#!/bin/bash

if [ -r '#ETCDIR#/simple-pki/ca.conf' ]; then
  . '#ETCDIR#/simple-pki/ca.conf'
fi

cd "${0%/*}"

remove_leading_spaces() {
  sed '
    s/^ \{'"$1"'\}//
    t
    d
  '
}

tmp_dir=$(mktemp -d)
trap 'rm -rf --one-file-system "${tmp_dir}"' EXIT

while read -r csr; do
  csr_local="${tmp_dir}/${csr##*/}"
  curl --connect-timeout 10 -Ss --insecure "${csr}" -o "${csr_local}"
  if ! content=$(
    openssl req -text -noout -verify -in "${csr_local}" 2>/dev/null
  ); then
    >&2 printf 'verify of %s failed - skipping\n' "${csr_local##*/}"
    rm "${csr_local}"
    continue
  fi

  content=$(
    printf '%s\n' "${content}" \
    | sed -n '
      /^Certificate Request:$/,/^\S/p
    ' \
    | remove_leading_spaces 4 \
    | sed -n '
      /^Data:$/,/^\S/p
    ' \
    | remove_leading_spaces 4
  )
  cn=$(
    printf '%s\n' "${content}" \
    | sed '
      s/^Subject: //
      t
      d
    ' \
    | tr -d ' ' \
    | tr ',' '/' \
    | sed 's@^.*/CN=@@'
  )
  sans=$(
    printf '%s\n' "${content}" \
    | sed -n '
      /^Requested Extensions:$/,/^\S/ p
    ' \
    | remove_leading_spaces 4 \
    | sed -n '
      /^X\S\+ Subject Alternative Name:\s*$/,/^\S/ p
    ' \
    | remove_leading_spaces 4 \
    | sed '
      s/, /\n/g
    '
  )
  if printf '%s\n' "${sans}" | grep -vq '^\(DNS\|IP\):'; then
    >&2 echo 'invalid sans - skipping'
    rm "${csr_local}"
    continue
  fi
  sans=$(
    printf '%s\n' "${sans}" \
    | sed '
      s/^\(DNS\|IP\)://
    '
  )
  ok_sans=$(
    printf '%s\n' "${cn}" "${sans}" \
    | while read -r san; do
      if ! curl --connect-timeout 10 -Ss --insecure 'https://'"${san}/${csr#*//*/}" \
        | diff -q - "${csr_local}"; then
        >&2 printf 'invalid san "%s" - skipping\n' "${san}"
        rm "${csr_local}"
        break
      fi
      printf '%s\n' "${san}"
    done
  )
  if [ ! -f "${csr_local}" ]; then
    continue
  fi
  if [ "$(printf '%s\n' "${cn}" "${sans}")" != "${ok_sans}" ]; then
    >&2 echo 'some san was invalid - skipping'
    rm "${csr_local}"
    continue
  fi
  if ! CA=signing-ca openssl ca -batch -name signing_ca \
    -config '#ETCDIR#/simple-pki/ca-ssl.conf' \
    -in "${csr_local}" \
    -out "${csr_local%.csr}.crt" \
    -extensions server_ext; then
    >&2 echo 'signing failed - skipping'
    rm -f "${csr_local}" "${csr_local%.csr}.crt"
    continue
  fi
  cat "${csr_local%.csr}.crt" '#ETCDIR#/simple-pki/ca/signing-ca.crt' '#ETCDIR#/simple-pki/ca/root-ca.crt' \
  > "${csr_local%.csr}.chain"
  rm "${csr_local}"
done

cd "${tmp_dir}"
tar -czf - *.crt *.chain