#!/bin/bash
# shellcheck source=kzcommon.sh
# ##############################################################################
# Back-up maken.
#
# Geschreven door Karel Zimmer <info@karelzimmer.nl>.
#
# Auteursrecht © 2007-2020 Karel Zimmer.
# GNU Algemene Publieke Licentie v3 <https://www.gnu.org/licenses/gpl.html>.
# ##############################################################################
# REL_NUM=35.05.04
# REL_DAT=2020-10-15
# REL_MSG="Ontkenning in 'if' verplaatst"

# ##############################################################################
# Settings
# ##############################################################################
source "$(dirname "$0")"/kzcommon.sh

# ------------------------------------------------------------------------------
# Global constants
# ------------------------------------------------------------------------------
readonly EXCLUDEFILE_DEFAULT=/root/.$PROGNAME-exclude-dflt
readonly EXCLUDEFILE_DEFAULT_CONTENT="\
/dev
/home/*/.adobe/Flash_Player/AssetCache
/home/*/.cache
/home/*/.ccache
/home/.ecryptfs
/home/gast
/home/*/.gvfs
/home/*/.recent-applications.xbel
/home/*/.recently-used.xbel
/home/*/snap/*/*/.cache
/home/*/snapshots
/home/*/.steam/root
/home/*/.thumbnails
/home/*/.xsession-errors
/proc
/run
/sys
/tmp"
readonly EXCLUDEFILE_OPTIONAL=/root/.$PROGNAME-exclude-opt
readonly RUN_AS_SUPERUSER=true
readonly TARGET_DEFAULT_1=/media
readonly TARGET_DEFAULT_2=backups
readonly TARGET_DEFAULT_3=$HOSTNAME
# In ISO 8601 is tijd-formaat basic 'hhmmss.sss' en extended is 'hh:mm:ss.sss'.
# Omdat bestandssystemen fat en ntfs die ':' niet ondersteunen gebruik ik '.'.
readonly TIMESTAMP=$(date +%Y-%m-%dT%H.%M.%S.%3N)

# Bij aanpassingen ook .completion aanpassen!
readonly OPTIONS_SHORT=$OPTIONS_SHORT_COMMON'e:t:'
readonly OPTIONS_LONG=$OPTIONS_LONG_COMMON',exclude:,target:'
readonly USAGE="Gebruik: $PROGNAME [-e|--exclude=UITSLUITEN]... \
[-t|--target=DOELMAP]
                  $OPTIONS_USAGE_COMMON
                  [SELECTIE...]

$OPTIONS_LONG_SHORT

$ARGUMENT_LONG_SHORT"
readonly HELP="Gebruik: $PROGNAME [OPTIE...] [--] [SELECTIE...]

Back-up maken.

Opties:
  $OPTIONS_LONG_SHORT

  $ARGUMENT_LONG_SHORT

  -e --exclude=UITSLUITEN
                      Sluit opgegeven bestand of map uit
  -t --target=DOELMAP Plaats back-up in de DOELMAP
$OPTIONS_HELP_COMMON

Argument:
  SELECTIE            Maak back-up van opgegeven mappen en bestanden"

# ------------------------------------------------------------------------------
# Global variables
# ------------------------------------------------------------------------------
declare -a EXCLUDE_ARGUMENT=''
declare ARGUMENT_SELECTION=false
declare -a SELECTION=''
declare -a SELECTION_ARGUMENT=''
declare -a SELECTION_DEFAULT=('/home' '/root')
declare BACKUP=''
declare BACKUP_CREATED=false
declare BACKUPFILE=''
declare BACKUP_TO_DELETE=''
declare -i SELECTIONSIZE_MACHINE=0
declare OPTION_EXCLUDE=false
declare OPTION_TARGET=false
declare SELECTIONSIZE_HUMAN=''
declare SPACE_OK=true
declare TARGET_ARGUMENT=''
declare TARGET='/mnt'

