LOG_FILE 2>&1
}

# Script per ssh auf Server $1 im Hintergrund starten
#
# ssh start in background
# -> https://stackoverflow.com/questions/29142/getting-ssh-to-execute-a-command-in-the-background-on-target-machine#comment107117479_29172
#
# $1 - Server
# $@ - Script incl. Parameter
#
run_script_remote() {
    local server=$1
    shift
    ssh $server "sudo sh -c 'nohup $@ &>/dev/null </dev/null &'"
}

# check if function $1 exists
#
# returns true/false
#
isFunction() { declare -Ff "$1" ; }

# check if $1 is error (!=0) and write result to log
#
# $1 - return code to check
# $2 - if set don't log success
#
# returns 0 if error, 1 otherwise!
#
is_error() {
    local rc=$1
    local mlog=$2
    if [ $rc -eq 0 ]; then
        if [ -z "$mlog" ]; then 
            mail_log $INFO "$SUCCESS"
        fi
        return 1
    else
        mail_log $ERROR "$ERR an error occured see $LOG_FILE"
        return 0
    fi
}

# check return code of piped programs
#
# $1, ff. - return codes
#
# returns 0 for success, 1 for one or more errors
#
check_pipe_rc() {
    local result=0
    local count=1
    local result_str
    for rc in $@; do
        if [ $rc -ne 0 ] ; then
            result=1
            result_str="${result_str}#${count} "
        fi
        let "count += 1"
    done
    if [ $result -ne 0 ]; then
        log $ERROR "$ERR in pipe $result_str"
    fi
    return $result    
}

# Dateien vom Server zur NAS verschieben
#
# $1 - Verzeichnis auf Server
# $2 - Ziel-Verzeichnis auf der NAS
#
# returns return code of mv
#
copy_to_nas() {
    log $DEBUG "$DBG copy_to_nas( $@ )"
    local source="$1"
    local target="$2"
    delete_dir "$target"
    if [ $? -ne 0 ]; then
        log $ERROR "$ERR directory \"$target\" could not be emptied"
        return 1
    fi
    check_directory "$target"
    is_error $? true && return 1

    log $DEBUG "$DBG > mv \"$source\"/* \"$target\""
    mv "$source"/* "$target" >>$LOG_FILE 2>&1
    return $?
}

# Ist $1 in der Liste der restlichen args $2, $3 ...
#
# zB. if is_in "foo" "foo" "bar" "foo bar" ; then ...
# Leere Liste liefert immer false
#
is_in() {
    local search="$1"
    shift 1
    local e
    for e in "$@"; do [[ "$e" == "$search" ]] && return 0; done
    return 1
}

# Alle Verzechnisnamen in einem Verzeichnis holen.
#
# $1 - Verzeichnis in dem gesucht wird als absoluter Pfad
# $2 ff. - auszuschliessende Verzeichnisse (kann leer bleiben)
#
iterate_dirs_in() {
    local dirname
    local root=$1
    shift 1
    for dir in $(find "$root" -maxdepth 1 -type d \! -wholename "$root"); do
        dirname=$(basename $dir)
        if ! is_in "$dirname" "$@"; then 
            echo "$dirname" 
        fi
    done
}

# create directory if it not exists
#
# $1 - dir to check
#
# returns 0 for success, 1 otherwise
#
check_directory() {
    log $DEBUG "$DBG check_directory( $@ )"
    local dir=$1
    if [ -d "$1" ]; then 
        return 0
    else
        log $DEBUG "$DBG > mkdir -p \"$1\""
        mkdir -p "$1" >>$LOG_FILE 2>&1 && return 0
        log $ERROR "$ERR could not create directory $1!"
        return 1
    fi
}

# Verzeichnis löschen
#
# Im Fehlerfall wird rc=1 zurückgegeben
#
# $1 - zu löschendes Verzeichnis
#
# returns 0 for success, 1 otherwise
#
delete_dir() {
    log $DEBUG "$DBG delete_dir( $@ )"
    local dir=$1
    log $DEBUG "$DBG > rm -rf \"$dir\"/*"
    rm -rf "$dir"/* >>$LOG_FILE 2>&1 && return 0
    # return error, so caller can decide what to do
    return 1
}

