#!/usr/bin/env bash

set -e

usage() {
    cat <<EOF >&2
Usage: $0 --hostname=zulip.example.com --email=admin@example.com [--method={webroot|standalone}] [--no-zulip-conf]
EOF
    exit 1
}

if [ "$EUID" -ne 0 ]; then
    echo "Error: This script must be run as root" >&2
    exit 1
fi

method=webroot
args="$(getopt -o '' --long help,hostname:,email:,method:,no-zulip-conf -n "$0" -- "$@")"
eval "set -- $args"
while true; do
    case "$1" in
        --hostname)
            DOMAIN="$2"
            shift
            shift
            ;;
        --email)
            EMAIL="$2"
            shift
            shift
            ;;
        --method)
            method="$2"
            shift
            shift
            ;;
        --no-zulip-conf)
            no_zulip_conf=1
            shift
            ;;
        --help)
            show_help=1
            shift
            ;;
        --)
            break
            ;;
    esac
done

if [ -n "$show_help" ]; then
    usage
fi

if [ -z "$DOMAIN" -o -z "$EMAIL" ]; then
    usage
fi

case "$method" in
    standalone)
        method_args=(--standalone)
        ;;
    webroot)
        method_args=(--webroot --webroot-path=/var/lib/zulip/certbot-webroot/)
        ;;
    *)
        usage
        ;;
esac

set -x

CERTBOT_PATH="/usr/local/sbin/certbot-auto"
# For reference https://certbot.eff.org/all-instructions/#debian-other-nginx
wget -q https://dl.eff.org/certbot-auto -O "$CERTBOT_PATH"
chmod a+x "$CERTBOT_PATH"

# First, we install the OS packages with --quiet, to suppress `apt`
# prompting the user for input.  This can't be part of the same
# invocation as gets the certs, since `certonly --quiet --force-interactive`
# rejects the Certbot ToS, causing Certbot to fail.
"$CERTBOT_PATH" --os-packages-only --quiet
# We don't use --no-interactive, because certbot needs to ask the user
# to agree to the Let's Encrypt Subscriber Agreement (aka ToS).
# Passing --force-interactive suppresses a warning, but also brings up
# an annoying prompt we stifle with --no-eff-email.
"$CERTBOT_PATH" certonly "${method_args[@]}" -d "$DOMAIN" -m "$EMAIL" --force-interactive --no-eff-email

symlink_with_backup() {
    if [ -e "$2" ]; then
        # If the user is setting up our automatic certbot-management on a
        # system that already has certs for Zulip, use some extra caution
        # to keep the old certs available.
        mv -f --backup=numbered "$2" "$2".setup-certbot || true
    fi
    ln -nsf "$1" "$2"
}

CERT_DIR=/etc/letsencrypt/live/"$DOMAIN"
symlink_with_backup "$CERT_DIR"/privkey.pem /etc/ssl/private/zulip.key
symlink_with_backup "$CERT_DIR"/fullchain.pem /etc/ssl/certs/zulip.combined-chain.crt

case "$method" in
    webroot)
        service nginx reload
        ;;
esac

if [ -z "$no_zulip_conf" ]; then
    crudini --set /etc/zulip/zulip.conf certbot auto_renew yes
fi

echo "Certbot SSL certificate configuration succeeded."