# ##############################################################################
# Functions
# ##############################################################################
check_input() {
    local exclude=''
    local -i exclude_arg_num=0
    local -i getopt_rc=0
    local -i select_arg_num=0
    local -i select_num=0
    local parsed=''
    local select=''

    set +o errexit
    parsed=$(
        getopt  --alternative                       \
                --options       "$OPTIONS_SHORT"    \
                --longoptions   "$OPTIONS_LONG"     \
                --name          "$PROGNAME"         \
                -- "$@"
        )
    getopt_rc=$?
    set -o errexit
    if [[ $getopt_rc -ne 0 ]]; then
        printf '%s\n' "$USAGELINE" >&2
        QUIET=true exit $ERROR
    fi
    eval set -- "$parsed"
    process_general_options "$@"

    while true; do
        case $1 in
            -e|--exclude)
                OPTION_EXCLUDE=true
                EXCLUDE_ARGUMENT[$exclude_arg_num]=$2
                (( ++exclude_arg_num ))
                shift 2
                ;;
            -t|--target)
                if $OPTION_TARGET; then
                    printf  "$PROGNAME: %s\n%s\n"   \
                            "optie '$1' éénmaal opgeven" "$USAGELINE" >&2
                    QUIET=true exit $ERROR
                else
                    OPTION_TARGET=true
                    TARGET_ARGUMENT=$2
                fi
                shift 2
                ;;
            --)
                shift
                break
                ;;
            *)
                shift
                ;;
        esac
    done

    if $OPTION_EXCLUDE; then
        for exclude in "${EXCLUDE_ARGUMENT[@]}"; do
            if ! [[ -e $exclude ]]; then
                printf  "$PROGNAME: %s\n%s\n"                       \
                        "bestand of map '$exclude' bestaat niet"    \
                        "$USAGELINE"                                \
                        >&2
                QUIET=true exit $ERROR
            fi
        done
    fi

    while [[ "$*" ]]; do
        ARGUMENT_SELECTION=true
        SELECTION_ARGUMENT[$select_arg_num]=$1
        (( ++select_arg_num ))
        shift
    done
    if $ARGUMENT_SELECTION; then
        for select in "${SELECTION_ARGUMENT[@]}"; do
            if ! [[ -e $select ]]; then
                printf "$PROGNAME: %s\n%s\n"    \
                        "bestand of map '$select' bestaat niet" "$USAGELINE" >&2
                QUIET=true exit $ERROR
            fi
        done
        for select_num in "${!SELECTION_ARGUMENT[@]}"; do
            SELECTION[$select_num]=$(
                readlink    --canonicalize \
                            "${SELECTION_ARGUMENT[$select_num]}"
                )
        done
    else
        if [[ -d /etc/libvirt ]]; then
            SELECTION_DEFAULT+=('/etc/libvirt' '/var/lib/libvirt')
        fi
        for select_num in "${!SELECTION_DEFAULT[@]}"; do
            SELECTION[$select_num]="${SELECTION_DEFAULT[$select_num]}"
        done
    fi

    check_user
    # Na check_user voor toegang tot media.
    remove_old_configuration
    request_input
}

remove_old_configuration() {
    rm --force /root/.backup-exclude-*
}

request_input() {
    local -A media=()
    local media2=false
    local media_found=false
    local medium=''

    if $OPTION_TARGET; then
        TARGET=$TARGET_ARGUMENT
        media_found=true
    else
        # Vul associatief array met aangekoppelde media-namen.
        # ----------------------------------------------------
        # - findmnt wordt door mount aangeraden, speciaal voor in scripts.
        # - options=rw, alleen beschrijfbare bestandssystemen gebruiken (en
        #   bijvoorbeeld geen iso9660, d.i. een CD of DVD).
        while read -r medium; do
            if $media_found; then
                # Meer dan één aangekoppeld medium gevonden.
                media2=true
            fi
            media_found=true
            media[$medium]=$medium
            TARGET=$medium/$TARGET_DEFAULT_2/$TARGET_DEFAULT_3
        done < <(
            findmnt --list          \
                    --noheadings    \
                    --options=rw    \
                    --output=TARGET |
            grep    --word-regexp   \
                    --regexp=$TARGET_DEFAULT_1
            )
    fi
    if $media2; then
        # Meer dan één aangekoppeld medium gevonden.
        media_found=false
    fi
    if $media_found; then
        if ! [[ -e $TARGET ]]; then
            mkdir   --parents       \
                    "$TARGET"       |& $LOGCMD
        fi
    else
        if $OPTION_GUI; then
            request_input_gui
        else
            request_input_tui
        fi
    fi

    BACKUPFILE=backup_${HOSTNAME}_${ID}_$TIMESTAMP.tar
    BACKUP=$TARGET/$BACKUPFILE
}

request_input_gui() {
    local title='Kies een map om de back-up in te plaatsen'

    set +o errexit
    # Constructie '2> >($LOGCMD)' om stderr naar de log te krijgen.
    # Voorbeeld: Unable to init server: Kon niet verbinden:
    #            Verbinding is geweigerd
    #        en: (zenity:47712): Gtk-WARNING **: 10:35:49.339:
    #            cannot open display:
    TARGET="$(
        zenity  --file-selection            \
                --width     600             \
                --height    50              \
                --title     "$title"        \
                --filename  "$TARGET"       \
                --directory                 \
                2> >($LOGCMD)
        )"
    # shellcheck disable=SC2181
    if [[ $? -ne 0 ]]; then
        warning 'Geen map geselecteerd.