# ----- backup -----

# Slashes "/" im Pfadnamen durch Dashes "-" ersetzen, so dass der String als Dateiname verwendet werden kann.
#
# $1 - path 
backup_file_prefix() {
    echo "$1" | sed -E 's/^\///' | sed -E 's/\//-/g'
}

# Verzeichnise unter $1 in .tgz.gpg-Dateien sichern.
#
# $1 - Verzeichnis, das gesichert wird: alle Verzeichnisse darunter werden einzeln als .tgz.gpg-Datei gesichert
# $2 - Zielverzeichnis für .tgz.gpg-Dateien
# $3 ff. - Verzeichnisse, die nicht gesichert werden sollen (kann leer bleiben)
#
# returns 0 for success, 1 otherwise (Fehlerprotokollierung muss aufrufende fn erledigen)
#
backup_all_dirs() {
    log $DEBUG "$DBG backup_all_dirs( $@ )"
    local root=$1
    local target=$2
    shift 2
    local prefix=$(backup_file_prefix $root)
    local tar_file
    local dir

    for dir in $(iterate_dirs_in "$root" "$@"); do
        tar_file="$target/$prefix-$dir.$EXT"

        backup_dir "$root" "$tar_file" "$dir"
        if [ $? -ne 0 ]; then return 1; fi

        create_list "$tar_file" "$dir"
        if [ $? -ne 0 ]; then return 1; fi

        test_integrity "$tar_file"
        if [ $? -ne 0 ]; then return 1; fi
    done
    return 0
}

# Einzelnes Verzeichnis sichern.
#
# $1 - Pfad um Verzeichnis, das gesichert werden soll
# $2 - Zielpfad und -name für das Archiv
# $2 - zu sicherndes Verzeichnis
#
# returns 0 for success, 1 otherwise
#
backup_dir() {
    log $DEBUG "$DBG backup_dir( $@ )"
    local root=$1
    local archive=$2
    local dir=$3
    log $DEBUG "$DBG > tar -c -z --numeric-owner --one-file-system --sort=name --exclude \"@eaDir\" -C \"$root\" \"$dir\" | gpg --batch -c --passphrase xxxx -o \"$archive\""
    tar -c -z --numeric-owner --one-file-system --sort=name --exclude "@eaDir" -C "$root" "$dir" 2>>$LOG_FILE  | gpg --batch -c --passphrase $PASSPHRASE -o "$archive" 2>>$LOG_FILE 
    check_pipe_rc ${PIPESTATUS[@]}
    return $?
}

##
# auto backup handling
#
# hostname-scripte setzen vars und definieren Funktionen backup_daily1, 2, usw. und backup_weekly1, 2, usw.
# in den Funktionen werden die vars für den einzelnen backup gesetzt (target, excludes, usw.)
# hier wird dann dass hostname-script gesourced (s.o.) und in einer Schleife werden die
# entsprechend en backup_*-Funktionen aufgerufen
#
# returns 0 for success, 1 otherwise
#
do_auto_backup() {
    log $DEBUG "$DBG do_auto_backup( $@ )"
    local func=$1
    local count=1
    local rc
    
    if ! $func$count 2>/dev/null ; then  # Seiteneffekt: $func$count wird ausgeführt
        log $ERROR "$ERR keine Backup-Function $func$count() für $HOST_NAME."
        exit 1 # kein Mail-Benachrichtigung!
    fi
    set_log_info

    mail_log $INFO "$INF prepare backup"
    before_backup
    is_error $? && return 1

    delete_dir "$BACKUP_TARGET" 

    mail_log $INFO "$INF check backup directory"
    check_directory "$BACKUP_TARGET"
    is_error $? && return 1

    until ! $func$count 2>/dev/null # Seiteneffekt: $func$count wird ausgeführt (für nächste Schleife)
    do 
        mail_log $INFO "$INF backing up directories in $BACKUP_SOURCE"
        backup_all_dirs "$BACKUP_SOURCE" "$BACKUP_TARGET" "${BACKUP_EXCLUDE_DIRS[@]}" 
        is_error $? && return 1
        let "count += 1"
    done
}

set_log_info() {
    local targ
    if [ -z "$NAS_TARGET" ]; then 
        targ=$BACKUP_TARGET
    else
        targ=$NAS_TARGET
    fi
    mail_log $INFO ">>> "
    mail_log $INFO ">>> backup to : $targ"
    mail_log $INFO ">>> log file  : $LOG_FILE"
    mail_log $INFO ">>> "
}

backup_daily() {
    # "master"-Server startet Backup auf NAS
    if [ -d $BACKUP_MASTER_CHECK ]; then
        log $DEBUG "$DBG starting daily backup on $NAS_HOSTNAME"
        run_script_remote $NAS_IP "$NAS_SCRIPT -d"

