#!/bin/sh
set -eu

domain="${LETSENCRYPT_DOMAIN:-azionelab.org}"
email="${LETSENCRYPT_EMAIL:-}"
staging="${LETSENCRYPT_STAGING:-1}"
renew_interval="${LETSENCRYPT_RENEW_INTERVAL_SECONDS:-43200}"
retry_interval="${LETSENCRYPT_RETRY_SECONDS:-300}"

case "$domain" in "" | *[!A-Za-z0-9.-]* | .* | *. | *..*) echo "Invalid LETSENCRYPT_DOMAIN." >&2; exit 1 ;; esac
[ -n "$email" ] || { echo "LETSENCRYPT_EMAIL is required when Let's Encrypt is enabled." >&2; exit 1; }
case "$staging" in 0 | 1) ;; *) echo "LETSENCRYPT_STAGING must be 0 or 1." >&2; exit 1 ;; esac
case "$renew_interval:$retry_interval" in *[!0-9:]* | :* | *:) echo "Certbot intervals must be positive integers." >&2; exit 1 ;; esac
[ "$renew_interval" -gt 0 ] && [ "$retry_interval" -gt 0 ] || { echo "Certbot intervals must be positive." >&2; exit 1; }

staging_argument=""
[ "$staging" = 0 ] || staging_argument="--staging"
trap 'exit 0' TERM INT

while :; do
    if certbot certonly --webroot --webroot-path /var/www/certbot --preferred-challenges http \
        --cert-name "$domain" --domain "$domain" --email "$email" --agree-tos --non-interactive \
        --keep-until-expiring $staging_argument; then
        delay="$renew_interval"
    else
        echo "Certificate request failed; retrying after ${retry_interval}s." >&2
        delay="$retry_interval"
    fi
    sleep "$delay" &
    wait $! || true
done