Geen back-up gemaakt!'
        QUIET=true exit $WARNING
    fi
    set -o errexit
}

request_input_tui() {
    declare medium=''

    printf "$PROGNAME: %s\n" "geef '--target DOELMAP' op" >&2
    if $media2; then
        # Meer dan één aangekoppeld medium gevonden.
        printf '%s\n' 'Voor aangekoppelde media:'
        for medium in "${!media[@]}"; do
            printf '   --target %s\n' "${media[$medium]}/$TARGET_DEFAULT_2"
        done
    fi
    printf '%s\n' "$USAGELINE" >&2
    QUIET=true exit $SUCCESS
}

process_input() {
    local size_num=0
    local size_unit=''
    local text=''
    local title='Back-up maken'

    printf '%s\n' "$EXCLUDEFILE_DEFAULT_CONTENT" > "$EXCLUDEFILE_DEFAULT"

    if $OPTION_EXCLUDE; then
        for exclude in "${EXCLUDE_ARGUMENT[@]}"; do
            printf '%s\n' "$exclude" >> "$EXCLUDEFILE_OPTIONAL"
        done
    else
        printf '\n' > "$EXCLUDEFILE_OPTIONAL"
    fi

    text='Bepaal grootte van de back-up (dit kan even duren)'
    if $OPTION_GUI; then
        # Met "|& zenity --progress" worden globale variabelen uit
        # aangeroepen functies niet doorgegeven, vandaar de
        # 'process substitution' met "> >(zenity ...)".
        determine_selection_size > >(
            zenity  --progress              \
                    --pulsate               \
                    --auto-close            \
                    --no-cancel             \
                    --width     600         \
                    --height    50          \
                    --title     "$title"    \
                    --text      "$text"     \
                    2> >($LOGCMD)
            )
    else
        info "$text ..."
        determine_selection_size
    fi

    text='Controleer beschikbare schijfruimte (dit kan even duren)'
    if $OPTION_GUI; then
        check_space > >(
            zenity  --progress              \
                    --pulsate               \
                    --auto-close            \
                    --no-cancel             \
                    --width     600         \
                    --height    50          \
                    --title     "$title"    \
                    --text      "$text"     \
                    2> >($LOGCMD)
            )
    else
        info "$text ..."
        check_space
    fi

    if $SPACE_OK; then
        size_num=${SELECTIONSIZE_HUMAN%?}
        size_unit=${SELECTIONSIZE_HUMAN: -1}
        text="Back-up:\t$BACKUPFILE\nVan:\t\t${SELECTION[*]} \
[$size_num ${size_unit}iB]\nNaar:\t\t$TARGET"
        create_backup
    fi

    if ! $BACKUP_CREATED; then
        warning '\nGeen back-up gemaakt!'
        QUIET=true exit $WARNING
    fi
}

determine_selection_size() {
    SELECTIONSIZE_HUMAN=$(
        du  --apparent-size                         \
            --block-size=1                          \
            --exclude-from="$EXCLUDEFILE_DEFAULT"   \
            --exclude-from="$EXCLUDEFILE_OPTIONAL"  \
            --human-readable                        \
            --summarize                             \
            --total                                 \
            "${SELECTION[@]}"                       \
            2> >($LOGCMD)                           |
        awk 'END{print $1}'
        )

    SELECTIONSIZE_MACHINE=$(
        du  --apparent-size                         \
            --block-size=1                          \
            --exclude-from="$EXCLUDEFILE_DEFAULT"   \
            --exclude-from="$EXCLUDEFILE_OPTIONAL"  \
            --summarize                             \
            --total                                 \
            "${SELECTION[@]}"                       \
            2> >($LOGCMD)                           |
        awk 'END{print $1}'
        )
}

check_space() {
    local filesys=''
    local free_human=''
    local -i free_bytes=0
    local -i sourcedir_size_bytes=0
    local mounted=''

    sourcedir_size_bytes=$(
        du  --apparent-size                         \
            --block-size=1                          \
            --exclude-from="$EXCLUDEFILE_DEFAULT"   \
            --exclude-from="$EXCLUDEFILE_OPTIONAL"  \
            --summarize                             \
            --total                                 \
            "${SELECTION[@]}"                       \
            2> >($LOGCMD)                           |
        awk 'END{print $1}'
        )
    free_bytes=$(
        df  --block-size=1  \
            "$TARGET"       |
            awk 'END{print $4}'
        )

    if [[ $sourcedir_size_bytes -gt $free_bytes ]]; then
        free_human=$(
            df  --human-readable \
                "$TARGET"        |
                awk 'END{print $4}'
            )
        filesys=$(
            df  "$TARGET"        |
            awk 'END{print $1}'
            )
        mounted=$(
            df  "$TARGET"        |
            awk 'END{print $6}'
            )
        warning "
Kan geen back-up plaatsen.