        # alte Logs löschen (nur auf einem Server ausführen)
        prune_logs
    fi

    # ggf. weekly backup parallel starten (z.ZT. nur auf NAS)
    if [ $HAS_WEEKLY -a $WEEKLY_DAY -eq $DAY ]; then
        log $DEBUG "$DBG starting weekly backup"
        sleep 2 # wg. log name
        nohup $THIS_SCRIPT -w >>$LOG_FILE 2>&1 </dev/null &
    fi

    mail_log $INFO ">>>>>>>>>> daily auto backup $VER for $HOST_NAME <<<<<<<<<<"

    do_auto_backup backup_daily

    # after_backup() muss immer laufen, damit ggf. docker wieder gestartet werden kann
    mail_log $INFO "$INF finishing backup"
    after_backup
    is_error $?

    mail_log $INFO ">>>>>>>>>> end of auto backup"
    fix_acls
    send_mail_log "Daily Backup"

}
backup_weekly() {
    mail_log $INFO ">>>>>>>>>> weekly auto backup $VER for $HOST_NAME <<<<<<<<<<"

    do_auto_backup backup_weekly

    mail_log $INFO "$INF finishing backup"
    after_backup
    is_error $?

    mail_log $INFO ">>>>>>>>>> end of auto backup"
    fix_acls
    send_mail_log "Weekly Backup"
}

# ----- integrity -----

# Integrität des Archivs testen, indem es entschlüsselt, entpackt 
# und der Inhalt auf /dev/null ausgegeben wird.
#
# $1 - Archiv
#
# returns 0 for success, 1 otherwise
#
test_integrity() {
    log $DEBUG "$DBG test_integrity( $@ )"
    local archive=$1
    log $DEBUG "$DBG > gpg --batch --decrypt --passphrase xxxx \"$archive\" | tar -xzO"
    gpg --batch --decrypt --passphrase $PASSPHRASE "$archive" 2>>$LOG_FILE | tar -xzO >/dev/null 2>>$LOG_FILE
    check_pipe_rc ${PIPESTATUS[@]}
    return $?
}

# ----- restore -----

# Restore aus Archiv
#
# Wird nach $RESTORE_PATH ausgegeben und mit root-Rechten 
# auf der NAS ausgeführt.
#
# $1 - Archiv, mit Pfad ab $NAS_ROOT
# $2 ff. - zurückzusichernde Dateien/Verzeichnisse
#
restore() {
    log $DEBUG "$DBG restore( $@ )"
    local archive=$1
    shift
    echo "--- Restore ---"
    echo "--- archive: $archive"
    echo "--- files:   $@"
    echo "--- to:      $RESTORE_PATH"    
    echo
    echo "Restore started on NAS, see e-mail"
    echo
    run_script_remote $NAS_IP "$NAS_SCRIPT --rx $archive $@"
}

# Restore 
#
# Beim Restore einzelner Dateien wird nur die ownership der Datei
# restored, nicht die des Pfades zur Datei!
#
do_restore() {
    if [ "$HOST_NAME" != "$NAS_HOSTNAME" ]; then
        restore $@
        exit
    fi

    local archive=$1
    shift
    mail_log $INFO ">>>>>>>>>> restore $VER for $HOST_NAME <<<<<<<<<<"
    mail_log $INFO ">>> restore from: $archive"
    mail_log $INFO ">>> files       : $@" 
    mail_log $INFO ">>> restore to  : $RESTORE_PATH"
    mail_log $INFO ">>> log file    : $LOG_FILE"
    log $DEBUG "$DBG > gpg --batch --decrypt --passphrase xxxx \"$NAS_ROOT/${archive/#\//}\" | tar -xzv --directory $RESTORE_PATH $@"
    gpg --batch --decrypt --passphrase $PASSPHRASE "$NAS_ROOT/${archive/#\//}" 2>>$LOG_FILE | tar -xzv --directory $RESTORE_PATH $@ >>$LOG_FILE 2>&1
    check_pipe_rc ${PIPESTATUS[@]}
    is_error $?
    mail_log $INFO ">>>>>>>>>> end of restore"
    send_mail_log "Restore"   
}

