#!/bin/bash

# Copyright (c) 2016 Peter Palfrader <peter@palfrader.org>
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

set -e
set -u

cd ~/certs

if [ "$#" != 1 ]; then
  echo >&2 "Usage: $0 <fqdn>"
  exit 1
fi

cn="$1"
shift

if ! [ -e "$cn.key" ] ; then
  echo >&2 "$cn.key does not exist."
  exit 1
fi

tmpdir=$(mktemp -d)
trap "rm -rf '$tmpdir'" EXIT

chain=""
if [ -e "$cn-letsencrypt.pem" ] ; then
  pem="$cn-letsencrypt.pem"
elif [ -e "$cn.pem" ] ; then
  pem="$cn.pem"
elif [ -e "$cn-selfsigned.pem" ] ; then
  pem="$cn-selfsigned.pem"
  echo >&2 "Warning: only selfsigned cert available for $cn."
else
  echo >&2 "Error: no cert available for $cn."
  exit 1
fi

chain="$tmpdir/chain.pem"
(cat "$pem"         ; echo) >> "$chain"

max_length=10

if [ -e "$cn-chain.pem" ]; then
  (cat "$cn-chain.pem"; echo) >> "$chain"
else
  last_pem="$pem"

  issuers_uri="$(openssl x509 -in "$last_pem" -noout -text | grep 'CA Issuers - URI:' | cut -d':' -f2-)"
  while [ "${issuers_uri#http}" != "$issuers_uri" ] && [ "$max_length" -gt 0 ]; do
    # we include the EE, but not the root certificate in our chain.
    intermediate="$tmpdir/intermediate"
    intermediatepem="$tmpdir/intermediate.pem"
    wget -q -O "$intermediate" "$issuers_uri"
    if grep -q "BEGIN CERTIFICATE" "$intermediate"; then
      mv "$intermediate" "$intermediatepem"
    elif [ "${issuers_uri%.p7c}" != "${issuers_uri}" ]; then
      openssl pkcs7 -inform DER -in "$intermediate" -outform PEM -print_certs -out "$intermediatepem"
    else
      openssl x509  -inform DER -in "$intermediate" -outform PEM -out "$intermediatepem"
    fi

    # do not include roots
    issuer="$( openssl x509 -in "$intermediatepem" -issuer -noout | cut -d'=' -f2-)"
    subject="$(openssl x509 -in "$intermediatepem" -subject -noout | cut -d'=' -f2-)"
    if [ "$issuer" = "$subject" ]; then
      break
    fi

    (cat "$intermediatepem"; echo) >> "$chain"

    last_pem="$intermediatepem"
    issuers_uri="$(openssl x509 -in "$last_pem" -noout -text | grep 'CA Issuers - URI:' | cut -d':' -f2-)"

    max_length=$((max_length - 1))
  done
fi


(
cat "$chain"

size=$(openssl rsa  < "$cn".key -text -noout | awk -F: '$1 ~ "Private-Key" {print $2}' | sed -r 's/[^0-9]*([0-9]*).*/\1/g')
if [ -e extra/dh-"$size".pem ]; then
  cat extra/dh-"$size".pem;
else
  echo >&2 "Warning: No extra/dh-$size.pem file found."
fi

) > $cn-combined.crt
ln -sf "$cn-combined.crt" "$cn.crt-chained"