#!/bin/bash
# shellcheck source=kzcommon.sh
# ##################################################################################################
# Back-up maken.
#
# Geschreven door Karel Zimmer (https://karelzimmer.nl).
# ##################################################################################################
# REL_NUM=35.03.03
# REL_DAT=2020-08-01
# REL_MSG='Logboekeldingen bij het afsluitnen met een waarschuwing (signal_exit_warning)'

# ##################################################################################################
# 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=$OPTIONS_SHORT_COMMON'e:gt:'
readonly OPTIONS_LONG=$OPTIONS_LONG_COMMON',exclude:,gui,target:'
readonly USAGE="Gebruik: $PROGNAME [-e|--exclude=UITSLUITEN]... [-g|--gui] [-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
  -g --gui            Start in grafische modus
  -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 -A MEDIA=()
declare ARGUMENT_SELECTION=false
declare -a SELECTION=''
declare -a SELECTION_ARGUMENT=''
declare -a SELECTION_DEFAULT=('/home' '/root')
declare BACKUP=''
declare BACKUP_CREATED=false
declare BACKUPDIR='/mnt'
declare BACKUPFILE=''
declare BACKUP_TO_DELETE=''
declare -i SELECTIONSIZE_MACHINE=0
declare MEDIA2=false
declare MEDIA_FOUND=false
declare OPTION_EXCLUDE=false
declare OPTION_TARGET=false
declare SELECTIONSIZE_HUMAN=''
declare SPACE_OK=true
declare TARGET_ARGUMENT=''

# ##################################################################################################
# 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
                ;;
            -g|--gui)
                OPTION_GUI=true
                shift
                ;;
            -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 medium=''

    if $OPTION_TARGET; then
        BACKUPDIR=$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]=$medium
            BACKUPDIR=$medium/$TARGET_DEFAULT_2/$TARGET_DEFAULT_3
        done < <(
            findmnt --list          \
                    --noheadings    \
                    --options=rw    \
                    --output=TARGET |
            grep    --regexp=$TARGET_DEFAULT_1
            )
    fi
    if $MEDIA2; then
        # Meer dan één aangekoppeld medium gevonden.
        MEDIA_FOUND=false
    fi
    if $MEDIA_FOUND; then
        if [[ ! -e $BACKUPDIR ]]; then
            mkdir --parents "$BACKUPDIR" |& $LOGCMD
        fi
    else
        if $OPTION_GUI; then
            request_input_gui
        else
            request_input_tui
        fi
    fi

    source /etc/os-release
    BACKUPFILE=backup_${HOSTNAME}_${ID}_$TIMESTAMP.tar
    BACKUP=$BACKUPDIR/$BACKUPFILE
}

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

    set +o errexit
    BACKUPDIR="$(
        zenity  --file-selection            \
                --width     600             \
                --height    50              \
                --title     "$title"        \
                --filename  "$BACKUPDIR"    \
                --directory                 \
                2> >($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...'
    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...'
    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 ${size_unit}iB]\n\
Naar:\t\t$BACKUPDIR"
        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 "$BACKUPDIR" | awk 'END{print $4}')

    if [[ $sourcedir_size_bytes -gt $free_bytes ]]; then
        free_human=$(df --human-readable "$BACKUPDIR" | awk 'END{print $4}')
        filesys=$(df "$BACKUPDIR" | awk 'END{print $1}')
        mounted=$(df "$BACKUPDIR" | 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='Nog uitstaande schrijfoperaties uitvoeren (dit kan even duren) ...'
    if $OPTION_GUI; then
        sync |
        zenity  --progress              \
                --auto-close            \
                --no-cancel             \
                --time-remaining        \
                --width     600         \
                --height    50          \
                --title     "$title"    \
                --text      "$text"     \
                2> >($LOGCMD)
        sync_rc=$?
    else
        info "$text"
        sync | pv --width 31
        sync_rc=$?
    fi
    set -o errexit

    BACKUP_TO_DELETE=''
    if [[ $tar_rc -ne 0 || $sync_rc -ne 0 ]]; then
        error "Back-up maken is mislukt.

Geen back-up gemaakt!"
        exit $ERROR
    fi

    BACKUP_CREATED=true
    if [[ "$BACKUPDIR" == /media/* ]]; then
        chmod --recursive a=rwx "$(stat --format=%m "$BACKUPDIR")/$TARGET_DEFAULT_2"
    fi
}

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

    if [[ "$BACKUPDIR" == /media/* ]]; then
        exit_msg="$exit_msg\n\nKoppel zelf (veilig!) het aangesloten 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