# ----- archive content ------

# Inhalt des Archivs in eine Textdatei ausgeben.
#
# $1 - Archiv
#
# returns 0 for success, 1 otherwise
#
create_list() {
    log $DEBUG "$DBG create_list( $@ )"
    local archive=$1
    log $DEBUG "$DBG > gpg --batch --decrypt --passphrase xxxx \"$archive\" | tar -tzv | tee \"$archive.$LIST_EXT\""
    gpg --batch --decrypt --passphrase $PASSPHRASE "$archive" 2>>$LOG_FILE | tar -tzv 2>>$LOG_FILE | tee "$archive.$LIST_EXT" >/dev/null 2>>$LOG_FILE
    check_pipe_rc ${PIPESTATUS[@]}
    return $?
}

# Liste der Archives auf stdout ausgeben
#
# Zeigt alle Archive incl. Verzeichnis (ohne $NAS_ROOT) an
#
# z.B.
#    $NAS_ROOT = /volume1/nfs/backups
#    ...
#    /daily/synology/backup.3/volume1-nfs-Server.tgz.gpg
#    /weekly/synology/volume1-media-books.tgz.gpg
#
# returns 0 for success, 1 otherwise
#
list_archives() {
    log $DEBUG "$DBG list_archives()"
    local target=$1
    local targ=${NAS_ROOT//\//\\\/} # slashes escapen
    log $DEBUG "$DBG > find \"$NAS_ROOT\" -type f -name \"*.$EXT\" | sed -E \"s/^$targ//\""
    find "$NAS_ROOT" -type f -name "*.$EXT" 2>>$LOG_FILE | sed -E "s/^$targ//" 2>>$LOG_FILE | sort
    check_pipe_rc ${PIPESTATUS[@]}
    return $?
}

# Inhalt des Archivs $1 auf stdout ausgeben
#
# $1 - Archiv-Datei mit Pfad ab $NAS_ROOT
#
# returns 0 for success, 1 otherwise
#
list_archive_content() {
    log $DEBUG "$DBG list_archive_content( $@ )"
    local archive=$1
    log $DEBUG "$DBG > cat \"$NAS_ROOT/${archive/#\//}.$LIST_EXT\""
    cat "$NAS_ROOT/${archive/#\//}.$LIST_EXT" 2>>$LOG_FILE
}

# ----- export -----

# Synology-NAS (0) or not (1 - linux)?
#
is_synology() {
    if [ -f $SYNO_USB ]; then
        return 0
    else
        return 1
    fi
}

# Find exfat formatted device
#
# returns device name
#
get_usb_device() {
    if is_synology; then
        echo $(get_usb_device_syno)
    else
        echo $(get_usb_device_linux)
    fi
}

# USB-HDD auf Synology-NAS ermitteln
#
get_usb_device_syno() {
    log $DEBUG "$DBG get_usb_device_syno()"
    log $DEBUG "$DBG > $SYNO_USB -enum | grep -v devices | wc -l"
    if [ "$($SYNO_USB -enum 2>>$LOG_FILE | grep -v devices 2>>$LOG_FILE | wc -l 2>>$LOG_FILE)" != "1" ]; then
        mail_log $ERROR "$ERR no USB device or too many found @$HOST_NAME."
        return 1
    fi
    log $DEBUG "$DBG > $SYNO_USB -enum | grep -v devices"
    echo $($SYNO_USB -enum 2>>$LOG_FILE | grep -v devices 2>>$LOG_FILE)
    return 0
}

