#!/bin/bash
# shellcheck source=kzcommon.sh
###############################################################################
# Beeldbestanden downloaden.
#
# Geschreven door Karel Zimmer <info@karelzimmer.nl>.
#
# Auteursrecht (c) 2014-2021 Karel Zimmer.
# GNU Algemene Publieke Licentie <https://www.gnu.org/licenses/gpl.html>.
#
# RelNum=16.02.01
# RelDat=2021-04-01
###############################################################################


###############################################################################
# Global constants
###############################################################################

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

readonly SEARCH_FOR=SHA256SUMS
readonly SOURCE_1=http://releases.ubuntu.com
readonly SOURCE_2=http://cdimage.ubuntu.com
readonly TARGET=$HOME/Downloads

# Bij aanpassingen ook .completion aanpassen!
readonly OPTIONS_SHORT=$OPTIONS_SHORT_COMMON'c'
readonly OPTIONS_LONG=$OPTIONS_LONG_COMMON',checksums'
readonly USAGE="Gebruik: $PROGRAM_NAME [-c|--checksums] $OPTIONS_USAGE_COMMON"
readonly HELP="Gebruik: $PROGRAM_NAME [OPTIE...]

Beeldbestanden downloaden.

Opties:
  -c --checksums
                download alleen de controlebestanden
$OPTIONS_HELP_COMMON"


###############################################################################
# Gobal variables
###############################################################################

declare FULL_VS=''
declare OPTION_CHECKSUMS=false


###############################################################################
# Functions
###############################################################################

check_input() {
    PARSED=$(
        getopt  --alternative                       \
                --options       "$OPTIONS_SHORT"    \
                --longoptions   "$OPTIONS_LONG"     \
                --name          "$PROGRAM_NAME"     \
                -- "$@"
        )       || GETOPT_RC=$?
    if [[ $GETOPT_RC -ne 0 ]]; then
        printf '%s\n' "$USAGELINE" >&2
        exit $ERROR
    fi
    eval set -- "$PARSED"
    process_general_options "$@"

    while true; do
        case $1 in
            -c|--checksums)
                OPTION_CHECKSUMS=true
                shift
                ;;
            --)
                shift
                break
                ;;
            *)
                shift
                ;;
        esac
    done

    if [[ "$*" ]]; then
        printf  "$PROGRAM_NAME: %s\n%s\n"   \
                'geen argumenten opgeven'   \
                "$USAGELINE"                >&2
        exit $ERROR
    fi

    # Een non-gui script gestart met optie gui.
    if $OPTION_GUI; then
        OPTION_GUI=false
        TERMINAL=true
    fi

    check_user
}


process_input() {
    FULL_VS="$(lsb_release --description --short | awk '{print $2}')"
    read -rp  "Wat is de Ubuntu-versie? [$FULL_VS]: "
    if [[ $REPLY ]]; then
        FULL_VS="$REPLY"
    fi

    if $OPTION_CHECKSUMS; then
        download_checksums
        info "Controlebestanden zijn gedownload en staan in $TARGET.
"
    else
        download_isos
        download_checksums
    fi
}


download_isos() {
    cd "$TARGET"
    rm --force {u,xu,lu}buntu-*.iso*

    URL_LIST="\
$SOURCE_1/$FULL_VS/ubuntu-$FULL_VS-desktop-amd64.iso
$SOURCE_1/$FULL_VS/ubuntu-$FULL_VS-live-server-amd64.iso
$SOURCE_2/lubuntu/releases/$FULL_VS/release/lubuntu-$FULL_VS-desktop-amd64.iso
$SOURCE_2/xubuntu/releases/$FULL_VS/release/xubuntu-$FULL_VS-desktop-amd64.iso"

    # max-args=1 zorgt ervoor dat per invoerregel 1 opdracht wordt gestart.
    # max-procs=4 zorgt ervoor dat maximaal 4 parallele taken worden gestart.
    printf '%s\n' "$URL_LIST" | xargs --max-args=1 --max-procs=4 wget
}


download_checksums() {
    cd "$TARGET" || exit $ERROR
    rm --force {u,xu,lu}buntu-*-SHA256SUMS

    wget    --output-document=ubuntu-$SEARCH_FOR    \
            $SOURCE_1/"$FULL_VS"/$SEARCH_FOR
    wget    --output-document=xubuntu-$SEARCH_FOR   \
            $SOURCE_2/xubuntu/releases/"$FULL_VS"/release/$SEARCH_FOR
    wget    --output-document=lubuntu-$SEARCH_FOR   \
            $SOURCE_2/lubuntu/releases/"$FULL_VS"/release/$SEARCH_FOR
}


term_script() {
    info "Om de $SEARCH_FOR-controlebestanden op te splitsen voer uit:
    ${BLUE}kzspsum${NORMAL}


Om de beeldbestanden (.iso) te controleren voer uit:
    ${BLUE}cd $TARGET;$SEARCH_FOR --check *.$SEARCH_FOR; cd -${NORMAL}"

    exit $SUCCESS
}


###############################################################################
# Main line
###############################################################################

main() {
    init_script
    check_input "$@"
    process_input
    term_script
}


main "$@"


# EOF