#!/bin/bash

set -e

usage () {
	echo "usage: create_offlinerepo.sh repodir isofile [list of packages]" >&2
	echo >&2
	echo "Downloads all packages required to fully update the system in 'isofile' and" >&2
	echo "to install the listed packages and adds them to the package archive in 'repodir'." >&2
	exit 1
}

dest="$1"
shift || usage
iso_file="$1"
shift || usage
packages="$@"

: ${workspace:="/workspace"}
APT_SOURCE_URL_OVERRIDE="http://ftp.halifax.rwth-aachen.de/ubuntu/"

rm -rf "$workspace"/offlinerepo
mkdir -p "$workspace"/offlinerepo
mkdir -p "$dest"

7z e -so "$iso_file" casper/filesystem.squashfs > "$workspace"/offlinerepo/filesystem.squashfs
unsquashfs -no-progress -no-xattrs -d "$workspace"/offlinerepo/squashfs-root "$workspace"/offlinerepo/filesystem.squashfs

source "$workspace/offlinerepo/squashfs-root/etc/lsb-release"
echo "deb $APT_SOURCE_URL_OVERRIDE ${DISTRIB_CODENAME} main restricted universe multiverse" > "$workspace/offlinerepo/squashfs-root/etc/apt/sources.list"
echo "deb $APT_SOURCE_URL_OVERRIDE ${DISTRIB_CODENAME}-security main restricted universe multiverse" >> "$workspace/offlinerepo/squashfs-root/etc/apt/sources.list"
echo "deb $APT_SOURCE_URL_OVERRIDE ${DISTRIB_CODENAME}-updates main restricted universe multiverse" >> "$workspace/offlinerepo/squashfs-root/etc/apt/sources.list"
echo "deb $APT_SOURCE_URL_OVERRIDE ${DISTRIB_CODENAME}-backports main restricted universe multiverse" >> "$workspace/offlinerepo/squashfs-root/etc/apt/sources.list"
apt-get -o Dir="$workspace"/offlinerepo/squashfs-root update

{
	apt-get -o Dir="$workspace"/offlinerepo/squashfs-root upgrade --print-uris -qq
	apt-get -o Dir="$workspace"/offlinerepo/squashfs-root install --reinstall --print-uris -qq $packages
} | cut -s -d"'" -f2 | while read url; do wget -q -nc -P "$dest" "$url"; done
apt-get -o Dir="$workspace"/offlinerepo/squashfs-root install --reinstall --print-uris -qq $packages

mkdir -p "$dest/dists/$DISTRIB_CODENAME/lip/binary-amd64"
# For some reason apt does not like the gziped package list in the installed system. Leaving the packages list uncompressed solves the problem.
#( cd "$dest" && dpkg-scanpackages . | gzip > "dists/$DISTRIB_CODENAME/lip/binary-amd64/Packages.gz" )
( cd "$dest" && dpkg-scanpackages . > "dists/$DISTRIB_CODENAME/lip/binary-amd64/Packages" )

cat <<EOF > "$dest/dists/$DISTRIB_CODENAME/lip/binary-amd64/Release"
Archive: $DISTRIB_CODENAME
Version: $DISTRIB_RELEASE
Component: lip
Origin: Ubuntu
Label: Ubuntu
Architecture: amd64
EOF

touch "$dest/.aptignr"
cat <<EOF > "$dest/Release"
Origin: Ubuntu
Label: LIP Ubuntu Extra Packages
Suite: $DISTRIB_CODENAME
Version: $DISTRIB_RELEASE
Codename: $DISTRIB_CODENAME
Date: $(LC_ALL=C date -u)
Architectures: amd64
Components: lip
Description: $DISTRIB_DESCRIPTION
EOF

# Maybe sort files into the usual directory structure ("pool/main/g/glib2.0...")