# exfat-formatierte USB-HDD auf Linux-Server ermitteln
#
get_usb_device_linux() {
    log $DEBUG "$DBG get_usb_device_linux()"
    local fstype=exfat 
    local lsblk="lsblk -o KNAME,TYPE,SIZE,MODEL,FSTYPE"
    local device
    log $DEBUG "$DBG $lsblk | grep $fstype | wc -l"
    if [ "$($lsblk 2>>$LOG_FILE | grep $fstype 2>>$LOG_FILE | wc -l 2>>$LOG_FILE)" != "1" ]; then
        mail_log $ERROR "$ERR could not query devices."
        return 1 
    fi
    
    log $DEBUG "$DBG $lsblk | grep $fstype | sed -E 's/^(\S*).*$/\1/'"
    device=$($lsblk 2>>$LOG_FILE | grep $fstype 2>>$LOG_FILE | sed -E 's/^(\S*).*$/\1/' 2>>$LOG_FILE) 
    if [ -z "$device" ]; then
        mail_log $ERROR "$ERR no exfat USB device found."
        return 1
    fi

    echo $device
    return 0
}

# Mount UsB-HDD
#
# returns mount point
#
mount_usb_device() {
    if is_synology; then
        echo $(mount_usb_device_syno $1)
    else
        echo $(mount_usb_device_linux $1)
    fi
}

# Check if auto mounted device is exfat and return mount point
# (fn for consitence with linux fn)
#
# $1 - device name
# returns mount point
# 
mount_usb_device_syno() {
    log $DEBUG "$DBG mount_usb_device_syno( $@ )"
    local device=$1
    log $DEBUG "$DBG > $SYNO_USB -info $device | grep -i \"file system\" | sed -E \"s/.*:\s*(.*)\s*/\1/\""
    local fs=$($SYNO_USB -info $device 2>>$LOG_FILE | grep -i "file system" 2>>$LOG_FILE | sed -E "s/.*:\s*(.*)\s*/\1/" 2>>$LOG_FILE)
    if [ "$fs" != "exfat" ]; then
        mail_log $ERROR "$ERR device $device not exfat formatted."
        return 1
    fi
    # get mount point
    log $DEBUG "$DBG > $SYNO_USB -info $device | grep -i \"mount path\" | sed -E \"s/.*:\s*(.*)\s*/\1/\""
    local mount_point=$($SYNO_USB -info $device 2>>$LOG_FILE | grep -i "mount path" 2>>$LOG_FILE | sed -E "s/.*:\s*(.*)\s*/\1/" 2>>$LOG_FILE)
    if [ $? -ne 0 ] || [ ! -d $mount_point ]; then
        mail_log $ERROR "$ERR mount point \"$mount_point\" does not exist."
        return 1
    fi
    echo $mount_point
    return 0
}

# USB-HDD auf Linux-Server mounten
#
# $1 - device (ohne /dev/)
# return moint point
#
mount_usb_device_linux() {
    log $DEBUG "$DBG mount_usb_device_linux( $@ )"
    local device=$1
    local mount_point=/var/mnt/backup
    check_directory $mount_point
    if [ $? -ne 0 ]; then
        mail_log $ERROR "$ERR mount point \"$mount_point\" does not exist."
        return 1
    fi
    log $DEBUG "$DBG mount /dev/$device $mount_point"
    mount /dev/$device $mount_point >>$LOG_FILE 2>&1
    if [ $? -ne 0 ]; then
        mail_log $ERROR "$ERR mounting /dev/$device failed."
        return 1
    fi
    echo $mount_point
    return 0
}

# unmount USB-HDD
#
umount_usb_device() {
    if is_synology; then
        umount_usb_device_syno $1
        return $?
    else
        umount_usb_device_linux $1
        return $?
    fi
}

# USB-HDD auf Synology-NAS unmounten
#
# $1 - device name
#
umount_usb_device_syno() {
    local device=$1
    log $DEBUG "$DBG umount_usb_device_syno( $@ )"
    log $DEBUG "$DBG > $SYNO_USB -umount $device"
    $SYNO_USB -umount $device >>$LOG_FILE 2>&1
    return $?
}

# USB-HDD auf Linux-Server unmounten
#
# $1 - device (ohne /dev/)
#
umount_usb_device_linux() {
    local device=/dev/$1
    log $DEBUG "$DBG umount_usb_device_linux( $@ )"
    log $DEBUG "$DBG > umount $device"
    umount $device >>$LOG_FILE 2>&1
    return $?
}

