#!/usr/bin/env bash

trap "exit 1" TERM
export TOP_PID=$$

readonly PROGRAM_NAME=$(basename $0)
readonly PROGRAM_LOC=$(readlink -m $(dirname $0))
readonly ARGS="$@"
readonly ARG_COUNT="$#"

error () {
  local readonly message=$1; shift

  echo $message
  echo

  exit 1
}

file_error () {
  local readonly file=$1; shift

  error "File $file does not exist"
}

hash_error () {
  local readonly file=$1; shift
  local readonly cert_type=$1; shift

  error "File $file is not a $cert_type file"
}

usage () {
  echo usage: $POGRAM_NAME CERTIFICATE_FILE KEY_FILE CSR_FILE
  exit 0
}

md5 () {
  local readonly modulus=$1; shift

  echo $modulus \
    | openssl md5
}

hash_certificate () {
  local readonly certificate=$1; shift
  out=$( openssl x509 -noout -modulus -in $certificate 2>/dev/null )

  if [ $? -ne 0 ]; then
    hash_error $certificate certificate
  fi

  echo $(md5 $out)
}

hash_key () {
  local readonly key=$1; shift
  out=$( openssl rsa -noout -modulus -in $key 2>/dev/null )

  if [ $? -ne 0 ]; then
    hash_error $key key
  fi

  echo $(md5 $out)
}

hash_csr () {
  local readonly csr=$1; shift
  out=$( openssl req -noout -modulus -in $csr 2>/dev/null )

  if [ $? -ne 0 ]; then
    hash_error $csr csr
  fi

  echo $(md5 $out)
}

incorrect_number_of_arguments () {
  test $ARG_COUNT -ne 3
}

file? () {
  local readonly file=$1

  [[ -f $file ]]
}

main () {
  local readonly certificate=$1; shift
  local readonly key=$1; shift
  local readonly csr=$1; shift

  if incorrect_number_of_arguments; then
    usage
  fi

  if ! file? $certificate; then
    file_error $certificate
  fi

  if ! file? $key; then
    file_error $key
  fi

  if ! file? $csr; then
    file_error $csr
  fi

  echo $(hash_certificate $certificate)
  echo $(hash_key $key)
  echo $(hash_csr $csr)
}

main $ARGS