Te weinig schijfruimte op $mounted (bestandssysteem $filesys)
voor het plaatsen van back-up $BACKUPFILE.

Benodigd is ${SELECTIONSIZE_HUMAN}iB, beschikbaar is ${free_human}iB.

Maak ruimte vrij op $mounted (bestandssysteem $filesys),
of gebruik een ander medium met minimaal ${SELECTIONSIZE_HUMAN}iB beschikbaar
zoals een USB-stick of externe harddisk."
        SPACE_OK=false
    else
        SPACE_OK=true
    fi
}

create_backup() {
    local -i size_num=0
    local -i tar_rc=0
    local -i sync_rc=0
    local size_unit=''

    BACKUP_TO_DELETE=$BACKUP

    set +o errexit
    if $OPTION_GUI; then
        tar --create                                \
            --directory=/                           \
            --exclude-from="$EXCLUDEFILE_DEFAULT"   \
            --exclude-from="$EXCLUDEFILE_OPTIONAL"  \
            --file=-                                \
            "${SELECTION[@]}"                       \
            2> >($LOGCMD)                           |
        (
        pv  --numeric                               \
            --size="$SELECTIONSIZE_MACHINE"         \
            > "$BACKUP"
        )   2>&1                                    |
        zenity  --progress                          \
                --auto-close                        \
                --no-cancel                         \
                --time-remaining                    \
                --width     600                     \
                --height    50                      \
                --title     "$title"                \
                --text      "$text"                 \
                2> >($LOGCMD)
        tar_rc=$?
    else
        info "$text"
        tar --create                                \
            --directory=/                           \
            --exclude-from="$EXCLUDEFILE_DEFAULT"   \
            --exclude-from="$EXCLUDEFILE_OPTIONAL"  \
            --file=-                                \
            "${SELECTION[@]}"                       \
            2> >($LOGCMD)                           |
        pv  --size="$SELECTIONSIZE_MACHINE"         \
            > "$BACKUP"
        tar_rc=$?
    fi

    text="Gegevens schrijven naar $BACKUPFILE (dit kan even duren) ..."
    if $OPTION_GUI; then
        sync                                        |
        zenity  --progress                          \
                --pulsate                           \
                --auto-close                        \
                --no-cancel                         \
                --width     600                     \
                --height    50                      \
                --title     "$title"                \
                --text      "$text"                 \
                2> >($LOGCMD)
        sync_rc=$?
    else
        info "$text ..."
        sync
        sync_rc=$?
    fi
    set -o errexit

    # tar_rc=0 Succesvolle beëindiging.
    # tar_rc=1 Sommige bestanden verschillen. Deze afsluitcode betekent dat
    #   sommige bestanden zijn gewijzigd tijdens het archiveren en dus bevat het
    #   resulterende archief niet de exacte kopie van de bestandsset.
    # tar_rc=2 Fatale fout. Dit betekent dat er een fatale, onherstelbare fout
    #   is opgetreden.
    if [[ $tar_rc -eq 1 ]]; then
        log "Sommige bestanden zijn gewijzigd tijdens het maken van de back-up \
en deze wijzigingen zijn niet opgenomen in de gemaakte back-up."
    fi
    if [[ ( $tar_rc -ne 0 && $tar_rc -ne 1 ) || $sync_rc -ne 0 ]]; then
        error 'Back-up maken is mislukt.

Geen back-up gemaakt!'
        exit $ERROR
    fi

    BACKUP_TO_DELETE=''
    BACKUP_CREATED=true
}

term_script() {
    local exit_msg='De back-up is gemaakt.'

    if [[ "$TARGET" == /media/* ]]; then
        exit_msg="$exit_msg

Koppel zelf (veilig!) het back-up-medium af."
    fi
    info "$exit_msg"
    QUIET=true exit $SUCCESS
}

process_script() {
    check_input "$@"
    process_input
}

# ##############################################################################
# Main line
# ##############################################################################
main() {
    init_script
    process_script "$@"
    term_script
}

main "$@"

# EOF