# USB-HDD suchen und Backup-Typ ermitteln
#
# Der Typ wird über eine Datei auf der USB-HDD festgelegt:
#     /.backup#<typ>.tag -> z.B. /.backup#int1.tag => Typ=int1
#
# $1 - mount point
#
check_backup_device() {
    log $DEBUG "$DBG check_backup_drive( $@ )"
    local mount_point=$1
    local tagP1=".backup#"
    local tagP2=".tag"

    log $DEBUG "$DBG > ls $mount_point/${tagP1}*${tagP2} | wc -l"
    if [ "$(ls $mount_point/${tagP1}*${tagP2} 2>>$LOG_FILE | wc -l 2>>$LOG_FILE)" != "1" ]; then
        mail_log $ERROR "$ERR no tag found on device at $mount_point."
        return 1
    fi

    log $DEBUG "$DBG > ls $mount_point/${tagP1}*${tagP2} | sed -E \"s/.*$tagP1(.*)$tagP2/\1/\""
    local tag=$(ls $mount_point/${tagP1}*${tagP2} 2>>$LOG_FILE | sed -E "s/.*$tagP1(.*)$tagP2/\1/" 2>>$LOG_FILE)
    if [ $? -ne 0 ]; then
        mail_log $ERROR "$ERR no tag found on device at $mount_point."
        return 1
    fi
    echo $tag
    return 0
}

# Datei-Export auf Synology-NAS ausführen
#
# TODO mount, check, unmount muss raus -> fn macht synology + linux => if host == synology...
#      fn's ausser unmount liefern string|null => if -z error
#
do_export() {
    log $DEBUG "$DBG do_export ()"
    mail_log $INFO "$INF checking USB device."

    # get device
    local device=$(get_usb_device)
    if [ -z $device ]; then
        return 1
    fi

    # check if exfat | mount & get mount point
    local mount_point=$(mount_usb_device $device)
    if [ -z $mount_point ]; then
        return 1
    fi

    # find export type
    local backup_type=$(check_backup_device $mount_point)
    if [ -z $backup_type ]; then
        return 1
    fi
    mail_log $INFO "$SUCCESS"
    
    local source_path
    case $backup_type in 
        int1|int2|1|2)
            # daily + weekly backups -> Auslagerung 1+2, Backup 1+2
            if is_synology; then
                source_path="/volume1/nfs/backups"
            else
                source_path="/var/srv/nas/backups"
            fi
            ;;
        serien)
            # Serien -> Auslagerung
            if is_synology; then
                source_path="/volume1/media/serien"
            else
                source_path="/var/srv/media/serien"
            fi
            ;;
        video)
            # Video -> Auslagerung
            if is_synology; then
                source_path="/volume1/media/video"
            else
                source_path="/var/srv/media/video"
            fi
            ;;
        ?*)
            echo "ERROR unknown backup type $backup_type"
            return 1
            ;;
    esac

    mail_log $INFO ">>> "
    mail_log $INFO ">>> export type : $backup_type"
    mail_log $INFO ">>> export from : $source_path"
    mail_log $INFO ">>> log file    : $LOG_FILE"
    mail_log $INFO ">>> " 

    mail_log $INFO "$INF exporting $source_path -> $mount_point"
    log $DEBUG "$DBG rsync -rti --one-file-system --delete --stats --exclude=@eaDir --exclude='*'.$LIST_EXT $source_path $mount_point"
    rsync -rti --one-file-system --delete --stats --exclude=@eaDir --exclude='*'.$LIST_EXT $source_path $mount_point >>$LOG_FILE 2>&1
    is_error $?

    mail_log $INFO "$INF unmounting USB device $device."
    umount_usb_device $device
    is_error $? 

}

# Export Backups bzw. Medien-Verzeichnisse auf USB-HDD
#
# Der Export wird nur auf der NAS ausgeführt
# (und wird ggf. dort remote gestartet)
# 
export_backups() {
    if [ "$HOST_NAME" != "$NAS_HOSTNAME" ]; then
        run_script_remote $NAS_IP "$NAS_SCRIPT -e"
        exit
    fi

    mail_log $INFO ">>>>>>>>>> export $VER <<<<<<<<<<"

    do_export

    mail_log $INFO ">>>>>>>>>> end of export"
    send_mail_log "Export"
}