#!/bin/bash
set -ex

# default to Debian testing
DISTRO=${DISTRO:-debian}
RELEASE=${RELEASE:-buster}
ARCH=${ARCH:-amd64}
CONTAINER=${RELEASE}-${ARCH}
MAX_CACHE_AGE=604800  # one week
CACHE=${SEMAPHORE_CACHE_DIR:=/tmp}/${CONTAINER}.img.tar.gz

create_container() {
    # create autopkgtest LXC image; this sometimes fails with "Unable to fetch
    # GPG key from keyserver", so retry a few times
    for retry in $(seq 5); do
        sudo lxc-create -n $CONTAINER -t download -- -d $DISTRO -r $RELEASE -a $ARCH && break
        sleep $((retry*retry))
    done

    # unconfine the container, otherwise some tests fail
    echo 'lxc.apparmor.profile = unconfined' | sudo tee -a /var/lib/lxc/$CONTAINER/config

    sudo lxc-start -n $CONTAINER

    # enable source repositories so that apt-get build-dep works
    sudo lxc-attach -n $CONTAINER -- sh -ex <<EOF
sed 's/^deb/deb-src/' /etc/apt/sources.list >> /etc/apt/sources.list.d/sources.list
# wait until online
while [ -z "\$(ip route list 0/0)" ]; do sleep 1; done
apt-get -q update
apt-get -y dist-upgrade
apt-get install -y eatmydata
EOF
    sudo lxc-stop -n $CONTAINER

    # cache it
    sudo tar cpzf "$CACHE" /var/lib/lxc/$CONTAINER
}

# remove semaphore repos, some of them don't work and cause error messages
sudo rm -f /etc/apt/sources.list.d/*

# enable backports for latest LXC
echo 'deb http://archive.ubuntu.com/ubuntu xenial-backports main restricted universe multiverse' | sudo tee -a /etc/apt/sources.list.d/backports.list
sudo apt-get -q update
sudo apt-get install -y -t xenial-backports lxc
sudo apt-get install -y python3-debian git dpkg-dev fakeroot

AUTOPKGTESTDIR=$SEMAPHORE_CACHE_DIR/autopkgtest
[ -d $AUTOPKGTESTDIR ] || git clone --quiet --depth=1 https://salsa.debian.org/ci-team/autopkgtest.git "$AUTOPKGTESTDIR"

# use cached container image, unless older than a week
if [ -e "$CACHE" ] && [ $(( $(date +%s) - $(stat -c %Y "$CACHE") )) -le $MAX_CACHE_AGE ]; then
    sudo tar -C / -xpzf "$CACHE"
else
    create_container
fi