download.sh

#!/bin/bash

function error {
    echo "$1" 1>&2
    exit 1
}

function check_admin() {
    if [[ $EUID -ne 0 ]]; then
        error "RUN AS ROOT"
    fi
}

function change_owner() {
    chown -R _apt:root "$1" || error "FAILED TO CHANGE OWNER : $1"
}
function make_directory() {
    mkdir -p -m755 "$1" || error "FAILED TO MAKE DIRECTORY : $1"
    change_owner "$1" || error "FAILED TO CHANGE OWNER : $1"
}

function detect_os() {
    echo $(realpath $(dirname ${BASH_SOURCE[0]}))/$(lsb_release -si)-$(lsb_release -sr)
}

function download() {
    if ! apt-cache show "$1" >/dev/null 2>&1; then
        error "APT-CACHE NOT FOUND PACKAGE : $1"
    fi
    dpkg --print-foreign-architectures | grep -q i386 && sudo dpkg --remove-architecture i386
    PACKAGES_AND_DEPENDS=$(apt-cache depends --recurse --no-recommends --no-suggests --no-conflicts --no-breaks --no-replaces --no-enhances $1 | grep "^\w" | sort -u);
    apt download $PACKAGES_AND_DEPENDS
}

function scan() {
    dpkg-scanpackages --multiversion ./ /dev/null | gzip -9c >./Packages.gz
    echo -e "deb [trusted=yes] file://$ABSOLUTE_BASE_PATH ./" > sources.list
}

if [ $# -gt 0 ]; then
    COMMAND="$1"
    shift
else
    error "EMPTY COMMAND"
fi

check_admin

ABSOLUTE_BASE_PATH=$(detect_os)
make_directory $ABSOLUTE_BASE_PATH
cd $ABSOLUTE_BASE_PATH

if [ $COMMAND == "download" ]; then
    for PACKAGE in $*; do
        download $PACKAGE
        make_directory "$ABSOLUTE_BASE_PATH/$PACKAGE";
    done
    change_owner $ABSOLUTE_BASE_PATH
    scan
    elif  [ $COMMAND == "scan" ]; then
    scan
    elif  [ $COMMAND == "install" ]; then
    sudo apt update  -o Dir::Etc::sourcelist="$ABSOLUTE_BASE_PATH/sources.list" -o Dir::Etc::sourceparts="-" -o APT::Get::List-Cleanup="0"
    sudo apt install -o Dir::Etc::sourcelist="$ABSOLUTE_BASE_PATH/sources.list" -o Dir::Etc::sourceparts="-" -o APT::Get::List-Cleanup="0" $*
else
    error "INVALID COMMAND"
fi