#!/usr/bin/env bash
#
# This script handles adding custom apt repositories into
# /etc/apt/sources.list.d/ files.  It bundles the GPG keys which are
# used to verify the repositories (via `apt-key`), to explicitly pin
# the trusted signing keys, as opposed to blindly trusting HTTPS.
#
# Each /etc/apt/sources.list.d/foo.list file is created via `--list
# foo`, where `foo` defaults to `zulip`.  The default `zulip.list` is
# installed in `scripts/lib/install` / `tools/lib/provision.py`, and
# other `.list` files may be installed by Puppet.
set -x
set -e
set -u
set -o pipefail
shopt -s extglob

verify=false
args="$(getopt -o '' --long verify,list: -- "$@")"
eval "set -- $args"
LIST=zulip
while true; do
    case "$1" in
        --verify)
            verify=true
            shift
            ;;
        --list)
            LIST="$2"
            shift
            shift
            ;;
        --)
            shift
            break
            ;;
    esac
done

# Ensure the directory for LAST_DEPENDENCIES_HASH exists
mkdir -p /var/lib/zulip

SOURCES_FILE=/etc/apt/sources.list.d/$LIST.list
PREF_FILE=/etc/apt/preferences.d/$LIST.pref
STAMP_FILE=/etc/apt/sources.list.d/$LIST.list.apt-update-in-progress

ZULIP_SCRIPTS="$(cd "$(dirname "$(dirname "$0")")" && pwd)"
LIST_PATH="$ZULIP_SCRIPTS/setup/apt-repos/$LIST"
if ! [ -d "$LIST_PATH" ]; then
    echo "Not a valid value for --list: '$LIST'"
    echo ""
    echo "Valid values are:"
    ls -1 "$ZULIP_SCRIPTS/setup/apt-repos/"
    exit 1
fi

release="$(. /etc/os-release && printf '%s' "$VERSION_CODENAME")"

if [ ! -f "$LIST_PATH/$release.list" ]; then
    cat <<EOF
Unsupported release $release for sources.list file $LIST.  To add a
new release, make a $LIST_PATH/$release.list file based on existing
.list files in that directory.

EOF
    exit 1
fi

DEPENDENCIES_HASH="$(sha256sum "$LIST_PATH"/?(*.asc|"$release.list"|"$LIST.pref"|custom.sh) "$ZULIP_SCRIPTS/lib/setup-apt-repo")"
DEPENDENCIES_HASH_FILE="/var/lib/zulip/setup-repositories-state-$LIST"
# Ensure that DEPENDENCIES_HASH_FILE exists before hashing it.
touch "$DEPENDENCIES_HASH_FILE"
LAST_DEPENDENCIES_HASH="$(cat "$DEPENDENCIES_HASH_FILE")"

# First, we only do anything in setup-apt-repo if any of its inputs
# (apt keys, code, etc.)  changed.
if [ "$DEPENDENCIES_HASH" = "$LAST_DEPENDENCIES_HASH" ]; then
    exit 0
elif [ "$verify" == true ]; then
    exit 1
fi

# Hash to check if the configuration is changed by the script later.
hashes=$(sha256sum "$SOURCES_FILE" "$PREF_FILE" 2>/dev/null || true)

pre_setup_deps=(apt-transport-https ca-certificates gnupg curl)
if ! apt-get -dy install "${pre_setup_deps[@]}"; then
    apt-get update
fi
apt-get -y install "${pre_setup_deps[@]}"

apt-key add "$LIST_PATH/"*.asc
cp "$LIST_PATH/$release.list" "$SOURCES_FILE"

if [ -e "$LIST_PATH/$LIST.pref" ]; then
    cp "$LIST_PATH/$LIST.pref" "$PREF_FILE"
else
    rm -f "$PREF_FILE"
fi

if [ -e "$LIST_PATH/custom.sh" ]; then
    export LIST_PATH
    export STAMP_FILE
    bash "$LIST_PATH/custom.sh"
fi

if [ "$hashes" = "$(sha256sum "$SOURCES_FILE" "$PREF_FILE" 2>/dev/null || true)" ] && ! [ -e "$STAMP_FILE" ]; then
    echo "APT configuration did not change; skipping apt-get update"
else
    # We create this stamp file to ensure `apt-get update` will be run
    # the next time this script is invoked, and each time after, until
    # `apt-get update` finishes successfully.
    touch "$STAMP_FILE"
    apt-get update && rm -f "$STAMP_FILE"
fi

echo "$DEPENDENCIES_HASH" >"$DEPENDENCIES_HASH_FILE"